Vol. 62

January 1986

THE

No. 1

Pan-Pacific Entomologist

WERNER, F. G.-Frank Henry Parker 1910-1984 . 1

COHER, E. I.—Asian biting fly studies V: Tabanidae. Records from Thailand. 6

LIEBHERR, J. K. and A. E. HAJEK—Geographic variation in flight wing development and

body size of the tule beetle, Tanystoma maculicolle (Coleoptera: Carabidae). 13

HENDERSON, G. and R. D. AKRE—Dominance hierarchies in Myrmecophila manni (Or-

thoptera: Gryllidae). 24

FRANKIE, G. W., J. B. FRASER, and J. F. BARTHELL—Geographic distribution of Syn-

anthedon sequoiae and host plant susceptibility on Monterey pine in adventive and native

stands in California (Lepidoptera: Sesiidae). 29

McCLUSKEY, E. S. and J. S. NEAL—Time of nuptial flight in two ant species (Hymenoptera:

Formicidae). 41

RUST, R. W.—Seasonal distribution, trophic structure and origin of sand obligate insect com¬

munities in the Great Basin. 44

HYNES, C. D.—Description of a new species of Hexatoma (Hexatoma ) from California (Ti-

pulidae: Diptera). 53

UDOVIC, D.—Floral predation of Yucca whipplei (Agavaceae) by the sap beetle, Anthonaeus

agavensis (Coleoptera: Nitidulidae). 55

FELLIN, D. G.—Movement and distribution of Pleocoma larvae in western Oregon coniferous

forest soils (Coleoptera: Scarabaeidae). 58

SANTIAGO-BLAY, J. A.—Morphological malformations am ong scorpions of Puerto Rico and

the adjacent islands. 77

GRISWOLD, T.— Notes on the nesting biology of Protosmia ( Chelostomopsis ) rubifloris (Cock¬

erell) (Hymenoptera: Megachilidae). 84

GOEDEN, R. D. and F. L. BLANC—New synonymy, host, and California records in the genera

Dioxyna and Paroxyna (Diptera: Tephritidae). 88

PARKER, F. D., T. L. GRISWOLD, and J. H. BOTSFORD-Biological notes on Nomia

heteropoda Say (Hymenoptera: Halictidae) . 91

SCIENTIFIC NOTES.23, 83

SAN FRANCISCO, CALIFORNIA • 1986

Published by the PACIFIC COAST ENTOMOLOGICAL SOCIETY

in cooperation with THE CALIFORNIA ACADEMY OF SCIENCES

The Pan-Pacific Entomologist

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PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 1-5

Figure 1. Frank Henry Parker, undated. Courtesy of Persis Parker.

1 The University of Arizona Agricultural Experiment Station, Journal Series No. 4069.

Frank Henry Parker

1910 - 1984 1

Floyd G. Werner

Department of Entomology, University of Arizona, Tucson, Arizona 85721.

Frank Parker was bom June 16, 1910 at Little Silver, New Jersey. Entomologists

have known him as a long-term resident of 6-Shooter Canyon, near Globe, Ar-

PAN-PACIFIC ENTOMOLOGIST

izona. His family moved to Globe in 1914, and purchased the ranch from the

original homesteader. Frank graduated from Globe High School at the age of 14,

but was denied entrance to the University of Arizona because of his age, and

spent several years working in the Globe area, constructing some of the first barbed

wire fencing in that region, before continuing his education.

He entered the University of Arizona in the Fall of 1927, for a major in

Entomology and Economic Zoology. His interest in insects, beetles in particular,

had started when another well-known coleopterist, Douglas K. Duncan, came to

the canyon on collecting trips. Mr. Duncan was employed in the Globe post office

and was acquainted with Frank, Sr. through the latter’s employment as a postman

on the Globe area rural route.

Even with a grazing allotment on adjacent National Forest land, the Parker

ranch did not support the Parker family. The Parkers put in an orchard and a

market garden, watered by a quite elaborate system of ditches from 6-Shooter

Creek. This creek, starting high in the Pinals, runs most of the time during the

winter, and well into the summer during a wet year. Summer rains can cause it

to roar.

Frank’s labels for the ranch are “Globe, Ariz.”; Duncan chose “base of Pinal

Mts.” The localities are the same. Much of what was collected probably came

from the lower part of the canyon, because that is where the ranch houses are.

Collecting trips onto the upper part of the ranch would have been called “Pinal

Mts.” by both collectors. The “Pioneer Pass” of Wickham is in the upper part of

the ranch, where dense stands of chaparral oak dominate the scene. The creek

bottom has a good mix of mesophytic vegetation, but the sides of the canyon are

definitely desertic, with a thin stand of grass and some small shrubs.

At the University, Frank found kindred spirits in E. D. Ball and A. A. Nichol.

The department hired him as a laboratory assistant, for the many things that

entomologists are used to doing, including pinning an infinity of points for the

leafhopper collections of Ball and Nichol’s mirids. Ball was Dean of the College

of Agriculture for part of this time, but continued his work on Homoptera even

while a dean, favoring work in the early morning, which he considered the best

time to get things done. The Ball collection went to the U.S. National Museum.

I have not seen it, but the selection of Arizona species of leafhoppers that came

back to the University of Arizona, in recognition of the state’s claim to part of

the material, was itself quite impressive. For at least part of the time in his

undergraduate years, Frank worked at the Tucson “bug station” of the Office of

the State Entomologist. This was an entomological quarantine station, which could

cover part of the entrance roads into the state, on a stretch of highway with the

unoriginal name of “Miracle Mile.” Frank’s transportation was a bicycle, and the

roads were mostly dirt or gravel. He told of the joys of the trip to Sabino Canyon

and how easy it was to stop and look at vegetation from a bicycle. The Santa Rita

Range Reserve, which appears on his labels as “Santa Rita RR,” was also within

his travel circle. A label vagary of this period is his “Tuczon” labels. For these

there is a simple explanation. The department had a printing press and a few

fonts of type. What with labels left set up and type lost, the lower case “s” was

at a premium. Frank used a long list of locality labels, and fitted them to field

locations quite precisely.

Frank graduated from the university in 1932, and married Per sis Stewart the

VOLUME 62, NUMBER 1

same year. The Parkers had three children, Caroline, Frank and Stan. In the early

1930’s, Frank took to the road collecting and tried to make a living selling spec¬

imens. During this period he was employed to an extent by Owen Bryant, who

lived in Tucson. The commercial collecting venture was pretty well concentrated

into the years 1934 and 1935, with Persis a partner on most of the trips.

He started into a graduate program at the University of California in 1937, and

there became acquainted with E. C. Van Dyke and F. E. Blaisdell. He would

certainly have gone through the program if financial problems and a bout with

pneumonia had not interfered. He had found employment and housing as care¬

taker of a large church in Berkeley, but apparently had little time to collect, because

I haven’t found any specimens in his collection from that period. He was in

Berkeley less than a year.

For some years Frank then worked as a professional entomologist in the Office

of the Arizona State Entomologist. Phoenix was his home base most of the time.

We can put dates on his other duty stations from the labels in his collection.

During one period the Parkers moved to Blythe, California and Frank worked at

the station at Ehrenberg, across the Colorado River in Arizona. In the days before

air conditioning, being stationed in Ehrenberg during the summer was hard time.

I first became acquainted with Frank when I started working on the genus

Epicauta in 1942. My undergraduate employment was for 18 hours a week at the

Museum of Comparative Zoology, in the beetle room, with easy access to the

LeConte collection. In the course of sorting and arranging the general collection,

I discovered that the genus Epicauta had a good many undescribed species hidden

by misidentifications. Comparison with the critical types was easy, so I selected

this genus to revise for an honors thesis in biology. It didn’t seem as if there was

anyone working on it at the start, but correspondence with H. S. Barber, I think,

finally put me into contact with Frank. He also had been working on the genus,

and must have been farther along than I. But he had nothing but encouragement

for my efforts, and I submitted the thesis, which became the basis for a published

revision. World War II and a year in the Philippines for the Field Museum

intervened for me. I wrote Frank from the Philippines and arranged to visit him

in Phoenix on the way back, in July 1947. He and Louis Lauderdale, then the

State Entomologist, took me along on a week’s field trip through southeastern

Arizona. I had gotten used to a certain level of insect populations in the Philip¬

pines, and provided myself with pill boxes and other storage supplies at this scale.

The abundance and diversity of the insects that I collected on this trip filled all

the boxes in the first couple of days.

I started graduate school that Fall, but Bill Nutting and I were back in Arizona

in the summers of 1948 and 1949, running circuits around the state following

Frank’s advice and using the ranch as base. Frank and his family had moved to

the ranch in the winter of 1947, and were busily engaged in making a living

ranching, selling fruit, mostly peaches as I remember, and eggs.

Frank lived at the ranch from then on, but in 1952 was employed by the

Inspiration Consolidated Copper Company at its Miami mine. He and D. K.

Duncan were clerks for the electrical department. Sharing the job made getting

off for a collecting or fishing trip easier. They worked together on beetles at night

over many years, identifying specimens and interpreting keys. During his em¬

ployment by Inspiration Consolidated, Frank moved from the electrical depart-

PAN-PACIFIC ENTOMOLOGIST

ment to the mechanical engineering department, to the Christmas mine, and finally

to the computer division of the Miami mine. He retired in 1970 as chief systems

analyst.

Over the years there has always been a string of visitors to the ranch, to see

Frank and his collection and to collect in the canyon. Frank had built a small

adobe building to house the collection in 1933, and kept it there until he and

Persis moved to the main ranch house in 1972. Frank, and the whole family,

were ever alert to rare beetles in the canyon. Frank continued collecting trips, but

over the years found his familiar haunts and camping areas increasingly crowded.

One other car in a campground made a crowd. He and “Dune,” D. K. Duncan,

made forays into the Sierra Anchas and to the White Mountains trout fishing,

and the Parker family to Cholla Bay and Rocky Point in Sonora for ocean fishing.

The early day trips to the Mexican localities were over long stretches of roads of

dirt, sand or worse, with the problem of an overheated engine one to be reckoned

with. On one such trip tomato juice substituted for water in a Model T Ford. No

matter what the objective, every trip was a collecting trip.

The high price of Schmitt boxes early drove both Parker and Duncan to make

their own housing. The design they settled on was a large double Schmitt, Parker’s

larger than Duncan’s. The pinning bottom changed over the years. An early choice

was composition cork, which they discovered, as many entomologists did, was

quite corrosive to pins. The softer grades of wall board were substituted, but these

were too hard for easy pinning, especially for the smaller sizes of insect pins. For

his best boxes Frank finally used dried flower stalks of century plants, cut length¬

wise. These are very soft near the center, much harder near the rinds.

Mr. Duncan notified us in 1963 that he wanted to donate his collection to the

University of Arizona. He had sold some of the choicest specimens to Edith

Mank, who had offered him a dollar a species for anything that she did not have

in her collection. But the collection was a major addition, in both species and

localities of collection.

Frank had become acquainted with another beetle collector in Phoenix, Peter

C. Grassman, at first when Mr. Grassman was in high school. Mr. Grassman

made boxes like Frank’s and was well started on a beetle collection when World

War II intervened. He left his collection with Frank when he entered the military,

and was killed in action in the Battle of the Bulge. Frank donated the Grassman

collection, a large part of his own, and the tiger beetles from the Duncan collection,

with the intention of using the extra space in boxes to expand the parts of his

collection that he still retained.

Ill health forced him to early retirement. Despite problems, he remained cheerful

and calm, and ever ready to discuss the issues of the day or the populations of

beetles with family and visitors. We asked him to run a light trap for us at the

house, and he kept this going until his final day at the ranch, when he entered the

hospital in Phoenix and died four days later, on August 18, 1984.

Mrs. Parker has donated the balance of the Parker collection to the University

of Arizona, along with the journals and reprints. The Meloidae and Buprestidae,

which were his favorites, are particularly impressive. Parker and Duncan kept

good track of publications on the beetle fauna of Arizona. Frank had copies of

essentially all of the pertinent literature on Meloidae, part of which were typed

from the originals when he was at Tucson or Berkeley. There is a start on a catalog

VOLUME 62, NUMBER 1

of the beetles of Arizona, with many records entered. Frank’s interleaved copy

of the Leng catalog has been annotated from the supplements, and has many other

entries.

The combined Parker-Duncan-Grassman collections are the product of over a

century of diligent collecting of beetles and some other groups of insects. Some

of the localities represented have changed vastly over the past 50 years, and many

that were easy to get to in the past have now been blocked off for the insect

collector. It isn’t easy to come up with a conspicuous beetle that these collectors

did not find. Much of my collecting has been in the small to minute size range,

where additions are easier. But one of Frank’s recommendations, which I have

passed on to others, is a good one. Never abandon a good collecting site for

another that you think will be better. It almost always isn’t, and you never seem

to get back to the good place in time to capitalize on it. Perhaps this is more true

in an arid area than elsewhere, but it certainly holds here.

List of Publications

Ball, E. D., and F. H. Parker. 1946. Some new North American Idiocerus (Homoptera: Cicadellidae).

Joum. Kansas Entomol. Soc., 19:73-82.

Parker, F. H. 1947. A new Paratyndaris from Arizona (Coleoptera, Buprestidae). Bui. Brooklyn

Entomol. Soc., 42:31-33.

-. 1955. A new species of Schizillus (Coleoptera: Tenebrionidae). Pan-Pac. Entomol., 31:148-

150.

Werner, F. G., W. R. Enns, and F. H. Parker. 1966. The Meloidae of Arizona. Ariz. Agric. Exp.

Sta. Tech. Bui. 175, 96 pp.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 6-12

Asian Biting Fly Studies V: Tabanidae.

Records from Thailand

Edward I. Coher

Division of Natural Sciences, Southampton College, L.I.U., Southampton, New

York 11968.

Following the work of Burton (1978) it would seem inappropriate to add another

study to the tabanid fauna of Thailand. However, the material under consideration

in the present study was collected by this author almost 20 years earlier; at that

time it was recognized to include a number of new forms, all of which have since

been described by Burton (1978) or Philip (1960a). The collections reported in

this study strongly supplement that of Burton and provide much new data on

the distribution of southern Thailand species.

1. Tabanus agnoscibilis Austen, 1922

1922. Austen, Bull. Ent. Res. 12:453, f.

1978. Burton, Tabanini of Thailand: 100, synonymy.

A single male taken at a light in my living quarters. This is the first record of

this species from Chiengmai Province.

Record. — Chiengmai Province, Chiengmai, 10 July 1959.

2. Tabanus aurilineatus Schuurmans Stekhoven, 1926

1926. Schuurmans Stekhoven, Treubia 6-Suppl.:231, f, m.

1978. Burton, Tabanini of Thailand:68.

Two specimens were captured at a light at about 2200 hours in jungle villages.

Both specimens agree well with the form ascribed to this species by Burton. The

frontal callus of the two is like that figured by Schuurmans Stekhoven (fig. 94b).

This is the first record of this species in Trang Province.

Records. — Trang Province, Lamor, Vill. #4, 9 May 1960, f; Vill. #3, 8 June

1960, f.

3. Tabanus brunnicolor Philip, 1960

1960b. Philip, Studies Inst. Med. Res. Malaya No. 29:43, new name for T. brun-

neus Macquart, 1834, f, m, synonymy.

The tomentum of the subcallus and clypeus is whiter in a specimen taken in

May. Also, its median dorsal abdominal triangular markings are narrower and

somewhat shorter and whiter and the ventral abdominal markings do not show

median darker areas as clearly as specimens taken in June.

I am not sure why Burton did not include this species in his review of the Thai

fauna.

All specimens were taken along the edge of a jungle stream.

Records.— Trang Province, Chong, 13 May, 15, 24 June 1960, 3f.

VOLUME 62, NUMBER 1

4. Tabanus brunnipennis Ricardo, 1911

1911. Ricardo, Rec. Indian Mus. 4:160, f.

1978. Burton, Tabanini of Thailand:70.

Of three specimens representing this form, the one from Sarapee is darkest with

a strongly contrasting mid-dorsal abdominal stripe and lateral spots on TII; there

are faint small lateral spots on Till.

Records.— Chiengmai Province, Sarapee, Vill. #5, 23 July 1959, f; Trang Prov¬

ince, Bang Mark, 29 April 1960, f, Trang, 10 May 1960, f.

5. Tabanus ceylonicus Schiner, 1868

1868. Schiner, Reise Novara, Diptera, Band 2:93, f.

1978. Burton, Tabanini of Thailand:38, synonymy.

Record.— Chiengmai Province, Chiengmai, 1 Nov. 1959, f.

6. Tabanus dissimilis Ricardo, 1911

1911. Ricardo, Rec. Indian Mus. 4(6): 180, f.

1960b. Philip, Stud. Inst. Med. Res. Malaya No. 29:45.

The frontal callus of a single specimen agrees well with that figured by Ricardo

(fig. 15) and by Schuurmans Stekhoven (1926:369). The center of distribution of

this species seems to be to the south of Thailand. Burton (1978) did not include

this species in his review although Schuurmans Stekhoven (1928:443) reported

it from Trang Province.

Record. —Trang Province, Trang, 3 March 1959, f.

7. Tabanus hybridus Wiedemann, 1828

1828. Wiedemann, Aussereuropaische zweifliigelige Insekten 1:57, f.

1926. Schuurmans Stekhoven, Treubia 6-Suppl.:235.

These Thai specimens agree well with the form recorded by Philip (1960b:48)

from Malaya; the frons corresponds closely to that figured by Schuurmans Stek¬

hoven (Text fig. 97a). The series shows very little variation and I suggest that the

variable Schuurmans Stekhoven material should be examined to determine whether

more than a single species is involved. Secondly, the Wiedemann type, or topotypic

material from Macao, needs to be studied to determine if it, the Philip material

and specimens included here as hybridus are conspecific.

This is the first record of this species from Thailand and for the time, it represents

the northernmost population of hybridus. Capture was along a jungle stream.

Records.— Trang Province, Chong, 19 May 1960, f; 15 June 1960, 8f; 29 June

1960, 5f.

8. Tabanus subhybridus Philip, 1960

1960a. Philip, Studies Inst. Med. Res. Malaya No. 29:22, f.

This species was taken flying with hybridus and can be distinguished from it

by its deeper orange appearance. Although Philip indicates that his specimens are

rather small (13 mm), the forms from Thailand are equivalent in size to hybridus.

PAN-PACIFIC ENTOMOLOGIST

Despite other minor differences, these southern Thai forms correspond quite

closely to the description of subhybridus.

This is the first record of this species from Thailand and it represents the

northernmost population of subhybridus. All were taken in a Shannon trap along

a jungle stream.

Records. — Trang Province, Chong, 15 June 1960, 2f; 29 June 1960, f.

9. Tabanus konis Philip, 1960

1960a. Philip, Studies Inst. Med. Res. Malaya No. 29:17, f.

1978. Burton, Tabanini of Thailand:99, synonymy.

Four specimens were taken at a light. The series represented by these collections

is highly variable in respect to size (10-13 mm) and markings; abdominal tergites

vary from entirely concolorous to with up to the first four tergites lighter than the

posteromost ones. Totally unrubbed specimens have scattered light-colored me-

sonotal and scutellar setae and a distinct median dorsal abdominal line of these

on TI-TVI, the line being slightly expanded laterally on TI.

Records.—C hiengmai Province, Chiengmai, 6, 10, 19 July 1959, 3f; Tawan

Tan, 14 July 1959, 2f; Chompu, 27 July 1959, f; Sarapee Distr., July 1959, f.

10. Tabanus leucocnematus (Bigot) 1892

1892. Bigot, Mem. Soc. Zool. France 5:656, Atylotus leucocnematus, f.

1926. Schuurmans Stekhoven, Treubia 6-Suppl.:321, redescription.

This, the earliest-named species of a large group of radiating Asian tabanids of

distinctive appearance, includes the biannularis group of Philip (1962) and Burton

(1978:17). This large complex would be better called the leucocnematus group.

Considerable speciation has occurred and I attribute 28 species to it, some of

which, including the name species, are poorly known. The characteristics defining

this group are a combination of the following: subcallus bare; callus subrectangular

and either wider than high or higher than wide, connected or not to an oval¬

shaped median callus which may be as large as the callus; scutellum with white

or yellow pollinosity and setae, in most species contrasting sharply with a darker

scutum which may have a band of light pollinosity and setae along the anterior

margin; white or yellow tibiae with apical dark rings; abdomen generally with

distinctive bands or wide spots along the posterior margin of some of the tergites.

Preliminary evidence seems to indicate that the polymorphic form of the sper-

mathecae in each species I have studied as well as the highly membranous char¬

acteristic of the spermathecal ducts serve to indicate the close relationships within

this group. Much more study needs to be done before incorporating these char¬

acteristics into the diagnosis of this group. If these characteristics should prove

to be valid after widespread study of species considered to be in the group, it

would be valid to resurrect the subgenus Callotabanus Szilady, 1926. Burton

(1978:14) has discussed the validity of Callotabanus based on other criteria; I am

not in accord with either his treatment of the subject nor with that of Philip.

Within this complex, color and pattern generally fall into three major and one

unique ( T. equicinctus S.S.) category.

I have seen a single rather denuded female from Boun Tay, nr. Phong Saly,

Indochina, 6 January 1929 (R. Wheeler) and I have a single female from Trang

VOLUME 62, NUMBER 1

Province, Chong, Vill. #1, 19 May 1960 (Surin et al.) which are provisionally

referred to this species. Neither specimen is in perfect condition and they may

not be conspecific with leucocnematus nor with each other. Differences are found

in their size and in the color of their frontal areas; the antennae of the Thai

specimen are missing. A study of the internal characteristics of the type and any

specimens which have been referred to this species is necessary to resolve the

identity and distribution of leucocnematus.

11. Tabanus caduceus Burton, 1978

1978. Burton, Tabanini of Thailand:27, f.

A single female flying at the same time as macdonaldi and griseipalpis was

taken in a Shannon trap along a jungle stream just above a waterfall. In the field,

its larger size and the anterior infuscation of its wing quickly separated it from

those species. This is the southernmost collection of caduceus in Thailand, others

being from the northern province of Chiengmai.

Record. — Trang Province, Chong, 15 June 1960, f.

12. Tabanus griseipalpis Schuurmans Stekhoven, 1926

1926. Schuurmans Stekhoven, Treubia 6-Suppl.:312, f.

1978. Burton, Tabanini of Thailand:28.

At the time of original description, Schurrmans Stekhoven described a single

female of this species from Nakon Sri Tamarat in southern Thailand along with

specimens from Sumatra and Java. There is some reason to wonder if these are

conspecific considering the differences he noted in the frontal area of the head

and in the subcallus. Burton indicates that of two specimens from Trang which

Schuurmans Stekhoven later determined as griseipalpis (1928:443), one is cer¬

tainly not.

Examination of my series of nine specimens shows the basal callus and median

callus of eight of them to be separated and much like that in the 1926, Textfig.

142b (Java). The ninth has a partial lateral connection between the calli. Thus, a

worn specimen could conceivably appear as Textfig. 142c (Thailand). Addition¬

ally, the subcallus of all my specimens is as figured in 142c which shows a median

projection on the lower margin. Burton describes “a considerable amount of yellow

hair on both the anterior portion and the hind margin of the scutum, . . . .” Such

setation is sparse anteriorly and either absent or virtually so on the posterior

scutum of all of my specimens.

Until the types can be studied, it appears that the best course is to refer my

series to that of the Schuurmans Stekhoven species.

All specimens were taken in a Shannon trap; that in May from jungle surround¬

ing a small village, those in June from jungle along a stream above a waterfall.

Records. —Trang Province, Chong, 15 June 1960, 8f; Vill. #1, 19 May 1960, f.

13. Tabanus macdonaldi Philip, 1960

1960a. Philip, Stud. Inst. Med. Res. Malaya, No. 29:18, f.

Although my specimens show some differences from the original description,

they agree in many characteristics with macdonaldi. The differences are as follows:

PAN-PACIFIC ENTOMOLOGIST

median callus shaped like a broad arrowhead; calli red-brown rather than black;

TI-II with yellowish pollinose markings; no banding whatsoever on the stemites.

Field notes mention a single green eye band. I hesitate to erect a new taxon for

this form in the present state of knowledge of the leucocnematus group.

This is a jungle species and was taken in a Shannon trap along a jungle stream

above a waterfall.

Records. — Trang Province, Chong, 19 May 1960, f; 15 June 1960, 2f.

14. Tabanus monilifer (Bigot) 1892

1892. Bigot, Mem. Soc. Zool. France 5:654, f, Atylotus monilifer.

1978. Burton, Tabanini of Thailand: 104.

The most southern population of this species is represented by this collection.

The spur vein which is rather short in this series does not occur at all on the wing

of one specimen. Taken along a jungle stream.

Records. —Trang Province, Chong, 13 May 1960, 2f; 19 May 1960, 2f; 24 May

1960, f.

15. Tabanus pristinus Burton, 1978

1978. Burton, Tabanini of Thailand:84, f.

My specimens agree well with the original description except that those taken

in October and December exhibit dark abdominal stemites. One of the specimens

is almost twice the bulk of the other two although the difference in length is only

about 4mm.

Records. —Chiengmai Province, Chiengmai, 29 October 1959, f; 23, 26 Decem¬

ber 1959, 2f.

16. Tabanus striatus Fabricius, 1787

1787. Fabricius, Mantissa Insectorum 2:356, f.

1981. Burger and Thompson, Proc. Entomol. Soc. Washington 83:340, review of

the striatus complex, figures.

Records.— Chiengmai Province, Chiengmai, 10 July 1959, f; 4 August 1959, f.

17. Tabanus unicus Burton, 1978

1978. Burton, Tabanini of Thailand: 116, f.

There are some differences between my specimens and the holotype. My south¬

ern forms have a darker and differently shaped subcallus and less developed

markings on the abdominal tergites. Data on the collection of these specimens

are not available and they can only be recorded as having been taken in Trang

Province between early March and the middle of July 1959.

18. Chrysops dispar (F.), 1798

1798. Ent. Syst. Suppl.:567, Tabanus, m.

1960b. Philip, St. Inst. Med. Res. Fed. Malaya No. 29:38.

My personal experience with this species involves its distribution in both Thai¬

land and Nepal. Except for darker pigment in high altitude Nepalese specimens,

I find no differences in the populations from these two areas. This fly was on the

VOLUME 62, NUMBER 1

wing in large numbers during early and middle June in north central Nepal; a

single specimen was collected in the south central terai during early July and the

coloration of this specimen is very much like those from Thailand.

Records.— Chiengmai Province, Chiengmai, 1959; 28 June, 2f; 10 July, f; 13

July, f; Sarapee District, July, 6f; Vill. #4, 23 July, 2f; 6 July, f; Trang Province,

Bang Mark, 26 April 1960.

19. Chrysops jbcissimus Walker, 1857

1857. Walker, J. Linn. Soc. London 1:112, fixissima, f.

A single female taken in a Shannon trap within the edge of the jungle during

the early afternoon. This represents the first record for this species in Thailand;

its principal distribution lies to the south of this area.

Record. —Trang Province, Chong, 15 June 1960.

Discussion

Three species of Tabanus and one of Chrysops are reported for the first time

from Thailand; these are T. hybridus, T. subhybridus and T. macdonaldi from

Malaya and C. fixissimus. Two other species, T. brunnicolor and T. dissimilis are

confirmed as part of the Thai fauna. Others of the nineteen (19) tabanid species

reported represent extensions of the range of these forms in Thailand or in respect

to their total known range.

Problems with speciation and variation occur in respect to the leucocnematus

group. Further studies are needed to ascertain the identity of a number of forms

described by several authors and the relationship of those to forms such as those

included in this review.

A review of some major assemblages of species flying on the same date and

often at the same hours is of some interest.

19 May 1960. Chong: griseipalpis, hybridus, macdonaldi and monilifer.

15 June 1960. Chong: brunnicolor, caduceus, griseipalpis, hybridus, macdonaldi,

subhybridus and C. fixissimus.

29 June 1960. Chong: hybridus and subhybridus.

10 July 1959. Chiengmai: agnoscibilis, konis, striatus and C. dispar.

23 July 1959. Sarapee: brunipennis and C. dispar.

All collections at Chong were taken at the same site.

Specimens will be deposited at the California Academy of Sciences, Cornell

University and the National Museum of Natural History.

Acknowledgments

I would like to thank Dr. Peter F. Beales, WHO, OMS, Geneva, Switzerland

for his cooperation and aid in the capture of a number of these forms. Dr. L. L.

Pechuman of Cornell University has made material of a number of Thai species

available, resulting in more critical comparison of my material with Burton’s than

descriptions alone would allow.

Literature Cited

Austen, E. E. 1922. Some Siamese Tabanidae. Bull. Ent. Res., 12(4):431-455.

Bigot, J. M. F. 1892. Descriptions de Dipteres nouveaux. Mem. Soc. Zool. France, 5:602-691.

PAN-PACIFIC ENTOMOLOGIST

Burger, J. F., and F. C. Thompson. 1981. The Tabanus striatus complex: a revision of some Oriental

horse fly vectors of surra. Proc. Entomol. Soc. Washington, 83:339-358.

Burton, J. J. S. 1978. Tabanini of Thailand above the Isthmus of Kra (Diptera: Tabanidae). Ento¬

mological Reprint Specialists, Los Angeles, 165 pp.

Fabricius, J. C. 1787. Mantissa insectorum sistens species nuper detectas. Vol. 2, Impensis Christ.

Gotti. Proft, Hafniae, 1-382.

-. 1798. Supplementum entomologiae systematicae. Hafniae, 1-572.

Philip, C. B. 1960a. Malaysian parasites XXXV. Descriptions of some Tabanidae (Diptera) from

the Far East. Stud. Inst. Med. Res., Fed. Malaya, No. 29:1-32, 27 figs.

-. 1960b. Malaysian parasites XXXVI. A summary review and records of Tabanidae from

Malaya, Borneo and Thailand. Stud. Inst. Med. Res., Fed. Malaya, No. 29:33-78, 2 Pis., 2 figs.

-. 1962. A review of the Far Eastern biannularis group of Tabanus. Pacific Insects, 4(2):293-

301.

-. 1969. Supplemental notes on the Far Eastern biannularis group of Tabanus. J. Med. Ent.,

6(2): 197-198.

Ricardo, G. 1911. A revision of the species of Tabanus from the Oriental region, including notes

on species from surrounding countries. Rec. Indian Mus., 4:111-258, 2 Pis.

Schiner, J. R. 1868. Diptera. IN Reise der osterreichischen Fregatte Novara um die Erde. Zool. theil.

Band 2, Abt. 1, B, 1, Wien, aus der K.-K. Hof- und Staatsdruckerei, vi + 1-388 pp., pis. 1-4.

Schuurmans Stekhoven, J. H. 1926. The bloodsucking arthropods of the Dutch East Indian Archi¬

pelago VII. The tabanids of the Dutch East Indian Archipelago (including those from neighboring

countries). Treubia, 6(Suppl.): 1-552, pis. 1-18.

-—. 1928. The bloodsucking arthropods of the Dutch East Indian Archipelago IX. Recent col¬

lections of tabanids from Sumatra, middle east Borneo, Soemba etc. Zool. Jahrb. Abt. System.

Okol. Geogr. Tiere, 54(5-6):425-448, figs. 1-5.

Szilady, Z. 1926. New and Old World horseflies. Biol. Hungarica, 1(7): 1-30, figs. 1-7, PI. 4.

Walker, F. 1857. Catalogue of the Dipterous Insects collected at Sarawak, Borneo, by Mr. A.R.

Wallace, with descriptions of new species. J. Linn. Soc. London Zool., 1:105-136.

Wiedemann, C. R. W. 1828. Aussereuropaische Zweiflugelige Insekten Schulz, Hamm. l:xxxii, 1-

608, Pis. 1-6.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 13-22

Geographic Variation in Flight Wing Development and Body

Size of the Tule Beetle, Tany stoma maculicolle

(Coleoptera: Carabidae)

James K. Liebherr and Ann E. Hajek

Department of Entomology, Cornell University, Ithaca, New York 14853.

Abstract.— The tule beetle, Tanystoma maculicolle (Coleoptera: Carabidae), a

common ground beetle in California, shows considerable geographic variability

in flight wing development and body size. Flight wings may be fully developed

or reduced to flap-like stubs. Ecologically marginal populations on the mainland

exhibit high percentages of fully winged individuals, whereas populations from

more mesic habitats and from the California Channel Islands are predominantly

brachypterous. Populations with high percentages of macropterous individuals

are restricted to ecologically marginal habitats, suggesting frequent extinction and

recolonization in these areas.

On the mainland, body size increases clinally from south to north. Stepping-

stone gene flow between mainland populations would facilitate this clinal varia¬

tion. Body size of Channel Island populations varies erratically from south to

north but is positively correlated with the floristic diversity of the islands.

The tule beetle, Tanystoma maculicolle (Dejean), is a common carabid beetle

of mesic, open and woodland habitats in California, northern Baja California,

and southern Oregon (Liebherr, 1985). In California, it occupies lowland habitats

in the Central Valley which are hot and dry during the summer, along with more

mesic, mid-elevational habitats in the foothills of the Coast Range and Sierra

Nevada. Coast Range habitats receive more winter rain than Central Valley hab¬

itats, and the climate is moderated by a maritime influence. Sierra Nevada foothill

habitats regularly receive winter rains and snow, as well as spring and summer

runoff from snowfall at higher elevations. Tule beetle larvae develop during the

winter, and most adults eclose from March to June (Liebherr, 1984). Thus, the

occurrence of the larvae and pupae, the stages most susceptible to desiccation, is

synchronized with the period of winter rains.

The tule beetle exhibits flight wing dimorphism across its distributional range

(Liebherr, 1985). The macropterous morph possesses a well-developed flight ap¬

paratus; the metepistemum is elongate, and internal apodemes of the metanotum

are evident. The flight wings range from 1.3 to 1.5 x the length of the elytra. The

brachypterous morph has a much shorter metepistemum, the internal apodemes

of the metanotum are much reduced, and the flight wings are short scale-like flaps

that extend only to the base of the abdomen.

This paper first describes the geographic variation in flight wing configuration

in this species, and investigates the relationship between habitat stability and

flight wing development. Secondly, the patterns of body size variation on the

PAN-PACIFIC ENTOMOLOGIST

mainland are compared with those on the California Channel Islands. Comparison

of the isolated populations on islands with ecologically marginal populations on

the mainland suggests fundamental differences in selective regimes acting on the

two types of populations.

Materials and Methods

Our evaluation of the geographic distribution of macroptery and brachyptery

in T. maculicolle is based on museum material used in a taxonomic revision of

the genus Tanystoma (Liebherr, 1985). Presence or absence of fully developed

flight wings can be observed through the semi-hyaline areas of the maculate elytra,

or by lifting the apex of an elytron. To determine the geographic distribution of

fully flighted forms, we excluded specimens possibly collected at light. Although

this results in fewer samples, it eliminates any bias toward flighted forms. Data

for males and females were recorded separately for flight wing dimorphic popu¬

lations. Because no difference in flight wing configuration was attributable to sex,

the sexes were pooled in all samples. Specimens collected on different dates at

particular localities were also pooled because no temporal variation was observed

in the material at hand.

We used elytral length as a measure of body size. Elytral length is highly cor¬

related with overall body size (Liebherr, 1986), and measurement of the elytra

rather than overall body length eliminates error due to the posture of pinned

specimens. Elytra were measured from the tip of the mesoscutellum to the elytral

apex. Specimens were held horizontally in a rotatable specimen holder, and mea¬

sured using a calibrated ocular grid. On average, females are larger than males,

so the sexes were analyzed separately. Seven mainland localities were compared

to 7 samples from the Channel Islands. Twenty individuals of each sex were

measured for most localities; the smaller sample sizes from some localities are

due to a shortage of material. Results are portrayed using Dice-Leraas diagrams

with the modifications suggested by Simpson et al. (1960).

As body size of the beetles varies among the California Channel Islands, bio¬

logical attributes of the islands were investigated to determine whether they are

correlated with the pattern of body size variation. Floristic diversity, measured

by the number of plant associations present on each island (Philbrick and Haller,

1977), was used as an independent variable upon which elytral length was re¬

gressed. Floristic associations that occur in habitats unsuitable for T. maculicolle

were excluded from the analysis; this limited the associations tallied to island

chaparral, valley and foothill grassland, southern coastal oak woodland, island

woodland, southern riparian woodland, Bishop pine forest, Torrey pine forest,

and coastal marsh (Philbrick and Haller, 1977).

Results

The proportion of macropterous individuals ranges from 1.0 (Warner Springs,

Brentwood) to 0 (San Jacinto Mtns., several Channel Islands, Three Rivers, Ti-

buron, and Oroville) (Appendix 1). The pattern of flight wing variation is a mosaic,

with abrupt frequency changes occurring over short distances within the species’

range (Fig. 1). For example, the macropterous Warner Springs sample (n = 17)

was taken at most 70 km away from the totally brachypterous San Jacinto Moun¬

tains sample {n = 13) (different at P < 0.001, chi-squared = 30.3, d.f. = 1). The

VOLUME 62, NUMBER 1

Figure 1. Percentage of macropterous (solid) and brachypterous (open) Tanystoma maculicolle

from 34 localities in California and northern Baja California (see Appendix 1 for numbers of specimens

in each sample).

Tipton sample (n = 8) has 7 individuals winged, whereas the Three Rivers sample

(n = 11) from 55 km away is 100% brachypterous (different at P < 0.001, chi-

squared = 15.3, d.f. = 1).

In general, populations from the floor of the Central Valley, Los Angeles, and

the southernmost portion of the range exhibit the highest fraction of fully winged

individuals. Populations along the coast are more variable. The Carmel and Big

Sur samples contain 27% and 37% macropterous beetles, whereas other coastal

samples (San Luis Obispo, Paso Robles, Paraiso Springs, Stanford, Tiburon, Hop-

land, Humboldt Co.) range from 0 to 13% macropterous. The few samples avail¬

able from higher elevations (e.g., Three Rivers [250 m], West Point [650 m], and

San Jacinto Mtns.) exhibit a high proportion of brachypterous beetles.

Almost all beetles on the Channel Islands are brachypterous. Sample sizes are

quite large for most of the islands, and only the Sta. Catalina, San Nicolas, and

Sta. Cruz island samples contain any macropterous individuals. The only fully

winged beetle from Sta. Catalina Isl. is teneral, indicating this specimen actually

eclosed on the island. San Nicolas Isl., the most isolated of the islands and farthest

from the mainland, has 5% macropterous individuals. The closest mainland sam¬

ples to compare with the Channel Island populations are San Diego and Los

Angeles. These samples contain 52 and 43% macropterous individuals, respec¬

tively.

PAN-PACIFIC ENTOMOLOGIST

□ZZ h ; Y . "; ::..lb ■ .M| ffl

1 20

i—gtoj-

- 1 1 3 -1 DIXON

20 1

I 1 ~~| -1 WEST POINT

1 20

- 1 I -1 STANFORD

I | I -1 PASO ROBLES

-1 SAN MIGUEL I.

- fjiW -1 STA. ROSA I.

-1 STA. CRUZ I.

ANACAPA I.

-1 LOS ANGELES

-1 SAN NICOLAS I.

-1 STA. CATALINA I.

SAN CLEMENTE l.

-1 SAN DIEGO

H MANEANDERO

— i - 1-1 - 1 - 1 - 1 —

4.75 5.0 5.25 5.50 5.75 6.0

—i-1-1—

6.25 6.50 6.75

I- 111(51

-1 DIXON

-1 WEST POINT

-1 STANFORD

-1 PASO ROBLES

SAN MIGUEL I.

STA. CRUZ I.

STA.

ROSA I.

ANACAPA I.

LOS ANGELES

SAN NICOLAS I.

—I STA. CATALINA I.

SAN CLEMENTE I.

-1 SAN DIEGO

MANEANDERO

4.75 5.0 5.25 5.50 5.75 6.0 6.25 6.50 6.75 7.0

elytral length (mm)

Figure 2. Dice-Leraas diagram showing elytral length for 7 California mainland (open) and 7

Channel Island (shaded) populations. Range shown as long line; box represents 95% confidence interval

about mean (x ± t 0 5i x s/ n' h )\ number above mean is sample size. Samples are ordered by latitude,

from south to north. A) Males. B) Females.

VOLUME 62, NUMBER 1

Table 1. Mean elytral length for males and females of Tanystoma maculicolle from the Channel

Islands, and the number of plant associations on each island suitable for habitation by the species.

Island

x (33)

JC (99)

# plant associations

San Clemente

4.91

4.99

Sta. Catalina

5.82

5.83

San Nicolas

5.44

5.55

Anacapa

5.18

5.55

Sta. Cruz

5.76

5.98

Sta. Rosa

5.98

6.39

San Miguel

5.45

5.61

Average elytral length varies from 4.92 mm (San Clemente Isl.) to 6.06 mm

(Dixon and Stanford) for male beetles, and 4.98 mm (San Clemente Isl.) to 6.38

mm (Sta. Rosa Isl.) for females (Fig. 2). Mainland populations of both males and

females exhibit a relatively smooth increase in body size from south to north.

Maneandero, Baja California averages the smallest of the mainland samples, San

Diego and Los Angeles average somewhat larger, and the 4 northernmost samples

are the largest of the mainland samples. Within sample variability is similar in

all 7 mainland samples.

The Channel Island samples exhibit a very erratic pattern of body size variation

from south to north (Fig. 2). San Clemente Isl. beetles are significantly smaller

than those of any other island or mainland population, except the small sample

of beetles from Anacapa Isl. The Sta. Catalina, Sta. Cruz, and Sta. Rosa samples

have the largest beetles among the island populations. Several beetles from Sta.

Rosa Isl. are actually larger than any of the other mainland or island specimens.

The variation in body size is much greater among the island populations than

among populations from the larger mainland area. When differences between the

geographically adjacent localities in Figure 2 are averaged, for males the change

in elytral length per km map distance is 0.039 mm/km in the island populations

versus 0.00087 mm/km for the mainland populations ( t = 85.7, d.f. = 12, P c

0.01). For female beetles, adjacent island populations differ in elytral length by

an average of 0.046 mm/km, whereas mainland populations change by 0.00095

mm/km (7 = 58.2, d.f. — 12, P 0.01).

For our 7 Channel Island samples, average elytral length is positively correlated

with the number of plant associations available to T. maculicolle on each island

(Table 1, Fig. 3). For males, the regression of elytral length on number of plant

associations produces the equation y = 0.099x + 5.11, with a slope significantly

different from zero {t = 2.73, d.f. = 6, P < 0.05). The regression accounts for

nearly 60% of the variation in the data set. Female beetles are also larger on

floristically more diverse islands (y = 0.108x + 5.27; t = 2.39, d.f. = 6, P <

0.05). Over 53% of sample variation can be accounted for by this regression. In

both sexes, beetles from San Clemente Island are much smaller than expected

based on the regression (P < 0.001 for both sexes).

A very limited sample of male beetles from Guadelupe Isl., Baja California

Norte, has an average elytral length of 5.33 mm (n = 5, range 5.11-5.73 mm).

The body size on Guadelupe Isl. does not differ significantly from that at Ma¬

neandero, the nearest mainland locality.

PAN-PACIFIC ENTOMOLOGIST

Figure 3. Regression of average elytral length (mm) on number of plant associations suitable for

Tanystoma maculicolle males (•) and females (A) on the California Channel Islands (see Table 1).

Discussion

Wing polymorphism. — A dispersal polymorphism can be interpreted as an evo¬

lutionary response that permits a species to utilize a mosaic of stable and tem¬

porary habitats. Darlington (1943) reported that brachypterous carabids are con¬

centrated in mountains and mountainous islands, apparently because flight is not

required in these limited habitats. Brachyptery is not limited to mountain inhab¬

iting populations of Notiophilus biguttatus (F.) in Bohemia. Lowland populations

may also contain up to 30% brachypterous individuals (Honek, 1981), demon¬

strating that higher altitudes are not the only habitats in which brachyptery can

occur.

Based on data from carabid species that had colonized areas glaciated during

the last glaciation, Lindroth (1969, 1979) hypothesized that regions with high

percentages of brachypterous individuals had served as glacial refugia. He argued

that these more stable areas maintained wingless stocks, whereas colonization of

newly available habitats proceeded by macropterous propagules. Such a relation¬

ship between habitat age and brachyptery has also been reported for 3 species of

capniid Plecoptera in Alberta (Donald and Patriquin, 1983). Vepsalainen (1978)

adds that isolation is frequently characteristic of brachypterous populations in

genetically determined polymorphic species. Among Gerridae (Hemiptera), iso¬

lated populations receive few macropterous colonists, enhancing the trend toward

brachyptery.

Southwood (1962) extended Lindroth’s historically based hypothesis, general-

VOLUME 62, NUMBER 1

izing that dispersal from habitats of origin is the means by which species colonize

changing or temporary habitats. This hypothesis has been corroborated by nu¬

merous studies of insects (Greenslade and Southwood, 1962; Den Boer, 1970,

1971, 1979; Denno, 1976, 1979; Vepsalainen, 1978). Maintaining a fraction of

vagile colonizing individuals in a population assures the ability to colonize nearby

habitats where extinction has occurred.

For Tanystoma maculicolle, an hypothesis of relatively frequent extinction and

refounding of populations due to environmental fluctuations in marginal habitats

is consistent with our findings. Localities in the Central Valley, and lower ele-

vational sites in the southern part of the range have the highest percentage of

winged individuals. These localities are the most unpredictable in terms of habitat

suitability for these winter and spring breeding beetles; i.e., winter rainfall is the

least and its occurrence sporadic. By comparison, the more mesic mainland hab¬

itats which receive more winter rain, and the geographically isolated Channel

Island populations have higher percentages of brachypterous individuals.

That the Channel Islands were never connected to the mainland during Pleis¬

tocene sea-level fluctuations is now well established (Junger and Johnson, 1980).

We conclude therefore that the islands were colonized by T. maculicolle from the

adjacent mainland. The relatively high percentage of macropterous individuals

in Los Angeles and San Diego suggests that the islands were colonized by winged

propagules, and that selection pressure is acting against macroptery on the islands.

Although colonization of the islands by macropterous individuals is most likely,

brachypterous beetles may also have colonized as suggested by As (1984) for

carabids colonizing islands in the Baltic Sea.

Several bases for selective advantage of winglessness on islands have been

proposed. The notion that winged individuals may be blown away from suitable

habitats or face more environmental hazards on islands has been attributed to

Darwin (1859), and recently supported by Den Boer et al. (1980) and Bengtson

and Eriksted (1984). Several of the Channel Islands (San Clemente, Sta. Catalina,

Sta. Cruz, Sta. Rosa) are large enough to support a number of localized populations

of T. maculicolle. These local populations occur in a variety of woodland and

grassland habitats. In this case it is apparent that flight activity would not nec¬

essarily result in movement to unsuitable habitats, or off-island dispersal. We feel

an hypothesis in which the frequency of macropters is reduced solely due to

dispersal cannot completely explain the near total brachyptery on the Channel

Islands.

Other hypotheses for the evolution of brachyptery stem from Darlington’s

(1943) suggestion that brachypterous individuals are favored when dispersal is

not required for maintenance of the population. Among gerrids (Vepsalainen,

1978; Zera, 1984) and aphids (Wratten, 1977), flightless morphs are more fecund

and frequently develop faster than flighted morphs. Such an occurrence would

give a selective advantage to brachypterous individuals of T. maculicolle if den¬

sity-dependent mortality acted on the populations. One such mortality factor

operating within populations could be cannibalism. The larval stages of T. ma¬

culicolle are voracious predators, and often cannibalistic when reared together

(Liebherr, 1984, unpubl. data). T. maculicolle is a very common species, often

occurring in dense populations. If the larvae of wingless individuals develop faster,

cannibalism would exert strong selective pressure to reduce the frequency of slower

PAN-PACIFIC ENTOMOLOGIST

developing macropters in dense populations. A combination of intrasite advantage

for brachypters, and lack of winged immigrants due to isolation would be sufficient

to explain the absence of macropters on the Channel Islands.

Body size. — Body size in mainland populations of T. maculicolle increases

clinally from the southern to northern limits of the distributional range (Fig. 2).

The gradual change in body size is consistent with an isolation by distance model

of differentiation (Wright, 1943) influenced by uniformly changing selection pres¬

sure.

In Eusattus muricatus LeConte, a sand dune inhabiting tenebrionid beetle,

specimens from southern California are larger than specimens from northern

California (Doyen and Rogers, 1984). A longer period for larval development in

the southern portion of the range is believed to be the determinant for larger body

size. Southern populations of this univoltine species can develop year round,

whereas northern populations must cease activity during winter.

The tule beetle breeds during the rainy California winter and teneral adults are

present from March to June (Liebherr, 1984). Large body size in northern pop¬

ulations is associated with the longer rainy season there. Southern populations

have a much shorter period for larval development because of the shorter rainy

season. The converse dines in body size variation observed in E. muricatus and

T. maculicolle can both be related to the length of the larval developmental period.

Differences in habitat preference and phenology appear to govern the difference

in body size dines between these species.

The pattern of body size variation among all of the Channel Islands is a mosaic

(Fig. 2), but is positively correlated with floristic diversity (Table 1, Fig. 3). The

variety of plant associations on an island can be considered an indication of the

general suitability of an island for larval development. It is not known whether

floral diversity is indicative of general moisture conditions, the quality or quantity

of prey, or other factors influencing the size of adult T. maculicolle.

The 4 northern Channel Islands (San Miguel, Anacapa, Sta. Rosa, and Sta.

Cruz) were united in a superisland, Santarosae, during periods of maximum sea-

level lowering in the Pleistocene (Wenner and Johnson, 1980). Yet, distinct dif¬

ferences in body size exist among tule beetle populations on these islands today.

The San Miguel and Anacapa populations have significantly smaller beetles than

those on Sta. Cruz or Sta. Rosa. The intense stripping of vegetation on San Miguel

Isl. (Johnson, 1980) has left only valley and foothill grassland (Philbrick and

Haller, 1977) as habitats suitable for T. maculicolle. Due to its small size, Anacapa

Isl. also has only grassland for T. maculicolle to inhabit. The Sta. Rosa and Sta.

Cruz islands have a variety of chaparral, and oak and pine woodlands that are

suitable for tule beetle populations. Among these 4 islands, the divergence in body

size has occurred since the fragmentation of Santarosae. Whether differential

selection pressures have resulted in genetic change among the island populations

remains to be studied.

Conclusions

Tanystoma maculicolle populations that are isolated on islands or in ecologi¬

cally marginal areas on the mainland possess fundamentally different character¬

istics. Island populations are predominantly brachypterous, with this reduced

vagility suggesting very limited among-island dispersal. Island populations are

VOLUME 62, NUMBER 1

long-lived enough for substantial among-island divergence in body size to have

arisen. In contrast, marginal mainland populations possess mostly winged indi¬

viduals, and appear to be in genetic contact with adjacent populations based on

clinal variation in body size. Population extinction is judged to be a relatively

common occurrence on the mainland, based on the low frequency of brachyp-

terous individuals in many of these populations.

Acknowledgments

We thank the following curators and institutions for use of material: Lee H.

Herman, Jr., American Museum of Natural History; David H. Kavanaugh, Cal¬

ifornia Academy of Sciences; John A. Chemsak, California Insect Survey, Uni¬

versity of California, Berkeley; Robert O. Schuster, University of California, Da¬

vis; Cornell University Insect Collection; Charles L. Hogue, Los Angeles County

Museum; Alfred F. Newton, Jr., Museum of Comparative Zoology, Harvard

University; John D. Lattin, Oregon State University. John T. Doyen and Catherine

A. Tauber provided helpful reviews of the manuscript. This research was sup¬

ported by Hatch Project NY(C) 139406 to JKL.

Literature Cited

As, S. 1984. To fly or not to fly? Colonization of Baltic islands by winged and wingless carabid

beetles. J. Biogeog., 11:413-426.

Bengtson, S.-A., and K. E. Erikstad. 1984. Wing polymorphism in Amara quenseli (Schonherr)

(Coleoptera: Carabidae) in Iceland. Entomol. Scand., 15:179-183.

Darlington, P. J., Jr. 1943. Carabidae of mountains and islands: data on the evolution of isolated

faunas, and on atrophy of wings. Ecol. Monog., 13:37-61.

Darwin, C. 1859. The origin of species. John Murray, London, 502 pp.

Den Boer, P. J. 1970. On the significance of dispersal power for populations of carabid-beetles

(Coleoptera: Carabidae). Oecologia (Berl.), 4:1-28.

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to the carabid beetles in a cultivated countryside. Fortschr. Zool., 25:79-94.

-, T. H. P. Van Huizen, W. Den Boer-Daanje, B. Aukema, and C. F. M. Den Bieman. 1980.

Wing polymorphism and dimorphism in ground beetles as stages in an evolutionary process

(Coleoptera: Carabidae). Entomol. Gener., 6:107-134.

Denno, R. F. 1976. Ecological significance of wing polymorphism in Fulgoroidea which inhabit tidal

salt marshes. Ecol. Entomol., 1:257-266.

-. 1979. The relation between habitat stability and the migratory tactics of planthoppers

(Homoptera: Delphacidae). Misc. Publ. Entomol. Soc. Amer., 11:41-49.

Donald, D. B., and D. E. Patriquin. 1983. The wing length of lentic Capniidae (Plecoptera) and its

relationship to elevation and Wisconsin glaciation. Can. Entomol., 115:921-926.

Doyen, J. T., and E. Rogers. 1984. Environmental determinants of size variation in Eusattus mu-

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Greenslade, P. J. M., and T. R. E. Southwood. 1962. The relationship of flight and habitat in some

Carabidae (Coleoptera). The Entomologist, 95:86-88.

Honek, A. 1981. Wing polymorphism in Notiophilus biguttatus in Bohemia (Coleoptera, Carabidae).

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PAN-PACIFIC ENTOMOLOGIST

Liebherr, J. K. 1984. Description of the larval stages and bionomics of the tule beetle, Tanystoma

maculicolle (Coleoptera: Carabidae). Ann. Entomol. Soc. Amer., 77:531-538.

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Appendix 1

Sample localities and numbers of brachypterous (B) and macropterous (M)

individuals used in analysis of flight wing variation.

MEX: B.C. Norte, Guadelupe Isl. (4B, 1M); MEX: B.C. Norte, Maneandero

(14B, 10M); MEX: B.C. Norte, Ensenada (5B, 11M); CA: San Diego Co., San

Diego (14B, 15M); CA: S.D. Co., Warner Sprs. (0B, 17M); CA: Riverside Co.,

San Jacinto Mtns. (13B, 0M); CA: L.A. Co., Los Angeles (50B, 38M); CA: L.A.

Co., Antelope (3B, 5M); CA: L.A. Co., San Clemente Isl. (168B, 0M); CA: L.A.

Co., Sta. Catalina Isl. (35B, 1M); CA: Ventura Co., San Nicolas Isl. (113B, 6M);

CA: Sta. Barbara Co., Anacapa Isl. (13B, 0M); CA: Sta. Barb. Co., Sta. Cruz Isl.

(93B, 1M); CA: Sta. Barb. Co., Sta. Rosa Isl. (35B, 0M); CA: Sta. Barb. Co., San

Miguel Isl. (46B, 0M); CA: Kern Co., Tehachapi Mtns. (4B, 5M); CA: Kern Co.,

Bakersfield (10B, 7M); CA: S.L.O. Co., San Luis Obispo (15B, 2M); CA: S.L.O.

Co., Paso Robles (26B, 3M); CA: Tulare Co., Tipton (IB, 7M); CA: Tulare Co.,

Three Rivers (11B, 0M); CA: Monterey Co., Big Sur (5B, 3M); CA: Mont. Co.,

Paraiso Spgs. (27B, 2M); CA: Mont. Co., Carmel (8B, 3M); CA: Sta. Clara Co.,

Stanford (62B, 1M); CA: Alameda Co., Arroyo Mocho (37B, 3M); CA: Marin

Co., Tiburon (19B, 0M); CA: Contra Costa Co., Brentwood (0B, 13M); CA: Solano

Co., Dixon (33B, 19M); CA: Calaveras Co., West Point (52B, 1M); CA: Sac’to.

Co., Sacramento (11B, 7M); CA: Yuba Co., Yuba City (4B, 5M); CA: Butte Co.,

Oroville (8B, 0M); CA: Mendocino Co., Hopland (9B, 1M); CA: Humboldt Co.

(pooled localities) (7B, 1M); OR: (pooled localities) (9B, 2M).

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, p. 23

Scientific Note

A Collection of Four Species of Tabanid Flies Taken from an

Anaconda Snake in Peru in May 1984

This note is to report identification of 4 species of Tabanidae (Diptera) among

17 flies taken by Dr. W. Pulawski of California Academy of Sciences while the

flies were biting a large Anaconda snake. The snake was a lethargic, recently-fed

specimen on the bank of a tributary of the Rio Tambopata, Peru, on 6 May 1984.

The specimens are deposited in the entomology collections of the California

Academy of Sciences (CAS), Smithsonian Institution (SI), and Universidad Na¬

tional de San Marcos, Lima, Peru (UNSM).

The specimens, all females, comprised 4 species in 3 genera of the subfamily

Tabaninae as follows: Phaeotabanus innotescens (Walk.), 5 (CAS, SI, UNSM);

Tabanus dorsiger ssp. stenocephalus Hine, 1 (CAS); T. d. ssp. modestus Wied.,

10 (CAS, SI, UNSM); and Stenotabanus incipiens (Walk.), 1 (CAS). The last 2

were reported to me by Dr. F. Medem of Colombia, South America (Philip, 1976,

Pan-Pac. Entomol., 52:83-88) as feeding exclusively on tethered caimans, even

in the presence of nearby persons, while the first 2 species were taken occasionally

on those reptiles.

Only P. innotescens has not been reported to invade Central America; the others

have been recorded as far north as Honduras or Guatemala.

It is an interesting corollary that I have since discovered in our collection another

female of P. innotescens identified in 1981 by Dr. G. B. Fairchild of University

of Florida (ret.) labelled “biting caiman” in Colombia (upper Amazon tributary)

in 1971.

Cornelius B. Philip, Department of Entomology, California Academy of Sci¬

ences, Golden Gate Park, San Francisco, California 94118.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 24-28

Dominance Hierarchies in Myrmecophila manni

(Orthoptera: Gryllidae ) 1

Gregg Henderson and Roger D. Akre 2

Department of Entomology, Washington State University, Pullman, Washing¬

ton 99164-6432.

Myrmecophila manni Schimmer are small, apterous crickets found only in

association with ants. Their primary host in southeastern Washington is the west¬

ern thatching ant, Formica obscuripes Forel (Henderson, 1985). A study of these

crickets was initiated in 1983 to investigate their biology and relationship with

the host ants. Observations of the behavior of the crickets soon revealed that they

establish linear dominance hierarchies in the laboratory. Field crickets also es¬

tablish hierarchies in laboratory populations (Kato and Hyasaka, 1958), but these

hierarchies are usually associated with territoriality (Alexander, 1961). The pur¬

pose of this paper is to report the hierarchy, how it is established and maintained,

and its possible roles.

Materials and Methods

Crickets were collected from colonies of F. obscuripes in the vicinity of Pullman,

Whitman Co., WA. They were transported to the laboratory in small containers

with a layer of plaster of Paris/charcoal in the bottom. This layer was moistened

with distilled water to maintain a high humidity since the crickets were very

susceptible to desiccation.

Initially, crickets were maintained without ants in 6.5 x 15 cm plastic containers

to determine if ants were necessary for their survival (Henderson, 1985). The

containers also had a thin layer of plaster of Paris/charcoal that was moistened

with distilled water to maintain humidity. Honey on paper toweling was supplied

as food, and it was replaced at least once a week.

Observations of aggression between crickets soon developed into the present

study on dominance hierarchies. Crickets in three containers were used. One

contained 5 adult male and 3 adult female M. manni. The males were identified

by a letter designation for observations, A-E. Most of the crickets were recog¬

nizable by size or general appearance. Males A and B were the largest of the five,

and about the same size. However, A was missing one hind leg. Male C was the

smallest, with males D and E being slightly larger. The latter were marked with

White-out® for rapid identification purposes since they were similar in size. Fe¬

males were identified, and their behavior was recorded. A second container housed

two immature crickets and a single F. obscuripes worker. One of these crickets

was obviously larger, and was probably a later instar. The third container housed

3 1st instars (1.4 mm), one 2nd instar (1.8 mm), and 2 F. obscuripes workers.

1 Scientific Paper Number 7217, Washington State University, College of Agriculture and Home

Economics Research Center, Pullman. Work conducted under project 0037.

2 Research Assistant and Entomologist, respectively.

VOLUME 62, NUMBER 1

( 3 )

Figures 1-3. Diagrammatic representation of dominance hierarchies among male M. manni. Let¬

ters represent individual males. Numbers indicate the number of aggressive interactions between

adversaries. Arrows point from the winner to the loser of the fights.

Most observational periods of the crickets were one hour in duration, and they

were made at random times during the 24 hour cycle. A total of 31 recordings

were made from 1 July to 22 August 1984.

Results

A linear dominance hierarchy existed among male M. manni. Two hundred

twenty male-male and 101 female-male aggressive interactions were recorded.

Interactions were categorized into four distinct types. Type 1 consisted of a head

thrashing duel. Crickets, upon contacting each other, faced off and moved their

heads in an up and down swinging motion in an attempt to bring their head over

that of their opponent’s and to strike downward. This sometimes caused physical

damage when the mandibles of one cricket struck the unsclerotized cervical region

of the other. Bouts usually lasted about 2 sec and were terminated when one

cricket broke off the attack and moved away. Just prior to fully retreating, the

loser turned away from the winner, and one or both crickets then shook their

cerci in quick, lateral motions of short duration (ca. one sec). Type 2 interactions

were characterized by less aggressive behavior than in Type 1. Interactions in¬

volved cereal shaking by one or both crickets (as in Type 1 interactions), stilt¬

walking, (one cricket lifted its body high off the substrate and walked in a slow,

stiff gait toward its adversary), or head bobbing, (one cricket moved its head up

and down in a manner similar to that in Type 1 interactions but slower and with

PAN-PACIFIC ENTOMOLOGIST

Table 1. Frequency of Type 1-4 interactions between crickets.

Type of interactions

Total

Male-male interactions

109

220

Male-female interactions

101

reduced intensity). Type 3 interactions involved one cricket butting another and

chasing the latter from its position. Type 4 interactions were characterized by one

cricket lowering its head and body so that it laid flush with the substratum and

did not move despite persistent head butts by its opponent, a position, apparently,

of complete subordination.

The dominance order in a five male hierarchy, observed from 1 to 20 July is

shown in Figure 1. Male A was dominant over the other four crickets, and fought

its closest rival, male B, more often than any other opponent (n = 29). Similarly,

male B fought often with its close rivals, male C (n = 11) and male E (n = 13).

Males D and E did not establish a clear dominant-subordinate relationship since

both fought and won equal numbers of fights with each other (n = 3 and n = 3).

In fact, encounters between the more subordinate males were limited. Possibly,

their rank in the hierarchy caused them to avoid interactions.

Type 1 interactions were most often observed between close rivals with the

exception of male E. Male E interacted with male A in Type 1 displays and was

the only cricket other than male B to challenge the dominant male. Interactions

between crickets did not appear to become less aggressive over time. Type 1

interactions continued to occur despite the apparent dominance of one cricket

over another. However, Type 2 interactions were the most common behavior

when crickets came into contact with each other (Table 1).

Upon the death of male B, a new linear dominance was established, but the

same dominant-subordinate relationship among the remaining crickets was main¬

tained (Fig. 2). Observations of this hierarchy were made from 20 July to 6 August,

at which time male A died. Male E was the only cricket to challenge male A, and

on two occasions it inflicted telling blows with its head to the dominant male.

Both fights occurred while the crickets were positioned on the wall of the container.

Immediately after the mandibles of male E contacted the neck region of male A,

the dominant male dropped to the ground and then moved in an uncoordinated

fashion as it rubbed its head against the side of the container. This did not,

however, seem to give male E an advantage in later battles with male A.

The study was continued 6-22 August with the remaining 3 males (Fig. 3).

However, the dominance order of this latter group remained unstable. Males C

and D remained dominant over male E, but a single male did not dominate.

Male-female encounters. —Generally, females were much less active than males

so that interactions with other crickets were minimal and were usually initiated

by males. Interactions between males and females involved mostly Type 3 and

4 interactions. Even the most subordinate male dominated a female. However,

just prior to egg laying (ca. three days) a noticeable change in female aggressiveness

was evident, and Type 1 and 2 interactions, where females won over males

occurred (n = 15). In 40, Type 3 interactions males followed females and then

went into a mating posture for 1-5 sec (Henderson, 1985). This behavior suggests

VOLUME 62, NUMBER 1

Figure 4. Dominant male interfering in subordinate male’s courtship of female. Note spermato-

phore on the subgenital plate of the subordinate male (arrow).

that males interact with females in an attempt to mate and these interactions

probably have little to do with dominance.

Immatures. — Competition among immature crickets was observed as they strig-

ilated and engaged host ants in trophallaxis (n = 22). Crickets usually maintained

at least a 40° angle, 1-2 mm from other crickets when simultaneously strigilating

on an ant. Displacement resulted when crickets were closer than these minimum

spacing requirements. Displacement of first instars by second instars indicated

that size was a key factor influencing dominance among the immatures. The same

dominance relationship was observed in the container with the two larger im¬

matures of undetermined age; the larger dominated the smaller immature. Com¬

petition among first instars was also evident but a dominance relationship was

not determined because of the difficulty of distinguishing individuals.

Discussion

Size and age seem to play a role in the dominance hierarchies of M. manni.

Conversely, Alexander (1961) found that age, but not size was a factor in the

establishment of dominance hierarchies among field crickets. The large males A

and B were always the dominants during this study, and second instars displaced

the smaller, first instars to feed on the ants. In addition, the stilt-walking displays

in Type 2 interactions also suggest that size is important in maintaining domi-

PAN-PACIFIC ENTOMOLOGIST

nance. A similar behavior observed by Holldobler (1976) in competing Myr-

mecocystus mimicus Wheeler ants led him to suggest that stilt-walking is done so

that the ant will appear larger and that this had a potential effect on the outcome

of the encounter. However, size is obviously not the only factor influencing dom¬

inance since male C was much smaller than its subordinates D and E. It is perhaps

somewhat ironic that size plays a role in dominance hierarchies in M. manni

since its myrmecophilous life style, undoubtedly, caused this cricket to be the

smallest of all crickets.

All reasons ascribed for the establishment of dominance hierarchies suggest

that the dominant individual attains an advantage towards some limiting resource.

Nutritional advantages along with an increase in reproduction are associated with

dominance in Polistes wasps (Pardi, 1948). Nutritional advantages may also be

a factor in M. manni dominance relationships since immatures fought for troph-

allaxis or strigulation on a host ant. However, for adult males, mating seems to

be the major reason for the establishment of dominance. Successful mating was

linked to the establishment of territories in field crickets (Alexander, 1961), but

no advantage in fighting by M. manni was ever detected due to position in the

container. Although males mark areas where they lead females for mating, these

areas are not defended and cannot be considered territories (Henderson, 1985).

However, subordinate males were sometimes displaced by a dominant when they

attempted to mate with a female (Fig. 4) (Henderson, 1985). Although the evidence

collected during this study is minimal, it suggests that mating may be one of the

primary reasons for dominance hierarchies in M. manni.

Acknowledgments

We thank R. Sites, R. Zack, and G. Sehlke for comments on improving the

manuscript.

Literature Cited

Alexander, R. D. 1961. Aggressiveness, territoriality and sexual behavior in field crickets (Orthoptera:

Gryllidae). Behaviour, 17:130-223.

Henderson, G. 1985. The biology of Myrmecophila manni Schimmer (Orthoptera: Gryllidae). M.S.

thesis, Department of Entomology, Washington State University, 83 pp.

Holldobler, B. 1976. Tournaments and slavery in a desert ant. Science, 192:912-914.

Kato, M., and L. Hayasake. 1958. Notes on the dominance order in experimental populations of

crickets. Ecol. Rev., 14:311-315.

Pardi, L. 1948. Dominance order in Polistes wasps. Physiol. Zool., 21:1-13.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 29-40

Geographic Distribution of Synanthedon sequoiae and Host

Plant Susceptibility on Monterey Pine in Adventive and

Native Stands in California (Lepidoptera: Sesiidae)

Gordon W. Frankie, Jack B. Fraser, and John F. Barthell

Department of Entomology, University of California, Berkeley, California 94720.

Abstract. — A systematic survey of larval Synanthedon sequoiae in adventive

and native California stands of Monterey pine, Pinus radiata, indicated that the

insect is mostly restricted to urban northern California. High densities of S.

sequoiae were found north of San Francisco to Ft. Bragg in mostly inland valleys;

around the southern portion of the San Francisco Bay; and around Monterey Bay.

Pinus radiata, P. patula and P. thunbergiana were preferred hosts in urban areas;

whereas P. canariensis, P. halepensis and P. pinea appeared largely resistant.

Synanthedon sequoiae was significantly more abundant on host trees that had

been pruned. The current practice of planting fast-growing pines, especially Mon¬

terey pine, in urban landscapes makes it likely that S. sequoiae will spread more

widely through the state, eventually establishing in the Central Valley and in

southern coastal cities. An isolated infestation in southern California and another

in the Sierra-Nevada foothills support this possibility.

The sequoia pitch moth, Synanthedon sequoiae (Hy. Edwards), 1 occurs through¬

out western North America (Essig, 1926; Keen, 1952; Ohmart, 1981). Larvae feed

and develop locally on phloem, cambium and, to a limited extent, on xylem

tissues in branches and trunks of numerous native and exotic pine species (Weid-

man and Robbins, 1947) and on Douglas fir, Pseudotsuga menziesii (Mirb.) (Fur-

niss and Carolin, 1977). Their feeding results in a colorful, red-brown mass of

pitch and frass that protrudes noticeably from the wood substrate. Occasionally,

this localized feeding causes weakened branches, but rarely branch dieback. Two

reports (Brunner, 1914; Powers and Sundahl, 1973) suggest that under certain

conditions S. sequoiae may become a forest pest. However, greatest concern for

the insect stems from the unsightliness of pitch masses on ornamental trees (Payne,

1973; Ohmart, 1981; Koehler et al., 1983).

Although some general biological and behavioral information has been gen¬

erated on S. sequoiae, much remains to be learned about its habits. Interest in

the insect increases yearly due to a general awareness of its potential as a pest in

ornamental landscapes. Information gaps include the lack of data on its current

distribution in specific geographic areas, especially where pines are being used

extensively in landscape plantings. Further, although S. sequoiae is known to use

numerous pine species as hosts (Weidman and Robbins, 1947), preferred and

non-preferred (resistant) species have yet to be appropriately designated. Finally,

1 Formerly in the genus Vespamima.

PAN-PACIFIC ENTOMOLOGIST

several factors that render a host attractive have been suggested (see above ref¬

erences), but more work is needed on this aspect. In particular, previous host

damage appears to be the most important factor predisposing a tree to infestation

(Weidman and Robbins, 1947; Powers and Sundahl, 1973; Koehler et al., 1983).

In this paper we report results of a survey that systematically examined the

distribution of S. sequoiae on Monterey pine in adventive (mostly urban) and

native stands in California. Tabulated infestation sites on surveyed trees (esp.

pruned versus unpruned) provided new insights on the attraction of S. sequoiae

to its host trees. Finally, an assessment of preferred ornamental pine species in

urban areas and an evaluation of potential for spread to new areas are offered.

Methods and Materials

Monterey pine was used in 1981 as the primary host for surveying S. sequoiae

infestations in numerous adventive and in three native endemic stands. Suitability

as an index host derives from its known wide-spread distribution in California

and general attractiveness to the insect (Engelhardt, 1946; Payne, 1974; Koehler

et al., 1983). Five different geographic zones were recognized and used in the

survey (Fig. 1). The first of these was the north coastal zone. The second was the

San Francisco Bay Area, which included the northern, southern and eastern sec¬

tions of the Bay Area. The third zone was the central coastal region that extended

from just south of San Jose along the coast to just beyond Santa Barbara in southern

California. The fourth was the Central Valley, which extended from Redding to

Bakersfield. Finally, the south coastal zone included the greater southern California

coastal region. Specific adventive sites within each zone were preselected on a

map at intervals of approximately 30 km. Native sites, all of which were in the

central coastal zone, were selected in different representative sublocations that

were easily accessible (steep hillside forests were avoided).

Forty Monterey pines were selected for survey in adventive and native sites in

zones I—III from northern California (Fig. 1). In some Central Valley and southern

coastal sites (zones IV and V) it was not always possible to locate 40 planted

Monterey pines. Where this was a problem, other pine species known to host S.

sequoiae were surveyed to supplement the available Monterey pines, the com¬

bination of which amounted to 40 sampled trees.

In adventive stands (usually urban plantings in cities), about half the trees were

unpruned and half were pruned. Pruning ranged from one or two branches sawed

close to the trunk to a complete pruning of all branches up to three meters on the

trunk. Adventive stands consisted of variously aged hedgerow and specimen trees

in industrial and recreational parks, around schools, or in wind breaks along

coastal roads. Estimated tree age ranged from 6-30 years; however, surveyed trees

at a given adventive location were usually of one age class. On rare occasions,

two or three smaller groups of trees (each variously aged) had to be sampled within

a few hundred meters to achieve a sample size of 40.

In each of the three native Monterey pine stands on mainland California (Ano

Nuevo, Monterey and Cambria) three subsites were selected for survey (Fig. 1).

Forty unpruned trees of mixed ages were chosen at each of these nine subsites.

Natural branch pruning, which was common on older trees in native stands, was

not considered equivalent to artificial pruning in urban areas.

Trees in both types of stands were individually inspected on trunks, branches

VOLUME 62, NUMBER 1

Figure 1. Geographic zones surveyed for 5. sequoiae pitch masses. Zone I: north coastal; zone II:

San Francisco Bay Area; zone III: central coastal; zone IV: Central Valley; zone V: south coastal.

A— endemic stands of Monterey pine; •—cities having general geographic significance or unique S.

sequoiae infestations.

and nodal/intemodal areas, as well as the unions where pine cones attached to

branches. To assist in this process binoculars were used for many of the taller

trees. On rare occasions where infestations were suspected high in the crown, trees

were climbed to make a closer inspection. Very large, old trees, although rarely

encountered, were bypassed because of the difficulty of assessing infestations at

the highest crown levels.

Three distinct infestation types, new, old and reinfestations, on trunks and

branches were recognized. New infestations were reddish-brown in color, had a

glistening, pitchy appearance and protruded noticeably from'the wood substrate.

Old infestations were grey in color, hardened, protruding or flat and were often

large and cracked in appearance. They remain recognizable on trees for several

years. Finally, reinfestations were characterized by new flows of red-brown resin

and frass that exuded from the margins and/or center of old pitch masses.

An arbitrary system of infestation categories was established to generally assess

low, moderate and high levels of pitch masses (all types) in the surveyed stands.

A low level had 1-40 infestations; 41-80 constituted the moderate level; and a

high level consisted of more than 80 infestations.

PAN-PACIFIC ENTOMOLOGIST

Collection records of S. sequoiae were examined and compiled from the fol¬

lowing California collections and museums: State Department of Food and Ag¬

riculture, Sacramento; California Academy of Sciences, San Francisco; Natural

History Museum of Los Angeles County, Los Angeles; University of California,

Riverside.

Results

California Survey Results

New, old and reinfestations of S. sequoiae were noted and compiled for each

of 97 adventive sites and 9 native subsites in the California survey. Sampling

revealed that the insect was established in the north coastal region of California

which includes geographic zones I—III (Fig. 1, Tables 1 and 2). The survey did

not detect S. sequoiae in the Central Valley or the south coastal region (zones IV

and V in Fig. 1 and additional distribution information below). Overall, much

higher levels of S. sequoiae were recorded on trees in adventive as compared to

native stands (Tables 1 and 2).

Using the arbitrary system of infestation categories, each site was placed into

a low, moderate or high infestation level. All sites were then grouped to determine

where the insect was least and most abundant in the state. Most sampled areas

had no infestations or low levels, including 8 of 9 natural areas (Tables 1 and 2).

Only the adventive stands at Willits and Fremont I and the Monterey B natural

site were found to contain moderate levels. Twelve sites, all adventive, had high

levels and these were distributed primarily in three regions: two in the north coast

(Ukiah and Napa), seven around the south end of San Francisco Bay, and three

in the north section of the central coastal zone. Sites at Mountain View, Sunnyvale,

San Jose I and II and Carmel had exceptionally high infestation levels with total

infestations exceeding 300 per site (Table 1). Although high densities were re¬

corded from these three regions, a few of the included stands in each region had

relatively few or no pitch masses (e.g., Cloversdale, Healdsberg and Rohnert Pk.

in zone I; San Carlos and Menlo Pk. in zone II; Davenport and Salinas in zone

III; see Table 1).

The percentage of trees infested was almost always greater in pruned versus

unpruned adventive stands (Table 1). San Jose II was an obvious exception to

this generality. It was common for some trees at a site to be highly infested while

other surrounding or nearby trees had only a few pitch masses. This uneven

distribution is reflected in part by high variances of the means reported in Table

1. There was no obvious reason for differences in the uneven distribution of pitch

masses on comparable nearby trees. Other workers (cf. Powers and Sundahl, 1973)

have also observed clear differences in infestation levels among trees in affected

stands.

1 New, old and reinfestations.

2 Pruned and unpruned P. radiata, halepensis and thunbergiana, and to a limited extent canariensis,

muricata and sabiniana.

3 Pruned and unpruned P. halepensis only.

4 Pruned and unpruned P. halepensis, thunbergiana, and to a lesser extent canariensis.

VOLUME 62, NUMBER 1

Table 1. Numbers of infestations, 1 percent trees infested and mean numbers (± SD) of Synanthedon

on unpruned and pruned trees in adventive sites in five geographic zones (see Fig. 1). Unless otherwise

indicated, surveyed trees were Monterey pine.

Location

Nos. infestations

% trees infest.

x nos. infest, per infest, tree

Unpruned

Pruned

Unpruned

Pruned

Unpruned

Pruned

I. North Coastal

Willits

21%

11.5 ± 14.7

Ukiah

1.3 ± 0.6

7.1 ± 6.0

Healdsburg

1.0 ± 0

Rohnert Pk.

1.0 ± 0

Napa

212

1.5 ± 0.6

15.1 ± 22.0

Albion, Areata, Cloverdale, Eureka, Ft. Bragg, Jenner, and Pt. Arena: none

with infestations.

II. San Francisco Bay Area

Novato

1.0 ± 0

San Rafael

2.0 ± 0

Mill Valley

1.7 ± 0.6

San Bruno

3.9 ± 3.1

Burlingame

245

11.3 ± 21.7

Menlo Pk.

4.0 ± 4.8

3.4 ± 3.4

Mt. View

240

17.3 ± 17.6

12.6 ± 16.1

Sunnyvale

336

1.6 ± 0.9

17.7 ± 16.2

Santa Clara

4.8 ± 3.4

4.3 ± 1.9

San Jose I

100

314

6.3 ± 3.8

17.3 ± 16.9

San Jose II

429

168

22.6 ± 11.5

10.5 ± 11.5

Livermore

216

10.4 ± 9.5

9.0 ± 8.4

Fremont I

2.7 ± 2.1

Fremont II

1.0 ± 0

Hayward

1.0 ± 0

Castro Valley

1.0 ± 0

Oakland

1.0 ± 0

Piedmont

1.0 ± 0

Albany

3.0 ± 2.6

Vallejo II

4.0 ± 0

Alamo, Berkeley, Concord, Crockett, Daly City, El Cerrito, El Sobrante, Richmond, San Carlos,

San Francisco, San Gregorio, San Leandro, Sausalito, Stinson Beach, Union City and Vallejo I:

none with infestations.

III. Central Coastal

Davenport

1.0 ± 0

Santa Cruz

157

3.9 ± 6.7

8.7 ± 11.1

Watsonville

100

2.7 ± 1.4

8.3 ± 8.9

Salinas

7.7 ± 7.6

Carmel

459

4.7 ± 5.2

20.9 ± 17.9

Atascadero, Gaviota, Lompoc, Los Padres, Lucia, Morro Bay, Pismo Beach, San Miguel and

Santa Maria: none with infestations.

IV. Central Valley

Bakersfield, 2 Chico, Davis, Delano, 2 Fairfield, 2 Madera, 2 Merced, 2 Modesto, Orland, 3 Oroville,

Red Bluff, Redding, Sacramento, 2 Selma, 2 Stockton, Tracy, 2 Tulare, 2 Turlock, 2 Yuba City/Marys¬

ville: none with infestations.

V. South Coastal

Beverly Hills, 2 Buena Park, 2 Chula Vista, Compton, 2 Laguna Hills, 2 Long Beach, 2 National City, 2

North Hollywood, 2 Oceanside, Pasadena, 2 Pomona, 2 San Clemente, 2 San Diego, 4 Simi Valley,

Ventura 2 and Woodland Hills 2 : none with infestations.

PAN-PACIFIC ENTOMOLOGIST

Table 2. Numbers of infestations, 1 percent trees infested and mean numbers (± SD) of Synanthedon

infestations on 40 Monterey pines at each native subsite.

Location

Nos. infestations

% trees infest.

x no. infest, per infest, tree

Ano Nuevo 2

Site C

2.0 ± 1.4

Monterey

Site A

1.7 ± 0.9

Site B

3.4 ± 2.4

Site C

1.5 ± 0.8

Cambria

Site A

2.9 ± 1.8

Site B

2.8 ± 1.0

Site C

1.9 ± 1.5

1 New, old and reinfestations.

2 No. infestations at subsites A and B.

The type of infestation (i.e., new, old or reinfestation) was tabulated for each

site to assess the relative infestation age of a particular stand. In the following

account, only those sites having greater than 20 infestations were examined (Tables

1 and 2). In virtually all adventive and native stands there were considerably

more old or new infestations than reinfestations. Further, most sites (71%) had

more old as compared to new infestations; the opposite relationship was noted

at Santa Clara, Santa Jose I, Livermore, Santa Cruz, Watsonville and Salinas. In

these cases, it appeared that the trees supported incipient or growing populations

of S. sequoiae.

Examination of tabulated data provided information on preferred infestation

sites on individual trees (Tables 3 and 4). Comparing overall infestations on trunks

and branches of adventive trees, approximately twice as many were found on the

trunks (Table 3). Pruned sites on both trunks and branches had about three times

as many infestations as did the respective unpruned sites, and the differences in

both cases were significant (£-test, P = 0.005). On the lower halves of trees about

four times as many infestations were recorded as compared to the upper halves

(each half included trunks and branches) (Table 3). Further, pruned areas had

significantly more infestations than unpruned areas, regardless of tree half. The

same general infestation patterns were also observed on native trees where sub¬

stantially more infestations were recorded on trunks versus branches and on lower

versus upper halves of trees (Table 4).

Pitch masses were found on adventive or native trees at the following specific

locations: nodes (bases of branches), intemodes, injured or pruned areas, previous

infestations, and pine cone attachment points on branches. To gain insight on

which locations were preferred, new infestations only were tabulated from all

survey trees (Table 5). In the case of unpruned trees, nodes and intemodes were

the preferred sites. To a slightly lesser extent, previous infestations were also

preferred. New pitch masses were relatively uncommon on injured sites and pine

cone bases in this group of trees. In the case of pruned trees, nodes and intemodes

had considerably more pitch masses than the other sites, including those injured

or pruned. Previous infestations and pine cone bases were the least preferred in

this group.

VOLUME 62, NUMBER 1

Table 3. Total numbers of infestations 1 on trunks versus branches and on lower versus upper

halves of unpruned and pruned Monterey pines in adventive stands.

Location

Total nos. of infestations per zone

Trunk

Branches

Unpruned

Pruned

Unpruned

Pruned

N. Coastal

254

S.F. Bay Area

491

1078

243

616

Central Coastal

448

292

Totals:

556

1780

268

999

P = 0.005

r = 5.19

Lower half

Upper half

N. Coastal

279

S.F. Bay Area

647

1352

342

Central Coastal

548

190

Totals:

719

2179

105

597

P = 0.005

t = 4.45

t= 5.1

1 New, old and reinfestations.

In 1943 and 1944, Weidman and Robbins (1947) recorded the distribution and

numbers of S. sequoiae pitch masses on 3690 pine trees at the Eddy Arboretum

in Placerville, California (Fig. 1). They found evidence of the insect on 33 pine

species and four hybrids. Based on total numbers of pitch masses per 100 trees,

they constructed a list of the most frequently infested pine species. According to

their tabulation, Monterey pine was one of the least infested pines. However, it

seems that variously-treated trees at the arboretum may have influenced this

tabulation. For example, some pine species were pruned; others were not. A few

pine species were extensively drilled by sapsucking woodpeckers; others were

scarcely affected or lacked drillings entirely. Further, infestations were often lo¬

calized within the arboretum. Thus, the Weidman and Robbins (1947) listing

serves best as guide only for those species that are likely to host S. sequoiae. To

develop a more accurate scale of relative suitability or susceptibility by host pine

species would involve a considerable testing effort, exposing reared adult moths

to trees standardized for such characteristics as age, size and pruning activity.

Although this type of testing was beyond the scope of the current investigation,

a group of similarly-treated ornamental pines was surveyed in the city of San Jose

to develop information on the question of relative host susceptibility. San Jose

Table 4. Total numbers of infestations 1 on trunks versus branches and on lower versus upper

halves of Monterey pines in native stands.

Location

Total nos.

of infestations per site

Trunk

Branches

Lower Vi

Upper Vi

Ano Nuevo

Monterey

Cambria

Totals:

123

114

New, old and reinfestations.

PAN-PACIFIC ENTOMOLOGIST

Table 5. Total numbers of new infestations only on five specific sites on adventive and native

Monterey pines.

Infestation site

Nos. of new infestations

Unpruned

Pruned

Nodal (intact)

198

274

Intemodal (intact)

157

299

Injury and/or pruning

121

Previous years’ infest.

141

Pine cone base

was chosen since the insect was found to be very active there (Table 1). Repre¬

sentatives of five common pine species were selected throughout the city (Table

6). They ranged in age from 10-25 years, and each tree had some evidence of

past flush pruning on the trunk. Comparing the San Jose results with those of

Weidman and Robbins (1947), there was agreement in relative susceptibility for

three species, P. canariensis, P. pinea and P. thunbergiana. However, for three

species ( radiata, patula and halepensis ) there were considerable differences in

survey results. With regard to P. halepensis, our supplemental observations in

other California cities (unpub.) indicated that this species is only an occasional

host, especially if unpruned (see also results of Westlake Village survey below).

Additional sites throughout California were examined, and these locations pro¬

vide supplemental information on the current geographic distribution of and

relative susceptibility of host pine species to S. sequoiae.

Ft. Bragg. —Surveyed Monterey pine in this city showed no evidence of S.

sequoiae (Table 1), which is consistent with its general distribution in this geo¬

graphic zone (Fig. 1). However, a later examination of another group of Monterey

pines in Ft. Bragg revealed that the insect occurred there in low numbers. Rather

than resurvey the second group, two other common pines, P. muricata and P.

contorta were examined for the insect. Twenty pruned and 20 unpruned orna¬

mental trees, mostly 5-20 years old, of each species showed the insect in low

densities in P. muricata (total of 39 masses) and in high densities in P. contorta

(total 126 masses). These results indicated that S. sequoiae can effectively use

other pine species as hosts, even in the presence of Monterey pine. It is noteworthy

that both pines occur natively in and around Ft. Bragg, and thus the infestation

was considered long-standing in the area.

Hollister. — At a nursery just north of the city, about 60,000 Monterey pines

are grown in pots for use as Christmas trees (Fig. 1). Trees were first planted at

this site in 1980, and S. sequoiae first appeared on a few trees in late 1983. A

survey in early 1985 of several hundred trees in three age classes revealed the

following distribution. One year old trees were almost entirely free of the insect;

two year olds had a frequency of about 1%; three year olds had a 10% infestation

rate. Most infested trees had a single pitch mass.

Although S. sequoiae is considered new to this locality, its potential as a major

pest in such a pine plantation is recognized on the basis of several factors. It does

not usually infest such small sized trees; larger diameter wood is generally required

to support developing larvae. Further, the vigorous handling trees receive during

repotting and shearing, and the rapid growth they experience through generous

applications of drip-irrigated water and fertilizer may be predisposing them to

VOLUME 62, NUMBER 1

Table 6. Numbers of infestations and percent trees infested with Synanthedon on pruned Pinus

species in San Jose.

Pinus species

Nos.

infestations

% trees

infested

Est. relative

attract.

Relat. attract,

cf. Weidman

& Robbins (’47)

P. radiata I 1

314

low

P. radiata II 2

168

low

P. patula

117

low

P. thunbergiana

mod

P. halepensis

low?

mod-hi

P. canariensis

NR 3

none

P. pinea

NR 3

low

1 San Jose I from Table 1.

2 San Jose II from Table 1.

3 NR—none recorded. Occasionally, pruned or injured trees have been observed with a few pitch

masses, however.

the insect. Finally, the nursery is in close proximity to Monterey Bay (zone III—

Fig. 1), one of the regions where S. sequoiae was found in high densities (Table 1).

Westlake Village. — The Westlake Village Golf Course, located in the south

coastal zone (Fig. 1), was the only site in southern California where S. sequoiae

was found. The golf course was not part of the systematic survey, but rather it

resulted from an information inquiry about the moth during the time of the

statewide survey in 1981. The site contained more than 300 Monterey pine, with

some P. halepensis and P. pinea; the majority of these trees were planted in 1967.

Most Monterey pines were infested with the insect, and many were highly infested.

Two trees were exemplary: one had 225-250 pitch masses; the second had 350-

400 (new, old and reinfestations). Only a few infestations were found on some

individuals of P. halepensis, and one infestation was located on P. pinea.

Infestations of S. sequoiae at Westlake differed from others in the state in two

respects. First, the pitch masses were about twice as large as masses in any other

location. The weight of some caused them to fall from trees and litter the edges

of fairways. Secondly, masses were commonly found on the upper trunk region

and associated branches. This unique distribution appeared to be related to bark

lesions that commonly occurred in the upper crown. Lesions were small and

irregularly shaped and may have resulted from localized feeding by squirrels or

other rodents. Although none of these mammals were actually sighted at Westlake,

in Pacific Grove (Central Coastal zone, Fig. 1) squirrels have been observed

chewing lesions of this type in Monterey pine branches.

The first pitch masses at Westlake were noticed by grounds keepers in 1980.

By 1981, the numbers of new masses far outnumbered old ones, indicating that

the population was still developing. Despite the observed high densities in 1981,

it appeared that the golf course infestation was highly localized since various

ornamental pines examined in 1982 in a residential neighborhood around the

golf course showed no evidence of the insect. Further, at a nearby golf course in

Camarillo, 10-year-old Monterey pines (and P. halepensis ) showed similar lesions

on branches and trunks but no evidence of S. sequoiae.

Placerville. — Pines at the Eddy Arboretum in Placerville were examined in 1981

and 1982 for pitch masses of S. sequoiae. A few masses were found on some

PAN-PACIFIC ENTOMOLOGIST

representatives of several pine species; however, none of the affected species

appeared to be as susceptible as reported by Weidman and Robbin (1947) in their

1943-1944 assessment of the S. sequoiae infestation. Because of these low den¬

sities it was impossible to sort out the most and least susceptible pine species.

Overall, the infestation was assessed as persisting at low densities, which may be

characteristic of older trees that have not been damaged for several years.

Collection records from major California collections and museums were of

limited use in supplementing the state distribution pattern of S. sequoiae. Most

collections were taken from Monterey pine in northern California, especially

around the south end of the San Francisco Bay and from the Carmel/Monterey

area. In southern California, only a very few collections were available, and these

were from pines in natural forests at higher elevations (~ 1500 m). One of these

was taken from P. coulteri at the Arrowhead area of the San Bernardino Moun¬

tains. Two collections each were from P. coulteri and P. jeffreyi at Idyllwild

(vicinity of Mt. Baldy) in the San Jacinto Wilderness Area.

Discussion

Overall results of the systematic survey, supplemental observations in specific

locations and museum records indicated that S. sequoiae is mostly a coastal to

somewhat inland insect in urban northern California. More specifically, the moth

is found in relatively high densities in three general areas. The first extends from

Ft. Bragg to San Francisco, just east of the coastal mountains (Fig. 1 and Table

1). The second area occurs around south San Francisco Bay (mostly San Mateo

and Santa Clara Counties). Payne (1974) also noted a high frequency of S. sequoiae

in Santa Clara Co. The third area is located around Monterey Bay, immediately

coastal and slightly inland, and includes the cities of Santa Cruz, Watsonville,

Hollister and Carmel.

Additional collecting from native pines (P. coulteri, P. jeffreyi, P. ponderosa

and P. sabiniana) in the inland mountains of northern and southern California

would probably reveal a more widespread distribution of the insect in the state.

The observations at Placerville and collections from the San Bernardino and San

Jacinto mountains provide evidence for this possibility. The long-standing infes¬

tations of S. sequoiae in Placerville and the new infestations at Hollister and

Westlake Village also suggest that the insect has the capacity to establish high

populations in new areas. The popular trend of using fast-growing pines in many

urban California landscapes, especially in southern California and in the cities of

the Central Valley, may increase the chances of new localized infestations.

Based on our observations statewide and the observations of other workers

(Brunner, 1914; Engelhardt, 1946; Weidman and Robbins, 1947; Powers and

Sundahl, 1973; Payne, 1974), it was possible to sort the urban ornamental pines

into two major groups; preferred and non-preferred species. In the preferred

category were P. radiata, P. patula, P. thunbergiana, P. muricata, P. contorta and

P. ponderosa (the latter three species are only occasionally used in urban California

landscapes). Pines showing resistance to S. sequoiae were P. canariensis, P. hale-

pensis and P. pinea. Pinus halepensis can best be described as generally resistant,

but susceptible under some circumstances. Pinus canariensis, P. pinea and P.

halepensis become slightly more susceptible as hosts only if they have experienced

substantial pruning or other mechanical damage.

VOLUME 62, NUMBER 1

Because of its rapid growth and desirable form, it is likely that Monterey pine

will continue to be widely planted in urban California, despite its susceptibility

to the moth. However, in areas where S. sequoiae is common, P. halepensis may

be substituted for P. radiata owing to its general resistance to the insect and

similarity in size, form, texture and needle color with P. radiata. It is likely that

this option will only be considered by land owners and managers when S. sequoiae

or other insect pests such as bark beetles severely damage Monterey pine. This

was the case at Westlake Village Golf Course where S. sequoiae and Ips bark

beetles threatened to seriously damage about one-third of the standing trees.

It seems clear that certain human activities, especially pruning or similar me¬

chanical injury, predispose host trees to S. sequoiae. This was experimentally

demonstrated by Koehler et al. (1983) and by our comparative survey on unpruned

and pruned trees in adventive and native stands of Monterey pine. Other factors

that render host trees more susceptible include the activities of rodents, wood¬

peckers (Weidman and Robbins, 1947), increment borers (Powers and Sundahl,

1973), and damage by moving vehicles and support wires/metal stakes left in

place too long (Payne, 1974). Powers and Sundahl (1973) also suggest that rapidly

growing trees have a higher risk of infestation by S. sequoiae. Our experience

with fast-growing Monterey pines in Hollister and elsewhere support their ob¬

servation. Overall, the evidence indicates that tree stress leading to bark rupture

or reduced outer bark thickness will encourage entry of the insect.

Several other studies have demonstrated the relationship between increased

borer infestations and human-induced tree stress. Potter and Timmons (1981)

showed that trunk wounding and exposure to sun were the most important factors

predisposing flowering dogwoods in Kentucky to the dogwood borer, Synanthedon

scitula (Harris). Frankie and Koehler (1971) and Frankie and Ehler (1978) de¬

scribed how larval infestations of the cypress bark moth, Laspeyresia cupressana

(Kearfl), increased on Monterey cypress that had been stressed through rapid

growth and mechanical bark ruptures in urban California environments. Byers et

al. (1980) reported that the smaller European elm bark beetle, Scolytus multi-

striatus (Marsh.) was more attracted to pruned limbs of European and Siberian

elms compared to healthy, non-pruned limbs in California. Landwehr et al. (1981)

found that native elm bark beetles, Hylurgopinus rufipes (Eichhoff), were more

attracted to pruned versus unpruned American elms in Minnesota. Their work

also showed that treating pruned sites with wound dressing compound would

reduce the number of incoming bark beetles. Finally, collection notes by Engel-

hardt (1946) on U.S. sesiids suggest that larvae of several species are commonly

associated with fast growing trees, especially in urban or suburban settings. The

implication is obvious; that trees in well cared for human environments are

apparently more attractive than conspecific hosts in natural environments. En-

gelhardt mentions that one sesiid, Vitacea scepsiformis (Hy. Edwards), is excep¬

tional in this regard; it thrives on host plants in cultivation and is very rare or

absent in natural habitats.

Acknowledgments

We thank C. McGowan and R. Mandel for their assistance in the statewide

Synanthedon sequoiae survey. P. H. Amaud, Jr. (Calif. Acad. Sciences), L. R.

Brown (Univ. Calif., Riverside), T. D. Eichlin (Calif. Dept. Food and Agric.) and

PAN-PACIFIC ENTOMOLOGIST

R. R. Snelling (Los Angeles Co. Museum) kindly provided us with collection

records of S. sequoiae. J. K. Grace and C. S. Koehler reviewed an early draft of

this paper. The Elvenia J. Slosson Fund, California Agricultural Experiment Sta¬

tion and El Modeno Gardens, Inc. provided support for this research.

Literature Cited

Brunner, J. 1914. The sequoia pitch moth, a menace to pine in western Montana. U.S. Dept. Agr.

Bull. No. 111.

Byers, J. A., P. Svihra, and C. S. Koehler. 1980. Attraction of elm bark beetles to cut limbs of elm.

J. Arboriculture, 6:245-246.

Engelhardt, G. P. 1946. The North American clear-wing moths of the family Aegeriidae. Bull. U.S.

Nat’lMus., 190:1-222.

Essig, E. O. 1926. Insects of western North America. The MacMillan Co., New York.

Frankie, G. W., and L. E. Ehler. 1978. Ecology ofinsects in urban environments. An n. Rev. Entomol.,

23:367-387.

-, and C. S. Koehler. 1971. Studies on the biology and seasonal history of the cypress bark

moth, Laspeyresia cupressana, Can. Entomol., 103:947-961.

Fumiss, R. L., and Y. M. Carolin. 1977. Western forest insects. U.S. Dept. Agr. Misc. Publ. 1339.

Hall, R. W., and L. E. Ehler. 1980. Population ecology of Aphis nerii on oleander. Env. Entomol.,

9:338-344.

Keen, F. P. 1952. Insect enemies of western forests. U.S. Dept. Agr. Misc. Publ. 273.

Koehler, C. S., G. W. Frankie, W. S. Moore, and V. R. Landwehr. 1983. Relationship of infestation

by the sequoia pitch moth (Lepidoptera: Sesiidae) to Monterey pine trunk injury. Environ.

Entomol., 12:979-981.

Landwehr, Y. R., W. J. Phillipson, M. E. Ascemo, and R. Hatch. 1981. Attraction of the native elm

bark beetle to American elm after the pruning of branches. J. Econ. Entomol., 74:577-580.

Ohmart, C. P. 1981. An annotated list of insects associated with Pinus radiata D. Don in California.

Forest Research CSIRO, Div. Rept. No. 8.

Payne, P. B. 1974. Sequoia pitch moth on Monterey pine. Coop Extern, Univ. of California, OSA-

270.

Potter, D. A., and G. M. Timmons. 1981. Factors affecting predisposition of flowering dogwood

trees to attack by the dogwood borer. HortScience, 16:677-679.

Powers, R. F., and W. E. Sundahl. 1973. Sequoia pitch moth: a new problem in fuel-break construc¬

tion. J. Forestry, 71:338-339.

Weidman, R. H., and G. T. Robbins. 1947. Attacks of pitch moth and turpentine beetle on pines

in the Eddy Arboretum. J. Forestry, 45:428-433.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 41-43

Time of Nuptial Flight in Two Ant Species

(Hymenoptera: Formicidae)

Elwood S. McCluskey and Jack S. Neal

(ESM) Biology and Physiology Departments, Loma Linda University, Loma

Linda, California 92350; (JSN) Biology Department, Loma Linda University,

Loma Linda, California 92350.

Abstract. — A flight of Myrmecocystus ewarti was seen near Palm Desert, Cali¬

fornia, at 1500 on 30 December. It is reported because neither hour nor date has

been published for this species; and more important, because this genus varies

more than most in flight and worker timing among species. This is the first winter

flight record for the genus. Secondly, a flight of Pogonomyrmex californicus was

seen near Riverside, California, at 1015 on 4 October, surprising because the

flights usually occur in June and July.

A single flight of each of two species is reported here: Myrmecocystus ewarti

Snelling because we are aware of no published record for this species; and Po¬

gonomyrmex californicus (Buckley) because it was seen at an unusually late date.

M. ewarti was observed by JSN and P. californicus by ESM.

Myrmecocystus ewarti

The nest was about 8 km north of Palm Desert, California, in a Larrea-Encelia

desert community. The entrance was a 2 cm hole straight down, in a wash area.

The ground had been moist several days before, indicating a previous rain.

The nest was observed several times on 30 December 1983, as noted below.

The day was sunny and warm, becoming partly shaded by cloud by 1500 (PST);

the temperature at the surface then was 23°C in the sun and 15° in the shade; at

7 cm deep it was 19°.

1415: Passed by nest and noticed nothing.

1500: About 300 workers moving in unusual zigzag pattern within 1-m radius

of entrance. About 15 males motionless on pebbles, some taking flight. Four

females emerged gradually from nest and were collected.

1600: 20 workers only were left.

Several days later, 3 January 1984, this nest was observed again. The afternoon

was clear and sunny, with surface temperature in the sun 24-27°. The ground was

now quite dry. No ants were seen at 1445, 1500, or 1550; 2 workers were inside

the entrance at 1520. (At a nearby nest of M. mimicus 100 workers and 2 males

[in the entrance] were seen at 1500.)

The two dates listed by Snelling (1976) when alates of M. ewarti have been

found in the nest, 26 January and 1 March, are both in the winter like the flight

reported here.

Published records of flight time for other species in the genus include M. men-

PAN-PACIFIC ENTOMOLOGIST

dax, 18 July at 1610 (Wheeler, 1908); M. mexicanus, 24-28 July, 1922-1936

(Conway, 1980); M. mimicus, July, 1730-1900 and 0600-0700 (Bartz and Holl-

dobler, 1982); M. pyramicus, 7 April, near sundown (Smith, 1951 with Snelling,

1976); M. testaceus, early spring and midautumn, late afternoon (Snelling, 1976).

A second morning-flying species is M. depilis, July, 0600 (G. Alpert, personal

communication). Thus there is more spread of both date and hour of flight than

for most genera (cf. McCluskey, 1974); and our new record (M. ewarti) adds yet

another season, winter.

Pogonomyrmex califortiicus

Published records of date of flight include 27 June-15 July (Michener, 1942)

and June-July (Mintzer, 1982). Through the years locally the flights have often

been observed (such as collecting the alates for laboratory study, McCluskey and

Carter, 1969) from the first of June into August. So imagine my surprise to

encounter a flight in the fall. A couple times in preceding days a female had been

noticed at a nest, but thought to be merely a straggler left over for some reason.

The nest openings were in a crack of the pavement of a parking lot in Loma

Linda (near Riverside, CA), where I passed one or more times a day; the colony

had been there for many years. At 1005 on 4 October 1983 I noticed many alate

females out. So observations were made as follows:

1010: About 150 females out at three exits, massed in usual way (somewhat in

rows around exits); also many workers. No males seen now or later.

1005-1035: Large number continued out, sometimes spreading to a meter be¬

yond exits, both females and workers running excitedly. Several females flew,

perhaps one per minute for a while (but could never verify by sighting against

sky). A student who stopped by (1015-1020) also said he saw them fly. Sunny

and warm (hot sitting in sun) most of time, but dimmed by clouds part of time.

Often a breeze. By 1035 number out had dropped to a half or third.

1055: Only 7 females out.

1100: Sun much dimmed by clouds; shade air temperature 24°C.

Between 1035 and 1055: Checked six other nests, mostly in more typical habitat,

as along railroad siding. Workers but no alates out. More cloudy by now. Ground

wet from heavy rain 30 September.

In conclusion, this report adds another species flight hour and date for a genus

that deserves further analysis because of unusual diversity in timing. Secondly,

it provides a reminder that variability in biological phenomena within a species

should not be overlooked.

Acknowledgments

We thank R. R. Snelling for determining M. ewarti, and the Geoscience Re¬

search Institute for grant support.

Literature Cited

Bartz, S. H., and B. Holldobler. 1982. Colony founding in Myrmecocystus mimicus Wheeler (Hy-

menoptera: Formicidae) and the evolution of foundress associations. Behav. Ecol. Sociobiol.,

10:137-147.

Conway, J. R. 1980. The seasonal occurrence of sexual brood and the pre- and post-nuptial behavior

of the honey ant, Myrmecocystus mexicanus Wesmael, in Colorado. J. N.Y. Entomol. Soc., 88:

7-14.

VOLUME 62, NUMBER 1

McCluskey, E. S. 1974. Generic diversity in phase of rhythm in myrmicine ants. J. N.Y. Entomol.

Soc., 82:93-102.

-, and C. E. Carter. 1969. Loss of rhythmic activity in female ants caused by mating. Comp.

Bioch. Physiol., 31:217-226.

Michener, C. D. 1942. The history and behavior of a colony of harvester ants. Scientific Monthly,

55:248-258.

Mintzer, A. C. 1982. Copulatory behavior and mate selection in the harvester ant, Pogonomyrmex

californicus (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am., 75:323-326.

Smith, M. R. 1951. Two new ants from western Nevada (Hymenoptera, Formicidae). Great Basin

Naturalist, 11 (3—4):91—96.

Snelling, R. R. 1976. A revision of the honey ants, genus Myrmecocystus (Hymenoptera: Formicidae).

Nat. Hist. Mus. Los Angeles County, Science Bull., 24:1-163.

Wheeler, W. M. 1908. Honey ants, with a revision of the American Myrmecocysti. Bull. Amer.

Mus. Nat. Hist., 24:345-397.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 44-52

Seasonal Distribution, Trophic Structure and Origin of Sand Obligate

Insect Communities in the Great Basin

R. W. Rust

Biology Department, University of Nevada, Reno, Nevada.

Recent surveys of insects in western North American sand dunes (Hardy and

Andrews, 1979, 1981; Andrews et al., 1979; Cobb, 1981; Bechtel et al., 1981,

1983; Rust et al., 1983) have established the presence of unique, often endemic

groups of Coleoptera, Hemiptera and Orthoptera. These species are referred to

as sand obligate species and are defined as species whose life history activities are

restricted to sand dune environments (Koch, 1961; Hardy and Andrews, 1976).

I will show that sand obligate (SO) species from one sand dune, Sand Mountain,

Nevada, are principally detritivores and carnivores that occur either throughout

the year or in cold, winter months. The distribution of sand obligate faunas in

several dunes in the Great Basin Desert of the United States may possibly be

explained by examination of past climatic conditions during the Pleistocene in

the Great Basin. The hypothesis being examined is that the present distributions

and restriction of the sand obligate fauna is a result of contraction of Pleistocene

sand areas with decreasing aridity in recent times.

Study Area

Sand Mountain dune is approximately 46 km ESE of Fallon, Churchill County,

Nevada (39°20'N-118°20'W) and is 1250 m in elevation. It is an active star dune

of approximately 3.2 km 2 and results from eolian sand deposited during the

Turupah and Fallon formations of about 4000 years before present (B.P.) (Mor¬

rison and Frye, 1965). Sparse dune vegetation consists of the shrubs Atriplex

confertifolia, Tetradymia tetrameres, Chrysothamnus viscidiflorus, Eriogonum

kearneyi, Psorothamnus polyadenitis and the grass Oryzopsis hymenoides. The

dune was sampled 18 times from June 1979 through June 1980.

Monthly average temperature and precipitation from Fallon, Nevada (39°27-

118°47'W and 1208 m elevation) for a thirty year period are given in Table 1

(USDC 1970). Sand Mountain is in the cold desert of North America with cold,

wet winters (—0.4 to 5.8°C and 1 to 1.6 mm) and hot, dry summers (10 to 22°C

and 0.5 to 1.8 mm). Thirty year mean monthly temperatures were analyzed by

Fisher’s L.S.D. test to determine which months have equal mean temperatures.

L.S.D. valve was 0.73°C or all monthly means are significantly different from each

other.

Methods and Materials

Several collecting techniques were used. Permanent pitfall traps were 0.95 L

(11.5 cm diameter) plastic cartons buried level with the sand surface and one-

third to one-half filled with ethylene glycol. Traps were covered with a 13 x 13

cm Masonite lid held 2 cm above the surface. Six traps were placed 10 meters

VOLUME 62, NUMBER 1

apart in a transect and six transects were used. Traps were operative for 30 days

between collecting periods. Temporary pitfall traps were 15 cm diameter ceramic

bowls placed level with the sand surface. Twelve traps placed 10 meters apart

represented a transect and six transects were used. Temporary pitfall traps were

used for 12 to 18 hr during a survey period and trapping duration was determined

by the length of the night. Hand held lamps were used in searching the dune for

nocturnal species. Sand was sifted through two screens of 12 x 12 mm and 1.5

x 1.5 mm mesh to recover subsurface arthropods. Surface sand to a depth of 0.4

to 0.5 m both from beneath vegetation and open sand (non-vegetated areas) was

sifted. During surveys, four or five different sites on the dune were visited and

sampled and the sites were varied each survey.

All specimens were sent to taxonomists for identification (see Bechtel et al.,

1981, 1983; Rust et al., 1983 for listings). Four of the species were determined

as new to science. These species will be described by taxonomists and are here

treated as species unique to Sand Mountain, NY.

Trophic level placement of species was based on field observations, dissection

of digestive tracts and literature citations. When few specimens were available or

species specific literature was not available, then trophic level assignment was

based on generic patterns.

Spearman’s rank correlation test was used to compare a species monthly abun¬

dance to both mean monthly temperature and precipitation. The hypothesis being

tested is that a species monthly abundance ranking is independent of either month¬

ly temperature or precipitation ranking.

Results

Sixteen species are recognized as sand obligate, 3 herbivores, 4 carnivores and

9 detritivores (Table 1). Serica species (Scarabaeidae) adults were found from

May to June and were observed feeding of Psoralea lanceolata (Fabaceae) and

Ambrosia acanthicarpa (Asteraceae). Larvae were recovered in October and March-

April from sand beneath the roots of Oryzopsis hymenoides (Poaceae). Their guts

contained masticated plant material. Cardiophorus species (Elateridae) adults were

found from November to March and were recovered from sand beneath several

dune shrubs. A single larva was taken in May. Cardiophorus have unknown feeding

habits. The larval mouth opening is small suggesting that they probably take only

liquid food. Edrotes ventricosus (Tenebrionidae) was present in all months but

November to January. La Rivers (1947) observed E. ventricosus feeding on salt-

grass, Destichlis spicata, brome grass, Bromus tectorum, Russian Thistle, Salsola

kali, and wild onion, Allium sp. and considered it a strict herbivore. SO carnivores,

Rhadine myrmecodes (Carabidae), and Mecynotarsus delicatulus (Anthicidae) were

present in all months, Philothris species (Histeridae) was found during the winter

months, and Tetragonoderus pallidus (Carabidae) was present from May to Sep¬

tember. Of the detritivores, Niptus ventriculus (Ptinidae) (Hinton, 1941; Brown,

1959), Eusattus muricatus (Doyen, 1984 for recent review), Lariversius tibialis

(gut analysis, unpublished data), and Trogloderus costatus (La Rivers, 1946; Tan¬

ner and Packham, 1965; Thomas, 1979) (Tenebrionidae) were present in all months.

Chilometopon brachystomum (Doyen, 1982) (Tenebrionidae) was present during

the summer months. Aegialia hardyi (Rust and Hanks, 1982), Aphodius nevadensis

(gut analysis, unpublished data), and Coenonycha species (Scarabaeidae) were

Table 1. Seasonal distribution of sand obligate insects from Sand Mountain, Nevada from June 1979 through June 1980, larval numbers are given in parentheses.

Species dry weight is given in milligrams (E means estimated dry weight because of few specimens). Mean monthly temperature and precipitation based on a

thirty year average are given for Fallon, Nevada.

Species

Weight

Jan

Feb

Mar

Apr

May

June

July

Aug

Sept

Oct

Nov

Dec

Herbivores

Cardiophorus species

6.0E

(1)

Serica species

14.8

(17)

(37)

(10)

Edrotes ventricosus

13.7

Carnivores

Mecynotarsus delicatulus

5.0

296

Rhadine myrmecodes

94.0

Tetragonoderus pallidus

18.5

Philothrus species

2.0E

Detritivores

Ammobaenetes lariversi

40.1

Niptus ventriculus

6.6

Aegialia hardyi

2.2

158

(79)

(144)

(38)

Aphodius nevadensis

5.4

(26)

(21)

Coenonycha species

10.0E

Chilometopon brachystomum

20.0E

Eusattus muricatus

133.0

372

Lariversius tibialis

19.1

482

241

Trogloderus costatus

18.9

210

Average temperature °C

-0.4

3.0

5.8

9.7

14.2

18.5

22.7

21.2

16.9

11.0

4.6

0.7

Average precipitation mm

12.4

16.0

13.9

9.6

18.5

11.4

4.8

4.3

5.5

10.6

9.1

11.6

PAN-PACIFIC ENTOMOLOGIST

VOLUME 62, NUMBER 1

Table 2. Spearman’s rank correlation and probabilities of species monthly abundance to monthly

temperature and monthly precipitation 30 year averages and probability levels. Rankings are from

high to low for monthly species abundance, temperature and precipitation.

Temperature Precipitation

Species*

Mecynotarsus delicatulus

0.805

0.002

0.005

-0.631

0.02

0.05

Neptus ventriculus

0.335

0.20

0.50

-0.482

0.10

0.20

Rhadine myrmecodes

-0.108

0.50

0.136

0.50

Tetragonoderus pallidus

0.80

0.20

-0.90

0.10

Ammobaenetes lariversi

0.797

0.002

0.005

-0.203

0.50

Aegialia hardyi

-0.660

0.05

0.10

-0.482

0.20

0.50

Aphodius nevadensis

0.375

0.50

0.825

0.10

0.20

Edrotes ventricosus

0.595

0.10

0.20

-0.412

0.20

0.50

Eusattus muricatus

0.715

0.01

0.02

-0.548

0.05

0.10

Lariversius tibialis

0.692

0.01

0.02

-0.475

0.10

0.20

Trogloderus costatus

0.795

0.002

0.005

-0.319

0.20

0.50

* Cardiophorus species, Philothris species, Coenonycha species and Chilometopon brachystomum

were not analyzed because of limited number of specimens and Serica species and also Coenonycha

species and Chilometopon brachystomum were not analyzed because of insufficient sample size for

Spearman’s rank correlation test.

found during the winter months. Larvae of Aegialia hardyi and Aphodius neva-

densis were found from March to May in sand beneath dune vegetation. Am-

mobaenetes lariversi (La Rivers, 1948) (Rhaphidophoridae) adults and nymphs

were found in all months with most individuals obtained from July to October.

Spearman’s rank correlation of species monthly abundance to either monthly

temperature or precipitation 30 year averages (Table 2) indicate that Mecynotarsus

delicatulus, Ammobaenetes lariversi, Eusattus muricatus, Lariversius tibialis, and

Trogloderus costatus were significantly, positively correlated with monthly tem¬

peratures and only Mecynotarsus delicatulus was significantly, negatively corre¬

lated with monthly precipitation. Eusattus muricatus shows a possible negative

relationship with monthly precipitation.

Discussion

Three seasonal activity patterns exist in the sand obligate species: 1) continuous

year-round, 2) summer-warm months, and 3) winter-cold months. Carnivores

Rhadine myrmecodes, and Mecynotarsus delicatulus, and detritivores Ammo¬

baenetes lariversi, Niptus ventriculus, Eusattus muricatus, Lariversius tibialis, and

Trogloderus costatus are active year-round. Herbivores Serica species, and Edrotes

ventricosus, carnivore Tetragonoderus pallidus, and detritivore Chilometopon

brachystomum, are summer-warm month species, with E. ventricosus extending

into the cooler winter months. Winter-cold month species are herbivore Cardi¬

ophorus species, carnivore Philothrus species, and detritivores Aegialia hardyi,

Aphodius nevadensis, and Coenonycha species. Winter activity of Cardiophorus

species may represent non-feeding adults that mate and deposit eggs during this

period. Other populations of Cardiophorus species from Great Basin sand dunes

show similar adult winter activity periods (Hardy and Andrews, 1976; E. C.

Becker, pers. comm.).

Comparisons of seasonal activity patterns of other populations of SO species

PAN-PACIFIC ENTOMOLOGIST

(Table 3) are in general the same as Sand Mountain. Notable exceptions are

Tetragonoderus pallidus showing gradually year-round activity in populations at

decreasing latitude or reduced cold-winter months, Niptus ventriculus with re¬

duced hot-summer month activity with decreasing latitude, and Trogloderus cos¬

tatus showing a reduction in the winter-spring activity with decreasing latitude.

Year-round and winter-cold active SO species are responding to both the phys¬

ical and biotic factors during the cold period. During the cold-month period,

warming of surface and subsurface (10 to 15 cm) above ambient produced an

environment allowing both adult and larval activity (Rust and Hanks, 1982).

Maximum precipitation during the cold period, with monthly averages above

average monthly precipitation for Oct., Dec., Jan., Feb., and Mar. and fall only

slightly below in Nov. (Table 1), produces a humid environment for adults and

especially immatures developing during this period. Combination of lower tem¬

peratures and more precipitation reduces evaporative losses from subsurface sand

which prolongs humid conditions, reducing desiccation problems for the winter

active species. Hot, dry summers may represent conditions that are physically

unsuitable for many of the smaller SO species and only larger (10 mg or more)

species can escape by active temporal movements (Holm and Edney, 1973).

The addition of leaves and flowers from deciduous shrubs on the dune (Eri-

ogonum kearneyi, Chrysothamnus viscidiflorus, Tetradymia tetrameres, Atriplex

confertifolia, Psorothamnus polyadenius and Psoralea lanceolata ) will be at a

maximum during the start of the cold-month period adding to the organic base

for the detritivores. Plant materials are trapped in the sand that collects around

the stems of the perennial shrubs, the site where most of the winter active species

were collected (Rust and Hanks, 1982). The combination of detritus availability,

temperature and moisture conditions favorable to both adults and immatures

may explain the winter activity period observed in many SO species.

Long distance dispersal characters, wings, of the SO species divide them into

two groups: 1) winged and 2) wingless or brachypterous. Serica species, Tetrago¬

noderus pallidus, and Philothris species are winged and capable of flight. Rhadine

myrmecodes, Niptus ventriculus, Edrotes ventricosus, Eusattus muricatus, Lari-

versius tibialis, and Ammobaenetes lariversi have no wings and Cardiophorus

species, Mecynotarsus delicatulus, Aegialia hardyi, Aphodius nevadensis, Coenon-

ycha species, and Chilometopon brachystomum have brachypterous wings and

flight is most likely impossible.

The wingless condition of most of the SO species may represent a derived state

of recent origin resulting in reduced chances of being blown away from the dune.

However, except for Chilometopon brachystomum, the wingless tenebrionids be¬

long to genera or tribes that are primatively flightless (Doyen, 1968, 1972; Arnett,

1960). Active sand dunes are limited in their distribution and size in Great Basin

and the chances of being blown to a new dune are considered extremely rare.

Sand dunes may be viewed in the same manner as remote oceanic islands with

respect to the evolution of flightlessness (Darlington, 1943). An individual of

Aegialia crescenta from Cresent Dune, NV was observed being blown across the

dune in a wind storm. The individual was unable to stop itself (unpublished

observation). In Chilometopon brachystomum, Doyen (1982) found that the bra¬

chypterous condition produced wings that still showed distinct anterior venation

indicating recent origin. The wings of Aegialia hardyi, Aphodius nevadensis, Me-

Table 3. Seasonal distribution of sand obligate Coleoptera species from eight sand dunes in southwestern United States: Sand Mountain Dune (present study):

Blow Sand Mountains Dunes, Nevada (Bechtel et al., 1983): Eureka Valley Dune, California; Owens Lake Dune, California; Cadiz Dune, California; Rice Dune,

California; Palen Dune, California; and Algodones Dune, California (Andrews et al., 1979). Dunes are arranged latitudinally from north, Sand Mountain, to south,

Algodones Dune. Winter (W) November to February, spring (S) March to May, summer (S) June to August and fall (F) September to October (after Andrews et

al., 1979).

Sand

Blow

Eureka

Owens

Cadiz

Rice

Palen

Algodones

Species

s s

Mecynotarsus

delicatulus

Tetragonoderus

pallidus

Neptus

ventriculus

Edrotes

—

ventricosus

Eusattus

muricatus

—

Lariversius

tibialis

Trodloderus

—

costatus

—

4 ^

VOLUME 62, NUMBER 1

PAN-PACIFIC ENTOMOLOGIST

cynotarsus delicatulus, Coenonycha species, and Cardiophorus species are reduced

to very short paddle-like structure without any trace of venation. This being

interpreted as an older condition than that of C. brachystomum.

The hypothesis being presented is that the present distributions and restriction

of the sand obligate fauna in the southwestern United States is a result of past

climatic conditions and contraction of sand areas with decreasing aridity in recent

times. This hypothesis is not new; Howden (1963) suggested that distribution

patterns observed in eight genera of flightless Scarabaeid beetles found in North

America can best be explained by past climatic conditions during the Pre-Pleis¬

tocene and Pleistocene periods in non-glaciated areas. La Rivers (1946) also

suggested that the subspeciation observed in Trogloderus costatus may have been

associated with the desiccation of Pleistocene lakes in western Nevada and that

T. costatus nevadus is confined to the distribution of Lake Lahontan.

The Pleistocene is geologically noted for its glacial record (Flint, 1971) and

approximately 15 periods of cooling and warming have been associated with

glacial and interglacial periods (Kvasov, 1978). The past 40,000 years in the Great

Basin began with an interpluvial period lasting to near 25,000 B.P. Two pluvial

periods lasted from 25,000 to 21,500 and 13,600 to 11,100 B.P. with high stands

of greater than 1300 m (Benson, 1978; Morrison, 1965). Numerous pluvial lakes,

the largest in the western Great Basin being Lake Lahontan (13,580 km 2 ) (Mifflin

and Wheat, 1979), existed throughout the Great Basin. Extensive sand shores and

sand deposits were present in the western lakes receiving discharge from the Sierra

Nevada Mountains (Morrison, 1964). Warm, arid conditions prevailed from 9000

to 5000 B.P. and during this time all lakes except Pyramid Lake (northwestern

Nevada) desiccated and during the last 5000 years Pyramid and Walker lakes

(west-central Nevada) have increased in size (Benson, 1978). Pluvial paleoclimates

have been estimated as approximately 5°F (2.77°C) cooler than present with a

corresponding increase in precipitation averaging 68% above present basin av¬

erages (Mifflin and Wheat, 1979).

Present species distributions potentially follow the eolian dispersal patterns of

the sands from points of deposition or distribution on pluvial lake shores to its

present position. Sand at Sand Mountain is from the Walker River drainage of

the Sierra Nevada Mountains (D. Trexler, USGS, Univ. Nevada, Reno, pers.

comm.) and has moved from 50 to 5 5 km to its present position at Sand Mountain.

One other active dune, Blow Sand Mountains, lies 25 km SSW of Sand Mountain

and is formed from the same sand deposit. All SO species except Cardiophorus

species, Aphodius nevadensis and Coenonycha species were present at Blow Sand

Mountains (Bechtel et al., 1981, 1983). Presently, we see widespread and/or newly

evolved populations of these past faunas trapped in the active sand dunes of the

intermountain basins. The widespread species are M. delicatulus, T. pallidus, N.

ventriculus, E. ventricosus, E. muricatus, and T. costatus, with Ammobaenetes

lariversi and A. hardyi and other possible Sand Mountain endemics represent the

newly speciated forms. Doyen and Slobodchikoff (1984) have shown the devel¬

opment of microgeographic races of the costal dune beetle Coelus ciliatus (Te-

nebrionidae) from different types of dunes without isolation. Populations inhab¬

iting the eolian and stabilized dunes were among the longest and smallest observed

for the species. Doyen and Rogers (1984) found that body size (elytral length and

width) in Eusattus muricatus was inversely associated with altitude and latitude

VOLUME 62, NUMBER 1

over a large geographic area and speculate that temperature (annual accumulated

day degrees) is involved with body size determination. Whether or not the wide¬

spread SO species are genetically different at different dunes within their geo¬

graphic ranges, it appears that the ephemeral nature of sand dunes may allow for

extremely rapid selection and isolation of SO species and populations.

Acknowledgments

I would like to thank R. C. Bechtel and L. M. Hanks for their assistance with

collecting activities and support during the project. This paper would not have

been possible without the help of numerous taxonomists in identification of the

insects collected. Drs. J. T. Doyen and D. R. Miller reviewed and commented

on the manuscript; their comments are appreciated and helpful.

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PAN-PACIFIC ENTOMOLOGIST

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Koch, C. 1961. Die Dunentenebrioniden der Namibnuste mit besonderer Berucksichtigung ihrer

Okologie (und Physiologie). Yerhand. XI Intern. Kongr. Entomol. (Vienna), 1:655-657.

Kvasov, D. D. 1978. The Barents ice sheet as a relay regulator of glacial-interglacial alternations.

Quater. Res., 9:288-299.

La Rivers, I. 1946. On the genus Trogloderus Le Conte (Coleoptera: Tenebrionidae). Entomol. News,

57:35-44.

-. 1947. A synopsis of the genus Edrotes (Coleoptera: Tenebrionidae). Ann. Entomol. Soc.

America, 40:318-328.

-. 1948. A synopsis of Nevada Orthoptera. Amer. Midi. Natur., 39:652-720.

Mifflin, M. D., and M. M. Wheat. 1979. Pluvial lakes and estimated pluvial climates on Nevada.

Nevada Bureau of Mines Bulletin, 94:1-57.

Morrison, R. B. 1964. Lake Lahontan: Geology of southern Carson Desert, Nevada. U.S. Geol. Surv.

Prof. Paper, 401:1-156.

-. 1965. Quaternary geology of the Great Basin. In H. E. Wright and D. G. Frey (eds.), The

Quaternary of the United States. Princeton University Press, Princeton, NJ.

-, and J. C. Frye. 1965. Correlation of the middle and late Quaternary successions of the Lake

Lahontan, Lake Bonneville, Rocky Mountain (Wasatch Range), southern Great Plains, and

eastern Midwest areas. Nevada Bureau of Mines Report, 9:1-45.

Rust, R. W., and L. M. Hanks. 1982. Notes on the biology of Aegialia hardyi Gordon and Cartwright

(Coleoptera: Scarabaeidae). Pan-Pacific Entomol., 58:319-325.

-,-, and R. C. Bechtel. 1983. Aculeata Hymenoptera of Sand Mountain and Blow Sand

Mountains, Nevada. Great Basin Natur., 43:403-408.

Tanner, V. M., and W. A. Packham. 1965. Tenebrionidae beetles of the Nevada test site. Brigham

Young Univ. Sci. Bull. Biol. Ser., 6:1-44.

Thomas, D. B. 1979. Patterns in the abundance of some tenebrionid beetles in the Mojave Desert.

Envir. Entomol., 8:568-574.

U.S.D.C. 1971. Climatography of the United States, No. 20-26. N.O.A.A. Prepared C. M. Sakamoto.

M.S., 22:1-4.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 53-54

Description of a New Species of Hexatoma ( Hexatoma) from

California (Tipulidae, Diptera)

C. Dennis Hynes

Department of Biological Sciences, California Polytechnic State University, San

Luis Obispo, California 93407.

Recently I received, and later found and reared, specimens of a crane-fly which

is recognized as a new species of the subgenus Hexatoma, genus Hexatoma. The

subgenus Hexatoma has two species recorded from the North American continent,

none from the western United States. All other species of the genus within the

United States are of the subgenus Eriocera. The types are preserved in the col¬

lection at California Polytechnic State University at San Luis Obispo, CA.

Hexatoma {Hexatoma) hartmani, New Species

Male.— Length 6.1-7 mm; wing 6.3-6.9 mm; antenna 0.71-1.7 mm.

Female. —Length 7.4 mm; wing 7.7 mm; antenna 1.5 mm.

Rostrum dark gray, short, palpi black. Antennae black, short, 7 segments; the

scape twice the length of the pedicel. The first flagellar segment twice the length

of the scape and pedicel combined. The last flagellar segment small, about one-

fourth the length of the penultimate segment. Head with the anterior vertex black.

Mesonotal praescutum with two yellowish stripes on either side of a dark brown

median line. Halteres at bases dark gray, remainder of stem and knob yellow.

Legs with the coxae, trochanter and femur black, the remainder of the leg gray.

Wing (Fig. 1) with ground color light yellow, radial and medial veins bordered

by darker coloration. Darkened areas also at base of cells R, M, origin of Rs, and

in the Cell IA toward the margin of the wing; dark brown bordering the vein Cu.

Venation with Sc, ending beyond the fork of Rs, Sc 2 at fork of Rs, Sc, alone equal

to the length of r-m. R 2 about its own length before the fork of R 3+4 ; Rs angulated

at origin; m-cu just beyond the fork of M. Vein M 1+2 present and reaching the

wing margin; other veins of M absent. Cell 1st M 2 preserved. Abdominal segments

uniformly dark gray, with white setae at edges of terga. Hypopygium dark gray

except on distal portion of the basistyle, which is yellow. Outer dististyle slender,

gently curved medially. Inner dististyle relatively large, fleshy, and cylindrical

with abundant erect setae. Aedeagus elongated, reaching back to about the level

of the dististyles, curved downward and inward at posterior third of its length.

Ovipositor of allotype is fleshy.

Holotype. —(male) Atascadero, CA, Atascadero Creek, March 19, 1984 (Hynes).

Allotype. — With the same data as given above for the holotype.

Paratypes. —Three males and 3 females, with same data as given for holotype;

one male (Tracey Estes) slide 1590 (wing and genitalia), April 2, 1983 Atascadero,

CA. All specimens, with the exception of the one collected by Miss Estes, were

reared from larvae and pupae.

I am pleased to name this fly after Dr. Margaret Hartman, whose work with

PAN-PACIFIC ENTOMOLOGIST

the Rangeland Crane-fly, Tipula simplex, has been of great value to the knowledge

of crane-fly biology.

Hexatoma hartmani is very much like Hexatoma microcera Alexander, but

readily told from this species by the coloration and the larger terminal segment

of the antennae. The retention of the Cell 1 st M 2 by the adult is not reflected by

differences in the larval stages. Consequently, the erection of a new subgenus on

this basis is not warranted. The preservation of the Cell 1st M 2 is much as in

Hexatoma (. Hexatoma ) schmidiana of Kashmir, Pakistan (Alexander, 1957a).

However, by its description, Hexatoma schmidiana has longer antennae and the

coloration very different. Another species with the Cell M 2 preserved was described

by Alexander in 1957 as Hexatoma coheri (Alexander, 1957b), placing it in the

subgenus Eriocera. He later explained that he did so on the basis of the elongate

antennae in the male (Alexander, 1958). Since the preservation of Cell M 2 is

accompanied by short antennae and the presence of a fleshy ovipositor in the

female, I am placing Hexatoma hartmani in the subgenus Hexatoma.

Numerous larvae and pupae were found in the sandy areas between mounds

of Carex senta which abounds along the edges of the stream.

Literature Cited

Alexander, C. P. 1957a. New or little-known Tipulidae (Diptera) CII. Oriental-Australasian species.

Ann. Mag. Nat. Hist., (12)10:97-115.

-. 1957b. Undescribed species of crane-flies from the Himalaya Mountains (Tipulidae, Diptera).

I. Jour. N.Y. Ent. Soc., 64:137-147.

-. 1958. New or little-known Tipulidae from eastern Asia (Diptera), XLV. Phil. Joum. Sci.,

86:405-409; 4 pits.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 55-57

Floral Predation of Yucca whipplei (Agavaceae)

by the Sap Beetle, Anthonaeus agavensis

(Coleoptera: Nitidulidae)

Daniel Udovic

Department of Biology, University of Oregon, Eugene, Oregon 97403.

Abstract. —Female sap beetles, Anthonaeus agavensis, oviposit in the flower

buds of Yucca whipplei. The larvae destroy both pollen and ovaries, causing

premature abortion of buds and flowers.

Adult sap beetles, Anthonaeus agavensis (Crotch) (Nitidulidae), are often found

on the flower stalks of Yucca whipplei Torrey (Agavaceae) in southern California.

They occur in large numbers at many of the sites where I have been studying the

pollination biology of Y. whipplei (Udovic, 1981, MS), particularly in coastal sage

scrub (Munz, 1973) south of the Los Angeles basin. Parsons (1943) reported that

the adults of this species occur in the flowers of Agave. However, of the 18 samples

of specimens with host-plant information in the collections of the University of

California, Berkeley, and the University of California, Riverside, 11 were found

on Y. whipplei, 2 others were probably on Y. whipplei, and 4 were on undetermined

species of Yucca\ none were reported from Agave (Powell, pers. comm.; Frommer,

pers. comm.). Since the larvae of many of the other members of its subfamily

(Cateretinae) live in seed capsules of various plants, Parsons (1943) conjectured

that the larvae of A. agavensis are associated with seed capsules of Agave. Here I

report observations showing that the beetle larvae are floral predators of Y. whip¬

plei that may significantly affect the plant’s floral display.

I observed adult and larval behavior during the spring of 1981 on the Ryan

Oak Glen Reserve northeast of Escondido, CA, in a coastal sage scrub community.

This site corresponds to CSS4 in Udovic (1981). Adults congregate in the open

flowers of Y. whipplei and are often found mating inside the flowers. The devel¬

oping branches of yucca inflorescences, together with their primordial flower buds,

are covered by protective bracts. Female A. agavensis are able to crawl beneath

the bracts, where they oviposit on the developing flower buds. Although I was

unable to determine how many eggs are placed in each bud, I never observed

more than one larva in a bud or flower. Inside the bud the larva feeds on the

anther sacs and burrows into and excavates the floral ovary, causing significant

damage. Completion of larval development takes approximately one week. If the

flower has not opened before the larva completes development the larva drills an

exit hole through the petals and drops to the soil. Since the duration of the flowering

season for Y. whipplei is usually two months or less, A. agavensis is probably

univoltine.

Many of the attacked buds are aborted by the plant before they open. Open

flowers that have been attacked by beetles typically wilt and abscise more rapidly

PAN-PACIFIC ENTOMOLOGIST

% Buds aborted

Figure 1. Frequency distribution for the percentages of flowers which aborted as buds among plants

flowering at Ryan Oak Glen in 1981. Aborted buds are a measure of the extent of floral predation by

Anthonaeus agavensis.

than neighboring uninfested flowers. The flowers are invariably too severely dam¬

aged to serve as pollen donors or to produce mature fruits. Furthermore, the

specialized pollinators of Yucca whipplei, the yucca moths, Tegeticula maculata

(Riley) (Lepidoptera: Incurvuriidae; Powell and Mackie, 1966; Aker and Udovic,

1981), apparently avoid damaged flowers. I have never observed female moths,

which also oviposit in floral ovaries, pollinating, ovipositing, or resting in damaged

flowers.

Damage to yucca inflorescences resulting from floral predation is quite variable

both within and between populations. I determined the total number of flowers

produced, the height of the flower stalk, and the number of buds aborted for each

of 40 plants at Ryan Oak Glen in 1981. Floral predation was the major cause of

abortion, although occasionally buds aborted for other reasons. The percentage

of aborted buds ranged from 2% to 57% (Fig. 1) with a mean value of 14.7% and

a 95% confidence range of 11.8%-18.8% (obtained using the arcsine transfor¬

mation and then backtransforming). Regressions of the percentage of aborted

buds on either the total number of flowers or on stalk height yield no significant

relation. At Pinyon Flat, CA, in the evergreen chaparral (corresponding to CH4

in Udovic, 1981), infestation rates in 1981 were much lower than at Ryan Oak

Glen. Only a few plants showed any signs of beetle attack with damage never

exceeding 5%. Although plants at this study site often abort buds, particularly

near the end of the flowering season (Aker, 1982), only a few of the aborted buds

which I examined showed any signs of beetle infestation. Perhaps the heaviest

VOLUME 62, NUMBER 1

infestation I’ve encountered was on the Elliot Reserve, east of San Diego, in 1979

(corresponding to CSS3 in Udovic, 1981). Although at that time no attempts were

made to quantify the extent of damage, most plants probably lost over 25% of

their flowers to beetle predation.

The extent of coevolution between A. agavensis and Y. whipplei deserves further

investigation. The beetle may be highly specialized, and may be an important

agent of selection on the plant’s floral display. Its interaction with yucca’s spe¬

cialized pollinator, the yucca moth, which competes with it for suitable oviposition

sites, also deserves further study.

Acknowledgments

I would like to thank Saul Frommer and Terry Seeno for help with identification,

Jerry Powell and Saul Frommer for providing information about the Berkeley

and Riverside collections, and Charles Aker, Peter Frank, and David Wagner for

comments on the manuscript. I am grateful to the University of California for

permission to study and use the facilities at the Philip Boyd Deep Canyon Reserve,

the Elliot Reserve, the Ryan Oak Glen Reserve, and the Pinyon Flat Geophysical

Observatory. I thank Frances Ryan and the late Lewis Ryan for their hospitality.

This work was partially supported by a small grant from the University of Oregon.

Literature Cited

Aker, C. L. 1982. Regulation of flower, fruit and seed production by the monocarpic perennial,

Yucca whipplei. J. Ecol., 70:357-372.

-, and D. Udovic. 1981. Oviposition and pollination behavior of the yucca moth, Tegeticula

maculata (Lepidoptera: Prodoxidae), and its relation to the reproductive biology of Yucca

whipplei (Agavaceae). Oecologia, 49:96-101.

Munz, P. A. 1973. A California flora and supplement. University of California Press, Berkeley, 1681

+ 224 pp.

Parsons, C. T. 1943. A revision of nearctic Nitidulidae (Coleoptera). Bull. Mus. Comp. Zool., 92:

121-278.

Powell, J. A., and R. A. Mackie. 1966. Biological interrelationships of moths and Yucca whipplei

(Lepidoptera: Gelechiidae, Blastobasidae, Prodoxidae). Univ. Calif. Publ. Ent., 42:1-46.

Udovic, D. 1981. Determinants of fruit set in Yucca whipplei : reproductive expenditure vs. pollinator

availability. Oecologia, 48:389-399.

-. MS. An experimental attempt to modify fruit production in Yucca whipplei. In Prep.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 58-76

Movement and Distribution of Pleocoma Larvae in

Western Oregon Coniferous Forest Soils

(Coleoptera: Scarabaeidae ) 1

David G. Fellin

U.S. Department of Agriculture, Forest Service, Intermountain Research Sta¬

tion, Forestry Sciences Laboratory, P.O. Box 8089, Missoula, Montana 59807.

Abstract.— The movement and spatial and vertical distribution of Pleocoma

larvae were studied in coniferous forests of western Oregon, incidental to a study

of larval feeding habits. Larvae are able to burrow, using their mandibles, through

hard and compact forest soil at rates up to 11 cm per day. With the exception of

first stage larvae and larvae preparing to moult or pupate in early fall, most larvae

actively burrow throughout the year. Larvae do not appear to travel for any length

of time in any particular direction. Larval populations in forested areas in western

Oregon are usually localized. More than 60 sample holes (1 m 2 and no less than

75 cm in depth) were dug searching for larvae. More than one-third produced no

larvae, and populations in the others ranged from 1 to 56. Larvae were found at

depths from 10 to 110 cm. Vertical distribution and, to a lesser extent, spatial

distribution of larvae appear to be influenced by a combination of factors, prin¬

cipally soil moisture, soil temperature, and the presence or absence of a silicate

clay layer. This silicate clay hardpan directly affects the distribution of smaller

coniferous roots—the principal source of food for Pleocoma larvae.

I studied the feeding habits of Pleocoma larvae in some old-growth coniferous

forests in western Oregon in the early 1960’s (Fellin, 1975). The study began

shortly after Stein (1963) confirmed that Pleocoma larvae feed on the roots of

forest trees. Five species of Pleocoma were studied: P. dubitabilis dubitabilis Davis 2 ,

P. carinata Linsley, and P. simi Davis primarily, and to a lesser extent P. minor

Linsley and P. crinita Linsley.

Incidental to that study, other studies and observations were made on the

biology, ecology, behavior, and distribution of Pleocoma spp. Many new localities

were recorded and described. Based on these and other locality descriptions, the

geographic distribution of all species of Pleocoma in Oregon was summarized and

the habitats for P. simi and P. carinata were described (Fellin and Ritcher, 1967).

Observations also were made on trapping male Pleocoma with female-baited traps

1 This investigation was supported chiefly by the Oregon Agricultural Experiment Station and

National Science Foundation Grants Numbers 14296 and 17935 and partially by the Intermountain

Research Station, USDA Forest Service.

2 According to Hovore (pers. comm.) the variety dubitabilis Davis was described in 1934 as a new

variety of Pleocoma staff Schaufuss. Later, it was considered by Linsley to be a distinct species but

inadvertently misspelled as P. dubitalis. This error of misspelling has persisted since that time.

VOLUME 62, NUMBER 1

Figure 1. Technique used to mark Pleocoma larvae. (Left) Thoracic area of seventh instar P.

dubitabilis showing minuten nadeln thrust through fleshy lobes at base of meso thoracic leg (15 x).

(Right) Thoracic area of seventh instar P. dubitabilis showing two black spots (arrow) caused by

darkening of haemolymph where lobes were punctured by minuten nadeln (25 x).

(Fellin, 1968). Observations on egg and larval biology and the flight characteristics

of adults were presented elsewhere (Fellin, 1981). This paper presents results from

studies of movement and spatial and vertical distribution of larvae.

Movement of Larvae

The movement of P. dubitabilis larvae in the soil was studied at a site in

McDonald Forest, 8 km north of Corvallis from 1 May to 31 October 1961. I

collected larvae at the study area and brought them to the laboratory for mea¬

surement and marking for later identification.

Each larva was pierced in one of its many fleshy areas, particularly along the

meso-ventral line of the thorax or abdomen, with a minuten nadeln (Fig. 1A).

Darkening of the haemolymph upon exposure to air left an obvious mark (Fig.

IB), and by piercing larvae on different segments or in different areas of the same

segment, numerous marking combinations were achieved. I noticed no ill effects

on the larvae as long as the puncture was made as far as possible out on the lobes.

Marked larvae were returned to the study area and placed in small niches in

the side of a sample hole that had not been refilled with soil. The niches were

then covered with a salve tin lid (Fig. 2A). After a week, lids were removed and

the soil dug away until the larvae were recovered and identified (Fig. 2B).

Because it was impossible to follow larval burrows through the soil, I used an

arbitrary method to determine how far larvae traveled. Vertical and lateral mea¬

surements were taken between the point at which a larva was released and the

point of recovery. From these measurements I computed two distances: (1) the

distance a larva would have traveled had it gone straight into the soil and then

PAN-PACIFIC ENTOMOLOGIST

Figure 2. Technique used in studying movement of larvae in the soil (Left) A larva is placed in a

small niche provided for it in the side of an old sample hole, and the niche is covered with a salve

tin lid. (Right) Searching for Pleocoma larvae that had been marked and placed on the side of the

sample hole 1 week prior.

at a right angle downward, upward, or to the right or left (the two perpendicular

sides of a right triangle), and (2) the distance traveled had it gone a direct route

from the point of release to the point of recovery (the hypotenuse of a right

triangle). The average of these two distances was used to estimate the distance

traveled during the week, then an average rate of movement per day was calculated.

Because Pleocoma larvae often follow winding paths through the soil, the cal¬

culated average rate of movement is probably conservative.

Burrow Construction and Method of Movement

Larvae move through the ground by biting away soil in front of them with their

mandibles and depositing it to their rear as they move. Each bite of soil is mo¬

mentarily held beneath the thorax by the thoracic legs. After a few bites, the

larva—holding the soil by its legs, mandibles, and maxillae—turns and deposits

this soil in the rear of the burrow. Here, presumably with the aid of secretions

from the mouth, it is cemented against the back wall, filling the burrow behind.

Cells removed intact from the soil reveal on their edges an interesting pattern

of marks made by the larval mandibles. The photographs in Figure 3 illustrate

this and establish that larvae move through the soil by use of the mandibles and

not by burrowing with the thoracic legs.

Larval movement through the soil depends mainly on three-point body contact.

By manipulating the dorsum of the abdomen, the anal area and the thoracic legs,

larvae are able to move through an open burrow fairly rapidly by pressing these

three points against the walls of the burrow. Pleocoma larvae are well adapted

for this type of movement; they possess many spine-like setae dorsally on most

abdominal segments and on the caudal segments where contact is made with the

soil. Necessity of three-point contact is shown by the helplessness of larvae trying

to move on a flat surface.

VOLUME 62, NUMBER 1

Figure 3. Cell showing pattern made by mandibles as larvae moved through the soil. (Top) Portion

of a P. simi cell halved lengthwise to show the mandible pattern on cell wall (2.5 x). (Bottom) Closeup

of individual mandible marks in the cell. Arrow points to a narrow ridge of soil formed at the point

where each mandible of a pair come together (10 x).

While moving through the soil, larvae maintain some distance of open burrow

behind them, the length of which often varies with depth, direction, size of larva,

or time of year. Fifth instar Pleocoma have been found with as much as 10 cm

of open burrow behind them.

PAN-PACIFIC ENTOMOLOGIST

Table 1. Average rate of movement of P. dubitabilis larvae through hard and compact forest soil

between early May and late October 1961. 1

Approximate instar

No. of larvae

Average rate of movement

(cm per day)

0.8

3.8

0.7

8.7

1.7

4.9

4.6

8-older

2.9

1 Data are not included for larvae preparing for or recovering from a moult.

Rate of Movement

Larvae are able to move through the hard and compact forest soil at speeds

varying from a little less than 1 cm per day to nearly 9 cm per day (Table 1).

Of the individual larvae observed, a fifth instar traveled the fastest, covering

about 11 cm per day between 27 April and 18 May. Also, a seventh and an eighth

instar burrowed 8.5 and 7.5 cm per day, respectively, during June.

Time of Year of Movement

First instars and young second instars were often collected in groups at or near

the site of oviposition, indicating these small larvae do not move far. First stage

larvae do not leave the egg niche moulting therein to second instars in early

October. Second stage larvae have been found in egg niches in mid-November;

evidently they do not begin to travel from the oviposition site until after that.

Most larvae actively burrow from early May to late October when larval move¬

ment was most intensively studied. Periodic observations from early November

to late April indicate that most larvae are active during this period as well.

However, between early August and late October, especially during September,

there is a general period of inactivity when larvae are moulting or pupating.

The number of days that larvae ceased burrowing during the moulting period

varied considerably between individuals. Some larvae slowed little in their move¬

ments prior to moulting, while others ceased movements entirely for as many as

21 days prior to the moult. Following the moult, some larvae began burrowing

almost immediately and others remained motionless for as many as 24 days before

they traveled again.

Direction of Movement

The inability to follow larval burrows through the soil made it difficult to

determine exactly which direction the larvae moved. Of the 46 larvae studied,

31 traveled predominantly downward, two traveled down and then up, and one

larva went up first and then down. Six larvae traveled horizontally, and the

direction that another six traveled is not known.

It appears that Pleocoma larvae generally do not travel for any length of time

in any particular direction. Open burrows behind larvae indicate that in the

relatively short distance of 5 to 10 cm, they may have traveled in several directions.

VOLUME 62, NUMBER 1

Figure 4. A typical larval sample collecting hole, 1 m 2 and about 120 cm deep.

For example, one medium-sized P. simi larva was found with 10 cm of open

burrow behind it, and in this distance had traveled upward, turned a bit, leveled

off, and turned twice more on a generally flat plane. Other Scarabaeidae larvae

also change direction of movement, often doubling back in the direction from

which they had burrowed (Hallock, 1935; Hawley, 1934).

There is no evidence that Pleocoma larvae migrate, in the sense of a continued

or prolonged movement in a direction and at a rate over which they have control

and resulting in a temporary or permanent change of habitat (Schneider, 1962;

Williams, 1957). Movement of Pleocoma larvae beneath the ground can probably

be characterized in terms of dispersal, defined by Schneider (1962) as a lengthening

of the average distance between neighboring individuals. The abundance and

distribution of the smaller coniferous roots, their principal diet in the forest

environment (Fellin, 1975), no doubt also influences the movement of Pleocoma

larvae.

Density of Larvae in the Soil

Because the primary objective of this study was to determine the feeding habits

of Pleocoma larvae in the coniferous forest environment, the goal in collecting

was to gather as many larvae as possible. Consequently, the number and location

of sampling holes was purposely, and not randomly, selected.

PAN-PACIFIC ENTOMOLOGIST

Table 2. Spatial distribution of P. dubitabilis larvae in coniferous forest soil at McDonald Forest

during 1961.

Date

Depth of hole

(cm)

Larvae/m 2

28 January

120

25 February

x 22

31 March

2 35

28 April

29 April

29 May

130

28 June

120

28 July

120

15 August

100

13 September

124

21 October

110

21 November

105

22 December

105

1 Unavoidable circumstances prevented the sampler from completing this hole. Had further digging

been possible more larvae may have been collected.

2 Fifteen of these 35 larvae were young second instars congregated in the same general area and

probably all from the egg complement of a single female.

Sites at which sample holes were dug and larvae collected were restricted to

known larval habitats or where adult males had been taken in flight. The sample

hole was 1 m 2 and dug at least 75 cm deep (Fig. 4). Any hole dug 75 cm deep

without larvae being found was abandoned. When larvae were found, the sample

hole was dug as least 15 cm deeper than where the deepest larva was found. The

depth at which larvae were collected was measured to the nearest 2 cm and depths

later grouped into 10 cm classes. Other investigators have also used some of these

procedures for collecting Scarab larvae—particularly determining depth of sample

holes (Ellertson, 1958; Hartzell and McKenna, 1939; Shorey and Gyrisco, 1960;

Travis, 1939).

Spatial Distribution of Larvae

I made 13 collections of P. dubitabilis larvae at the McDonald Forest study

site in 1961. Larval population densities averaged 16 larvae per m 2 and ranged

from 0 to 35 in sample holes varying from 75 to 130 cm in depth (Table 2).

Between May 1960 and October 1961, I made 17 collections of P. carinata

larvae at three sites in southwestern Oregon. Larval abundance varied from 0 to

15 per m 2 in sample holes ranging from 75 to 105 cm deep (Table 3). Six of the

17 sample holes, or about 35%, produced no larvae.

Thirty-one sample holes were dug searching for P. simi larvae at eight sites in

southwestern Oregon between May 1960 and December 1961. Fifteen of the 31

holes produced no larvae and five yielded only one larva. The two most dense

populations of 34 and 56 larvae per m 2 were collected at the same site (#19) in

May and March 1961, respectively (Table 4).

Four collections each of P. crinita and P. minor were made in forested areas

adjacent to Hood River Valley orchards, averaging, respectively, 2 and 5 larvae

per m 2 .

VOLUME 62, NUMBER 1

Table 3. Spatial distribution of P. carinata larvae in coniferous forest soil at three forested sites

in southwestern Oregon in 1960 and 1961.

Date

Site 1

Depth of hole

(cm)

Larvae/m 2

2 January 1961

3 January 1961

105

28 March 1961

10 May 1961

11 May 1961

105

12 May 1961

21 May 1960

18 July 1961

19 July 1961

2 September 1960

27 October 1961

1 The location of each site is as follows:

Elevation

Site #2—32 km east of Medford, Jackson Co. 762-822 m

Site #3—21 km east of Butte Falls, Jackson Co. —

Site #8—23 km northeast of Idleyld Park, Douglas Co. 700-762 m

Tables 3 and 4 show that larval populations of P. carinata and P. simi in forested

areas in southwestern Oregon are very localized. Had I dug sample holes at random

rather than in areas where larvae were known to occur or where adults had been

collected, the densities shown in the two tables would undoubtedly have been

even less.

The relative larval densities for the five species in coniferous forest soil are

compared to the larval densities for three species in some orchard soils (Table 5).

Larval populations in the Hood River apple orchards are quite high. Though

larval populations vary widely between and within orchards, with islands of high

Pleocoma density surrounded by areas where no larvae can be found, Zwick et

al. (1970) collected 4312 P. crinita larvae in the soil under one mature “Newton”

apple tree. One can easily see why larvae of P. minor and P. crinita are a serious

economic problem in these orchards.

Vertical Distribution of Larvae

Pleocoma dubitabilis larvae were collected at the McDonald Forest study site

in August and November 1960 and once each month during 1961. The vertical

distribution of these larvae (Fig. 5) indicate several points of biological signifi¬

cance: (1) From May to September larvae were generally absent from the upper

40 cm of soil, and only five larvae, all of a size large enough to pupate, were found

at depths shallower than 40 cm. (2) Larvae were generally deeper in the soil in

July than in any other summer month; with the exception of two larvae, none

were found shallower than 60 cm in July. (3) Between October and April, excluding

PAN-PACIFIC ENTOMOLOGIST

Table 4. Spatial distribution of P. simi larvae in coniferous forest soil at eight forested sites 1 in

southwestern Oregon in 1960 and 1961.

Date

Site 2

Depth of hole

(cm)

Larvae/m 2

7 January 1961

22 March 1961

130

2 56

22 March 1961

19 May 1960

20 May 1960

22 May 1961

26 May 1961

120

9 June 1960

16 June 1960

19 July 1960

26 August 1960

1 September 1960

7 December 1961

120

1 The location of each site is as follows:

Elevation

Site #10— 11 km north of Trail, Jackson Co. 850 m

Site #11 — 8 km west of Elkton, Douglas Co. 30 m

Site #14—8 km south of Eugene, Lane Co. 400 m

Site #16 — 3 km northwest of Drain, Douglas Co. 90 m

Site #19—10 km north of Oakland, Douglas Co. 200 m

Site #21—27 km northwest of Union Creek, Douglas Co. 850 m

Site #27—16 km northeast of Tiller, Douglas Co. —

Site #55 — 1 km south of Selma, Josephine Co. 400 m

2 Thirteen of these 56 larvae were small second instars congregated in the same general area and

probably all from the egg complement of a single female.

December, most larvae were fairly well distributed vertically through the soil. (4)

Of the 176 larvae represented in Figure 5, I collected 134, or 76% in a 50-cm

stratum between 41 and 90 cm in depth.

The vertical distribution of P. simi larvae from eight collections at five sites

(Fig. 6) reveals some interesting characteristics: (1) Frequency distributions A and

B in March and May, respectively, show a large congregation of larvae in a 20-

VOLUME 62, NUMBER 1

Table 5. Larval densities of the six western Oregon species of Pleocoma in some coniferous forest

and orchard soils.

Species

No.

Minimum

larvae/m 2

Maximum

Site

P. dubitabilis

Douglas-fir forest

P. simi

Douglas-fir forest

P. carinata

Mixed conifer forest

P. oregonensis 1

Beneath western yellow pine

P. oregonensis 1

Beneath cherry tree

P. crinita 1

Apple orchard

P. crinita

Mixed conifer forest

P. minor 1

—

227

Apple orchard

P. minor

Mixed conifer forest

1 Data from Ellertson and Ritcher (1959), recomputed from ft 2 to m 2 .

cm stratum between 61 and 80 cm; in no other P. simi collection was there such

a striking example of larval accumulation by depth. (2) Larvae presented in dis¬

tribution C were taken in December at the same site as those in distributions A

and B; there was, however, no accumulation of larvae at the lower depths in

December when larvae were generally evenly distributed between 21 and 110 cm

in the soil. (3) Though collected in 5 months and from four sites, larvae represented

by distributions D-H were generally in the upper layers of soil, mostly above 60

cm in depth.

P. carinata larvae were collected at relatively shallow depths in the soil. Fifteen

larvae collected on 21 May 1960 were generally less than 50 cm deep in the soil,

and six collected on 28 March were shallower than 70 cm.

Most P. dubitabilis larvae collected during the 4 summer months (June to

September) were generally fairly deep in the soil, usually below 40 cm (Fig. 5F-

I). P. simi larvae collected at other sites during those 4 months were generally

shallow in the soil, usually above 50 cm in depth, however (Fig. 6E-H).

Throughout this study, no Pleocoma larvae of any of the three species were

found below 110 cm in depth. This is considerably more shallow than the max¬

imum depth that larvae of other Pleocoma species and other genera of white grub

have been observed. P. minor larvae have been found as deep as 149 cm (Ellertson

and Ritcher, 1959) and P. puncticollis Rivers as deep as 240 cm (Linsley, 1938).

Larvae of P. linsleyi Hovore have been taken at depths of between 60 and 240

cm (Hovore, 1971). Larvae, pupae, and adults of P. conjungens lucia Linsley have

been collected from cells in rocky, clay soil at depths ranging from about 36 cm

to several meters below the soil surface (Hovore, 1977). White grubs of the genus

Phyllophaga have been found as deep as 190 cm in some Canadian soils (Hayes,

1929).

Environmental Factors Influencing Larval Distributions

On the basis of other Scarabaeid research, soil temperature, moisture, pH, and

profile were considered most likely to directly or indirectly influence larval density

in the soil, particularly vertical distribution, and to a lesser extent spatial distri¬

bution.

PAN-PACIFIC ENTOMOLOGIST

i—

CL¬

0-10

11-20

21-30

31-40

41-50

51-60

61-70

71-80

81-90

91-100

101-110

111-120 L

1 2 3 4 5

(A) JAN.

1 2 3 4 5

0-10

11-20

21-30

31-40

41-50

51-60

61-70

71-80

81-90

91-100

101-110

111-120

i r

(E)MAY

1 2 3 4 5

0-10

11-20

21-30

31-40

41-50

51-60

□

61-70

71-80

81-90

91-100

101-110

111-120

i i r

(I)SEPT.

FREQUENCY (No.of larvae)

12 3 4

] n

i r

(B) FEB.

12 3 4

(F) JUNE

12 3 4

(J)OCT.

(G) JULY

(K) NOV.

(D)APR.

(H) AUG.

(L) DEC.

Figure 5. Vertical distribution of Pleocoma dubitabilis larvae in the soil at McDonald Forest in

1960 and 1961. Hatched blocks indicate larvae collected in 1960.

I collected soil samples at four depths —15,45,75, and 105 cm—in each sample

hole to determine soil moisture content and soil pH.

Soil moisture was expressed in percentage of dry weight as outlined by Lyon

and Buckman (1948). By their procedure, 100 grams of soil was mixed, weighed,

air dried, and heated in an oven for 7 to 8 hours at 38 to 43°C, then cooled in a

desiccator and weighed again.

Soil samples for pH determination were collected in 1-pint waxed cardboard

containers. A 2-gram soil sample was suspended in 2 ml of distilled water in a

5-ml beaker. Micro-electrodes were immersed in the suspension and the pH read

VOLUME 62, NUMBER 1

FREQUENCY (No.of larvae)

1 2 3 4 5 6 7 8 9 1011 12

CL¬

(F)1 SEPT.,I960

Site no.10

0-10

11-20

21-30

31-40

41~50

51-60

i i i i i i i i i i i i

□

61-70

71-80

81-90

91-100

101-110

□

111-120

(A)22 MAR.,1961

Site no.19

0-10

11-20

21-30

□

31-40

41-50

51-60

61-70

71-80

81-90

91-100

i—

101-110

111-120

Site no.19

0-10

11-20

21-30

31-40

41-50

51-60

61-70

71-80

81-90

91-100

101-110

111-120

(B) 26 MAY,1961

Site no.19

1 2 3 4 5

1 2 3

' VTH

(D) 7 JAN.,1961

Site no.14

(E)19 JULY,1960

Site no.14

12 3 4

(G) 26 AUG.,1960

Site no.16

(H)16 JUNE,1960

Site no.21

Figure 6. Vertical distribution of Pleocoma simi larvae in the soil at several forested sites in

southwestern Oregon in 1960 and 1961. Locations of sites are described in footnote 1, Table 4.

on a Beckman Model N portable pH meter 3 . All measurements were first made

using a buffer of pH 7; samples measuring 5.5 or below were rerun using a buffer

of pH 4 for a more accurate reading.

3 The use of trade, firm, or corporation names in this publication is for the information and con¬

venience of the reader. Such use does not constitute an official endorsement or approval by the U.S.

Department of Agriculture of any product or service to the exclusion of others that may be suitable.

PAN-PACIFIC ENTOMOLOGIST

MONTH

Figure 7. Soil temperatures at four depths during 1961 at McDonald Forest study area, 8 km north

of Corvallis.

At each of the four depths, I took soil temperatures by thrusting an ordinary

immersion-type 110°C etched-stem thermometer at least 4 cm laterally into the

soil and leaving it for at least 5 minutes before reading it.

The soil profile also was described for each sample hole.

Soil Temperature

At the McDonald Forest study area, where P. dubitabilis is found, soil tem¬

peratures at all depths were generally highest during the summer months and

lowest during the late fall, winter, and early spring months. During the summer

months, temperatures at the shallower depths were higher than those at lower

depths, but during the winter months the reverse was true (Fig. 7). This transition

in soil temperature was responsible for two temperature overturns during the year,

when temperatures at all four depths were equal or nearly so. During the spring

overturn in April, soil temperature at all four depths was 9°C while during the

fall overturn in late September to early October 1961 temperatures at all four

depths were 12 to 13°C.

The general absence of P. dubitabilis larvae above 40 cm during the 5 summer

VOLUME 62, NUMBER 1

JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.

MONTH

Figure 8. Soil moistures at four depths during 1961 at the McDonald Forest study area, 8 km

north of Corvallis.

months from May to September seems to be correlated with higher soil temper¬

ature at the 15-cm depth during this period. This is not a strong relationship,

however, because temperatures at 45 and 75 cm during these 5 months were

within 1 to 1.5°C of temperatures at 15 cm. Moreover, in May, July, and Sep¬

tember, the difference in soil temperature between the 15- and 45-cm depths was

only 0.5°C or less.

Pleocoma dubitabilis larvae did not appear to seek the soil stratum with the

least temperature fluctuation. Had they done so, they should have been congre¬

gated at a depth of 105 cm or deeper, where soil temperatures throughout the

year fluctuated the least (Fig. 7).

PAN-PACIFIC ENTOMOLOGIST

Soil temperatures taken with collections of P. simi and P. carinata larvae gen¬

erally followed the same seasonal pattern as shown for the P. dubitabilis collections

at the McDonald Forest study area (Fig. 7). Larvae of both P. simi and P. carinata,

however, were generally shallower than 60 cm during summer months when

temperatures were highest at the more shallow depths.

At least one site shows that no relationship appears to exist between soil tem¬

perature and vertical distribution of P. simi larvae (Fig. 6A-C). In May, when

soil temperatures at 15 cm were higher than temperatures deeper in the soil, most

larvae were congregated between 61 and 80 cm. In March, soil temperatures at

15 cm were cooler than those deeper in the soil, yet larvae were also congregated

between 61 and 90 cm—even a more striking congregation than in May. During

December, larvae were rather evenly distributed over a wide range in depths

between 21 and 110 cm, and soil temperatures varied from 5.5°C at 15 cm to

8.0°C at 110 cm.

Soil Moisture

At the P. dubitabilis sites in McDonald Forest, percentage soil moisture was

generally lower at all depths from June through October and higher from No¬

vember through May. As with soil temperature, there was an overturn in soil

moisture percentage twice a year, although the transposition in May to June and

October to November is a bit indistinct (Fig. 8).

The generally drier soil at the 15- and 45-cm levels seems to be related to the

absence of larvae at these levels from June through September (Fig. 5). In October,

percentage soil moisture, though remaining low at 45 cm, increased at the 15-cm

depth with the onset of fall rains, accompanied by the movement of some larvae

to the more shallow depths (Fig. 5 J). However, this apparent response to increased

soil moisture is not supported by larval distributions in May and December (Fig.

5E, L). In those months, percentage soil moisture was highest at the 15- and 45-

cm stratum, yet larvae were generally concentrated below 40 and 60 cm, respec¬

tively. October, November, and January to April moisture percentages at 15 and

45 cm were relatively high, yet larvae were reasonably well distributed in these

strata. Other Scarabaeid larvae are known to move deeper into the soil as the

upper layers dry out during the summer months (Shorey and Gyrisco, 1960;

Rudolph, 1950).

Soil moisture percentages fluctuated least at the 105-cm level at the McDonald

Forest study area in 1961 (Fig. 8). Pleocoma dubitabilis larvae, however, did not

appear to search out the depth at which soil moisture was most stable or they

would have congregated at 105 cm or deeper in the soil.

The relationship of P. simi and P. carinata larvae to percentage soil moisture

is about the same as their respective relationship to soil temperatures. Soil mois¬

ture percentages taken with collections of larvae of these species are similar to the

seasonal pattern shown for P. dubitabilis (Fig. 8). As was found with soil tem¬

peratures, larvae of P. simi and P. carinata generally burrowed at relatively shallow

depths during that period of the year when the soil there was driest.

Although apparently only weakly related to vertical distribution of Pleocoma

larvae, variations in percentage soil moisture could influence their spatial density.

Infestations of other root-feeding Scarabaeid larvae are often light in poorly drained

locations (Shorey et al., 1960; Nitto and Tachibana, 1955; Forbes, 1907; Smith

VOLUME 62, NUMBER 1

and Hadley, 1926). Excessively dry soil, however, can at times be detrimental to

Scarab larvae (Smith and Hadley, 1926; Travis, 1939).

Soil pH

Soil pH did not appear to be a factor affecting the vertical distribution of P.

dubitabilis larvae at McDonald Forest or P. simi or P. carinata at the various

sites where they were collected. There was a slight increase in acidity with depth,

averaging a pH of about 0.3 between 15 and 105 cm.

Though not apparently tied to vertical distribution of Pleocoma larvae, soil pH

could influence their spatial density. A generally low pH seems to be correlated

with higher larval population of the Japanese beetle (Polivka, 1960; Wessel and

Polivka, 1952), Phyllophaga sp. (Hammond, 1949), and the European chafer

(Shorey et al., 1960).

Soil Profile

Spatial distribution of Pleocoma larvae probably is not influenced by soil profile,

but the vertical distribution of larvae apparently is influenced by the presence of

a silicate clay horizon (hardpan or fragipan) at some sites. When a clay horizon

was present, larvae were often congregated just above it, and when the horizon

was absent there was usually no significant congregation of larvae by depth.

At the P. dubitabilis site at the McDonald Forest study area, no silicate clay

horizon exists as attested by the vertical distribution of larvae collected there.

Throughout the year there was no congregation of larvae at either shallow depths

or deeper in the soil (Fig. 5); even in those months when I collected only a few

larvae (i.e., September), they were rather well distributed vertically.

All collections of P. simi and P. carinata were made in coniferous forests in

Lane, Douglas, and Jackson Counties, each lying in a major soil type characterized

by horizons of silicate clay accumulation (Knox, 1962). The depth of the clay

hardpan varied considerably between sites. At some sites it was relatively deep,

80 to 85 cm, and fairly regular, while at others it was as shallow as 15 cm and

generally irregular and undulating.

The presence of a silicate clay hardpan at most sites where P. simi larvae were

collected is reflected in the vertical distribution of larvae. At site #19, for example,

a definite silicate clay hardpan existed at about 95 cm, and the horizon boundary

was fairly regular. In all three collections at that site (Fig. 6A-C) the majority of

the larvae were above 90 cm. The concentration of larvae immediately above

that hardpan is particularly evident in the March and May collections (Fig. 6A,

B). At other P. simi sites the hardpan was encountered at relatively shallow depths.

Without exception, larvae collected at these sites were above the hardpan (Fig.

6D-H).

Clay hardpans and other soil characteristics are also known to affect the vertical

movements of other Scarab larvae, especially Phyllophaga (Granovsky, 1958;

Travis, 1939).

A silicate clay horizon may also affect maximum depth of oviposition, thus

indirectly influencing vertical distribution of Pleocoma larvae, at least soon after

hatching. On 8 July 1960,1 collected a female P. dubitabilis and her 64 eggs at a

forested site 3 miles north of Brownsville in Linn County. She was taken at 47

PAN-PACIFIC ENTOMOLOGIST

cm and her first eggs had been deposited at 58 cm. At about 60 cm there was a

horizon of silicate clay accumulation.

Discussion

The vertical distribution of Pleocoma larvae and, to a lesser extent, the spatial

distribution probably are influenced by an interaction of factors. During the sum¬

mer months most larvae probably avoid the upper layers of soil as temperatures

there increase and the soil dries out. If no silicate clay layer is encountered, or if

the hardpan is relatively deep, larvae are able to burrow as deep as necessary to

find moisture and temperature conditions more suitable than near the surface. If

a fairly shallow silicate clay layer is present, it obstructs the larvae in their move¬

ment downward while retreating from unsuitable conditions near the surface.

Because Pleocoma larvae are known to be capable of burrowing into very hard

soil (Davis, 1934), including a hard clay layer, the silicate clay horizon may only

indirectly restrict the downward movement of the larvae through the direct effect

of the clay layer on tree roots. An obstructing layer such as a fragipan will cause

a proliferation of Douglas-fir roots (and no doubt roots of other conifers) resulting

in a greater density of rooting just above the fragipan (McMinn, 1963).

When the silicate clay layer is shallow, larvae probably tolerate suboptimum

temperature and moisture conditions in the presence of abundant food (coniferous

roots) immediately above the clay hardpan rather than burrow down into or below

the rootless hardpan, even though temperature and moisture conditions there

might be more suitable. This would account for finding many P. simi and P.

carinata larvae at very shallow depths at sites where the silicate clay horizon was

correspondingly shallow, even during summer months when most larvae in soils

without shallow hardpans are deeper in the soil. In orchard soils, Ellertson and

Ritcher (1959) found the character of the subsoil affected penetration of orchard

tree roots and the vertical distribution of P. crinita and P. minor.

At the McDonald Forest study area, many prepupal P. dubitabilis larvae were

found at depths less than 30 cm during the summer months when all other larvae

at that area were deeper in the soil. This indicates that the intrinsic behavioral

trait to pupate at shallow depths outweighed the effect of warmer and drier soil—

apparently unfavorable to most larvae. In these cases then, the physiological or

developmental state of the larvae is yet another factor influencing the vertical

distribution of Pleocoma larvae in the soil.

With other Scarabaeids a complex interaction of factors is responsible for the

vertical movements of larvae (Fidler, 1936; Smith and Hadley, 1926; Nakashima,

1952; McCulloch and Hayes, 1923; Granovsky, 1956).

Different types of soil probably influence the spatial distribution and density

of P. dubitabilis, P. simi, and P. carinata, as they apparently do larvae of other

species of Pleocoma. The larvae of P. behrensii LeConte are found in soils that

are “. . . usually of a rich loamy or clayey nature, intermixed with humus ...”

(Rivers, 1890). And in collecting P. fimbriata LeConte, Hopping (1920) always

found females “. . . in the red soil.” At the type locality of three new sympatric

Pleocoma—P. marquai Hovore, P. rubiginosa Hovore, and P. hirticollis reflexa

Hovore (all described by Hovore, 1972)—larvae showed no apparent preference

for a particular soil type as the soils vary from hardpacked, decomposing granite

to a loose clay loam. Stein (1963) summarized the available information and,

VOLUME 62, NUMBER 1

though fragmentary, it clearly demonstrates that species of Pleocoma inhabit a

variety of soils. With other Scarab genera, lighter soils are more heavily infested

with Phyllophaga than heavier ones (Seamans, 1956), and highly impervious soils

are detrimental to Japanese beetle larvae (Smith and Hadley, 1926).

Acknowledgments

Professors Paul O. Ritcher (retired) and Julius A. Rudinsky (deceased) provided

funds for this work, and suggestions and criticisms during the study.

The manuscript was kindly reviewed by Dr. Richard L. Westcott and Dr.

Richard L. Penrose of the State Department of Agriculture, Salem, Oregon, and

by Dr. Frank T. Hovore of the Placerita Canyon Nature Center, Newhall, Cali¬

fornia.

Literature Cited

Davis, A. C. 1934. A revision of the genus Pleocoma. Bull. South. Calif. Acad. Sci., 33(3): 123-130.

Ellertson, F. E. 1958. Biology of some Oregon rain beetles, Pleocoma spp., associated with fruit trees

in Wasco and Hood River counties. Ph.D. dissertation, Ore. St. Univ., Corvallis, 129 pp.

-, and P. O. Ritcher. 1959. Biology of rain beetles, Pleocoma spp. associated with fruit trees

in Wasco and Hood River counties. Ore. Agric. Exp. Sta. Tech. Bull. 44, 42 pp.

Fellin, D. G. 1968. Further observations on trapping male Pleocoma with female-baited traps (Co-

leoptera: Scarabaeidae). Pan-Pac. Entomol., 44(l):69-70.

-. 1975. Feeding habits of Pleocoma larvae in coniferous forests of western Oregon. Northwest

Sci., 49(2):71-86.

-. 1981. Observations on flight characteristics, and egg and larval biology of Pleocoma spp. in

western Oregon coniferous forests (Coleoptera: Scarabaeidae). Pan-Pac. Entomol., 57(4):461-

484.

-, and P. O. Ritcher. 1967. Distribution of Pleocoma species in Oregon with notes on the

habitats of P. simi and P. carinata (Coleoptera: Scarabaeidae). Pan-Pac. Entomol., 43(4):251-

263.

Fidler, J. H. 1936. An investigation into the relation between chafer larvae and the physical factors

of their soil habitat. J. Anim. Ecol., 5(2):333-347.

Forbes, S. A. 1907. On the life history, habits and economic relations of the white grubs and May

beetles. Bull. Illin. Agric. Exp. Sta., 116:447-480.

Granovsky, A. A. 1958. Ecological studies on the vertical movements in the life cycle of Phyllophaga.

Pp. 375-383 in Proc. 10th Inter. Congr. Entomol. Montreal, Vol. 3. Mortimer, Ottawa; 1956.

Hallock, H. C. 1935. Movements of larvae of the Oriental beetle through the soil. J. New York

Entomol. Soc., 43(4):413-425.

Hammond, G. H. 1949. Soil pH and intensity of Phyllophaga infestation. Pp. 13-18 in 79th Annu.

Report of the Entomol. Soc. of Ontario. Guelph, Ontario, Canada.

Hartzell, A., and G. F. McKenna. 1939. Vertical movements of the Japanese beetle larvae. Contrib.

Boyce Thompson Inst., 11(1):87-99.

Hawley, I. M. 1934. A preliminary report on the horizontal movement of grubs of the Japanese

beetle. J. Econ. Entomol., 27(2):503-505.

Hayes, W. P. 1929. Morphology, taxonomy and biology of larval Scarabaeoidea. Illin. Biol. Monogr.,

12(2): 1—119.

Hopping, R. 1920. Popular and practical entomology. Some winter insect life. Can. Entomol., 52(8):

217-218.

Hovore, F. T. 1971. A new Pleocoma from southern California with notes on additional species

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-. 1972. Three new sympatric Pleocoma from the southern Sierra Nevada Mountains of Cal¬

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-. 1977. New synonymy and status changes in the genus Pleocoma LeConte (Coleoptera:

Scarabaeidae). Coleopt. Bull., 31(3):229-238.

PAN-PACIFIC ENTOMOLOGIST

Knox, Ellis G. 1962. Soils. Pp. 43-45 in Richard M. Highsmith, Jr. (ed.), Atlas of the Pacific

Northwest, resources and development, 3rd ed. Ore. St. Univ. Press, Corvallis.

Linsley, E. G. 1938. Notes on the habits, distribution and status of some species of Pleocoma

(Coleoptera: Scarabaeidae). Pan-Pac. Entomol., 14(3):97-104.

Lyon, T. L., and H. O. Buckman. 1948. The nature and properties of soils, 4th ed. Macmillan, New

York, 499 p.

McCulloch, J. W., and W. P. Hayes. 1923. Soil temperature and its influence on white grub activities.

Ecology, 4:29-36.

McMinn, R. G. 1963. Characteristics of Douglas-fir root systems. Can. J. Bot., 41:105-122.

Nakashima, Toshio. 1952. Ecological studies on Anomala species (Scarabaeidae) in Hokkaido,

Sapporo, Japan. Hokkaido Univ., Coll, of Agric. Res. Bull. Coll. Exp. For., 16(1): 1-115.

Nitto, M., and K. Tachibana. 1955. An ecological study of May beetles on the coastal sand dune.

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Polivka, J. B. 1960. Effect of lime applications to soil on Japanese beetle larval population. J. Econ.

Entomol., 53(3):476-477.

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Seamans, H. L. 1956. Field crop and vegetable insects. Can. Entomol., 88(7):322-331.

Shorey, H. H., R. H. Burrage, and G. G. Gyrisco. 1960. The relationship between several environ¬

mental factors and the density of European chafer larvae in permanent pasture sod. Ecology,

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-, and G. G. Gyrisco. 1960. Effects of soil temperature and moisture on the vertical distribution

of European chafer larvae. Ann. Entomol. Soc. Am., 53(5):666-670.

Smith, L. B., and C. H. Hadley. 1926. The Japanese beetle. U.S. Dept. Agric., Circ. No. 363, 66 pp.

Stein, W. I. 1963. Pleocoma larvae, root feeders in western forests. Northwest Sci., 37(4):126-143.

Travis, B. V. 1939. Migrations and bionomics of white grubs in Iowa. J. Econ. Entomol., 32(5):

693-697.

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PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 77-82

Morphological Malformations Among Scorpions of Puerto Rico

and the Adjacent Islands

Jorge A. Santiago-Blay 1

Biology Department, Biology Museum, University of Puerto Rico, Rio Piedras,

Puerto Rico 00931.

Abstract. - Twenty-eight different malformations are detected and illustrated in

scorpions of Puerto Rico and adjacent islands. Malformations are more common

in buthids (17.5% of examined specimens) than in diplocentrids (4.7%). Pectinal

malformations are the most common among buthids (9.2%) whereas the arisal

of terminal leg spurs from tarsomere I instead of II is the most frequent among

diplocentrids (1.6%).

The “normal pattern” is a construct made after noticing a phenomenon re¬

peatedly in approximately the same way. Great deviations from the so-called

“normal pattern” are called abnormalities or, for this paper, malformations. Mal¬

formations can be intuitively viewed as very extreme values or “outliers” in a

frequency-class plot.

Malformations are one of the manifestations of biological phenomena, and,

therefore, are of interest to biology. They might be related to environmental events

such as radiation (Heatwole et al., 1970) or accidents, or to internal aspects of

the organisms in question such as molting (Curcic et al., 1983) or teratologies

(Holmberg et al., 1983; Walton et al., 1983).

When malformations affect structures of taxonomic importance problems might

arise in deciding whether the structure represents a character of taxonomic value

(Kaston, 1982; LourenQo, 1984; Mayr, 1968; Quintero, 1983; Tennenson and

Gotlfried, 1983). Usually, a thorough inspection of additional characters of the

specimen, especially if the malformation occurs in one member of paired struc¬

tures, and a good acquaintance with the group under study is very useful for

decision-making.

In scorpions striking malformations such as double tailed specimens have re¬

ceived much attention (Franganillo, 1937; Vachon, 1953). Less evident malfor¬

mations are only occasionally reported (Armas, 1977a; LourenQo, 1984) and most¬

ly in connection with taxonomic studies (Armas, 1976, 1977b; Francke, 1978).

To my best knowledge, only two preliminary attempts to evaluate the relative

occurrence of malformed structures in scorpions have been done and they show

that leg and pectine malformations are the most common and those on the telson,

pedipalps, and chelicera less frequent (Armas, 1977a; Gonzalez, 1984). These data

might be of importance in the evaluation of possible changes in the intensity of

factors causing malformations and, perhaps, might open new research avenues to

the understanding of their possible genetic basis (Curcic et al., 1983).

The purpose of this paper is to enumerate and illustrate most of the malfor-

1 Current address: Department of Entomological Sciences, University of California, Berkeley, CA

94720.

PAN-PACIFIC ENTOMOLOGIST

The acronyms herein used and their meanings are: AES (Agricultural Experiment Station, Ento¬

mology Museum, Rio Piedras, PR), BM (Biology Museum, University of Puerto Rico), JASB (author’s

personal collection), MSC (miscellaneous scorpion collections of several individuals available through

the author), UZM (Universitets Zoologisk Museum, Copenhagen, Denmark), WO (William Ortiz

personal collection available through BM), and ZM (Zoologisches Museum an der Humbolt Univer-

sitat, Berlin). Field data for each illustrated case follows figure title and scale.

Figures 1-13. 1. Reduced chelicera fixed finger of Centruroides sp. Scale line = 0.5 mm. MONA

IS: Trail from Sardinera to Capitan, 1979 (M. Alvarez and C. Aranda) (BM XVI-29). 2. Absence of

a lateral eye group of Heteronebo portoricensis Francke, 1978. Scale fine = 1 mm. GUAYACAN IS:

1 3, 22.IV.82, under rock (JASB) (JASB-196). 3. Asymmetrical carapace of Cazierius sp. Scale line =

1 mm. MONA IS: 1 3, Bajura de los Cerezos, 29.VIII.82 (C. Cianchini) (BM XVI-99). 4. Incomplete

pedipalp femur keel of Centruroides griseus. Scale line = 1 mm. BRITISH VIRGIN ISLANDS: 1 2

(subadult), Little Tobago Island, 4.IV.66 (Island Project Staff) (BM XVI-150). 5. Extra protuberance

on pedipalp chela of H. portoricensis. Scale line = 1 mm. PUERTO RICO: 1 2, Guanica, 12.III.72

VOLUME 62, NUMBER 1

mations found during the examination of 1245 specimens from Puerto Rico and

the adjacent islands and to evaluate the relative frequency of the most common

ones.

Results and Discussion

The following malformations were detected among the specimens studied: che-

licera fixed finger not reaching the level of the movable finger apex (Fig. 1), absence

of a lateral eye group (Fig. 2), carapace front margin deformed (Fig. 3), pedipalp

femur keel incomplete (Fig. 4), protuberance on pedipalp manus (Fig. 5), pedipalp

movable finger small (=not reaching the level of the fixed finger) (Fig. 6), pedipalp

movable finger large (Fig. 7), pedipalp manus and finger scarps (Fig. 8), absence

of supernumerary granules (Fig. 9), coalescence of non basal primary denticle

rows (Fig. 10), absence of primary row denticles (Fig. 11), extra supernumerary

granules (Figs. 12, 13), palp-fixed finger area incisioned (Fig. 14), terminal spurs

of legs arising from femur (Fig. 15), spurs arising from tarsomere I (Fig. 16),

tarsomeres I—II coalesced (Fig. 17), enlarged and bifid terminal spur (Fig. 18),

enlarged terminal dorsal leg spine (Fig. 19), extra pectinal tooth very reduced (Fig.

20) or deformed pectinal teeth (Fig. 21), scars on mesosomal terga (Fig. 22),

metasomal segment keels deformed (Fig. 23), incomplete (Fig. 24), or absent (Fig.

25), protuberance on metasomal keel (Fig. 26), aculeus and subaculear tubercle

deformed (Fig. 27), and telson vesicle with a scar (Fig. 28).

Malformations were found in 17.5% of the buthid specimens examined. Re¬

duced or deformed teeth in the pectines is the most common malformation (9.2%)

among specimens of this family. For example, 7.1% of the Centruroides griseus

(Koch, 1845) specimens and 3.9% of the Tityus obtusus (Karsch, 1879) examined

bear this malformation. Other commonly found malformations are: deformed

metasomal keels (3.7% of the C. griseus, 1.8% of the T. obtusus), joined primary

denticle rows (1.7% of the C. griseus, 1.4% of the T. obtusus ), and split primary

denticle rows (due to the absence of one or more of the denticles) (1.1% of the C.

griseus, 2.3% of the T. obtusus).

Among diplocentrid scorpions, malformations were found in 4.7% of the ex¬

amined individuals the most common being the arisal of the terminal leg spurs

from tarsomere I instead of II, which was detected in 1.6% of the diplocentrid

studied.

(unknown collector) (BM XVI-107). 6. Reduced movable finger of Cazierius sp. Scale line = 1 mm.

MONA IS: 1 $ (subadult), 4.VII.67 (unknown collector) (BM XVI-94). 7. Enlarged movable finger of

Centruroides griseus. Proximal arrow points possible origin of malformation. Scale line = 1 mm.

PUERTO RICO: 1 9 , Guanica State Forest, 3.IV.63 (F. Torres) (BM XVI-1). 8. Palm and movable

finger scarps of Tityus sp. Scale line = 1 mm. PUERTO RICO: 1 9 , Cayey, Guavate Forest, 3.III.77

(W. Ortiz) (WO-2). 9. Absence of a supernumerary granule of Centruroides sp. Scale line = 1 mm.

MONA IS: trail from Sardinera to Capitan, 1979 (M. Alvarez and C. Aranda) (BM XVI-29). 10.

Coalescence of non-basal primary denticle rows of Centruroides griseus. Scale line = 1 mm. PUERTO

RICO: 1 <5 [South West Puerto Rico], on a beach, 1.111.82 (R. Soto) (JASB-115). 11. Absence of a

denticle on a primary row of Tityus obtusus. Scale line = 1 mm. PUERTO RICO: 1 9 , Villalba, Toro

Negro Forest, 20.VII.82, “dry pinus” (C. J. Cianchini) (BM XVI-112). 12. Extra supernumerary

granules of Centruroides sp. Scale line = 1 mm. MONA IS: 1 9 , no more data. 13. Extra supernumerary

granules of Isometrus maculatus (DeGeer, 1778). Scale line = 1 mm. PUERTO RICO: 1 9 , El Yunque,

near La Mina, 1.X.63, loose bark (F. Torres) (BM XVI-42).

PAN-PACIFIC ENTOMOLOGIST

Figures 14-28. 14. Palm-fixed finger junction area of C. griseus incisioned. Scale line = 1 mm.

PUERTO RICO: 1 9 (juvenile), 18.XII.1888 (L. Krug) (ZM-7623). 15. Terminal leg spurs arising from

femur of C. griseus. Scale line = 1 mm. PUERTO RICO: 1 6, Faro Beach, 4.III.82 (W. Irizarry) (JASB-

145). 16. Terminal leg spurs arising from tarsomere I of Cazierius sp. Scale line = 0.5 mm. MONA

IS: Bajura de los Cerezos, 25.XI.80, under rocks (M. Alvarez and V. Quevedo) (JASB-18). 17. Co¬

alescence of tarsomeres I—II of H. portoricensis. Scale line = 1 mm. PUERTO RICO: 1 9, Ponce,

behind Holiday Inn Hotel, 30.VIII.81, under rock (M. E. Arroyo and JASB) (JASB-85). 18. Enlarged

and bifid terminal spur of C. griseus. Scale line = 0.25 mm. DESECHEO IS: 1 <3, 6.VI.80, in a Tillandsia

sp. (R. Thomas and JASB) (JASB-1). 19. Enlarged dorsal projection on tarsomere II of Centruroides

sp. Scale line = 0.5 mm. MONA IS: Mujeres Beach, 21.1.82, dry rotten tree (JASB) (JASB-11). 20.

Extra protuberance (fulcrum ?) between pectinal teeth of Centruroides sp. Scale line = 0.5 mm. MONA

IS: Meseta, unknown date (R. Santo Domingo) (BM XVI-30). 21. Deformed pectinal teeth of T.

VOLUME 62, NUMBER 1

Most of the buthids inhabiting the Puerto Rico region have about three times

more pectinal teeth than the diplocentrids, and therefore have a greater probability

of having a malformation in the pectinal teeth (assuming all other possible factors

equal). However, diplocentrids were found to have proportionately less frequency

of pectinal abnormalities than expected. On the other hand, diplocentrids tend

to be soil dwellers and are more likely than buthids to use the terminal segments

of the legs for digging in the ground (thus breaking segments and producing spurs

where they are usually not present).

Interestingly, malformations of the chelicera, chela manus or fingers, and telson,

all of which might decrease prey capture efficiency, were found very few times

(< 1%), although other malformations on structures not so directly related to prey

capture such as those on the pedipalp femur and tibia were also not frequent.

Acknowledgments

I wish to thank museum curators and workers whose help throughout the loan

of specimens and exchange of communications contributed to the fulfillment of

my M.S. thesis, a part of which this paper is: Mr. Luis F. de Armas (Coleccion

Zoologica, Academia de Ciencias de Cuba), Dr. H. Enghoff (Zoologisk Museum,

Copenhagen, Denmark), Dr. M. Moritz (Zoologishes Museum an der Humbolt

Universitat, Berlin), Mr. P. Hillyard [British Museum (Natural History), London,

Great Britain], Dr. J. E. Raastad (Zoologisk Museum, Universitet I Oslo), Dr. G.

Anderson (Goteborgs Naturhistoriska Museum, Sweden), Dr. T. Kronestedt (Na-

turhistoriska Riksmuseet, Stockholm, Sweden), Dr. G. B. Edwards (Florida State

Collection of Arthropoda, Gainesville), Dr. H. W. Levi (Museum of Comparative

Zoology, Harvard University, Cambridge, MA), Dr. N. I. Platnick (American

Museum of Natural History, New York, NY), and Dr. W. Pulawski (California

Academy of Sciences, San Francisco, CA).

Dr. Stanley C. Williams (San Francisco State University, CA) read the manu¬

script and suggested changes.

Literature Cited

Armas, L. F. de. 1976. Escorpiones del Archipielago Cubano. VI Familia Diplocentridae (Arachnida:

Scorpionida). Poeyana, 147:1-35.

-. 1977a. Anormalidades en algunos Buthidae (Scorpionida) de Cuba y Brazil. Poeyana, 176:

1 - 6 .

obtusus. Scale line = 0.5 mm. PUERTO RICO: 1 2, Orocovis, Sector Saltos Cabra, road 566, III. 1983

(Saltos Cabra School Students) (JASB-497). 22. Scars on mesosomal terga margins of T. obtusus. Scale

line = 1 mm. PUERTO RICO: 1 2, north side of Luquillo forest, 8.IV.61 (H. Heatwole) (BM XVI-

276). 23. Completely deformed metasomal keels of I. maculatus. Scale line = 1 mm. “VESTINDIEN”:

1 3, 12.VIII.1889 [M (=Meng)] (UZM). 24. Partially absent dorsal metasomal keel of T. obtusus. Scale

line = 1 mm. PUERTO RICO: 1 2, north side of Luquillo forest, 8.IV.61 (H. Heatwole) (BM XVI-

276). 25. Total absence of a dorsal metasomal keel of T. michelii. Scale line = 1 mm. PUERTO RICO:

1 2, 12.III.81 (A. Ramirez) (JASB-3). 26. Extra protuberance on a ventral metasomal keel of Tityus

sp. Scale line = 1 mm. PUERTO RICO: 1 2, Toa Baja, road 2, km 21.3, pitfall trap, 28.V.82 (JASB)

(JASB-35). 27. Partially deformed aculeus and subaculear tubercle of C. griseus. Scale line = 0.5 mm.

UNITED STATES VIRGIN ISLANDS: 1 juvenile, St. John, Caneel Bay, 4.V.83 (W. I. Knausenberger)

(MSC-2). 28. Vesicle scar of C. griseus. Scale line = 1 mm. PUERTO RICO: 1 3, Cabo Rojo, Boqueron,

12.11.82 (K. Rodriguez-Montalvo) (JASB-126).

PAN-PACIFIC ENTOMOLOGIST

-. 1977b. Redescripcion de Tityus obtusus (Karsch, 1879) (Scorpionida: Buthidae). Poeyana,

178:1-7.

Curcic, B. P. M., M. D. Krunie, and M. M. Brajkovie. 1983. Tergal and sternal abnormalities in

Neobisium Chamberlin (Neobisiidae, Pseudoscorpiones, Arachnida). J. Arachnol., 11:243-250.

Francke, O. F. 1978. Systematic revision of diplocentrid scorpions (Diplocentridae) from circum-

Caribbean lands. Sp. Publ., Mus. Texas Tech. Univ., 14:1-92.

Franganillo, P. 1937. Un monstruo aracnologico. Mem. Soc. Cubana Hist. Nat., 11:55.

Gonzalez-Sponga, M. A. 1984. Escorpiones de Venezuela. Cuademos Lagoven, 126 pp.

Heatwole, H., A. Rossy, I. Colorado, and R. Amadeo. 1970. Effects of radiation on a population of

the Puerto Rican tree snail Caracolus caracolla. In H. T. Odum (ed.), A Tropical Rain Forest.

Book 2. E-17-24. Office of Information Services. U.S. Atomic Energy Commission, Washington.

Holmberg, R. G., and E. G. Kokko. 1983. A blind Homolophus biceps (Arachnida: Opiliones).

Entomol. News, 94:49-52.

Kaston, B. J. 1982. Additional ocular abnormalities. J. Arachnol., 10:279-281.

Lourengo, W. L. 1984. Alguns casos de teratologia observados em escorpioes do genero Tityus

(Scorpiones, Buthidae). Rev. Bras. Biol., 44:9-13.

Mayr, E. 1969. Principles of systematic zoology. McGraw Hill Book Co., New York, 428 pp.

Quintero, D. 1983. Bifid spines in Paraphrynus azteca (Pocock) (Amblypygi: Phrynidae). J. Arachnol.,

11:99.

Tennenson, K. J., and P. K. Gotlfried. 1983. Variation in the structure of ligula of Tanypodinae

larvae (Diptera: Chironomidae). Entomol. News, 94:109-116.

Vachon, M. 1953. The biology of scorpions. Endevour, 12:80-89.

Walton, B. T., C. H. Ho, C. Y. Ma, E. G. O’Neill, and G. L. Kao. 1983. Benzoquinolindions activity

as insect teratogens. Science, 222:423.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, p. 83

Scientific Note

Notes on Valgus californicus Horn (Coleoptera: Scarabaeidae)

Valgus californicus is found throughout the southern Cascades and mountainous

areas of southern California. This species is mentioned as an inquiline in the nest

of the termite Zootermopsis angusticollis Hagen in the Pacific coast region by

Banks and Snyder (1920). Hinton (1930) remarked on collecting larvae, pupae

and adults beneath loose bark at the base of termite infested Sugar Pine ( Pinus

lambertiana Dougl.). He commented on the fact that the pupae were found in

cells constructed of termite castings. The third instar larvae of this species was

described by Ritcher (1966).

Linsley and Ross (1940) collected V. californicus in several localities in the San

Jacinto Mts., Riverside Co., California. All of the specimens were collected in

association with Zootermopsis sp. beneath the bark of Ponderosa Pine {Pinus

ponderosa Laws.).

During the months of April and May 1980, C. L. Bellamy, L. H. Shaw, R. K.

Yelten, and the author conducted several trips to the San Jacinto Mts. in search

of this uncommon scarab. Individuals were found in various localities, but Keen

Camp Summit, east of Mountain Center proved to be an ideal habitat. The area

had been logged many years before, leaving a number two or three foot high

stumps of P. ponderosa behind. Most of the stumps were heavily infested with

Zootermopsis. Several V. californicus were found beneath the bark at the base of

the stumps. By carefully chopping with a machete, the blind galleries in the dry,

upper portion of the stump were exposed, revealing as many as 48 individuals in

one stump. Both males, females, and copulating pairs were found in these galleries.

Termite activity was restricted to the moist environs below. Copious quantities

of termite castings had accumulated in the lower chambers and in spaces beneath

the bark. Third instar larvae were found in loose cells constructed from the

castings. No pupae were found. Attempts to rear the larvae to the imaginal stage

proved unsuccessful.

Literature Cited

Banks, N., and T. E. Snyder. 1920. A revision of the nearctic termites. Bull. U.S. Nat. Mus., 108:

1 - 211 .

Hinton, H. E. 1930. Observations on two California beetles. Pan-Pac. Entomol., 7(2):94-95.

Linsley, E. G., and E. S. Ross. 1940. Records of some Coleoptera from the San Jacinto Mountains,

California. Pan-Pac. Entomol., 16(2):75—76.

Ritcher, P. O. 1966. White grubs and their allies. Oregon State University Press, Corvallis, 219 pp.

Arthur V. Evans, Department of Entomology, University of Pretoria, Pretoria

0002, Republic of South Africa.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 84-87

Notes on the Nesting Biology of

Protosmia ( Chelostomopsis ) rubifloris (Cockerell)

(Hymenoptera: Megachilidae ) 1

Terry Griswold

Utah Agricultural Experiment Station, Utah State University, Logan, Utah

84322.

Abstract. — Nests of Protosmia ( Chelostomopsis ) rubifloris (Cockerell) (new com¬

bination) recovered from trap-nest blocks are described and aspects of the nesting

biology compared with related species. Like other Protosmia and the closely

related Heriades, P. rubifloris uses resin in constructing its nests. It apparently

differs from Protosmia (.Protosmia ) in its choice of nest site, utilizing cavities in

wood rather than snail shells, crevices in stones, or abandoned mud nests of other

bees and wasps. No parasites were found in this study. P. rubifloris was found to

overwinter as an adult, a condition uncommon among megachilids.

Protosmia ( Chelostomopsis ) rubifloris (Cockerell) is the sole representative in

the Nearctic of an otherwise Palaearctic and Ethiopian genus. It has previously

been regarded as belonging to the genus Chelostomopsis Cockerell, which is here

relegated to subgeneric rank. (Justification will be presented in a forthcoming

paper on the classification of heriadines.) This vernal bee is widely distributed in

cismontane California and sparingly north into Oregon and Washington west of

the Cascades. A disjunct population has also been recorded from the mountains

of northern Arizona (Hurd and Michener, 1955). The only previous reference to

the biology of P. rubifloris is a note that it was reared from the cones of Pinus

attenuata Lemmon in northern California (Hurd and Michener, 1955). In this

paper, notes are given on the nesting biology of another disjunct population, this

one from the higher desert ranges of the eastern Mojave Desert.

Methods

Trap-nest blocks were made from 2.5 x 15.2 cm (1" x 6") pine cut into 10 cm

lengths. Blocks were made by binding three such sections together side by side

with filament tape. Two burrows each of five hole sizes were drilled in a random

pattern into the end of each section. Hole diameters and depths were as follows:

2 mm, 45 mm deep; 3 mm and 4 mm, 60 mm deep; 6 mm and 8 mm, 90 mm

deep. An additional hole was drilled completely through the middle section to

allow attachment of the block using a nail. The design proved faulty in that the

filament tape deteriorated in the sun and heat. Consequently, the two outer sections

1 Contribution from Utah Agricultural Experiment Station, Utah State University, Journal Paper

No. 3092 and USDA-ARS-Bee Biology & Systematics Laboratory, Utah State University.

VOLUME 62, NUMBER 1

fell to the ground. Traps were put out at the beginning of April in the Providence

Mountains, New York Mountains, and the intervening Mid Hills of eastern San

Bernardino County, California. Trap sites were chosen along an elevational cline

(620-1730 meters), three traps to a site. Traps were nailed to trees (dead where

possible) or fence posts, one to two meters above the ground with entrance holes

facing southeast. They were recovered in early November. Rearing methods and

pollen analysis were as described by Parker (1981).

Results

Nesting habitat. — All nests of P. rubifloris were in the mountainous portion of

the desert at elevations of 1370 to 1650 meters in the pinyon-juniper woodland

plant community (Thome et al., 1981). Pinus monophylla Torr. and Frem. and

Juniperus osteosperma (Torr.) were common at all sites. Significant shrubby com¬

ponents of the vegetation included Artemesia tridentata Nutt., Ephedra viridis

Cov., Haplopappus spp., Guttierezia microcephala (DC.), Opuntia acanthocarpa

Engelm. & Bigel., Prunus fasciculata (Torr.), Purshia glandulosa Curran, Rhus

trilobata Nutt., Salvia dorrii (Kell.), Yucca baccata Torr., and at the lowest ele¬

vation site, scattered Yucca brevifolia Engelm. Associated cavity nesters in the

trap-nest blocks included Ashmeadiella (Arogochila) sp., Osmia marginata Mich-

ener, O. ( Chenosmia ) sp., Anthidium maculosum Cresson, Dianthidiumplatyurum

Cockerell, and at the lower elevational limit, Chalicodoma occidentalis (Fox).

Nests. -Thirty-nine nests of P. rubifloris from five sites were recovered. These

contained a total of 150 cells. Borings of 3 and 4 mm diameter were used exclu¬

sively by this bee. Assuming equal numbers of available holes, there appeared to

be no preference between the two sizes, with 18 and 21 holes respectively, utilized

(X 2 = 0.2, d.f. = 1, P > 0 .60). The number of cells per nest ranged from 1 to 7

(x = 4.0 ± 1.2, n = 37 since nests with supersedure were excluded from the anal¬

ysis). Again, no difference in number of cells was detectable between the two hole

sizes within the sample size ( t = 0.929, d.f. = 35, P > 0.30).

Nest construction. — Nest construction was initiated at the bottom of the burrow

in nearly all cases. Rarely (5% of all nests), an initial thin layer of resin less than

1 mm thick was applied to the bottom of the burrow. Cells were arranged linearly

in the burrow with 0.2 mm to 1 mm thick partitions composed of clear resin

separating the cells. Cell walls were not lined with resin though resin extended

slightly along the cell walls on both sides of the partition. Cells ranged in length

from 5 to 14 mm (Jc = 7.7 ± 1.8, n = 148). There was no significant difference

in length of cells between hole sizes (t = 0.0003, d.f. = 146, P > 0.50), perhaps

due to variations in expansion and contraction of the wood. But the length of

female cells (x = 8.5 ± 1.8, n = 34) was significantly greater ( t = 13.76, d.f. = 77,

P < 0.001) than the length of male cells (x = 7.0 ± 1.2, n = 45). Twenty-three

nests (59%) had an interstitial cell between at least two of the brood cells. In 9

nests (23%) these were present between all provisioned cells. All nests were plugged

upon completion of provisioning. Plugs varied in thickness from 1 mm to 8 mm

(x = 4.4 ± 1.9, n = 39) and were composed of translucent, colorless to golden

resin, sometimes with embedded bits of gravel. Plugs were either flush with the

nest entrance (36%) or recessed (64%) 1-19 mm within the burrow. In the former

case, the plug often bulged above the entrance. At least one vestibular cell (between

the last provisioned cell and the entrance plug) was present in 85% of the nests.

PAN-PACIFIC ENTOMOLOGIST

Four nests had two vestibular cells while two nests had three such cells. Vestibular

cells ranged in length from 3 to 29 mm (x = 11.8 ± 7.5, n = 41).

Provisions. —Pollen samples from ten cells covering four of the five sites were

analyzed. At the two lower elevation sites these consisted exclusively of Salvia

pollen. At the other two sites pollen was approximately equally divided among

Salvia, a legume, and an unknown pollen.

Cocoon and feces.— Cocoons consisted of a thin transparent white layer occu¬

pying all or nearly all of the cell. There was no nipple on the end of the cocoon.

Fecal pellets were yellow to amber, 0.6-0.8 mm long, 0.2 mm wide, sausage¬

shaped, straight or slightly curved, without a longitudinal groove, and bluntly

pinched off at both ends. Most fecal pellets were loosely clumped outside of the

cocoon at either end of the cell. A few were scattered along one side of the cell

and adhered to the outside of the cocoon. These were often flattened and occa¬

sionally were located between loose outer strands of the cocoon and the main

sheet-like layer.

Nest associates and mortality. —There were two incidents of supersedure. In

both cases P. rubifloris nested above cells of another bee: Ashmeadiella ( Arogo-

chila ) sp. in one case, Osmia (Chenosmia ) sp. in the other. One nest was destroyed

by an unknown predator which did not damage the plug or the outermost partition

but tunneled through the adjacent wood. One cell was destroyed by mold. There

was no parasitism. Immature mortality was extremely high (53%), and was likely

due, in part, to the faulty block design, which allowed the outer sections to fall

to the ground. The 62% mortality in the fallen sections was significantly higher

than the 41% mortality in the sections remaining in place (x 2 = 5.02, d.f. = 1,

P < 0.025).

Overwintering and sex ratio. —Protosmia rubifloris overwintered as an adult in

diapause. The sequence of cells in the nest normally followed a pattern of females

in interior cells and males in outer cells. In nests with two or more cells, 83% of

the first cells were female, while 85% of the outermost cells were male. Occasional

nests had the sexes intermingled or contained only male or female cells. A count

of all emerging adults plus dead pupae recognizable to sex, gave totals of 45 males

and 34 females resulting in a sex ratio of 1.32 males/females.

Discussion

Protosmia rubifloris uses resin in constructing its nests as do all other heriadines

whose nesting biologies are known. Its high developmental mortality is paralleled

by the 56.6% reported for H. carinatus by Matthews (1965). The extremely low

combined rate of parasitism-predation in P. rubifloris is comparable to the 1.6%

recorded for Heriades carinatus Cresson (Matthews, 1965) and appreciably less

than Maciel (1976) reported for H. truncorum (Linnaeus) (21.2% and 11.7% in

successive years), the only other heriadines for which such data exist. However,

this low rate may not accurately reflect the average rate for P. rubifloris since the

sample was small, and was from only one year.

The choice of nest site is similar to that recorded for most Heriades, but is in

marked contrast to that reported for typical Protosmia. Protosmia paradoxa (Friese)

(Mavromoustakis, 1939), P. exenterata (Perez) (Ferton, 1894), P. stelidoides (Pe¬

rez) (Ferton, 1909), and P. sideritis Tkalcu (1978) all nest in empty snail shells,

while P. monstrosa (Perez) uses crevices in stones (Mavromoustakis, 1939), and

VOLUME 62, NUMBER 1

P. glutinosa (Giraud) nests in the abandoned mud nests of other aculeates (Giraud,

1871).

Protosmia rubifloris differs from all other heriadines with known life cycles in

overwintering as an adult. Most Osmia and a few Megachile are the only other

megachilids reported to overwinter in this form (Stephen et al., 1969). Parker

(pers. comm.) has found a third genus of Megachilidae, the parasitic Dioxys,

overwintering as adults in the nests of Osmia. It has been suggested that this form

of life cycle is an adaptation for early spring emergence (Stephen et al., 1969).

This seems a plausible explanation for P. rubifloris. Collecting in the vicinity of

the nesting sites showed it to be one of the first megachilids active in the spring.

It was taken as early as mid April, flying with Osmia.

Acknowledgments

I wish to thank G. E. Bohart, F. D. Parker, V. J. Tepedino, and R. W. Thorp

for their manuscript reviews; and D. Veirs for analyzing the pollen samples.

Literature Cited

Ferton, C. 1894. Seconde note sur les moeurs de quelques Hymenopteres du genre Osmia Panzer,

principalement de la Provence. Act. Soc. Bordeaux, 47:203-214.

-. 1909. Notes detachees sur l’instinct des Hymenopteres melliferes et ravisseurs, 4e serie, avec

la description de quelques especes. Ann. Soc. Entomol. Fr., 77:536-586.

Giraud, J. 1871. Miscellanees Hymeopterologiques. III. Description d’Hymenopteres nouveaux avec

l’indicationdes moeurs de la plupart d’entre eux et remarques sur quelques especes deja connues.

Ann. Soc. Entomol. Fr., 1:389-419.

Hurd, P. D., Jr., and C. D. Michener. 1955. The megachiline bees of California. Bull. Calif. Insect

Surv., 3:1-247.

Maciel de A. Correia, M. 1976. Notes sur la biologie d 'Heriades truncorum L. Apidologie, 7:169-

187.

Matthews, R. W. 1965. The biology of Heriades carinata Cresson. Contrib. Amer. Entomol. Inst.,

1(3): 1-33.

Mavromoustakis, G. A. 1939. IX. On the bees of the genera Osmia and Megachile from Cyprus. I.

Ann. Mag. Nat. Hist., (11)4:154-160.

Parker, F. D. 1981. Nests and nest associates of a desert bee, Osmia marginata Michener. South¬

western Entomol., 6:184-189.

Stephen, W. P., G. E. Bohart, and P. F. Torchio. 1969. The biology and external morphology of

bees, with a synopsis of the genera of northwestern America. Agricultural Experiment Station,

Corvallis, Oregon, 140 pp.

Thome, R. F., B. A. Prigge, and J. Henrickson. 1981. A flora of the higher ranges and the Kelso

Dunes of the eastern Mojave Desert in California. Aliso, 10:71-186.

Tkalcu, B. 1978. Fiinf neue palaarktische arten der familie Megachilidae. Cas. Slez. Muz. Opava,

(A) 27:153-169.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 88-90

New Synonymy, Host, and California Records in the Genera

Dioxyna and Paroxyna (Diptera: Tephritidae)

R. D. Goeden and F. L. Blanc

(RDG) Department of Entomology, University of California, Riverside, Cali¬

fornia 92521; (FLB) 5309 Spilman Avenue, Sacramento, California 95819.

Abstract.—Paroxyna corpulenta (Cresson) is synonymized with P. genalis

(Thomson). New host-plant rearing records are reported for this redefined species.

Paroxyna sabroskyi Novak is initially recorded from a host plant, Stephanomeria

virgata Bentham, and from California. New rearing records for Dioxyna picciola

(Bigot) also are reported from the genus Coreopsis (Asteraceae).

Rearings of Paroxyna spp. from flower heads of Asteraceae collected in southern

and central California by RDG have yielded new host-plant and State records

and provided FLB new opportunity to study certain Paroxyna species taxonom-

ically. Specimens of tephritids formerly designated as P. genalis (Thomson, 1869)

and P. corpulenta (Cresson, 1907) by Foote and Blanc (1963), Foote (1967), and

Novak (1974) were reared from single samples of flower heads from each of several

plant genera and species, leading us, after close morphological examination, to

the inescapable conclusion that they are the same species.

Critical taxonomic study of the reared flies by FLB showed an intergradation

of morphological characters that until now have been used to separate populations

of genalis and corpulenta. The separation character most commonly used has been

the presence or absence of an amber color on the tip of the scutellum. Within

groups of flies reared from single head samples in the present study, a wide

variation occurred, ranging from flies with the scutellum amber over its terminal

Vi, to some with the scutellum amber only at the very tip, to some with amber

only on the ventral portion of the tip, to those with a totally dark brown scutellum.

The number or absence of very small hyaline spots in the dark area of cell r 3

directly posterior to the pterostigma also has been used to separate genalis from

corpulenta. Reared specimens in this study varied from none to three spots in

this area.

The degree of distinctiveness of the borders of the hyaline wing spots, and the

size of the hyaline spots in cell r 4+5 , are additional characters often used to separate

genalis and corpulenta. These characters were observed to be variable in all reared

samples.

The geographical distribution of the two formerly separated populations are

practically identical. Paroxyna genalis ’ records include California, Oregon, Wash¬

ington, British Columbia, N.W. Territories, Alberta, Wyoming, South Dakota,

Colorado, Utah, Arizona, and New Mexico. The distribution of P. corpulenta

VOLUME 62, NUMBER 1

Table 1. Paroxyna reared from Asteraceae flower heads in California.

Host-plant species

Sampling date

Location

No. reared as

corpu¬

lenta genalis

Venegasia carpesiodes de Can¬

dolle

30 V 1980

Gaviota, San Bernardino

Co.

Haplopappus linearifolius de

Candolle

27 V 1980

Devil’s Punchbowl, Los An¬

geles Co.

Haplopappus ericoides (Lessing)

12 XI 1980

Orcutt, Santa Barbara Co.

Hooker & Amott ssp. blakei

C. B. Wolf

Eriophyllum staechadifolium

Lagasca y Segura var. artemis-

13 XI 1980

Point Buchon, Santa Bar¬

bara Co.

aefolium (Lessing) Macbride

Layia platyglossa (Femald &

Macbride) Gray prob. ssp.

17 IV 1980

Howard Canyon, Santa Bar¬

bara Co.

campestris Keck

Senecio douglasii de Candolle

12 XI 1980

Orcutt, Santa Barbara Co.

var. douglasii

Haplopappus ericoides ssp.

7 XII 1982

Orcutt, Santa Barbara Co.

blakei

7 XII 1982

Los Osos, Santa Barbara

Co.

Madia sp. prob. elegans D.

Don

15 IV 1983

Santa Cruz Island, Santa

Barbara Co.

Senecio canus Hooker

26 VII 1983

Troy Meadows, Sequoia

Nat. Forest, Tulare Co.

25 VII 1984

Bald Mountain, Sequoia

Nat. Forest, Tulare Co.

Haplopappus linearifolius

17 IV 1984

Big Rock Canyon, Los An¬

geles Co.

Senecio integerrimus Nuttall

var. exaltatus (Nuttall) Cron-

20 VI 1984

Jackass Meadow, Sequoia

Nat. Forest, Tulare Co.

quist

Senecio douglasii var. monoen-

sis (Greene) Jepson

29 IV 1984

Silurian Hills, San Bernardi¬

no Co.

Senecio serra Hooker

25 VII 1984

Rattlesnake Creek, Sequoia

Nat. Forest, Tulare Co.

Haplopappus pinifolius Gray

16 X 1984

McCain Valley, San Diego

Co.

includes California, Oregon, Washington, British Columbia, Yukon, Alaska, N.W.

Territories, Montana, Idaho, Wyoming, Colorado, Nevada, Utah, Arizona, and

New Mexico (Novak, 1974; Blanc, unpublished data).

Rearing records of Paroxyna from mature flower heads of native Asteraceae

from central and southern California are given in Table 1. Plant nomenclature

follows that of Munz and Keck (1959) and Munz (1974). Both corpulenta and

genalis were reared from 14 of 16 flower head samples, which represents a lengthy

series of pairings of synphagous, congeneric species only observed by RDG this

once during 5 years of extensive rearings of flower heads. No other Paroxyna

PAN-PACIFIC ENTOMOLOGIST

species were reared from these 16 samples, which represent mostly new, host-

plant records for the redefined P. genalis (Wasbauer, 1972; Novak, 1974).

The authors conclude from the above morphological, distributional, and eco¬

logical data that Paroxyna corpulenta (Cresson) is a synonym of P. genalis (Thom¬

son).

Two males and one female of P. sabroskyi Novak were reared by RDG from

a quantity of flower heads of Stephanomeria virgata Bentham collected at Kennedy

Meadows, Sequoia Nat. Forest, SE Tulare Co., on 3 VIII 1983. This represents

the initial host-plant record for this species and the first record of its occurrence

in California (Novak, 1974).

New host-plant rearing records according to Novak (1974) for the closely related

tephritid Dioxyna picciola (Bigot), from mature, flower heads of four species of

Coreopsis (Asteraceae) are as follows: three males and five females from C. bigelovii

(Gray) Hall, Long Valley, Sequoia Nat. Forest, SE Tulare Co., 6 VI 1984; one

male and four females from C. douglasii (de Candolle) Hall, 3.3 km S of 29 Palms,

SW San Bernardino Co., 27 IV 1982; large, unrecorded number from C. gigantea

(Kellogg) Hall, Ocean Beach, Santa Barbara Co., 18 IV 1980; 18 males and 18

females from C. maritima (Nuttall) Hooker, Point Loma, San Diego Co., 7 IV

1980.

Acknowledgment

Our thanks to A. C. Sanders, Herbarium Scientist, Department of Botany and

Plant Sciences, University of California, Riverside, who identified most of the

plant species mentioned in this publication.

Literature Cited

Cresson, E. T., Jr. 1907. Some North American Diptera from the South West. Paper II. Am. Entomol.

Soc. Trans., 33:99-108, 1 pi.

Foote, R. H. 1967. Family Tephritidae. Pp. 568-678 in A. Stone et al. (eds.), A catalog of the Diptera

of America North of Mexico. USDA Handbook 276, 1696 pp.

-, and F. L. Blanc. 1963. The fruit flies or Tephritidae of California. Bull, of Calif. Insect

Survey, 7:1-117.

Munz, P. 1974. A flora of Southern California. Univ. of Calif. Press, Berkeley and Los Angeles,

1086 pp.

-, and D. D. Keck. 1959. A California flora. Univ. of Calif. Press, Berkeley and Los Angeles,

1681 pp.

Novak, J. A. 1974. A taxonomic revision of Dioxyna and Paroxyna for America north of Mexico.

Melanderia, 16:1-53.

Thomson, C. G. 1869. 6. Diptera. Species nova descripsit. Pp. 443-614 (=h. 12, no. 2) in K. Svenska

Vetenskaps-Akademien, Kongliga svenska fregatten Eugenies resa omkring jorden Pt. 2: Zool-

ogie, [Sec.] 1: Insekter, 617 pp., 9 pis. Stockholm, “1868”.

Wasbauer, M. S. 1972. An annotated host catalog of the fruit flies of America north of Mexico

(Diptera: Tephritidae). Calif. Dept, of Agric., Bur. Entomol., Occas. Papers, 19:1-172.

PAN-PACIFIC ENTOMOLOGIST

62(1), 1986, pp. 91-94

Biological Notes on Nomia heteropoda Say

(Hymenoptera: Halictidae ) 1

Frank D. Parker, Terry L. Griswold, and Joanne H. Botsford

USDA, ARS, Bee Biology & Systematics Laboratory, Utah State University,

UMC 53, Logan, Utah 84322.

Abstract.— Nests of Nomia heteropoda Say are described and illustrated. Nests

were constructed in sandy soil with short series of vertical cells (1-8) constructed

in lateral branches off the main burrow. Soil depth where the first cells were found

averaged 51.5 cm. No nest associates were found. Overwintering prepupae were

reared to adults. A brief comparison of nesting habits of related species is included.

The largest species of North American Halictidae, Nomia heteropoda Say, is

found throughout the southern part of the United States, with its distribution in

the Mississippi Valley extending northward (Hurd et al., 1980). Because females

prefer to nest in sand or sandy soil, populations are discontinuous throughout

this range (Blair, 1935). Surprisingly, biological information on this large and

showy species is scattered and scant. Most information is found in papers that

deal either with the systematics of the group or with biologies of other species.

For example, notes on nests discovered by Mickel and Dawson were recorded in

Blair’s (1935) systematic study. Cross and Bohart’s (1960) description of a single

nest of N heteropoda is found in a study on the biology of N. triangulifera Vachal.

A cell containing a pollen ball made by N. heteropoda was illustrated by Stephen,

Bohart, and Torchio (1969). Hurd et al. (1980) listed unpublished references on

the biology of this bee. The recent Hymenoptera Catalog (Krombein et al., 1979)

listed host plants, but failed to cite any references about its nesting habits.

This paper presents additional observations on the nests, cells, and immature

stages of N. heteropoda from a population nesting in sand dunes near Capital Reef

National Monument in Utah.

Nesting Site

A large aggregation of females (> 100) was found nesting in a sand dune formed

on the hills above the west bank of Sandy Creek, 5200', SSE Notom, Garfield

Co., Utah on September 16, 1983. The nesting site was in a 2500-m 2 blowout on

the southern slope of the dune. The nests were made in the bottom and along the

margins where the sides sloped at a 45-degree angle. The nests were characterized

and easily found by the large accumulation of sand surrounding the entrance. The

general area had abundant flowering plants of Helianthus petiolaris Nutt, which

both sexes of Nomia visited.

1 Contribution from Utah Agricultural Experiment Station, Utah State University, Journal Paper

No. 3129, and USDA-ARS-Bee Biology & Systematics Laboratory, Utah State University.

PAN-PACIFIC ENTOMOLOGIST

Figures 1-6. 1. Tumulus surrounding nest entrance. 2. Partially excavated cells made in a lateral

branch as seen from above. 3. A 3-celled series illustrating nest architecture in lateral branches. The

last cell is finished (waxed) but not provisioned. 4. Three views (dorsal, ventral, lateral) of overwintering

prepupae. Note the characteristic and extended dorsal lobes. 5. A typical cell that was excavated,

dried, and the loose sand removed. 6. Clay blocks with wax-lined holes used to rear Nomia larvae.

Nest Architecture

The entrance to each nest was surrounded by a large tumulus of sand. The

tumuli varied in shape both because of the frequent winds in the area and the

differences in ground slope. The tumuli were unusually large (about 10 cm wide

by 5 cm high, Fig. 1) and visible from a considerable distance. Nest entrances

were plugged when bees had ceased activities but were open when the bees were

foraging. Often, nest entrances were at the side of the tumulus where a vestibular

chamber was formed. These chambers appeared lined with some type of material

because they held together when the tumulus was blown away. In some nests,

VOLUME 62, NUMBER 1

however, the entrance was exposed when even this vestibular chamber had been

erased by the wind.

The initial slope of the 11-12 mm wide burrow varied from 45 degrees to

vertical. The lower portion of the burrow was vertical in all nests and extended

to an average depth of 71.8 cm (n = 4). In two nests, the burrow ended in a small

chamber where a dead female was found. The main shaft did not appear to have

a lining, although it was smooth. Cells were constructed in lateral burrows at a

60-degree angle downward from the main burrow. The average depth when

branching began was 51.5 cm (n = 9). The direction of these lateral burrows was

variable and not influenced by compass direction. There were series of cells in

each lateral burrow, and more than one lateral in two nests. The lateral burrows

were separated by as much as 10 cm between branching points along the main

tunnel.

The first cell in a lateral was 4.5 to 6 cm from the main burrow. Subsequent

cells in a series were 3 to 8.5 cm apart (n = 24) and progressively deeper (Fig. 2).

The number of cells in a lateral varied from 1-9 and averaged 3.6 (n = 13).

Individual cells were large and ranged from 33 to 45 mm long and from 10 to

12 mm wide. The top of the cell was narrowed subapically and formed a slight

neck (Fig. 3). At the time of excavation (in early November), most cells contained

overwintering prepupae (Fig. 4), but details of construction were evident in a few

incomplete cells. The basal portion of the finished cell was lined by a coating of

wax that extended up the side for 12 to 15 mm. No pollen provisions were found

during our excavations; however, Stephen et al. (1969) illustrated a pollen ball

made by this bee.

Some cells were cut from the surrounding soil and taken to the laboratory for

further study. After the sand had dried, it could be removed away from the cell

walls by gently rubbing it between the fingers. The resulting cells were elongate

(Fig. 5) and firm. Apparently, the female incorporated some type of material with

the sand during construction. The cell walls averaged 1-2 mm thick. The cells

were closed at the top by a plug of sand formed in a concentric circle with the

center left open. Above this plug, the entrance to the cell was filled with sand

(Fig. 3).

Larval feces at the bottom of the cells were deposited in short links that were

stacked on one another in a pile several mm high (Fig. 5).

No nest associates were found in this study and none were observed when the

nests were active. In some cells, spores of an unknown fungus were found on the

lining of the cell walls.

Some overwintering larvae were kept at 3°C from November until June and

then transferred to wax-lined clay blocks that were moistened and placed in petri

dishes (Fig. 6) and incubated at 30°C. Several larvae transformed to the pupal

stage and later both males and females emerged. These voucher specimens were

deposited in the collection at this Laboratory.

Discussion

The nesting biology and larval forms are similar to N. triangulifera (Cross and

Bohart, 1960). The details of nest architecture were similar; for example, the

arrangement of lateral burrows and placement of cells along the branches. More

cells/laterals were found in nests of N. triangulifera than in nests of N. heteropoda.

PAN-PACIFIC ENTOMOLOGIST

Also, the short lateral pockets along the main shaft reported in N. triangulifera

nests were not found in those of N. heteropoda. The pollen ball was similar in

both species, but obviously that of N. heteropoda was much larger. The depth of

the nests in this study were comparable, but other observers have reported N.

heteropoda nests to be much deeper (Blair, 1935). Nest depth is likely influenced

by soil moisture conditions and may be variable from site to site.

Acknowledgments

We would like to thank P. Torchio of this laboratory for use of his technique

for rearing the Nomia larvae. Our thanks to the following persons who offered

helpful manuscript suggestions: N. Youssef (Utah State University), R. Rust (Uni¬

versity of Nevada, Reno), and V. Tepedino (this laboratory).

Literature Cited

Blair, B. H. 1935. The bees of the group Dieunomia. J. New York Entomol. Soc., 43:201-215.

Cross, E. A., and G. E. Bohart. 1960. The biology of Nomia ( Epinomia ) triangulifera with com¬

parative notes on other species of Nomia. Univ. Kansas Sci. Bull., 41:761-792.

Hurd, P. D., W. E. LaBerge, and E. G. Linsley. 1980. Principal sunflower bees of North America

with emphasis on the southwestern United States. Smithsonian Contrib. Zool. 310, 158 pp.

Krombein, K. V., P. D. Hurd, Jr., D. R. Smith, and B. D. Burks. 1979. Catalog of Hymenoptera in

America north of Mexico, Vol. 2, Apocrita, pp. 1741-2209. Smithsonian Instit. Press, Wash¬

ington, D.C.

Stephen, W. P., G. E. Bohart, and P. F. Torchio. 1969. The biology and external morphology of

bees with a synopsis of the genera of northwestern America. Agric. Exper. Sta., Oregon St.

Univ., Corvallis, 140 pp.

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Pan-Pacific Entomologist

PULAWSKI, W. J .— Tachysphexperuanus, a new species related to Tachysphex galapagensis

Williams (Hymenoptera: Sphecidae). 95

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GIESBERT, E. F.—A new species of Strangalia (Coleoptera: Cerambycidae) from western

Mexico. 140

ULRICH, G. W. — Construction of a compact submersible aquatic light trap. 144

DOWELL, R. Y. and M. JOHNSON— Polistes major (Hymenoptera: Vespidae) predation of

the tree hopper, Umbonia crassicornis (Homoptera: Membracidae). 150

DARLING, D. C. and P. E. HANSON—Two new species of Spalangiopelta from Oregon

(Hymenoptera: Chalcidoidea), with a discussion of wing length variation. 153

ARNAUD, JR., P. H. and H. B. LEECH-George Pearson Holland 1911-1985 . 167

SCIENTIFIC NOTES. 119, 165

Publications received. 98, 118, 123, 149, 166

Financial statement Pacific Coast Entomological Society. 168

SAN FRANCISCO, CALIFORNIA • 1986

Published by the PACIFIC COAST ENTOMOLOGICAL SOCIETY

in cooperation with THE CALIFORNIA ACADEMY OF SCIENCES