A. C. Cole.
An Annotated List of the Ants of the Snake River Plains, Idaho (Hymenoptera: Formicidae).
Psyche 41(4):221-227, 1934.

This article at Hindawi Publishing: https://doi.org/10.1155/1934/81264
CEC's scan of this article: http://psyche.entclub.org/pdf/41/41-221.pdf, 468K
This landing page: http://psyche.entclub.org/41/41-221.html

The following unprocessed text is extracted automatically from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

19341 Ants of the Snake River Plains 221 AN ANNOTATED LIST OF THE ANTS OF THE
SNAKE RIVER PLAINS, IDAHO
(HYMENOPTERA :FORMICIDAE)
BY A. C. COLE, JR.
Twin Falls, Idaho
The ants of the Snake River Plains region, while compris- ing relatively few forms in comparison with other areas, are, however abundant in so far as the number of colonies is concerned. Floristically, the region is divided into (1) the vast semidesert plains of sagebrush, rabbitbrush, grease- wood, shadscale and bromegrass; (2) the tall perennial grass upland habitats, in which grow the Agropyrons and Stipas and subalpine meadow vegetation; and (3) the moun- tainous and hilly areas, chiefly inhabited by western yellow pine, with juniper and alder at slightly lower elevations. 1. Pogonomyrmex occidentalis Cresson1
This is the dominant and most abundant ant of the semi- desert areas. It usually builds pebble mounds with cleared surrounding area. Winged forms appear from late June to late July. Food consists of seeds of many plants although chiefly those of Bromus tectorum L. (Downy Bromegrass) when present. Crater nests of Dommyrmex pyramiczis are occasionally on the mound faces and in the denuded areas. 2. Pheidole californica Mayr.
This ant is abundant in sagebrush areas of the Snake River Canyon but decreases in number with northward pro- gression, being only occasional in the tall grass meadows. It nests beneath rocks, usually on hillslopes. Colonies are rather populous.
Soldiers are present, in proportion to
workers about one to ten. Food consists chiefly of small seeds and some insects. Winged forms appear in August. 'Determinations and checkings by Dr. M. R. Smith,



================================================================================

222 Psyche [~ecember
3. Pheidole oregonica Emery
P. oregonica occupies the same habitats as does P. cali- fornica, but its colonies are usually less populous. 4. Leptothorax curvispinosus rugatulzis Emery This ant is rather frequent in moist habitats near Twin Falls, Hagerman and Buhl, chiefly along the Snake River. Colonies are small, the workers timid and sluggish and the brood scant. Winged forms appear at Twin Falls in late September.
5. Leptothorax eldoradensis Wheeler
The species eldoradensis occurs in small numbers near Twin Falls, where it occupies small crater nests in moist areas.
6. Monomorium minimum Buckley
Occurring in small numbers, this species occupies either minute crater-nests or nests beneath fallen timber and loose rocks.
The populous colonies often contain several queens each. Winged forms appear in the nests from the middle of June to late August.
7. Monomorium pharaonis L.
One colony of this species was found under a house near Twin Falls. This locality is decidedly out of its normal range.
8. Solenopsis molesta Say
This ant is occasionally found beneath rocks in moist habitats throughout southern Idaho, and is usually observed in the superficial nest chambers of other ants (Formica fusca subsericea and F. fusca neorufibarbis Emery). 9. S. molesta validiuscula Emery
Much more abundant than the typical species, colonies of this variety are widely scattered throughout the region un- der discussion, but make their appearance only in moist areas. The nests are similar to those of the typical molesta but are more isolated and of smaller size.



================================================================================

19341 Ants of the Snake River Plains 223 10. Manica mutica Emery
One colony of this ant was observed beneath a large rock along a stream, thirty-five miles south of Twin Falls. It was quite small and the occupants, all workers, were sluggish and unoff ensive.
11. Myrmica brevinodis Emery
Three nests of this species, which is rather abundant in the Middle West, were beneath rocks in a very moist Agro- pyron repens area near Twin Falls.
12. M. brevinodis sulcinodoides Emery
Several colonies of this variety were beneath rocks in Hordeum jubatum areas along streams at Twin Falls. The workers were abundant and very sluggish. Winged forms appeared in the nests during early July. 13. Aphaenogaster uinta Wheeler
Six large colonies of uinta nested beneath rocks in the moist Snake River Canyon, near Twin Falls. Only the work- ers were found, all of whch were very timid. *
14. A. subterranea occid entalis Emery
This variety is rather commonly distributed in moist areas, where it builds small nests beneath rocks. Winged forms apear in July and August, depending upon the locality. 15. Stenarnma brevicorne var.
This undetermined variety of brevicorne is of lesser im- portance in the Twin Falls area, where it occupies very minute nests near streams or in other moist habitats. 16.
Crematogaster lineolata var. (near cerasi Fitch) Large colonies of this ant abounded beneath flat rocks throughout the semidesert area, being more numerous, how- ever, in rather moist places. Each colony contained many queens. Winged forms appeared in late June near Twin Falls.
17. Dorymyrrnex pyramicus Roger
Nests of this species-were found in limited numbers near



================================================================================

224 Psyche [December
Twin Falls, occupying small, flat crater-nests of fine sand, in open areas of the sagebrush semidesert, and occasionally on the faces and in the denuded areas of mounds of Pogono- myrmex occidentalis Cresson.
18. Tapinoma sessile Say
Large colonies of this very common and well known ant are beneath rocks in moist places. Winged sexes appear in late June at Twin Falls.
19. Zridomyrmex pruinosus var.
Populous colonies of very active workers of an un- described variety of pruinosus were found near Hagerman, inhabiting aggregated crater nests of fine sand in an area of greasewood.
20. Lasius niger americanus Emery
This very common occupant of the more moist areas throughout the state, nests beneath fallen timber or rocks, and more rarely occupies small, rude crater-nests of earth or sand. The workers are abundant and much brood develops into winged forms throughout June, July and August, de- pending upon the location of the nests. The ants are secre- tivorous and in some cases also scavengeristic. 21. L. niger sitkaensis Pergande
Although less common than the variety, americanus, sit- kawis is, nevertheless, a rather frequent occupant of moist places.
Its nests and habitats are almost identical with those of americanus.
22. L. umbratus mixtus aphidicola Walsh
This variety lives beneath stones in very moist areas throughout the Snake River Plains.
Its food consists chiefly
of secretions from aphids and coccids which are attended in the nests.
23.
Polyergus ruf escens breviceps Emery
Only one nest of this species, which contained many work- ers of Formica fusca subsericeal, was observed by the writer. 'Slave complex.




================================================================================

19341 Ants of the Snake River Plains 225 It was beneath a large flat rock on a dry sagebrush-covered hillslope in the Snake River Canyon, near Twin Falls. 24. Myrmecocystus melliger semirufus var. Numerous crater nests, about six inches in diameter, pre- dominated in a semidesert sand dune area near Indian Cove, and have also been found on sand hills near Buhl. The pop- ulous colonies contained both males and females in early June at Indian Cove. Repletes were not present. 25. M. yuma Whir.
Many small crater nests of fine sand were found on a sagebrush plain near Hammett.
The workers were very
active.
Winged forms appear in the nests during early July. Repletes were not found.
26. M. mexicanus var.
Sandy crater nests of an undescribed variety of mexicanus abounded in a sandy area near Indian Cove. Other localities include Hollister and Twin Falls. Males and females ap- peared in the nests in early June near Indian Cove and in late June near Twin Falls. True repletes were not present in the nests.
27.
Camponotus maculatus vicinus nitidiventris Emery This variety abounds beneath rocks in the more moist places of the sagebrush plains and in wooded areas of aspen and western yellow pine at higher elevations. The colonies
are large and the workers active. Males and females appear in the nests throughout June and July near Twin Falls. I have taken this ant as far north as Boise. 28. C. hyatti Emery
A very few colonies of this species were beneath rocks on rather moist sagebrush and bromegrass-covered hillslopes near Twin Falls.
29. C. modoc Whir.
This species is abundant in pine and aspen groves south of Rogerson. It inhabits nests in moist, rotting logs.



================================================================================

226 Psyche [~ecember
30. Formica rufa obscuripes Fore1
This ant is a very common occupant of the Snake River Plains? where? as populous colonies? it inhabits large thatched mounds, usually surrounding plants of sagebrush. It has been taken by the writer as far north as Stanley, where it is replaced by the variety melanotica Emery. Winged sexes appear during late June near Twin Falls. 31. F. subpolita Mayr.
Common to the semidesert plains and occurring through- out the state, this species is found inhabiting nests beneath rocks, and less commonly small crater mounds. Winged forms appear in early July at Twin Falls. Coccids and pseu-
doscorpions have been removed from nest chambers. 32. F. subpolita camponoticeps Whlr.
This variety is of less common occurrence than is the typ- ical species but? nevertheless, very often nests beneath rocks under similar conditions and in the same localities as the typical subpolita. Workers were infested with the fungus Laboul benia formicarum Thaxter.
33. F. fusca neoruftbarbis Emery
F. neorujibarbis lives beneath rocks or in earthen mounds in rather moist, shady and grassy areas throughout the Snake River plains. It feeds chiefly on honeydew and dead insects.
34. F. fusca subsericea Say
This very common ant is found in practically all parts of the region where it inhabits nests beneath rocks or occupies large earthen mounds.
35. F. fusca s~ba~enescens Emery
F. subznescens is more rare than is subsericea and occu- pies more moist habitats.
Where found? the nests are be-
neath large rocks.
The an thas been collected near Twin
Falls and Stanley.
36. F. neogaga,tes Emery
A few nests of this species have been found by the writer



================================================================================

19341 Ants of the Snake River Plains 227 in a deep canyon near Twin Falls. These were rather small and were beneath rocks on moist hillslopes covered with bunchgrass (Agropyron sp.) .
37. F. sanguine's subnuda Emery
Nests of subnuda were found, although rather infre- quently, from the southern border of the state northward to Boise.
The small colonies, in which abounded workers of F. fusca subsericea as slaves? were beneath large rocks in moist sagebrush areas.
38. F. sanguinea puberula Emery
Several small colonies of this ant were observed near Nampa, on the sagebrush plains.
Many of the adults were
infected with the fungus? Laboul benia f ormicarum Thaxtero 39. F. oreas comptula Wheeler
Three nests of this rather uncommon ant were found by the writer near Rogerson, beneath large flat rocks on a sage- brush-covered hillslope. Winged forms appeared in early July. Each of the nests contained two or three beautiful golden-yellow queens.
40. F. Zasioides vetula Whlr.
Several colonies of this ant were found at the upper limits of the Snake River Plains. The ants live beneath rocks in moist areas of abundant vegetation.




================================================================================