Temnothorax rugatulus

Higher elevation coniferous forest species which occurs in moist habitats, in shaded grassy slopes with pines or grasslands. Temnothorax rugatulus can also be found in pinyon-juniper and cool desert habitats. Nests have been found in the soil, under rocks, in decaying wood, in grasses and in trees. Colonies may be monogynous, typically with a single macrogyne queen, or polygynous, with multiple microgyne queens. (Mackay 2000)

Identification
Mackay (2000) - A member of the ''Temnothorax longispinosus species complex. Workers of this species have an 11 segmented antenna, a coarsely rugose dorsal surface of the head, the dorsum (and sides to a lesser extent) of the mesosoma and petiole are rugose as the head, the propodeal spines are well developed, longer than the distance between their bases, the dorsum of the postpetiole has rough punctures.

This species can be recognized by the coarse rugae on the head, the areas between the rugae are punctured, but shiny. This characteristic separates Temnothorax rugatulus from Temnothorax bradleyi and Temnothorax smithi. It is smaller than Temnothorax josephi and is basically concolorous medium yellowish-brown, often with dark infuscation on the head and mesosoma. The node of the petiole is rounded in profile, not truncate as in Temnothorax ambiguus. The subpetiolar process is often about as wide at the tip as it is at the base, although specimens that were previously referred to as Temnothorax rugatulus tend to have a tapered subpetiolar process. The propodeal spines are well developed which separates it from Temnothorax schaumii and Temnothorax whitfordi.

Distribution
Canada: British Colombia, Alberta.

United States: Washington, Oregon, Idaho, Montana, North Dakota, South Dakota, Wyoming, California, Nevada, Utah, Colorado, Arizona, New Mexico, Texas.

Mexico: Baja California.

Distribution based on Regional Taxon Lists
Nearctic Region: Canada, United States. Neotropical Region: Mexico.

Habitat
High elevation coniferous forest, shaded grassy slopes with pines or grasslands, pinyon-juniper and cool desert habitats.

Abundance
Common.

Biology
Nests often under rocks and in crevices on the underside of coarse rocks.

Idaho
Cole (1934): 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.

Nevada
Wheeler and Wheeler (1986): In Nevada Temnothorax rugatulus records are widely scattered, but absent from the southern quarter of the state. We have 30 records from 20 localities; 4,700-9,100 ft., mostly 6,000-7,000 ft. Fifteen records were from the Coniferous Forest Biome, 5 from the Pinyon-Juniper Biome, and 4 from the Cool Desert. Five nests were under stones, 8 were in rotten wood. This is a slow-moving ant.

New Mexico
Cole (1953, 1954): Colonies of Temnothorax rugatulus Emery were observed at an elevation of 6,350 ft. at Bandelier National Monument and 5 mi. E. of Taos, 7,350 ft. At both places nests were common beneath stones on shaded grassy slopes with pines. A number of the colonies was very populous and multiple queens were present.

Foraging/Diet
An study of starvation resistance by Ruppel and Kirkman (2005) produced the following findings.

Most of a set of 21 laboratory colonies were able to survive eight months without any food. Brood decline began first (after two months) and mortality was highest, worker decline was intermediate, and queen mortality started latest and remained lowest. Brood (its relative change during the first four months and the level of brood relative to colony size) was the only significant predictor of colony starvation resistance.

Most colonies survived four months of total starvation without a significant decline. While it was found that the number of brood and workers was dramatically reduced after eight months, this time period exceeds the annual period of productive warm weather activity in most Temnothorax rugatulus habitats.

From this study they conclude that most well-fed colonies could survive a whole season without food. Internal resources and brood are suggested to be the only effective mediators of starvation resistance in this species. The amount of brood continued to increase during the first two months without food, with the brood then becoming a source of nutrients once internal reserves were depleted. Colony size was not shown to provide does not confer any survival advantage.

Colony Attributes
Colony size averaged from 54 to 141 workers (15 subpopulations), with a significant difference between pologyne (91±85 (SD)) and monogyne colonies (65±42). (Rüppell et al. 2001)

Moglich (1978) studying a population of Temnothorax rugatulus in a mixed oak-juniper forest in the Chiricahua Mountains found colonies had an average of 109 workers (range 30 to over 200).

Males fat stores were found to be 10.1±9.0 (SD) μg, n=40; macrogyne fat stores 466.4±146.9 μg, n=35; microgynes fat stores 51.4±12.3 μg, n=10. Relative fat content was not correlated with head width in microgynes (rp=–0.19, P=0.60), but was in macrogynes (rp=0.42, P=0.01).(Rüppell et al. 2001)

Nests have been found in the soil, under and between rocks, in decaying wood, in grasses and in trees. Colonies will readily emigrate to new nest locations if a nest or micro-ecological conditions become unfavorable.

Moglich (1978) studying a population of Temnothorax rugatulus in a mixed oak-juniper forest in the Chiricahua Mountains described their nests, which were found under stones. Dry brown oak leaves, juniper needles, little twigs and a diversity of other plant materials formed the bases of the nest chambers, which showed flat, often unbroken surfaces. Thus the whole colony was exposed after the stone was turned. The ants were crowded together either on the top of the material or upside down on the stone ceiling. Sometimes, however, a few small chambers were built into the base of the nest. Although the space covered by the rock measured 219 x 292 cm2 (range 32-1 800 cm2) the nest chambers were considerably smaller (24 x 17 cm2; range 2.4-63 cm2). The walls confining the nest chambers were constructed out of fine material like soil and small vegetation particles. Mean nest density was 1.5 ± 0.9 per 9.3 m2).

Reproduction
There are two queen morphs in Leptothorax rugatulus. Microgynes, slightly larger than worker size, and macrogynes, which are roughly twice as large as workers. Genetic evidence shows that queens in polygynous colonies are related to each other, supporting the hypothesis that colonies with more than one queen commonly arise by the adoption of daughter queens into their natal colonies. The higher fat content of macrogynes, their predominance in monogynous societies and in small founding colonies, and their greater flight activity favor the view that macrogynes predominantly found colonies independently, while microgynes are specialized for dependent colony founding by readoption. Despite the potential for these two mating strategies to lead to the creation of distinctive genetic subpopulations, genetic diversity is likely maintained by queens mating randomly with males. (Rüppell et al. 1998, Rüppell et al. 2001, Rüppell et al. 2003)

Nest Migration
Temnothorax rugatulus use both tandem running and carrying behavior during nest emigration. Tandem running is strictly limited to the first phase of nest emigration, whereas carrying behavior is the predominant technique (84 %). Workers which are recruited by tandem running inspect the new nest site. If they accept it, they join the scout force and lead or carry nestmates to the new nest by themselves. (Moglich 1978)

Other Insects

 * Amecocerus sp. (Coleoptera: Melyridae; det. J.M. Kingsolver) was taken in a nest of Peavine Peak (Washoe Co.) at 6,800 ft. (Wheeler and Wheeler 1986)
 * Cysticercoids of a dilepidid cestode were found by dissection of aberrant yellowish workers and virgin queens of the ant Leptothorax rugatulus from several mountain ranges in the southwestern United States. The cestode was not positively identified, but cysticercoids are similar to those of the genus Anomotaenia previously found in related ants. (Heinze et al. 1998)

Castes
There are two queen forms, a microgyne and a macrogyne. Queens and males have been collected but have yet to be described.

Nomenclature

 *  rugatulus. Leptothorax (Leptothorax) rugatulus Emery, 1895c: 321 (w.) U.S.A. Taber & Cokendolpher, 1988: 95 (k.). Combination in L. (Myrafant): Smith, M.R. 1950: 30; in Temnothorax: Bolton, 2003: 272. Subspecies of curvispinosus: Wheeler, W.M. 1903c: 241. Revived status as species: Wheeler, W.M. 1917a: 509. Senior synonym of annectens, cockerelli, mediorufus: Creighton, 1950a: 269; of brunnescens: Mackay, 2000: 394.
 * annectens. Leptothorax curvispinosus subsp. annectens Wheeler, W.M. 1903c: 242, pl. 12, fig. 13 (w.) U.S.A. Subspecies of rugatulus: Wheeler, W.M. 1917a: 510. Junior synonym of rugatulus: Creighton, 1950a: 269.
 * brunnescens. Leptothorax rugatulus subsp. brunnescens Wheeler, W.M. 1917a: 510 (w.) U.S.A. Wheeler, G.C. & Wheeler, J. 1955b: 25 (l.). Combination in L. (Myrafant): Wheeler, G.C. & Wheeler, J. 1955b: 25. Senior synonym of dakotensis: Creighton, 1950a: 269. Junior synonym of rugatulus: Mackay, 2000: 394.
 * cockerelli. Leptothorax rugatulus var. cockerelli Wheeler, W.M. 1917a: 509 (w.q.) U.S.A. [First available use of Leptothorax curvispinosus subsp. rugatulus var. cockerelli Wheeler, W.M. 1903c: 241; unavailable name.] Junior synonym of rugatulus: Creighton, 1950a: 269.
 * mediorufus. Leptothorax rugatulus var. mediorufus Wheeler, W.M. 1917a: 510 (w.q.) U.S.A. Junior synonym of rugatulus: Creighton, 1950a: 269.
 * dakotensis. Leptothorax rugatulus subsp. dakotensis Wheeler, G.C. & Wheeler, E.W. 1944: 247 (w.) U.S.A. Junior synonym of brunnescens: Creighton, 1950a: 269.

Type Material
The original description lists specimens from Colorado and South Dakota. Creighton (1950) gives the type locality as Colorado "by present restriction. Mackay 2000 - ,

Worker
Testacea, capite abdomineque magis minusve (uscatis, capite thoraceque dense punctatis et cum rugis subtilibus longitudinalibus,antennis 11 articulatis, thorace breviusculo, dorso haud impresso, spinis vix curvatis, obliquis, mediocribus, acutis; petioli segmento 1. postice modice incrassato, 2. subtrapezoideo, scapo pedibusque haud pilosis.

Etymology
Morphology, in reference to the rugosity found on the body.

References based on Global Ant Biodiversity Informatics

 * Allred D. M. 1982. Ants of Utah. The Great Basin Naturalist 42: 415-511.
 * Allred, D.M. 1982. The ants of Utah. Great Basin Naturalist 42:415-511.
 * Amanda C. S., L. H. Fraser, C. N. Carlyle, and Eleanor R. L. Bassett. 2012. Does Cattle Grazing Affect Ant Abundance and Diversity in Temperate Grasslands? Rangeland Ecology & Management 65(3): 292-298.
 * Blacker, N.C. 1992. Some Ants from Southern Vancouver Island, British Columbia. J. Entomol. Soc. Bri. Columbia 89:3-12.
 * Blacker, N.C. 1992. Some ants (Hymenoptera: Formicidae) from Southern Vancouver Island, British Columbia. Journal of the Entomological Society of British Columbia 89:3-12
 * Borchert, H.F. and N.L. Anderson. 1973. The Ants of the Bearpaw Mountains of Montana (Hymenoptera: Formicidae). Journal of the Kansas Entomological Society 46(2):200-224
 * Browne J. T., R. E. Gregg. 1969. A study of the ecological distribution of ants in Gregory Canyon, Boulder, Colorado. University of Colorado Studies. Series in Biology 30: 1-48
 * Cole A. C., Jr. 1942. The ants of Utah. American Midland Naturalist 28: 358-388.
 * Cole, A.C. 1936. An annotated list of the ants of Idaho (Hymenoptera; Formicidae). Canadian Entomologist 68(2):34-39
 * Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Des Lauriers J., and D. Ikeda. 2017. The ants (Hymenoptera: Formicidae) of the San Gabriel Mountains of Southern California, USA with an annotated list. In: Reynolds R. E. (Ed.) Desert Studies Symposium. California State University Desert Studies Consortium, 342 pp. Pages 264-277.
 * Downing H., and J. Clark. 2018. Ant biodiversity in the Northern Black Hills, South Dakota (Hymenoptera, Formicidae). Journal of the Kansas Entomological Society 91(2): 119-132.
 * Emery C. 1895. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 8: 257-360.
 * Foitzik S., and Heinze, J. 1999. Non-random size differences between sympatric species of the ant genus Leptothorax (Hymenoptera: Formicidae). Entomologia Generalis 24: 65-74.
 * Gregg, R.T. 1963. The Ants of Colorado.
 * Hoey-Chamberlain R. V., L. D. Hansen, J. H. Klotz and C. McNeeley. 2010. A survey of the ants of Washington and Surrounding areas in Idaho and Oregon focusing on disturbed sites (Hymenoptera: Formicidae). Sociobiology. 56: 195-207
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Johnson, R.A. and P.S. Ward. 2002. Biogeography and endemism of ants (Hymenoptera: Formicidae) in Baja California, Mexico: a first overview. Journal of Biogeography 29:10091026/
 * Kannowski P. B. 1956. The ants of Ramsey County, North Dakota. American Midland Naturalist 56(1): 168-185.
 * La Rivers I. 1968. A first listing of the ants of Nevada. Biological Society of Nevada, Occasional Papers 17: 1-12.
 * Lavigne R., and T. J. Tepedino. 1976. Checklist of the insects in Wyoming. I. Hymenoptera. Agric. Exp. Sta., Univ. Wyoming Res. J. 106: 24-26.
 * Mackay W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444.
 * Mackay W. P., and E. E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 400 pp.
 * Mackay, W., D. Lowrie, A. Fisher, E. Mackay, F. Barnes and D. Lowrie. 1988. The ants of Los Alamos County, New Mexico (Hymenoptera: Formicidae). pages 79-131 in J.C. Trager, editor, Advances in Myrmecololgy.
 * Mackay, W.P. and E. Mackay. XXXX. The Ants of New Mexico
 * MontBlanc E. M., J. C. Chambers, and P. F. Brussard. 2007. Variation in ant populations with elevation, tree cover, and fire in a Pinyon-Juniper-dominated watershed. Western North American Naturalist 67(4): 469491.
 * Moody J. V., and O. F. Francke. 1982. The Ants (Hymenoptera, Formicidae) of Western Texas Part 1: Subfamily Myrmicinae. Graduate Studies Texas Tech University 27: 80 pp.
 * Newton, J.S., J. Glasier, H.E.L. Maw, H.C. Proctor and R.G. Footit. 2011. Ants and subterranean Sternorrhyncha in a native grassland in east-central Alberta, Canada. Canadian Entomologist 143:518-523
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Ostoja S. M., E. W. Schupp, and K. Sivy. 2009. Ant assemblages in intact big sagebrush and converted cheatgrass-dominates habitats in Tooele County, Utah. Western North American Naturalist 69(2): 223234.
 * Parson G. L., G Cassis, A. R. Moldenke, J. D. Lattin, N. H. Anderson, J. C. Miller, P. Hammond, T. Schowalter. 1991. Invertebrates of the H.J. Andrews Experimental Forest, western Cascade Range, Oregon. V: An annotated list of insects and other arthropods. Gen. Tech. Rep. PNW-GTR-290. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 168 p.
 * Ratchford, J.S., S.E. Wittman, E.S. Jules, A.M. Ellison, N.J. Gotelli and N.J. Sanders. 2005. The effects of fire, local environment and time on ant assemblages in fens and forests. Diversity and Distributions 11:487-497.
 * Smith F. 1941. A list of the ants of Washington State. The Pan-Pacific Entomologist 17(1): 23-28.
 * Smith M. R. 1952. On the collection of ants made by Titus Ulke in the Black Hills of South Dakota in the early nineties. Journal of the New York Entomological Society 60: 55-63.
 * Snelling R.R., M. L. Borowiec, and M. M. Prebus. 2014. Studies on California ants: a review of the genus Temnothorax (Hymenoptera, Formicidae). ZooKeys 372: 2789. doi: 10.3897/zookeys.372.6039
 * Van Pelt, A. 1983. Ants of the Chisos Mountains, Texas (Hymenoptera: Formicidae) . Southwestern Naturalist 28:137-142.
 * Vasquez-Bolanos M. 2011. Checklist of the ants (Hymenoptera: Formicidae) from Mexico. Dugesiana 18(1): 95-133.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Ward P. S. 1987. Distribution of the introduced Argentine ant (Iridomyrmex humilis) in natural habitats of the lower Sacramento Valley and its effects on the indigenous ant fauna. Hilgardia 55: 1-16
 * Wheeler G. C., and E. W. Wheeler. 1944. Ants of North Dakota. North Dakota Historical Quarterly 11:231-271.
 * Wheeler G. C., and J. Wheeler. 1986. The ants of Nevada. Los Angeles: Natural History Museum of Los Angeles County, vii + 138 pp.
 * Wheeler G. C., and J. Wheeler. 1987. A Checklist of the Ants of South Dakota. Prairie Nat. 19(3): 199-208.
 * Wheeler W. M. 1917. The mountain ants of western North America. Proceedings of the American Academy of Arts and Sciences 52: 457-569.
 * Wheeler, G.C. and J. Wheeler. 1978. Mountain ants of Nevada. Great Basin Naturalist 35(4):379-396
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.
 * Wheeler, G.C. and J. Wheeler. 1988. A checklist of the ants of Montana. Psyche 95:101-114
 * Wheeler, G.C. and J. Wheeler. 1988. A checklist of the ants of Wyoming. Insecta Mundi 2(3&4):230-239