Lasius coloradensis

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Lasius coloradensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Lasiini
Genus: Lasius
Species: L. coloradensis
Binomial name
Lasius coloradensis
Wheeler, W.M., 1917

MCZ-ENT00670718 Lasius coloradensis hal3-2.jpg

MCZ-ENT00670718 Lasius coloradensis had3-2.jpg

Specimen Label

This species nests under stones in rocky soils or sandy soils.

At a Glance • Temporary parasite  
 

Identification

The workers of this species have a petiole with a relatively sharp apex (as seen from the side), which is usually concave or notched as seen from the front. The hairs on the underside of the head are usually 0.20 mm or less in length, and usually cover only the posterior 3/4 or 1/2 of the length, the hairs on the gaster are usually less than 0.22 mm in length, and are uniformly distributed across the surface. The side of the second tergum of the gaster has dilute to moderate, appressed pubescence, the pubescence on the remainder of the ant is usually only moderately abundant. (Mackay and Mackay 2002)

Keys including this Species

Distribution

Ranges from New Mexico, Colorado, and Utah north to Manitoba and west to Alberta and Oregon.

Distribution based on Regional Taxon Lists

Nearctic Region: Canada, United States (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

A dated view of Lasius coloradensis occurrence records (open circles) Wing 1968

Habitat

Ranging from prairies and deciduous forests, ponderosa pine - Gamble oak transition, to coniferous forests. (Mackay and Mackay 2002)

Biology

Wing (1968) - Of the 70 samples received for study, 6 had associated data on nests; 1 colony was under cow dung, 4 were under stones. Sandy soil was indicated in 2 of the 6 samples. Most of the samples reported as Lasius claviger by Wheeler and Wheeler (1963) are coloradensis. The data of their paper suggest that many coloradensis nests are covered by stones. In the paper by Cole (1954), the colonies reported as coloradensis are Lasius latipes. One of those reported as latipes is coloradensis (N. Beaverhead). Two of those reported as claviger are coloradensis (Bandelier and Mescalero National Monuments). The 2 nests of coloradensis that could be associated with the data of this paper were under stones on dry grassy slopes under cover of scattered trees. Based on data associated with specimens and that in the literature references cited above, the altitudinal range of this species is from below 2000 to above 7000 feet.

This species belonged to what was long considered a separate genus (Acanthomyops). Wing (1968) published a revision of that taxon, summarizing some of their biology: These ants are exclusively subterranean in their habits, except for short periods of time just before and during nuptials. Nests are built in the soil, usually under the cover of objects such as stones or logs, but sometimes, especially in the Plains States, loosely compacted earthen mounds of varying size are made. Some taxa nest partially in rotted wood; these colonies are typically found in association with stumps and logs. Most taxa in the eastern states show a preference for fairly moist conditions, selecting fields, pastures, and woodlands as nesting sites. In the western states many taxa exhibit a greater tolerance for drier conditions in the selection of their nesting sites. Most myrmecologists believe that all species of Acanthomyops are temporary social parasites of Lasius. We have, however, very little evidence on the mode or modes of colony foundation in the genus - most of it being largely circumstantial. Work done by Tanquary (1911) represents the most determined effort to date to elucidate the nature of colony foundation in the genus. Methods of colony foundation in Acanthomyops are in critical need of solid evidence from field and laboratory studies. Many species of Acanthomyops are known to regularly attend subterranean aphids and coccids, which represent a wide variety of taxa. Probably the species whose biologies are unknown likewise subsist principally on the honeydew of these homopterous insects. At the time of the nuptial flights, which are more or less characteristic as to season for a given species, the workers in mature colonies of Acanthomyops open up the nest entrance widely by excavation. Nests in this condition are found readily even before the actual flights begin to occur. Flights occurring in natural surroundings often involve the participation of an extremely large number of alate individuals. The queens and males congregate on the ground, and, when the conditions are right, fly up into the air in large numbers. Later, many descend from their flight, often giving rise to large aggregations of ants in restricted local areas; this frequently leads to concern on the part of persons residing in the area. Nuptial flights sometimes originate from the basements of homes and stores. Confronted with the evidence of flights of the latter type, which usually take place during the winter months, occupants often fear that their buildings are infested with termites.

Reproduction

Wing (1968) - Of the 13 dated samples containing alates, July 30 and September 16 are the extreme dates for those associated with workers. One sample collected on September 16 contained alate and dealate queens but no workers. Another collected on December 27 contained only dealate queens. Wheeler and Wheeler (1963) listed September 16 as the latest date for collecting winged males and females of claviger (= mostly Lasius coloradensis). A comparison of the dates cited above with those given for claviger in the general section treating nuptial flights, indicates that the flights of coloradensis average much earlier than those of claviger.

Associations with other Organisms

Nest Guests - Schwartz (1895) reported that T. Ulke collected Adranes sp. near lecontei (Coleoptera: Pselaphidae) in the Black Hills of South Dakota. The host ant, listed as claviger, was probably Lasius coloradensis.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • coloradensis. Lasius (Acanthomyops) interjectus subsp. coloradensis Wheeler, W.M. 1917a: 532 (w.q.m.) U.S.A. Combination in Acanthomyops: Creighton, 1950a: 429; in Lasius: Ward, 2005: 13. Subspecies of claviger: Creighton, 1950a: 429; Raised to species: Buren, 1950: 185. See also: Wing, 1968: 78.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Wing 1968 Acanthomyops figs. 46-54

Wing (1968) - Very closely similar to Lasius claviger, but averaging and ranging smaller. Standing body hairs more numerous and shorter; this difference between the two sibling species is especially evident on the dorsum of the gaster. Also the second and third femora frequently have at least a few suberect standing hairs. Pubescence more dilute and longer. Body color averaging darker, usually a yellowish brown to brown.

Queen

Wing (1968) - Quite similar to claviger, but SI at least 67, usually 70 or more. Antennal scapes and funiculi never more than slightly clavate. Somewhat more pilose and less pubescent. Body color darker, usually a very deep brown, often appearing nearly black to naked eye.

Male

Wing (1968) - Similar to claviger, but smaller; usually AL 1.50 mm or less, HW 0.99 mm or less, SL 0.62 mm or less, and terminal width of pygostyle 0.03 mm or less. Scale width at level of petiolar spiracles not over 1.3 times its height above spiracles. Pilosity moderate; pubescence dilute to very dilute. Body color dark brown, often appearing black or nearly black to naked eye.

Hybrids

Wing (1968) described a hybrid form of this species.

Lasius latipes × coloradensis hybrid

When the manuscript of the present revision was nearing completion, I noted that Weber (1935) had reported collecting alpha-latipes queens on September 2, 1931 from Towner, McHenry Co., North Dakota. In this paper on Formica obscuripes, he reported on their collection as follows: "Live workers, males and dealate alpha and beta females of Lasius latipes Walsh were found in digging up an obscuripes nest at a depth of about two feet (61 cm.). They did not seem to be captive and were possibly an independent colony." Upon my request, Dr. Weber sent me a beta queen and 3 "alpha" queens, 1 lacking a head. He was unable to locate the workers and males. The study of these specimens was of particular interest, because I knew of no other alpha queens collected so far outside the known range of claviger. Claviger and coloradensis are so closely related that the previous absence of records of latipes × coloradensis seemed odd, especially since latipes × claviger is our most frequently collected hybrid taxon.

A study of these specimens showed the beta female to be a perfectly typical latipes queen. The three "alpha" females resembled latipes × claviger queens closely enough to pass for small variants of this hybrid. Assignment of these queens to latipes × coloradensis was based both on structural characters, largely metric, and the known ranges of claviger and coloradensis.

Queen

Bears a close resemblance to latipes × claviger, from which it cannot readily be separated.

Ranging and averaging smaller for most metric characters, but with AL, CI, and FI about the same, and SI higher than in latipes × claviger. Minor differences from latipes × claviger in conventional characters are: antennal scapes slightly less clavate, petiolar scale crest a little less blunt, and slight color differences. The head and appendages are light yellowish brown; the rest of the body a darker brown. Only a small proportion of the latipes × claviger queens appear bicolorous; they range and average somewhat darker than latipes × coloradensis.

Type Material

Wing (1968) - Type locality: Manitou, El Paso Co., Colorado. Location of types : Syntypes in the Museum of Comparative Zoology.

References

  • Bolton, B. 1995b. A new general catalogue of the ants of the world. Cambridge, Mass.: Harvard University Press, 504 pp. (page 53, catalogue)
  • Buren, W. F. 1950. A new Lasius (Acanthomyops) with a key to North American females. Proc. Entomol. Soc. Wash. 52: 184-190 (page 185, Raised to species)
  • Creighton, W. S. 1950a. The ants of North America. Bull. Mus. Comp. Zool. 104: 1-585 (page 429, Combination in Acanthomyops, and subspecies of claviger.)
  • Mackay, W. P. and E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, NY.
  • Ward, P.S. 2005. A synoptic review of the ants of California (Hymenoptera: Formicidae). Zootaxa 936: 1-68 (page 13, revived combination in Lasius (Acanthomyops))
  • Wheeler, W. M. 1917a. The mountain ants of western North America. Proc. Am. Acad. Arts Sci. 52: 457-569 (page 532, worker, queen, male described)
  • Wing, M. W. 1968a. Taxonomic revision of the Nearctic genus Acanthomyops (Hymenoptera: Formicidae). Mem. Cornell Univ. Agric. Exp. Stn. 405: 1-173 (page 78, see also)