Lasius crypticus

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Lasius crypticus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Lasiini
Genus: Lasius
Species: L. crypticus
Binomial name
Lasius crypticus
Wilson, 1955

Lasius crypticus casent0005402 profile 1.jpg

Lasius crypticus casent0005402 dorsal 1.jpg

Specimen labels

This species nests under stones in sandy soils to rocky loam soils. One nest was in a log. Brood was found in nests from March to August. A dealate female was collected on 5-viii-1994, under a stone. We collected foragers feeding on a dead beetle. Monomorium minimum lives in the nest. (Mackay and Mackay 2002)

Identification

All of the hairs on the scapes are appressed (except at apex). The eye is relatively large with 12 - 14 ommatidia in maximum diameter. The penultimate basal tooth is greatly reduced in size as compared to the adjacent basal teeth, and is often absent. This results in a wide gap between the other two basal teeth. It is advisable to look at a large series, as the small tooth differs greatly in size within a nest series, and sometimes between the two mandibles of a single individual. It is often difficult to separate this species from Lasius americanus, unless a large series is available. (Mackay and Mackay 2002)

Key to Lasius workers, queens, males

Keys including this Species

Distribution

Lasius crypticus has its center of abundance in the Great Plains of the western U. S. It apparently stops abruptly at the edge of the eastern deciduous forest, having never been collected east of the eastern tier of counties of North Dakota. It is relatively common in the Rocky Mountains and Great Basin, and reaches as far west as California, Oregon and Washington.

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Habitat

In New Mexico (Mackay and Mackay 2002) - Sagebrush, grasslands, pinyon-juniper, oaks woodlands, meadows, ponderosa pine-riparian, Douglas fir.

Biology

Wilson (1955) - The following generalizations are based on a few of my own observations along with field notes supplied me by G. C. Wheeler, A. C. Cole, and Borys Malkin. crypticus is most abundant in prairies and tends to replace neoniger in the most dry, exposed situations. In eastern Montana and southern Idaho it was found thriving in a short-grass prairie-semidesert transition. At Cascade, Idaho, and in several localities in New Mexico, it was taken in open pine forest. At Green Canyon Hot Springs, Idaho, it was found in dry willow-poplar woods. In the great majority of cases it has been found nesting under stones, but occasionally (e.g. Donnelly and Cascade, Idaho) it constructs neoniger-like craters in open soil.

No nuptial flights of this species have been recorded. Winged reproductives have been taken with workers from July 9 (Great Falls, Mont.) to August 31 (holotype nest series, Pembina Co., N. Dak.). The majority of such records fall in the last half of July and first half of August. This would seem to be strong prima-facie evidence that the reproductive period of crypticus precedes that of neoniger.

Castes

Nomenclature

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

  • crypticus. Lasius (Lasius) crypticus Wilson, 1955a: 104 (w.q.m.) U.S.A.

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

Description

A western North American species very similar to Lasius neoniger, differing principally in the scarcity of hairs on the scapes and fore tibiae, and by the darker body coloration of the worker and queen. Linked to the "neoniger complex" by the possession of clypeal and dentition characters detailed in the description of neoniger. Superficially resembles Lasius americanus and has been consistently determined as that species by past authors.

(1) In all three castes standing hairs are invariably absent on the scapes and fore tibiae along the plane of count (seta count, q. v.), while appressed decumbent hairs are rare or absent. These surfaces are covered only by a short, predominantly appressed pubescence.

(2) The worker and queen are almost invariably dark brown, rarely medium brown, opposed to the typically light brown coloration of neoniger. The males of the two species show broadly overlapping dark brown coloration.

(3) The worker has a proportionately shorter scape length than in neoniqer, a small number of series of medium-sized to large workers, when measured, fell between the alienus-niger and brunneus SI-HW regression zones, while several nanitic series fell along the extrapolated brunneus zone. However, crypticus and neoniger are too close to give this character diagnostic value by itself.

Type Material

Wilson (1955) - HOLOTYPE. A worker in the MCZ, selected from a large nest series collected four miles north of Gardar, Pembina Co., N. Dak., Aug. 31, 1949, with associated winged queens and males (E. L. Krause leg., ace. no. 138). PW 0.52 mm., HW 0.79 mm., SL 0.70 mm., SI 90, EL 0.19 mm., seta count O. Paranidotypes are in the Museum of Comparative Zoology, National Museum of Natural History, UMMZ, G. C. Wheeler Coll., Creighton Coll., and Cole Coll.

References

  • Mackay, W. P. and E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, NY.
  • Wilson, E. O. 1955a. A monographic revision of the ant genus Lasius. Bull. Mus. Comp. Zool. 113: 1-201 (page 104, worker, queen, male described)