Temnothorax gallae

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Temnothorax gallae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Temnothorax
Species: T. gallae
Binomial name
Temnothorax gallae
(Smith, M.R., 1949)

Temnothorax gallae casent0005684 profile 1.jpg

Temnothorax gallae casent0005684 dorsal 1.jpg

An arboreal nesting species that has been found inhabiting cynipid galls on the canyon live oak (Quercus chrysolepis Liebm.) and galls of Andricus spectabilis (Mackay, 2000). It is likely to be found in different types of oak woodland habitats.

Identification

Mackay (2000) - A member of the Temnothorax tricarinatus species complex. The entire dorsum of the head of this species is usually sculptured, with fine costulae mixed with the background punctures and the antenna has 12 segments. The propodeal spines are well developed, longer than the distance between the bases (shorter in smaller workers). The sides of the pronotum are rugose, as well as the top of the mesosoma (can be seen most easily by looking obliquely from the side), but the rugae on the sides of the pronotum are poorly defined and mixed with the background punctuation, and not shiny in the intrarugal surfaces. The rugae are somewhat mixed with the background punctures. The node ofthe petiole is somewhat sharp in profile, the top of the node is coarsely reticulo-rugose, and looks "pinched" or constricted laterally as seen from top, the subpeduncular tooth is well developed. The erect hairs are all blunt and short (about 0.05mm).

This species is similar to chandleri (see discussion of Temnothorax chandleri for details). It is easy to confuse with Temnothorax mariposa (=nitens), due to the shape of the petiole (also sharp in profile, but can be separated by the roughly sculptured head, which is predominantly smooth and shining in Temnothorax mariposa, and by the longer propodeal spines, much longer than space between bases, spines of Temnothorax mariposa about half the length of the distance between the spines). This species could also be confused with Temnothorax nevadensis. It differs in that the propodeal spines are long (nearly twice length of distance between bases), and are slightly incurved at the tips. The petiole has an appearance that it has been pinched from the sides, resulting in the sides of the node being slightly concave in the middle. In comparison, the propodeal spines of Temnothorax nevadensis are about the length of the distance between their bases (or less), but are also slightly incurved. The petiole is usually rounded or somewhat truncate in profile, but is not "pinched" from the sides and the top of the node is convex. This latter species is usually light brown in color. Temnothorax gallae is usually dark brown in color. This species superficially resembles Leptothorax muscorum, but has a well-defined medial carina on the clypeus.

Keys including this Species

Distribution

USA. California.

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Habitat

Nests in canyon oaks, in galls, and likely to be found in different types of oak woodland habitats.

Abundance

Not commonly collected.

Biology

Not much is known about the the biology of Temnothorax gallae. We can speculate that the biology of this species is likely to be similar to other North American species of this genus.

Temnothorax is a diverse genus but most species do show a remarkable consistency in some important aspects of their biology. Workers and colonies are small. As a group they nest in many places: small cavities in the soil, under or among stones or in small cavities in living or dead vegetation. Individually, most species have a strong preference for how and where they nest, e.g., there are gall nesting species, soil nesters, arboreal species, those that nest in small downed twigs, etc. Their nest entrances are often a cryptic, tiny hole that is only found by observing a worker exiting or entering the nest. A few common and abundant species are relatively well studied but the majority are rare or are rarely collected. For all but the most common and abundant species finding a nest is difficult because of the combination of their small colony size, small workers, unaggressive behavior, and diminutive, inconspicuous nests. In a few cases where we do know the diet of a species, it consists of sweet exudates and general scavenging of insect pieces and other items. It is presumed most of the unstudied Temnothorax have a similar diet. Aphid tending and hunting small soil arthropods may also be a part of their foraging repertoire. For all the consistency in these characters, individual species exhibit wide variation in others. Habitat affinities are often restrictive at the species level (but overall Temnothorax can be found in places that range from high elevation, high latitude, forests to hot, dry desert regions). Queen number is difficult to predict; there are species that are polygnous, monogynous, and even some species with seasonal polydomy that vary in nesting site queen number over the course of the year. There is also little consistency in color from species to species.

Associations with other Organisms

Other Insects

Smith (1949) reports Temnothorax gallae has been collected from twig galls made on the canyon live oak by the cynipid Heteroecus pacificus(Ashm.), H. sanctaeclarae (Fullaway) and Disholcaspis truckeensis (Ashm.) and Mackay (2000) states they will also nest in galls of Andricus spectabilis.

Plants

Nests in galls on canyon live oak Quercus chrysolepis (Liebm.).

Nomenclature

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

  • gallae. Leptothorax (Leptothorax) gallae Smith, M.R. 1949e: 112 (w.) U.S.A. Combination in L. (Myrafant): Smith, D.R. 1979: 1393; in Temnothorax: Bolton, 2003: 271. See also: Mackay, 2000: 346.

Type Material

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

Description

Worker

Worker.--Length 3 mm. Head measured through its greatest breadth and length, one and one-seventh times as long as broad, with approximately straight posterior border, rounded posterior corners and weakly convex, somewhat subparallel sides. Eye rather large, located at approximately the middle of the side of the head. Antenna 12-segmented; apex of scape failing by more than its greatest diameter to attain the posterior border of the head; funiculus with a 3-segmented club, which is scarcely longer than the remainder of the funiculus, last segment of the club longer than the combined length of the two preceding segments. Frontal area present but not strongly defined. Middle of the anterior border of the clypeus with a distinct but weak impression or emargination. Mandible 5-toothed. Thorax slender, highest in the vicinity of the junction of the promesonotum, sloping both anteriorly and posteriorly from this region; from above, widest in the pronotum and narrowest at the base of the epinotal spines, with rounded humeri and obsolescent or missing dorsal thoracic sutures, also lacking the mesoepinotal impression. Epinotal spines fairly robust, not strongly divergent, longer than the distance between their bases. Femora and tibia, especially the former, noticeably incrassated. Peduncle of petiole with a small but distinct anteroventral tooth. Petiolar node, in profile, angular, the anterior slope almost straight, the posterior slope shorter and more irregular than the anterior. Postpetiolar node, from above, about one and one-fourth times broader than long, with rounded humeri and subparallel sides, somewhat constricted in the posterior half. Gaster with distinct angles.

Mandibles striate, also punctate. Clypeus with about 7 to 9 prominent carinae, one of them median and the other lateral. Head densely and minutely punctate with the front bearing delicate longitudinal rugulae. Cheeks rugulose or rugulosepunctate. Thoracic dorsum rugulosepunctate, the rugulae most evident on the promesonotum; meso and metapleurae longitudinally rugulose punctate. Petiolar and postpetiolar nodes more minutely rugulosepunctate than the thorax.

Head, thorax, petiole and postpetiole subopaque frontal area and gaster shining. In some lights the head is almost shining.

Body with moderately abundant, coarse, suberect to erect, pale yellowish or grayish hairs; those on the gaster more abundant than elsewhere. Antennae and legs hairless, bearing only appressed pubescence.

Brown; posterior part of gaster and much of head blackish.

Queen

Queens have been collected but this caste is undescribed.

Male

Males have been collected but this caste is undescribed.

Etymology

Descriptive. Named for its propensity to nest in galls.

References

  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 271, Combination in Temnothorax)
  • MacKay, W. P. 2000. A review of the New World ants of the subgenus Myrafant, (Genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology. 36:265-444.
  • Smith, D. R. 1979. Superfamily Formicoidea. Pp. 1323-1467 in: Krombein, K. V., Hurd, P. D., Smith, D. R., Burks, B. D. (eds.) Catalog of Hymenoptera in America north of Mexico. Volume 2. Apocrita (Aculeata). Washington, D.C.: Smithsonian Institution Pr (page 1393, Combination in L. (Myrafant))
  • Smith, M. R. 1949e. A new Leptothorax commonly inhabiting the canyon live oak of California (Hymenoptera: Formicidae). Psyche (Camb.) 56: 112-115 PDF
  • Snelling, R.R., Borowiec, M.L. & Prebus, M.M. 2014. Studies on California ants: a review of the genus Temnothorax (Hymenoptera, Formicidae). ZooKeys 372, 27–89 (doi: 10.3897/zookeys.372.6039)