Solenopsis texana

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Solenopsis texana
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species complex: molesta
Species: S. texana
Binomial name
Solenopsis texana
Emery, 1895

Solenopsis-cf-texana-MCZ001L.jpg

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Specimen Label

Synonyms

Solenopsis texana nests under ground, most specimens are collected in pitfall traps or in litter extractions. Pacheco and Mackay (2013) - One colony was collected under a stone in a Brachymyrmex sp. nest. This species nests in soils ranging from light brown clay to rocky loam. It is occasionally found in hollow twigs with Pseudomyrmex sp., with Tapinoma sp. and Camponotus tepicanus. Brood was collected in nests in May and September. A loose queen was collected in July suggesting flights occur then. Many specimens were collected in pitfall traps. It has been collected in a subterranean pitfall trap, or in litter extractions. Many other specimens were found in surface, subterranean and vegetation baits, including meal worms, fire ant bait and Vienna sausages as well as tuna fish baits.


At a Glance • Polygynous  

 

Photo Gallery

  • Workers with brood.
  • Typical habitat

Identification

A New World thief ant that is a member of the molesta species complex. (Key to New World Solenopsis Species Complexes)

Pacheco and Mackay (2013) – Worker - This species is minute and concolorous pale yellow to medium brown. The minor funicular segments are short at 0.100 rom in total length. The lateral clypeal teeth are angular and the extralateral teeth are solely present as bumps. The petiole is smooth and shiny with a ventral angle. Queen - It is necessary to have a queen as part of the series, in order to correctly identify this species. The queen is small, medium brown to yellowish-brown, with relatively small eyes (0.160 rom in greatest diameter). The metapleuron has horizontal striae and the sides of the petiole and postpetiole are finely striate, with scattered punctures. They are easily recognized by the color and the relatively small size of the eye. Male - The male is dark brown with pale brown appendages, with a head wider than long and developed clypeal carinae. The subpeduncular process is developed into a small angle. The dorsum of the petiole is low and rounded and the apex of the postpetiole is flattened.

Without queens, identification is very difficult, as workers are similar to those such as Solenopsis carolinensis, Solenopsis abdita and Solenopsis pollux.

They are most difficult to separate from Solenopsis carolinensis as they are nearly morphologically identical and their distributions overlap. The posterior tibial hairs are mostly appressed in S. texana, whereas they are mostly suberect in S. carolinensis, although this characteristic is highly variable. If more than half of the specimens in a series have suberect hairs present on the posterior tibiae, the series is more than likely to be S. carolinensis. They are separate species, as the queens are very different (with the eyes of S. carolinensis being very large), correct identifications of workers are extremely difficult.

Distinction from S. abdita is easier, as S. texana has a relatively longer scape, a relatively narrower petiole and is lighter in coloration (compared to the darker brown S. abdita). Moreover, S. abdita is reportedly only found in Florida, where S. texana apparently does not occur.

Solenopsis pollux is similar morphologically, and the two species overlap extensively in distribution. Workers of S. pollux have more than ten erect hairs on the promesonotum, whereas in S. texana there are nearly always fewer than 10 erect hairs, so in most cases, workers can be separated.

This species is also similar to Solenopsis salina, but can be separated as its cephalic punctures are fine and the lateral clypeal teeth are usually straight, while the cephalic punctures of S. salina are moderately coarse and the lateral clypeal teeth are often bent inward.

Workers of S. texana in Mexico can be easily confused with Solenopsis patriciae. Solenopsis texana workers are slightly less hairy, usually with fewer than 15 erect hairs on the first gastral tergum when viewed in profile, and most are shorter than 0.035 mm in length, whereas there are more than 15 in S. patriciae and most are longer than 0.036 mm in length. If there are queens in a series, it can be easily recognized as they are larger (see key) and brown in color, as compared to the smaller dark brown queens of S. patriciae. Solenopsis texana is much more common in Mexico than is S. patriciae (which is known only from the type locality in Tabasco) so a questionable series is probably S. texana.

This species could be confused with Solenopsis molesta as well. The minor funicular segments of S. texana are short, being less than 0.10 mm, while these segments of S. molesta are typically 0.15 mm in total length. The lateral clypeal teeth are poorly developed, but well developed with S. molesta.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Nearctic Region: Canada, United States (type locality).
Neotropical Region: Colombia, Costa Rica, Mexico, Panama.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Habitat

Pacheco and Mackay (2013) - Specimens were found in a variety of plant communities, including arid thorn shrubland, grasslands with scattered oaks, beech/magnolia forest, pine/hardwood forest, hardwood/oaks, riparian oak/cottonwood, disturbed rain forest, wet transitional tropical forest, montane hardwood/cloud forest transition, dense second growth tropical forest, old growth dry tropical forest, and in a cypress swamp, ranging from 10-2540 m in elevation.

Biology

Castes

Worker

Nomenclature

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

  • texana. Solenopsis pollux var. texana Emery, 1895c: 278 (w.) U.S.A. Forel, 1901e: 345 (q.m.); Wheeler, G.C. & Wheeler, J. 1955c: 136 (l.). Combination in S. (Diplorhoptrum): Creighton, 1950a: 238. Raised to species: Forel, 1901e: 345. Senior synonym of rosella: Creighton, 1950a: 238.
  • catalinae. Solenopsis texana subsp. catalinae Wheeler, W.M. 1904d: 269 (w.q) U.S.A. Junior synonym of texana: Pacheco & Mackay, 2013: 332.

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

Description

Worker

Pacheco and Mackay (2013) - Measurements (n=8). TL 1.23-1.35 (1.28); HL 0.390-0.438 (0.409); HW 0.312-0.360 (0.339); EL 0.036; ED 0.030; SL 0.252-0.300 (0.274); FSL 0.096-0.120 (0.109); CI 80.0-89.6 (82.8); SI 63.2-70.4 (66.8); PL 0.060-0.090 (0.072); PW 0.090-0.1 02 (0.095); PI 66.7-88.2 (75.3); PPL 0.078-0.102 (0.089); PPW 0.114-0.126 (0.119); PPI 68.4-85.0 (74.8); WL 0.270-0.300 (0.287); PSL 0.030; PSW 0.024-0.030 (0.028).

Yellowish-brown, gaster slightly darker; head rectangular, longer than wide, sides nearly straight, posterior border concave; four teeth or bumps on anterior clypeal margin, lateral teeth angular, extralateral teeth represented by simply swollen regions, clypeal carinae well defined; scape extends about ¾ length of distance to posterior lateral corners of head; minor funicular segments 3-8 ranging from 0.108-0.120 mm in total length; eye small (maximum diameter 0.030 mm); mesosoma deeply impressed at notopropodeal suture, groove breaks sculpture of mesosoma; punctures on mesosoma and gaster fine with surfaces between punctures smooth and shiny, pronotum and mesopleuron smooth and shiny, metapleuron with horizontal striae; posterior border of propodeum rounded, propodeal spiracle small (0.024 mm diameter); petiole wider than postpetiole (in profile) with rounded node, ventral process on peduncle of petiole formed into small angle, postpetiolar node oval, wider than petiolar node (viewed dorsally); sculpture of petiole and postpetiole smooth and shiny.

Hairy; scapes with numerous, erect and suberect hairs (0.020 mm); head with erect hairs (0.060 mm); mesosoma with several erect hairs (up to 0.100 mm); hairs on petiole, postpetiole and gaster similar to those on dorsum of mesosoma; hairs on tibiae suberect or appressed.

Queen

Pacheco and Mackay (2013) - Measurements (n=4). TL 3.12-3.84 (3.54); HL 0.558-0.600 (0.579); HW 0.480-0.516 (0.492); EL 0.174-0.204 (0.185); ED 0.150-0.162 (0.153); MOL 0.048-0.066 (0.060); MOD 0.060-0.072 (0.069); SL 0.360-0.420 (0.387); FSL 0.186-0.210 (0.197); CI 82.0-88.7 (85.0); SI 62.5-70.1 (66.8); PSL 0.060-0.066 (0.062); PSW 0.048-0.054 (0.053); PL 0.120-0.138 (0.129); PW 0.198-0.252 (0.225); PI 52.4-63.6 (57.7); PPL 0.168-0.198 (0.182); PPW 0.252-0.288 (0.273); PPI 60.9-71.4 (66.6); WL 0.720-0.840 (0.780).

Medium to light brown, head and gaster slightly darker; head rectangular, longer than wide, posterior border slightly concave medially; clypeal carinae and lateral teeth well-developed, extralateral teeth poorly developed and present only as swollen regions; frontal lobes vertically striated; eyes small; ocelli small (maximum diameter of medial ocellus 0.06 mm), diameter about ½ length of distance to lateral ocellus; scape extending more than ¾ length to posterior lateral corner of head; scutum with punctures similar to those on head, most other surfaces smooth and glossy, sides of propodeum with parallel striae, petiole and postpetiole finely striated, with scattered punctures; petiole wider than postpetiole when viewed in profile, petiolar node triangular, ventral peduncular process poorly developed, consisting of elongate tooth, postpetiole wider than petiolar node (viewed dorsally), oval, globose, postpetiole lacking tooth or flange ventrally.

Hairy; pilosity as in worker, except hairs slightly longer (hairs on scape up to 0.100 mm, those on head to 0.130 mm, hairs on dorsum of mesosoma dense, up to 0.120 mm, hairs on petiole, postpetiole and gaster similar to those on mesosoma; very coarse cephalic punctures, diameters about five times width of hair arising from them.

Male

Pacheco and Mackay (2013) - Measurements (n=1). TL 2.58; HL 0.360; HW 0.372; EL 0.192; ED 0.162; MOL 0.048; MOD 0.066; SL 0.18; FSL 0.720; CI 103.0; SI 50.0; PSL 0.048; PSW 0.054; PL 0.120; PW 0.162; PI 74.1; PPL 0.162; PPW 0.204; PPI 79.4; WL 0.660.

Dark brown, with pale brown appendages; head wider than long, posterior lateral margin above eye rounded; clypeal carinae developed, lateral clypeal teeth poorly developed; eyes relatively small; maximum diameter of median ocellus 0.054 mm; subpeduncular angle present, dorsum of petiole low and rounded; punctures on head and scutum small, remainder of ant smooth and glossy, except sides of propodeum, which are finely striated.

Hairy, scape with few suberect hairs, hairs on dorsum of head long (up to 0.070 mm) hairs on dorsum of mesosoma abundant (up to 0.100 mm), hairs on petiole, postpetiole and gaster similar to those on mesosoma.

Type Material

Texas (lectotype worker, 3 paralectotype workers [here designated], cotype #164 (Musee d'Histoire Naturelle Genève) and 1 paralectotype worker (MHNW).

References