Solenopsis abdita

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Solenopsis abdita
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species complex: molesta
Species: S. abdita
Binomial name
Solenopsis abdita
Thompson, 1989

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Specimen labels

The type material of Solenopsis abdita was collected from a palm log in Ft. Lauderdale, Florida (Thompson 1989). This species is also known to nest in rotten wood in pine oak forests and pine wetlands and has been collected in litter from a tree base. Moreover, S. abdita was collected in leaf litter from a slash pine stand north of buildings and from a long unburned sand pine scrub in Highlands County. (Pacheco and Mackay 2013)

Identification

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

Thompson (1989) - Worker small, pale species. Eyes somewhat small but darkly pigmented. General characters of workers very similar to carolinensis. There is no easy way to separate the workers of these two species. Measurements of HL, HW, SL, WL, EL etc. average smaller than for carolinensis, but fall within the lower carolinensis normal ranges. It has shorter, less-shiny pilosity than carolinensis, a smaller, rounder, darker eye, differently shaped promesopleural suture, and a more convex dorsal curvature to the thorax.

Queen small, and medium to dark brown with hyaline wings. Much smaller than the dark females of tennesseensis, tonsa and nickersoni. Most similar to picta but has a more robust thorax with a definite hump on the propodeum instead of a continuous curve, does not have a forward-placed petiolar node and has greater pilosity.

Male small, and medium to dark brown with hyaline wings. As with the female, the male is also smaller than other dark Florida species, except picta. Not easily separated from picta but, as with the female, the node of the petiole is not forward-placed.

Pacheco and Mackay (2013) – Worker - This species is concolorous golden yellow, with coarse punctures present on the dorsum of the head. There are two angular lateral clypeal teeth. The funicular segments 3-8 are short (0.078 mm). Most of the hairs present on the posterior tibia are appressed. Queen - The gyne has a golden brown body with yellow appendages (antennae and legs) and is similar to the worker with modifications present in the caste. The posterior propodeal margin has an angular ridge. The postpetiole is larger than the petiole when viewed dorsally and is globular in shape. Male - This caste is a golden brown color with yellow appendages. The anterior clypeal margin is straight. The posterior propodeal margin is rounded. The propodeal spiracle is large at 0.06 mm in length. The petiolar node is elongate compared to the postpetiole in profile.

Solenopsis abdita is difficult to separate from Solenopsis texana, unless queens are available, in which the queen of S. abdita is golden brown and Solenopsis texana yellow. The scapes of the workers are shorter (0.240 mm, head length 0.378-0.402 mm) and the petiole is relatively wider than in S. texana (0.060 mm, postpetiole width 0.078-0.090 mm). Based on material examined, S. texana apparently does not occur in Florida, where S. abdita is only known from Florida (although we feel it is likely to occur in the surrounding states). There should thus be little confusion between these two allopatric species from samples of known geographic province.

Solenopsis abdita may be confused with Solenopsis carolinensis as well, but the shorter scape and the wider petiole in the worker will distinguish it from S. carolinensis. The workers can often be separated as the posterior tibiae have appressed hairs, which are mostly suberect in S. carolinensis. If queens are available, they are separated by the darker color and the smaller eye, compared to the yellow queens of S. carolinensis. At the present time, S. carolinensis has not been reported from Florida.

Keys including this Species

Distribution

Florida

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

Biology

Thompson (1989) - Very little is known about this new species. I collected a large colony in a rotted palm log (26 April 1984, Broward Co.) in semiswamp. This is a polygynous species: there were 8 queens in the colony. It is easily cultured in the laboratory and thrives on honey and dead insects. The 1981 palm log colony produced hundreds of females but only two males in August 1985. In July-August 1986 hundreds of males and females were produced. These exhibited preflight behavior late in the morning, and mated in the laboratory, with numerous fertile females remaining amicably in the same container. I have not obtained laboratory mating with any other thief ant species. J. C. Trager collected abdita males at a Gainesville blacklight at 5:45a.m. on 26 June 1980, and found sexuals and workers of this species beneath a stone at the edge of woods on 29 June 1980.

Castes

Queen

Male

Nomenclature

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

  • abdita. Solenopsis abdita Thompson, 1989: 275, figs. 1-4 (w.q.m.) U.S.A. See also: Thompson & Johnson, 1989: 698.

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

Description

Worker

HL 0.34-0.39; HW 0.30-0.34; HI 92-94; SL 0.22-0.24; SI 58-67; WL 0.42-0.16, EL 0.03-0.03S (N = 12 from Alachua and Broward counties).

Structural Characters—Head rectangular, longer than broad with weakly convex sides and slightly excised posterior border. Eyes nearly circular, somewhat small, but darkly pigmented. Ventral border of head moderately convex.

Promesonotum in profile somewhat angular anteriorly, then slightly convex to the metanotal groove. Propodeum smoothly rounded in profile without definite base or declivity; combines with promesonotum to form a curve that is not flattened at the metonotal groove. Petiole in profile triangular with slightly rounded node and ventral swelling. Postpetiole noticeably wider than petiole when seen from above, weakly trapezoidal, and widest anteriorly.

Sculpture-Head with barely visible small punctures, these much stronger than on the thorax. Remainder of integment smooth and shining.

Pilosity-Head, in profile, with moderate numbers of short hairs, thorax and gaster with fewer, sometimes longer hairs.

Color—Pale yellow-orange shading to darker reddish-orange on the gaster and at various sutures.

Pacheco and Mackay (2013) - (n=6) (range with average in parentheses). TL 1.02-1.20 (1.12); HL 0.378-0.402 (0.389); HW 0.288-0.300 (0.297); EL 0.030; ED 0.018-0.024 (0.023); SL 0.240 (0.240); FSL 0.090-0.096 (0.091); CI 74.6-78.1 (76.46); SI 59.7-63.5 (61.8); PL 0.042-0.048 (0.044); PW 0.072-0.090 (0.083); PI 46.7-61.5 (53.9); PPL 0.072-0.084 (0.078); PPW 0.102-0.108 (0.105); PPI 66.7-77.8 (75.0); WL 0.240 (0.240); PSL 0.024-0.030 (0.025); PSW 0.018-0.024 (0.021).

Small, concolorous yellow species; lateral posterior margin of head quadrate, head longer than wide with coarse punctures present; lateral clypeal teeth present as angles with extralateral teeth present as bumps; clypeal anterior margin between lateral teeth lacking medial tooth, slightly concave in shape; eyes small with no more than five ommatidia; pronotum sloped posteriorly with notopropodeal suture depressed and notch shaped, metanotal groove breaking sculpture of meso soma, mesopleuron smooth, shiny, lacking striae or roughened sculpturing; posterior propodeal margin slightly angled with poorly defined ridge present, propodeal spiracle small (0.024 mm diameter); metapleuron with few, thin horizontal striae present that cover gland; petiole with rounded triangular node; postpetiole rhomboid oval when viewed in profile, both petiolar peduncle and postpetiole lack tooth or flange ventrally, with only very small subpeduncular.

Hairy with erect and suberect hairs covering all body surfaces; scape mostly with appressed hairs present; approximately 10 suberect hairs present on mesosoma when viewed in profile; hairs on posterior tibia mostly appressed; petiole and postpetiole have suberect hairs that curve posteriorly; gaster fully covered in suberect hairs.

Queen

HL 0.52-0.56; HW 0.52-0.56; HI 93-104; SL 0.34-0.38; SI 65-69; EL 0.18; WL 0.91-1.03 (N = 11 from Alachua and Broward counties).

Structural Characters—Head as long as broad with convex sides and straight or very slightly concave posterior border. Clypeal teeth weak. Eyes and ocelli small, ocelli not at all prominent but lying nearly flat to the head. Head distinctly more narrow behind than at eyes. Scapes short, not reaching posterior corners.

Thorax distinctly narrower than the head and nearly a perfect long oval with little or no widening at the wing insertions. Petiole with a high node, and without anterioventral teeth. Postpetiole, from above, wider than petiole and weakly trapezoidal with greatest width anteriorly.

Sculpture—Head with numerous well marked punctures. These are weaker but noticeable on the thorax.

Pilosity—Head with numerous hairs, pilosity less abundant on thorax, petiole, postpetiole and gaster.

Color—Head including mandibles, thorax, petiole, postpetiole and gaster can be medium reddish brown to almost black. Legs and antennae shade from light tan to medium brown. Wings hyaline.

Pacheco and Mackay (2013) - (n=2). TL 2.82-3.00 (2.91); HL 0.540 (0.540); HW 0.480 (0.480); EL 0.174-0.180 (0.177); ED 0.156 (0.156); MOL 0.042-0.048 (0.045); MOD 0.060 (0.060); SL 0.360 (0.360); FSL 0.150-0.162 (0.156); CI 88.9 (88.9); SI 66.7 (66.7); PSL 0.048 (0.048); PSW 0.042 (0.042); PL 0.090-0.102 (0.096); PW 0.180-0.210 (0.195); PI 48.6-50.0 (49.2); PPL 0.150-0.162 (0.156); PPW 0.240 (0.240); PPI 62.5-67.5 (65); WL 0.720 (0.720).

Concolorous golden brown with golden yellow appendages (antennae and legs); head quadrate and longer than wide with coarse punctures; lateral clypeal teeth not well developed and present as angles with extralateral teeth present as bumps; clypeal carinae present, well developed; torulae without striae; eye large (approximately 132 ommatidia); medial ocellus small; posterior margin of propodeum slightly angled, propodeal spiracle small at 0.03 mm in diameter; latitudinal striae present on metapleuron; petiole with triangular node, lacks tooth or flange at subpeduncular process; postpetiole globular node, lacks ventral tooth or flange.

Hairy with setae on all body surfaces; scape covered in suberect hairs equal or longer than width of scape; mesosoma, petiole, postpetiole and gaster covered with suberect hairs that curve posteriorly.

Male

HL 0.38-0.40; HW 0.50-0.52; HI 125-135; FL 0.90-0.95; EL 0.20-0.22; WL 1.0-1.06 (N = 6 from Alachua Co.).

Structural Characters—Head, excluding eyes, nearly square. Eyes occupy approximately 1/3 of total head width. Ocelli prominent. Eyes slightly longer than broad on the axis from mandible to lateral ocellus.

Thorax from above tapers smoothly from pronotum to propodeum. Corners of petiole sharp, angular and joined by a sharp and nearly straight ridge across. Petiole, from above, narrower than postpetiole and trapezoidal, with greatest width at the center. Postpetiole nearly circular from above.

Sculpture—Posterior 2/3 of thorax as well as petiole and postpetiole largely covered in granulate punctation. Remainder of integument smooth and shining.

Pilosity—Moderate numbers of clear, suberect hairs present on all body areas, but most numerous on head.

Color—Uniform medium brown, but specimens from the Keys are uniformly dark brown, almost black. Legs and antennae very light tan. Wings hyaline.

Pacheco and Mackay (2013) - (n=l). TL 2.64; HL 0.390; HW 0.402; EL 0.180; ED 0.174; MOL 0.054; MOD 0.078; SL 0.162; FSL 0.762; CI 103; SI 41.5; PSL 0.066; PSW 0.060; PL 0.090; PW 0.180; PI 50.0; PPL 0.120; PPW 0.198; PPI 60.6; WL 0.720

Concolorous golden brown with yellow appendages; posterolateral margin of head rounded, head wider than long; eyes large (approximately 280 ommatidia); posterior margin of head dorsal to ocelli granulate; medial ocellus large; striae present lateral to antennal insertion; posterior margin of propodeum rounded, propodeal spiracle large; metapleuron with latitudinal striae present; petiole wider than postpetiole when viewed in profile, both petiole and postpetiole lacking teeth or flanges ventrally.

Hair encompassing all body surfaces; suberect hairs cover mesosoma, petiole, postpetiole, as well as gaster with majority curving posteriorly.

Type Material

Holotype a worker from a large series of males, females and workers collected from a palm log, or subsequently reared by this colony, taken 26 April 1984 in Ft. Lauderdale, Broward Co., Florida, by C. R. Thompson. The holotype and several paratypes will be deposited in the Florida State Collection of Arthropods , with paratypes also deposited in Museum of Comparative Zoology and Los Angeles County Museum of Natural History.

No type material of this species has been found. It appears that Thompson never provided the type material to any of the specified museums.

Etymology

The word “abdita” is Latin for concealed or secret and is given to this species of the Florida thief ant complex because it so closely resembles the most common species, carolinensis.

References