Solenopsis pollux

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Solenopsis pollux
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species complex: molesta
Species: S. pollux
Binomial name
Solenopsis pollux
Forel, 1893

Solenopsis pollux casent0902345 p 1 high.jpg

Solenopsis pollux casent0902345 d 1 high.jpg

Specimen Labels

These ants can be found in mixed wood leaf litter and also nest under stones. It occurs in slashed and burned tropical forest (Mackay and Mackay 2002) as well as very arid acacia scrub (Colombia) to temperate forests, tropical old growth dry forest to wet mountain cloud forest, pines and hardwood forests, and disturbed deciduous forest. Foragers are attracted to Vienna sausage baits (surface and subsurface) as well as collected in pitfall traps. Solenopsis pollux was collected up to 1000m in elevation in Costa Rica. (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)

Pacheco and Mackay (2013) – Worker - This is a small concolorous yellow species with an elongate clypeus. The lateral teeth are well developed and the extralateral teeth are solely present as angles. The head is quadrate and coarsely punctated, resembling members of the pygmaea and fugax complexes; a character uncommon in the molesta group. The eye is small with only 3-5 ommatidia. The propodeal spiracle is small. There are horizontal striae present on the metapleuron. Queen - The queen is golden brown in coloration. Both the clypeal lateral and extralateral teeth are angulate. The clypeal carinae are weakly developed. The head is brown, the scapes are golden yellow. The three ocelli are clear and the eyes are black and large. The frontal lobes have vertical striae. The head, mesosoma, petiole, postpetiole and first tergite of the gaster are all densely covered in coarse punctures. The lower half of the propodeum has horizontal striae just below the spiracle. The petiole is wider than the postpetiole (viewed laterally). Male - The male is small and brown in color. The clypeus is slightly convex with no visible tooth or bump present on the anterior margin. There are thin rugulae present on the head that follow the contour of the head, in the middle of the head they are vertical and as they approach the antennal insertions they bend towards the sides of the head just above the eyes. The three ocelli are small and clear. Small punctures are present on all body surfaces. The antennae are long and golden yellow in color. Both nodes of the petiole and postpetiole are angular (lateral view).

Workers of S. pollux is highly variable in the following characteristics, clypeal teeth, size, cephalic punctures and shape of petiole, which can cause confusion with a multitude of similar species that overlap it in distribution.

The worker of S. pollux can be confused with those of Solenopsis abjectior (Argentina), but S. abjectior can be separated by having finer cephalic punctures and a narrower petiolar apex, in which the faces are nearly parallel in profile and about as wide at apex as at level of peduncle.

The workers are nearly identical to those of Solenopsis carolinensis (USA), but can be separated by the distributions. The eyes of the queen and male of S. carolinensis are larger than those of the sexuals of S. pollux. The node of the male of S. carolinensis is not as angulate as that of the male of S. pollux. Additionally, the queen and male of S. carolinensis are much lighter in color than the golden brown S. pollux.

Specimens from central Mexico south to Colombia are difficult to separate from Solenopsis patriciae and Solenopsis texana as the distributions overlap. The worker of S. pollux can nearly always be separated as the promesonotum has more than 10 erect hairs (seen in profile), whereas workers of the latter two species nearly always have fewer than 10 erect hairs in the same position. The queen of S. pollux is yellowish brown or pale brown, whereas the queens of the latter two species are dark brown.

The workers of S. pollux can be confused with Solenopsis maboya (Puerto Rico) in the Caribbean, but the worker of S. maboya is smaller, has coarse punctures on pronotum and has a larger head, and can be further distinguished from S. pollux by the small triangular petiole. The queen of S. maboya is a small black specimen whereas that of S. pollux is larger and paler in color.

Care must be taken in the Caribbean region where S. pollux and Solenopsis corticalis are common, as confusion could result between them, especially on the island of St. Vincent. The relatively abundant erect hairs on the dorsum of the promesonotum would separate the workers of S. pollux, from the worker of S. corticalis which generally has only a few hairs on the same surface.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Anguilla, Barbados, Belize, Brazil, Colombia, Costa Rica, Dominican Republic, Greater Antilles, Grenada, Haiti, Lesser Antilles, Martinique, Mexico, Panama, Puerto Rico, Saint Lucia, Saint Martin (French part), Saint Vincent and the Grenadines (type locality).

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Biology

Regional Notes

St Vincent

The opening text of the source (Forel 1893) for the following collection records, by H. H. Smith, states "These notes are given in full, as it is thought that the precise localities in which the species were met with may be of interest to local naturalists."

(28). Pretty common, forming small colonies at the roots of grass or herbage. I have never seen more than forty or fifty together. Sluggish .

(28a). Near Palmyra Estate (leeward), 1000 ft. Nov. 3rd. Shady place near a stream. A small colony at the roots of grass growing on a rock.

(28b). Fitz-Hugh Valley (leeward), 500 ft. Nov. 4th. Small passage in sod on a rock; shady place.

(28c). Wallilobo Valley; open place, at the roots of sod on a rock. Nov. 8th. Near sea-level.

(28d). Same locality as last. Another colony.

(28e). Wallilobo Valley, 500 ft.; under sod on a rock. A small colony.

(28f). Females found under the same sod with No. 28e, and presumably the same species.

(28g). Male, found under sod with Nos 28e and 28f.

(28h). (Doubtfully referred to this species). Near Palmyra (leeward), 100 ft.; under sod on rock.

(28i). Petit Bordelle Valley, 1200 ft. Nov. 13th. Shady banks of stream; under sod on a rock. No female could be found.

(28j). Cumberland Valley, 300 ft. (leeward), Dec. 2nd. Dry place; edge of forest, under sod on a rock. The community contained perhaps 200 ants, with numerous males, many of which flew away.

(28k). Windward, near seashore; at Robocca. Jan. 2nd. Under stone in it door-yard [?]. There were probably 200 workers, with about twenty females, in a small cavity under the stone.

(28l). Windward, near seashore; open, sandy bed of the Dry River. Jan 2nd. Under a stone. About 200 workers in a small cavity. No female could be found.

Castes

Nomenclature

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

  • pollux. Solenopsis pollux Forel, 1893g: 393 (w.q.m.) ANTILLES.

Description

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

Description

Worker

Solenopsis helena and pollux Forel 1985.jpg

1, 2 a 1, 4 mill. Voisine de lit precedente. Tete un peu plus longue que large, mais plus courte que chez la precedente. Mandibules armees de 4 dents, conformees du reste comme chez la precedente, mais avec le bord terminal un peu moins oblique. Epistome avec deux carenes aigues, rapprochees, terminees devaut par deux longues et fortes dents encore plus rapprochees quo chez l'espece precedente; a cote de ces dents, il n'y a qu'un feston lateral au bord anterieur qui est un peu moins avance que chez la precedente. Antennes et yeux comme chez la precedente. Thorax un peu plus court, avec l'echancrure meso-metathoracique plus faible. Le metanotum est faiblemont convexe et descend en talus, sans aucuno limite entre la face basale et la face declive. Premier article du pedicule comme chez la S. azteca, mais un peu plus attenue au sommet et moins haut. Second article tres court, petit, a poine incline en avant, plus large que long, Abdomen comme chez la precoeente.

La sculpture et la pilosite sont analogues a celles de la S. castor, mais les poils et les points piligeres sont bien plus abondants. La ponctuation est assez abondante sur la tete, la pilosite en partie oblique, plus courte que chez la S. Castor.

D'un janne uniforme, a peine le bord des mandibules et un nuage transversal sur le ler segment de l'abdomen sont ils un peu roussis.

Pacheco and Mackay (2013) - Measurements (n=5). TL 1.08-1.20 (1.132); HL 0.330-0.408 (0.368); HW 0.300-0.330 (0.314); EL 0.030-0.036 (0.034); ED 0.024-0.030 (0.028); SL 0.210-0.276 (0.244); FSL 0.084-0.108 (0.096); CI 87.9-134 (104); SI 60.3-77.6 (66.2); PL 0.048-0.054 (0.053); PW 0.084-0.096 (0.089); PI 50.0-64.3 (59.6); PPL 0.090-0.096 (0.095); PPW 0.108-0.144 (0.120); PPI 66.7-84.2 (79.6); WL 0.300; PSL 0.030; PSW 0.024.

Small, concolorous yellow; head longer than wide, with coarse cephalic punctures; clypeus elongate, lateral clypeal teeth well developed, extralateral teeth angulate; eye small with 3-5 ommatidia; scape does not reach posterior margin of head; pronotum and mesopleuron smooth and shiny; notopropodeal suture well depressed; breaks sculpture of mesosoma; posterior propodeal margin rounded; propodeal spiracle small (0.030 mm greatest diameter); metapleuron horizontally striate; petiole wide than postpetiole (viewed laterally); anterior and posterior faces ofpetiolar node converging and narrowest at apex viewed laterally.

Erect and sub erect hairs of various lengths cover all body surfaces; head with numerous erect and suberect hairs (0.030 mm); suberect hairs on petiole, postpetiole and gaster curve posteriorly.

Queen

L. 3, 3 a 3, 5 mill. Caracteres de l'ouvriere, mais los dents medianes de l'epistome sont plus courtes et les festons lateraux plus forts; les carenes sont plus ecartees. Tete rectangulaire-arrondie, un peu plus longue que large. Antennes de 11 articles; scapes comme chez l'ouvrie e.

Thorax aussi large que la tete, plus long que chez la S. castor, plus court que chez la S. corticalis. Face basale du metanotum plus longue que la face declive et separee d'elle par deux faibles elevations allongees et peu distinctes. Premier article du pediculo saus dent clessous, avec un noeud eleve, bion plus large que long, prosque squamiforme, mais elargi en bas, situe tout a fait en arriere et contigu sur toute sa hauteur au 2me article. La face anterieure de ce neoud est legerement concave, sa face posterieure convexe vers le haut. Le premier article du pedicule qui a une convexite translucide en dessous chez l'ouvriere n'est nullement convexe dessous chez la (convexe chez la S. castor). Second article du pedicule attenue en dessous, epais, arrondi et plus large que long en dessus un peu moins eleve que le noeud du 1er article. Abdomen long et grand. Ailes uniformement teintes de brunatre, avec les nervures et la tache marginale d'un brun clair. Cellule discoidale tres petite.

Lisse, luisante, avec de gros points piligeres espaces sur la tete et le thorax; sur l'abdomen ces points sont plus fins.

Pilosite jaunatre, assez courte, abondante, tres oblique sur les tibias et les scapes. Pubescence presque nulle.

D'un noir brunatre. Abdomen d'un brun fonce. Hanches et milieu des cuisses brunatres. Mandibules, antennes et le reste des pattes d'un jaune un peu rougeatre.

Pacheco and Mackay (2013) - Measurements (n=3). TL 3.38-3.72 (3.59); HL 0.516-0.570 (0.536); HW 0.522-0.570 (0.554); EL 0.162-0.198 (0.180); ED 0.150-0.162 (0.154); MOL 0.048; MOD 0.060; SL 0.378-0.390 (0.386); FSL 0.150-0.180 (0.166); CI 91.6-110 (104); SI 68.4-74.7 (72.1); PSL 0.048-0.066 (0.056); PSW 0.054-0.060 (0.056); PL 0.120; PW 0.228-0.240 (0.236); PI 50.0-52.6 (50.9); PPL 0.228-0.240 (0.236); PPW 0.240-0.252 (0.248); PPI 95.0-95.2 (95.2); WL 0.840.

Small, golden brown, with darker brown head, scapes golden yellow; head quadrate; lateral and extralateral clypeal teeth angulate; clypeal carinae weakly defined; ocelli clear, without pigment; eyes black, large; scape long, nearly reaching posterior border of head; mesosoma coarsely punctate, pronotum and mesopleuron smooth and shiny between punctures; metapleuron horizontally striate; petiole, postpetiole and first tergite of gaster densely covered with coarse punctures; petiole wider than postpetiole (viewed laterally); petiole and postpetiole striated horizontally.

Hairy, erect and suberect hairs of various lengths covering all body surfaces; nearly all punctures have suberect hair arising from them.

Male

L. 2, 7 a 2, 3 mill. Mandibules bidentees, tres etroites, avec le bord interne parallele au bord externe. Tete arrondie, un peu plus large que longue. Scapes un peu plus longs que larges. Premier article du funicule gros et globuleux; second article un peu plus long que le scape. Antennes de longueur mediocre. Metanotum arrondi. Premier article du pedicule comme celui d'un Leptothorax nylanderi, mais bien plus allonge, et a sommet plus tranchaut, c'est a dire que le sommet du noeud est tranchant et transversal, et que le noeud descend en long talus en avant et en court talus en arriere, sans former de petiole distinct. Second noeud plus large que long, anguleux lateralement.

Lisse, luisant, avec des points piligeres fort epars. Pilosite comme chez la, mais bien moins abondante. Entierement d'un noir a peine brunatre. Pattes et antennes brunes. Ailes comme chez la, mais plus faiblement teintes de brunatre.

Cette espece est completement differente de la precedente, de la S. corticalis et de la S. brevicornis par sa qui la rapproche plus de la S. fugax.

Pacheco and Mackay (2013) - Measurements (n=3). TL 2.69-2.88 (2.77); HL 0.402-0.456 (0.434); HW 0.534-0.558 (0.546); EL 0.210-0.240 (0.222); ED 0.180-0.198 (0.192); MOL 0.054; MOD 0.072-0.078 (0.076); SL 0.096-0.120 (0.106); FSL 0.900; CI 120-136 (131); SI 21.6-29.9 (25.6); PSL 0.060-0.066 (0.062); PSW 0.066-0.078 (0.070); PL 0.090; PW 0.180; PI 50.0; PPL 0.156; PPW 0.228; PPI 68.4; WL 0.720.

Small, concolorous brown, scapes golden yellow; head wider than long, thin rugulae follow contour of head, anterior margin of clypeus convex with no visible tooth or bump; three ocelli small and clear in color; small punctures present on all body surfaces; pronotum and mesopleuron smooth and shiny between punctures; metapleuron horizontally striated; petiolar and postpetiolar nodes angular, petiole wider than postpetiole (viewed laterally), petiolar peduncle lacking tooth or flange ventrally.

Hairy, erect and sub erect hairs present on body surfaces. Nearly all punctures have hair originating from them.

Type Material

Pacheco and Mackay (2013) - Forel coll. Antilles, St. Vincent (lectotype worker, 4 paralectotype workers, 3 paralectotype queens, 3 paralectotype males [here designated] Musee d'Histoire Naturelle Genève).

References