Monomorium trageri

A little collected southeastern US Monomorium species.

Identification
DuBois (1986) - A member of the Monomorium minimum species group. Queen Wingless (usually); mandible with 4 teeth, basal 2 reduced; head smooth and shining except for rugosities near lateral margin of clypeus; mesonotum lacking notal furrow. Worker Propodeum angular (basal face 1/2 as long as declivitous face); mesopleuron punctate; 8-12 erect to suberect setae on dorsum of alitrunk; PI 31-38 (35).

Monomorium trageri is likely to be confused with the following species: Monomorium ebeninum, Monomorium minimum, and Monomorium viridum. Queens of M. trageri may be separated from those of M. ebeninum since the latter have a flat or concave scutum and scutellum. Queens of M. trageri may be separated from those of M. viridum since the latter have a furrow on the mesonotum. Queens of M. trageri may be separated from those of M. minimum since the former have reduced sculpturing on the head; the only rugae are along the lateral margin of the clypeus. Monomorium minimum queens have more facial sculpturing. Workers of M. trageri may be separated from workers of the other three species since they have the basal face length of the propodeum less than the length of the declivitous face.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Biology
DuBois (1986) - (this first paragraph provides distribution details and is a little outdated, as of 2016 it is now known from more locations in 2016) This species is quite rare; it is known from only four localities in Florida. In addition to the type locality, specimens have been collected in Tallahassee, LaCrosse, and Punta Gorda. It is possible that earlier records of Monomorium minimum from Florida (e.g., Van Pelt, 1958) may have represented collections of this species. However, no specimens from these earlier studies could be located. It is more probable earlier records referred to Monomorium viridum which is more common in peninsular Florida, but does not range as far west as Tallahassee. Additional collecting in northern Florida and southern Georgia may elucidate the distribution of M. trageri.

Although details of nesting preferences are unknown (little can be inferred from 4 collections), the colony which yielded the holotype and paratypes was collected from beneath a board in a cow pasture (J. Trager, pers. comm) The colony collected in LaCrosse (Alachua Co.) was collected in cow dung. The type colony was reared in the laboratory from 5 April through 20 June when portions of it were killed. At that time, numerous males and queens were present. One male and queen were preserved in coitu indicating that mating may occur between males and closely related queens. Several Specimens examined are probably intersexes (female head and male alitrunk and gaster). These may have been caused by some form of mechanical damage to the developing individuals (W L. Brown, Jr., pers. comm).

Recently, James Trager provided additional specimens of the Gainesville colony. A few queens are winged, indicating that genes which code for wings are still present within this population; approximately 90 % of the queens are Wingless and 10% are winged.

Nomenclature

 *  trageri. Monomorium trageri DuBois, 1986: 109, figs. 7, 20, 133-148 (w.q.m.) U.S.A.

Worker
Head: (representing 1 locality; N=5) HL 0.45-0.52 (0.4-9), HW 0.35-0.45 (0.42), SL 0.25-0.38 (0.30), EL 0.08-0.10 (0.09), MOD 0.05-0.08 (0.07). Structure—CI 75-93 (86), SIL 48—76 (61), SIW 56-84 (72). Side of head convex. Scape reaching occiput but not surpassing it by length greater than length of pedicel. Mandible with 4 teeth )sometimes, basal 2 reduced(. Clypeal teeth sharp, of moderate length. Sculpture—Smooth and shining with moderate piliferous punctures evenly distributed throughout. Alitrunk: PW 0.25-0.28 (0.27), PL 0.15-0.20 (0.18), WL 0.45-0.53 (0.50). Structure—Propodeum angular, basal face 1/2 as long as declivitous face. PI 31-38 (35). Pilosity—Dorsal outline of alitrunk with 8-12 erect to suberect setae. Leg pilosity as in queen. Sculpture—Mesopleuron covered with dense, small, non-piliferous punctures. Anterior propodeal suture with short, parallel, moderate, longitudinal rugae. Petiole: Dorsum of node convex. Setae erect on dorsum of node, absent elsewhere. Postpetiole. Dorsum of node flat. Setae erect on dorsum and posterior surface of node, absent elsewhere. Gaster: Setae of first gastral tergite not projecting to level of dorsum of postpetiolar node. Color. Head dark brown (with bluish reflections) except as follows: antenna and mandible brown to light brown. Alitrunk brown to dark brown, legs light brown. Petiole, postpetiole, and gaster dark brown with bluish reflections. All setae white.

Queen
As described for Monomorium ebeninum except as follows. Head: (representing 2 localities; N=5) HL 0.62-0.70 (0.66) {0.68}, HW 0.53-0.62 (0.59) {0.53}, SL 0.38-0.55 (0.46) {0.55}, IOD 0.12-0.18 (0.15) {0.12}, OD 0.05 (0.05) {0.05}, EL 0.14-0.16 (0.15) {0.14}, MOD 0.10-0.11 (0.10) {0.10}. Structure—Cl 80-97 (88) {88}, SIL 59-81 (68) {81}, SIW 63-104 (78) {104}. Eye small to moderate in size. Scape usually not surpassing occiput )or surpassing it by less than length of pedicel(. Mandible with 4 teeth (basal two reduced). Clypeal teeth sharp, short to moderate in length. Frontal carinae diverging slightly posteriorly. Pilosity—Setae erect to suberect over entire surface of head except as follows: setae suberect to decumbent on mandible. Sculpture—Moderate, parallel, longitudinal rugae beginning all along lateral margin of clypeus, extending past antennal insertion and converging with frontal carina. Alitrunk: PW 0.42-0.48 (0.44) {0.42}, PL 0.25-0.31 (0.29) {0.30}, WL 102120 (1.13) {1.15}. Structure—Scutum and scutellum not depressed or flat. Mesopleural suture straight with no pits at either end. PI 24-28 (25) {26}. Sculpture—All sutures surrounding scutum and scutellum covered with small, dense, non-piliferous punctures. Propodeum covered with dense, small, non-piliferous punctures throughout (obscuring any trace of rugae on lower side of propodeum). Petiole. Setae appressed on anterior surface of node, erect to suberect on dorsum, side, and posterior surface of node, absent elsewhere. Dorsum of node smooth and shining with small piliferous punctures; side covered with moderate to large longitudinal and transverse rugae. Postpetiole. Dorsum of node slightly emarginate. Setae suberect to erect on dorsum, posterior surface, side, and venter of node, absent elsewhere. Dorsal surface of postpetiole smooth and shining with small piliferous punctures; lower 2/3 of side (below node) with small to moderate, dense, non-piliferous punctures. Gaster: Setae of first gastral tergite exceeding level of dorsum of postpetiolar node.

Male
Head: (representing 1 locality; N= 5) HL 0.55-0.60 (0.58), HW 0.70-0.72 (0.71), SL 0.25-0.30 (0.26), IOD 0.18-0.22 (0.19), OD 0.05-0.08 (0.06), EL 0.25-0.28 (0.27), MOD 0.15-0.18(O.17). Structure—CI 117-131 (124), SIL 42-50 (45), SIW 35-42 (36). Maxillary palp 2-segmented; labial palp 2-segmented. Frontal carinae diverging slightly posteriorly. Sculpture—Moderate to large, parallel, longitudinal rugae beginning all along lateral margin of clypeus, extending to level of middle of compound eye. Moderate, parallel, longitudinal rugae beginning all along distal border of clypeus (between clypeal teeth) and continuing up clypeus and from to level of antennal insertion. Several moderate, faint, semicircular rugae occurring on occiput and following contours laterally around occiput (these rugae are partially obscured by punctation). Alitrunk. PW 0.62-0.65 (0.64), PL 0.30-0.38 (0.34), WL 1.30-1.35 (1.33). Structure—Mesopleural suture straight with small pit present on both anterior and posterior ends. Metanotum (in lateral view) projecting to level of scutellum and propodeum. Propodeum angular, basal face 2/3 as long as declivitous face. Pilosity—Several setae suberect to erect on lower 1/3 of mesopleuron (katepisternum). Propodeum with 2-4 erect to suberect setae. Sculpture—Smooth and shining with large piliferous punctures on dorsum. Entire propodeum smooth and shining. Petiole: As in Figure 141. Dorsum of node flat to slightly emarginate. Setae erect to suberect on dorsum, side and posterior surface, absent elsewhere. Entire petiole smooth and shining; lower 1/3 of side with faint, moderate rugae. Postpetiole. Dorsum of node emarginate. Setae erect to suberect on anterior surface, side, posterior surface, and venter, absent elsewhere (including dorsum of node). Entire surface of postpetiole smooth and shining except for posterior 1/2 of node which is covered with small to moderate, non-piliferous punctures. Gaster: Setae of first gastral tergite not exceeding level of dorsum of postpetiolar node. Genitalia: Eighth sternite with emargination approximately as deep as wide. Ninth sternite with 10 erect setae. Aedeagus with 12 teeth, toothed margin rounded. Volsella with curved digitus and reduced cuspis; cuspis with 2 setae. COLOR: Head dark brown except as follows: antenna and clypeus brown. Alitrunk brown, legs yellow brown, wings hyaline. Petiole, postpetiole, and gaster brown to dark brown. Genitalia brown to yellow brown. All setae white.

Type Material
Holotype queen: Florida: Alachua Co., Gainesville, April 5, 1980, J. C. Trager. Holotype, deposited in, bears red, handwritten label: Monomorium trageri Holotype M. DuBois 1983. Paratypes are deposited as follows: CAS (1 queen, 1 male, 1 worker), (1 queen, 1 male, 1 worker), JCTPC (1 queen, 1 male, 1 worker), KU (1 queen, 2 males, 3 workers),  (1 queen, 1 male, 1 worker), MBDPC (1 queen, 2 males, 3 workers),  (1 queen, 1 male, 1 worker),  (1 queen, 1 male, 1 worker). All paratypes bear blue, handwritten labels: Monomorium trageri paratype M. DuBois 1983.

Etymology
This species is named in honor of James C. Trager, who provided many specimens of it.