Subfamily FORMICINAE
Tribe LASIINI

Nylanderia trageri Kallal and LaPolla, 2012
Nylanderia trageri, profile view of a worker from MS (click image to enlarge).

Nylanderia trageri , full face view of a worker (click image to enlarge).

Nylanderia trageri , side view of a worker (click image to enlarge).

Introduction
Ants in the genus Nylanderia (Formicinae) are relatively small, pale yellow to almost black, and can be distinguished from other Formicinae in our region by the coarse, long, barbed and usuallly dark setae (macrochaetae or macrosetae), which are arranged in distinct pairs on the dorsum of the head and mesosoma and scattered on the gaster.

Trager (1984) revised the genus, then called Paratrechina, for the continental United States. LaPolla et al. (2010) elevated the subgenus Nylanderia to the generic level, which in effect, meant that all Nearctic Paratrechina species except for P. longicornis were now placed in Nylanderia. In 2012, Kallal and Lapolla (2012) revived the genus and provided an updated key for the Nearctic region. However, there are still some undescribed species in this group that which may be parasitic on other Nylanderia species.  These species apparently do not have a worker caste, and the males are unusual in that they have characteristics of both males and workers. 

Nylanderia trageri was recently decribed as a unique species by Kallal and LaPolla (2012). This yellow woodland species lacks macrochaetae on the scapes and was previously considered a color morph of N. parvula.

Identification (from Kallal and LaPolla 2012)
Worker: 1.20-2.27 mm (TL). Color uniformly yellowish to yellowish-orange wtih head and gaster occasionly slightly darker, mesocoxae, metacoxae, and legs slightly lighter. Pubescence yellowish, scarce, lacking on mesosoma and gaster; macrochaetae brown. Head quadrate, without medial emargination posteriorly; with ocelli; scape relatively long, extending beyond posterior border of head by a length equal to 3-4 funicular segments.

Female: 3.54-4.25 mm (TL). Brown to yellowish brown with scapes, mandibles, and legs lighter. Entire body with dense pubescence that does not obscure the shiny cuticle.

Male: 2.02-2.07 mm (TL). Uniformly brown in color; scapes, mandibles, and legs yellowish-brown; and meso- and metacoxae occasionally lighter. Pubescence sparse to moderate on head, dense on mesonotum, and mostly laster on gaster. Genitalia with triangular parameres, digiti almost nearly long as adeagal valves, cuspides slightly less than half as long as digiti.

This species is most similar to N. parvula from which it differs by the workers being yellow instead of dark brown as in N. parvula.

Biology and Economic Importance
According to Kallal and LaPolla (2102), this species is found in leaf litter and rotting branches. In Mississippi we have found this species in hardwood and mixed pine-hardwood forests in the central to northeastern parts of the state and at edges of oak-hickory forests and Black Belt Prairie remnants in MS and similarly along the edge of a dolomite glade in AL. Typically, we have collected this species in leaf litter at bases of oaks and hickories, especially on slopes of relatively dry upland forests with somewhat sandy soils. We have found nests in leaf litter, but more commonly in white oak acorns on the ground. It is not known for sure when reproductive flights take place, but we have collected alate males in acorns in late August (MS).

Distribution
Alabama, Mississippi, Oklahoma, and Texas.

References

Kallal, R. J. and J. S. LaPolla. 2012. Monograph of Nylanderia (Hymenoptera: Formicidae) of the World, Part II: Nylanderia in the Nearctic. Zootaxa 3508: 1-64.

Lapolla, J. S., S. G. Brady, and S. O. Shattuck. 2010. Phylogeny and taxonomy of the Prenolepis genus-group of ants (Hymenoptera:  Formicidae).  Systematic Entomology 35: 118-131.

Trager, J. C. 1984.  A revision of the genus Paratrechina (Hymenoptera: Formicidae) of the continental United States. Sociobiology 9:  49-162.