Subfamily FORMICINAE
Tribe LASIINI
Nylanderia arenivaga (Wheeler)

Nylanderia arenivaga, profile view of an alate queen (click image to enlarge).

Nylanderia arenivaga, profile view of an alate queen (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 usually 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 arenivaga is a yellow to orangish-yellow species that is typically nests in sandy soils.

Identification (from Trager 1984 and Kallal and LaPolla 2012)
Worker: 1.84-2.63 mm (TL). Yellow to orangish-yellow with head slightly darker and posterior portion of gaster brownish. Overall shiny, with moderate cephalic pubescence, but pubescence on mesosoma and gaster mostly lacking. Scape with numerous short, dark colored macrochaetae (usually between 7 and 12) and gaster with abundant long, flexuous, dark macrochaetae. Head ovate and slightly emarginate along posterior border. Scape relatively long, extending beyond posterior border of head by a length equal to 3-4 funicular segments.

Female: 4.20-467 mm (TL). Yellow to orangish-yellow with portions of mesosoma and gaster yellowish-brown; cuticle smooth and shiny, but mostly obscured by dense yellowish pubescence; macrochaetae yellowish-brown.

Male: 1.77-2.26 mm (TL). Mostly brown with gaster usually darker brown than the rest of body and with tips of legs, mandibles, and antennae yellowish. Cuticle shiny when not obscured by pubescence; pubescence on head moderate, mesonotum with dense pubescence, and gaster mostly lacking pubescence. . Genitalia with long, triangular parameres that curve inward; digiti and cuspides long, slender, and curved toward each other.

Nylanderia arenivaga differs from N. phantasma and N. trageri by typically being larger, having more numerous scape macrochaetae, and longer and more flexous macrochaetae in general; from N. querna by having brownish coloration at the tip of the gaster and it habit of nesting in open sandy habitats; and from N. vividula and N. terricola by having denser cephalic pubescence.

Biology and Economic Importance
Nylanderia arenivaga is a nocturnal species that nests in open, yellow sand areas and prairie remnants in the eastern US. According to Trager (1984), nests are 20-30 cm deep with numerous flat, crater entrances clustered together suggesting either polydomy or at the least the ability for mulitiple colonies to coexit in close proximity. Alates have been reported in January, July and August and reproductive flights observed from January to April.

Distribution
Eastern US from Massachusetts to Florida and west to Louisiana and Arkansas.

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. 

 

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