Nylanderia faisonensis

Nylanderia faisonensis nests are found in leaf litter, rotten wood, and soil (Trager, 1984). Observed nests are shallow and likely temporal. Reproductives are reared in August through December, at which point they overwinter in the nest and fly between March and May, with southern populations flying earlier (Trager, 1984; Colby & Prowell, 2006) (Kallal & LaPolla, 2012).

Identification
Kallal & LaPolla (2012) - Uniformly brown in color (or with slightly darker gaster) with lighter, yellowish-brown mandibles and scapes, and strongly contrasting, pale whitish mesocoxae and metacoxae.

Compare with: Nylanderia austroccidua, Nylanderia concinna, Nylanderia flavipes, Nylanderia steinheili, Nylanderia terricola, Nylanderia vividula, and Nylanderia wojciki.

Nylanderia faisonensis is sympatric with numerous morphologically similar species. Most similar to this species is N. wojciki, as both share pale mesocoxae and metacoxae. The latter is typically bicolored, possesses less macrosetae on its scape and its known range is limited to the southeastern U.S. Nylanderia faisonensis is never truly bicolored, although its gaster may be darker brown than the rest of its body. Nylanderia concinna is also morphologically similar to N. faisonensis, but two major diagnostic features set them apart: N. faisonensis has very pale whitish mesocoxae and metacoxae, while N. concinna has medium brown (lighter than mesosoma) mesocoxae and metacoxae; N. faisonens also typically lacks the neat band of pubescence across the anterior edge of the propodeum. In the northeastern U.S., N. faisonensis is most likely to be confused with the introduced species, ''N. flavipes. Nylanderia flavipes is typically bicolored and possesses ocelli that are apparent, which N. faisonensis'' lacks. Nylanderia vividula and N. terricola are both known to possess lighter mesocoxae and metacoxae, however, both of these species have very sparse cephalic pubescence whereas it is dense in N. faisonensis. Finally, the worker of the Caribbean species N. steinheili, may be confused with N. faisonensis, but N. steinheili has a distinctly pubescent mesosoma.

Distribution
Eastern US, west to Texas and Arkansas.

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

Habitat
Mesic decidous forest and pine forest.

Biology
Kallal & LaPolla (2012) - This species is a common member of the ant fauna in mesic, deciduous forests and, to a lesser extent, pine forests, making it one of the most numerous ants in the eastern half of the United States. Along with Aphaenogaster rudis and Prenolepis imparis, Nylanderia faisonensis is one of the dominant species in the northeastern U.S. (Lynch et al., 1980; Lynch, 1981; Lynch & Johnson, 1988). It has been observed as far west as Texas and Arkansas (General & Thompson, 2008). In general, they are tolerant and submissive to sympatric species in studies on dominance and coexistence with other ants (Lessard et al., 2009). An undescribed socially parasitic Nylanderia species (n. sp. 1) is known to parasitize N. faisonensis populations in northern Florida (Cover et al., in prep).

Nomenclature

 *  faisonensis. Prenolepis (Nylanderia) arenivaga var. faisonensis Forel, 1922: 98 (w.) U.S.A. Kallal & LaPolla, 2012: 19 (q.m.). Combination in Paratrechina (Nylanderia): Emery, 1925b: 221; in Nylanderia: LaPolla, Brady & Shattuck, 2010a: 127. Junior synonym of arenivaga: Creighton, 1950a: 408. Revived from synonymy and raised to species: Trager, 1984b: 93.

Worker
Kallal & LaPolla (2012) - Measurements (n=24) TL: 1.85–2.56; HW: 0.44–0.59; HL: 0.59–0.74; EL: 0.14–0.17; SL: 0.62–0.82; PW: 0.34–0.46; WL: 0.59–0.85; GL: 0.67–1.23; PH: 0.17–0.29; PFL: 0.52–0.65; PFW: 0.14–0.20. SMC: 5–12; PMC: 2–6; MMC: 2–4. Indices: CI: 80–85; REL: 20–27; SI: 107–124; FI: 88–98.

Uniform brown in color, or often with darker brown gaster; antennae and mandibles yellow; mesocoxae and metacoxae pale and whitish, strongly contrasting with mesosoma; cuticle smooth and shiny; cephalic pubescence dense; mesosoma and gastral pubescence virtually absent. Head ovate; posterior margin slightly emarginated medially; scapes surpass posterior margin by first 3–4 funicular segments; ocelli generally not apparent. Pronotal anterior face at approximately 45°; pronotum inflected with pronotal anterior face slightly shorter than pronotal dorsal face; anterior margin of mesonotum continuous with pronotal margin; propodeum gently rounded with shorter dorsal face.

Queen
Kallal & LaPolla (2012) - Measurements (n=5) TL: 3.37–4.14; HW: 0.75–0.80; HL: 0.69–0.79; EL: 0.23–0.25; SL: 0.80–0.87; PW: 0.74–0.90; MW: 0.66–0.81; WL: 1.01–1.25; GL: 1.59–2.20; PH: 0.37–0.50; PFL: 0.65–0.75; PFW: 0.20–0.23. SMC: 4–10; PMC: 4–6; MMC: 4–14; MtMC: 1–3. Indices: CI: 91–102; REL: 30–33; SI: 102–112; FI: 81–95.

Uniform light brown in color; mesocoxae and metacoxae slightly lighter brown; gaster slightly darker brown; cuticle smooth ad shiny; body with dense pubescence; macrosetae brown. Head as broad as it is long; scapes surpass posterior margin by first 3 funicular segments. Propodeum with very short dorsal face and long declivitous face.

Male
Kallal & LaPolla (2012) - Measurements (n=6) TL: 1.91–2.37; HW: 0.47–0.52; HL: 0.51–0.59; EL: 0.17–0.21; SL: 0.53–0.74; PW: 0.40–0.54; MW: 0.38–0.48; WL: 0.62–0.81; GL: 0.61–0.98; PH: 0.23–0.30; PFL: 0.47–0.66; PFW: 0.13–0.17; PL: 0.16–0.25. SMC: 4–7; MMC: 6–12; MtMC: 2–3. Indices: CI: 87–94; REL: 34–36; SI: 104–129; FI: 92–113.

Overall medium brown; scapes and joints of legs yellowish-brown; mesocoxae and metacoxae pale and whitish, strongly contrasting with the rest of the body; gaster often darker brown; cuticle smooth and shiny; cephalic pubescence moderate to dense; mesosoma with dense pubescence on the mesonotum; gastral pubescence absent; macrosetae dark brown. Head as broad as it is long; eyes weakly convex, scarcely extending beyond lateral margins of the head in full face view; scapes surpass posterior margin by first 3–4 segments; mandibles with long, straight inner mandibular margin, a basal angle of approximately 90°, and a smooth masticatory margin with large apical tooth and sometime smaller subapical teeth (up to 4 denticles present in one specimen). Mesosoma enlarged to accommodate flight muscles; in lateral view, pronotal margin short and relatively straight; propodeum with long, sloped dorsal face becoming steeply sloped at inflection point to declivitous face. Genitalia: parameres laterally oriented, triangular; digiti slightly angled; cuspides about half as long, curving dorsally; rounded teeth present on both structures where they meet; aedeagal valves triangular, teeth absent; ninth sternite with long lateral apodemes and thin medial apodeme.

Additional References

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