Nylanderia

Neartic
species key - Kallal & LaPolla 2012

Kallal & LaPolla (2012) - The fauna in the Nearctic region is comprised of 14 native species and 5 introduced species. This constitutes a relatively small percentage of the Nylanderia species of the world (LaPolla et al., 2011a). In the Nearctic, observed worker morphological variation lies primarily in overall setation and pubescence patterns. Although most species have relatively sparse pubescence on the mesosoma, this is variable, and introduced species may be broadly recognized by the presence of denser mesosoma pubescence. Males are typically pubescent on the dorsum and queens are uniformly pubescent, as is common in Nylanderia queens from other parts of the world. Cephalic pubescence varies greatly across the species, from virtually absent to being very dense. Coloration ranges from what is perhaps the palest ant in the world, Nylanderia phantasma, to dark brown, as in Nylanderia parvula. Hues of brown and yellow are very common, and multiple species have contrasting mesocoxae and metacoxae as compared to their mesosoma. Males and queens are frequently a little darker than workers of the same species. Cuticular sculpturing is not observed in any Nearctic species.

Males of Nearctic Nylanderia are the best known of any the world’s faunas, with males associated with every species. Given the morphological similarities in the worker caste, the value of male characters cannot be overstated. Paramere shape varies from triangular as is seen in most species to being digitiform, as in Nylanderia bruesii. The digiti are typically about twice as long as the cuspides. The aedeagal valves are similarly convergent with a general triangular shape common in virtually all species. Finally, dissection of the genitalia reveals wide variation in the shape of the ninth sternite, suggesting this feature may be of more value than has been suggested in past works on the genus (Krafchick, 1959).

Nearctic
Kallal & LaPolla (2012) - Nearctic Nylanderia species have been collected from southern Canada in the north to central Mexico in the south. Habitats range from deciduous forests to subtropical scrub to arid deserts. Virtually no collections of native species have been recorded from the northwest. Species richness appears to be highest in the southeastern United States. The presence of new species in relatively well collected areas of the Nearctic (for example, the highlands of the central United States and the deserts of the southwestern United States) is surprising, and is indicative of the need for continued collecting of this genus even in well studied areas.

Reproductives are reared in the summer, overwinter as adults, and fly in the first warm, humid days of spring and summer (Trager, 1984; Ichinose, 1987). More exact dates of flights vary based on local climate, and some species in regions that are warm year round may fly at any time (Trager, 1984). Nests are typically found in leaf litter and rotting wood, although some species are known to have specific habitat requirements, including white sand for Nylanderia phantasma and marshes for Nylanderia concinna. Nests may be permanent or temporary, with the latter as in Nylanderia terricola in forest leaf litter (Lynch et al., 1980). There are three known, but undescribed, workerless social parasite Nylanderia species that will be published at a later date (Cover et al., in prep).

Introduced, non-native species are known in the Nearctic region, having been introduced from both Asia and the Neotropics. The species Nylanderia bourbonica, Nylanderia steinheili, Nylanderia pubens, and Nylanderia fulva can be found in the Gulf states, particularly Texas and Florida. Nylanderia fulva is an aggressive invasive that successfully colonized multiple Caribbean islands before arriving in the United States. It appeared first in Texas but has likely spread throughout the entire southeastern part of the country (Gotzek et al., 2012). Workers of this species are impossible to separate from another introduced species, Nylanderia pubens. At this time it appears N. pubens has only been introduced to Florida. Nylanderia flavipes was introduced from Asia in the early 1900’s and has since colonized much of New England and the Mid-Atlantic, particularly in urban areas. It appears to be displacing the native species, Nylanderia faisonensis, in some places (Trager, 1984; Wetterer, 2011). Another species,Nylanderia guatemalensis, has not been found in the Nearctic, despite previous reports of its presence in the region (Trager, 1984). Given its widespread distribution across the Caribbean, and suspected invasive habit, it has the potential to be an invasive species in the Nearctic region.

Nomenclature

 *  NYLANDERIA [Formicinae: Plagiolepidini]
 * Nylanderia Emery, 1906b: 133 [as subgenus of Prenolepis]. Type-species: Formica vividula, by original designation.
 * Nylanderia subgenus of Paratrechina: Emery, 1925b: 217; Creighton, 1950a: 405; Smith, D.R. 1979: 1443.
 * Nylanderia raised to genus: Wheeler, W.M. 1936b: 210; Kempf, 1972a: 166.
 * Nylanderia junior synonym of Paratrechina: Trager, 1984b: 51.
 * Nylanderia revived from synonymy, status as genus: LaPolla, Brady & Shattuck, 2010a: 126.
 * Nylanderia senior synonym of Andragnathus: LaPolla, Brady & Shattuck, 2010a: 126.
 * ANDRAGNATHUS [junior synonym of Nylanderia]
 * Andragnathus Emery, 1922d: 111. Type-species: Andragnathus hubrechti, by monotypy.
 * Andragnathus junior synonym of Paratrechina: Agosti & Bolton, 1990a: 75.
 * Andragnathus junior synonym of Nylanderia: LaPolla, Brady & Shattuck, 2010a: 126.

Additional References

 * [[Media:Agosti & Bolton 1990a.pdf|Agosti, D.; Bolton, B. 1990a. The identity of Andragnathus, a forgotten formicine ant genus (Hym., Formicidae). Entomol. Mon. Mag. 126: 75-77 PDF]]