Azteca aurita group

Based on [[Media:Longino J 2007.pdf|Longino, J.T. 2007. A taxonomic review of the genus Azteca in Costa Rica and a global revision of the aurita group. Zootaxa. 1491:1-63. PDF]]

Species

 * Azteca aurita
 * Azteca lallemandi
 * Azteca lanuginosa
 * Azteca nanogyna
 * Azteca pilosula
 * Azteca schimperi

Diagnosis
Queen and worker: Palpal formula 4,3; middle and hind tibia lacking apical spur; anteromedial border of clypeus strongly convex and extending well beyond anterolateral clypeal lobes, HLB/HLA > 1.04. Queen: general body size small, similar in size to major workers; integument extremely smooth and shining, glass-like, with appressed pubescence extremely dilute; pilosity, when present, a stubble of short, stiff, fully erect setae; petiole bluntly subpyramidal to bilobed, never flat and scale-like.

Worker: Head always cordate, with variable tendency for posterolateral portions of occipital border to be drawn out into angular projections; scape, tibiae, lateral and posterior margins of head, and mesosomal dorsum devoid of setae; mandibles either of two forms, both unique to the species group: (1) dorsal surface strongly flattened, densely and finely striate, mat, or (2) dorsal surface convex and shiny, masticatory margin strongly sinuous, with large, projecting apical tooth; petiole as in queen.

Biology
Members of the A. aurita species group are widespread but rare. They construct carton nests on the branches of trees, nests which are always bare of epiphytes (they do not form ant gardens).

The diminutive and highly derived queens of the group suggest a social parasitism syndrome (Forel 1928, Hölldobler and Wilson 1990). Species in the A. aurita group have queens that are about the same size as workers, and the gaster is very small in proportion to the rest of the body. This contrasts with more typical Azteca species, which have queens much larger than workers and with large gasters, presumably full of resources for founding new colonies on their own. It is difficult to imagine the small aurita-group queens doing so, and a more likely scenario is for aurita-group queens to insinuate themselves into established colonies of other species, killing the host queen and having the host workers rear the parasites’ offspring. It is not even clear how they function once established; aurita-group colonies are enormous, and it seems paradoxical that such small queens could generate sufficient eggs to populate them. The morphology of Azteca nanogyna carries this paradox to an extreme, and a possibility in this case is that A. nanogyna is a workerless social parasite.