Cephalotes spp.
Cephalotes is a very distinctive genus of over 130 species immediately identifiable by the bimorphic or polymorphic worker caste, heavily armored cuticle, flattened head, deeply excavated antennal scrobes capable of receiving the entire antennae, large eyes situated at the apex of the antennal scrobe, and apedunculate petiole. The genus is restricted to the New World tropics and subtropics, with three species extending their range into the southern United States: C. varians (Florida), C. texanus (Texas), and C. rowheri (southern Arizona). Cephalotes was revised by De Andrade & Baroni Urbani (1999), who proposed the ecological success of the genus is owed to the following traits: 1) frequent polyandry, 2) a diet based largely on a very abundant resource like pollen, 3) nesting in pre-existing plant cavities, 4) appearance (among most species) of a separate caste of soldiers devoted essentially to the defense of the nest, 5) a high frequency of spontaneous mutation, and 6) a morphology particularly suitable to passive defense.
There is some question as to whether the Florida population of C. varians is native (e.g. Deyrup et al., 1988; Deyrup et al., 2000)or introduced (e.g. Wittenborn & Jeschke, 2011). The species is otherwise known only from the Bahamas and Cuba (De Andrade & Baroni Urbani, 1999). Deyrup et al. (2000)refrained from classifying C. varians as introduced to Florida, arguing that the species may have been transported in floating trees, and dislodged mangroves in particular. Non-native Cephalotes species, including the widespread C. pusillus (Klug), are occasionally intercepted at US ports of entry.