Acromyrmex insinuator new species: an incipient social parasite of fungus-growing ants

The two known social parasites of fungus-growing ants (tribe Attini) occupy an advanced grade of social parasitism characterized by absence of a worke r caste and highly derived morphology and behavior. In contrast, the Panama nian Acromyrmex insinuator new species, described here, appears to occupy a n early grade of social parasitism in which males, females, and minor worke rs are nearly indistinguishable from those of the host species. Based on al lozyme and morphological evidence, the host, A. octospinosus ssp. echinatio r, is clearly different and reproductively isolated from the sympatric A. o ctospinosus ssp. octospinosus, and is therefore elevated to species status.