In recent years, it has become clear that there is great deal of variation in sex biasing strategies in ant societies. The breeding system—the number, relatednesses, and relative reproductive outputs of queens within a colony—constitutes a key feature of social life.

Kunming Institute of Zoology (KIZ) researchers, Douglas W. Yu in collaboration with his research team investigated sex allocation in the Neotropical ant Allomerus octoarticulatus var. demerarae.

They found that this species exhibits a strongly split sex ratio, with 80% of mature colonies producing !90% of one sex or the other. Their genetic analyses (DNA microsatellites) reveal that Allomerus has a breeding system characterized by almost complete monogyny and a low frequency of polyandry.

Contrary to theoretical explanations, they found no difference in worker relatedness asymmetries between female- and male-specialist colonies. Furthermore, no clear link was found between colony sex allocation and life history traits such as the number of mates per queen, or colony size, resource level, or fecundity. They also failed to find significant support for male production by workers, infection by Wolbachia, local resource competition, or local mate competition.

They precluded the possibility that Allomerus exhibits split sex ratios because of the evolution of alternative biasing strategies in queens or workers, as recently proposed in the literature.

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