Genetic relatedness and queen number in a neotropical swarm-founding wasp, Polybia emaciata

The maintenance of eusociality in neotropical, swarm-founding wasps is difficult to explain because brood relatedness is predicted to be very low due to the presence of multiple queens in each colony and because workers are not morphologically constrained from laying eggs. Analysis of 4 morphological measures revealed no physical reasons why workers could not lay eggs in Polybia emaciata. A large variance in queen number, high queen relatedness, and a significant negative correlation between mean queen number and number of eggs per queen strongly suggest that cyclical oligogyny is probably the most important, and possibly the only, mechanism maintaining high relatedness in P. emaciata. Preferential care by workers of closely related kin on a discrete section of a comb is another possible mechanism that requires further research. However, inbreeding and unequal egg-laying by active queens are not important in elevating relatedness in P. emaciata.