Paternity, reproduction and conflict in vespine wasps: a model system for testing kin selection predictions

Abstract.

The Vespinae wasps (Vespa, Provespa, Dolichovespula, and Vespula) are an excellent group for testing kin selection predictions. There is considerable variation in kin structure and conflict resolution in a group of known phylogeny where all species have a similar basic biology: morphologically distinct queens and workers, and annual nests headed by a single queen. Vespine kin structure can be described by a single variable "effective paternity", which is defined by queen mating frequency and sperm use. Low effective paternity, which causes high worker relatedness, is basal in the group (Vespa, Dolichovespula), with high paternity (ca >2) restricted to Vespula whose queens mate more and use sperm more equally. Paternity variation correlates well with observed patterns of reproduction and conflict. As predicted by theory, male production by workers is common in Dolichovespula but not in Vespula where worker policing occurs (Vespula vulgaris). The theory is also supported by intercolony variation in Dolichovespula, with facultative worker policing (Dolichovespula saxonica) and sex allocation biasing by workers (D. arenaria) occurring in response to paternity. In addition, queen loss in reproductive colonies of nine species is negatively correlated with paternity, in line with the prediction that matricide is only expected at low paternity. However, paternity does not explain the reproductive characteristics of Vespa crabro. Although paternity in V. crabro is only 1.1, the same as the mean in six Dolichovespula species, its reproductive behaviour is different from Dolichovespula. More like Vespula, V. crabro has worker policing, workers that rarely have active ovaries, and little queen loss in reproductive-phase colonies.