Worker Age, Ovary Development, and Temporal Polyethism in the Swarm-Founding Wasp Polybia occidentalis (Hymenoptera: Vespidae)

I measured oocyte sizes of Polybia occidentalis workers to assess whether ovary development corresponded with adult age or with individual variation in behavior. Workers exhibited temporal polyethism by first working inside the nest, then performing on-nest tasks, and later foraging and defending the nest. Individuals varied in their ages at first performance of each of these sets of behavioral acts. Ovary development corresponded strongly with adult age. Workers' ovaries declined quickly after an initial phase of partial development. The period of ovary decline overlapped with the age range at which most workers began performing tasks on the exterior nest surface. However, after accounting for age effects, individual behavioral differences (rate of temporal polyethism and performance of foraging and defense tasks) did not correspond with ovary development. These data suggest that ovary development had little or no effect on variation in task performance by P. occidentalis workers on the nest surface.