Juvenile hormone titer and advertised quality are associated with timing of early spring activity in Polistes dominulus foundresses

Abstract

Timing of diapause termination has an important influence on individual reproductive success, but relatively little research has explored how individuals differ in their response to diapause termination cues. We tested individual variation in the timing of post-diapause activity in Polistes dominulus paper wasps. Wasps were overwintered in a temperature-controlled chamber. In the spring, ambient temperature was gradually increased and the time each foundress became active was recorded. Timing of post-diapause activity was most strongly associated with the facial patterns that function as a conventional signal of quality. Foundresses with facial patterns indicating high quality became active at lower temperatures than individuals with facial patterns indicating low quality. Early diapause termination is associated with dominance, so the relationship between diapause termination and facial patterns provides a mechanism linking facial patterns with dominance. Body weight and mating status did not influence timing of post-diapause activity. Juvenile hormone (JH) titer at the time of diapause termination was also measured in a subset of foundresses. There was no JH titer threshold for diapause termination. Instead, our results suggest that individuals may have different threshold responses to JH, as individuals that became active at a lower temperature had lower JH titers than individuals that became active at a higher temperature. Overall, there is substantial individual variation in response to diapause termination cues and the variation is likely to have important impacts on the fitness of nest-founding females.