Seasonal dynamic shifts in patch exploitation by a parasitic wasp

Abstract

We developed and tested predictions of a dynamic life history model that is concerned with how temperate-zone parasitic wasps adjust patch residence time and tendency to superparasitize when expectation of life and habitat quality varies. The theory predicts that wasps with short life expectancy should continue to search longer and superparasitize more frequently than similar wasps with long life expectancy. Similarly, wasps with long life expectancy that forage in habitats where patches are already heavily exploited should continue to search longer and superparasitize more frequently than similar wasps foraging in habitats where patches are relatively unexploited. In contrast, the theory predicts that wasps with short life expectancy will be insensitive to habitat quality. We tested the predictions on Drosophila parasitoids (Lep-topilina heterotoma) by (1) rearing wasps under fall and summer photoperiod (i.e., short versus long life expectancy) and (2) giving wasps foraging experience on different quality patches (i.e., exploited versus unexploited habitats). Results of the experiments corroborated our predictions. We discuss how parasitic wasp behavior can be shaped by globally predictable and locally unpredictable events.