Tritrophic interactions: Effects of caterpillar host plants on predatory paper wasps

Abstract

The effects of sunflower (Helianthus annuus) and groundcherry (Physalis pubescens), two hosts of the tobacco budworm (Heliothis virescens), on predation by paper wasps (Polistes arizonensis) were examined. Initially it was found that P. arizonensis foragers took more caterpillars from H. annuus plants than P. pubescens in paired-choice tests. Regarding physical aspects of the plants, wasps took longer to locate prey on artificial plants with higher leaf surface areas and gave up searching faster on artificial plants with more complex architectures. In paired-choice tests for chemical effects, wasps chose more caterpillars within H. annuus odor than in P. pubescens odor. They also chose more H. annuus-reared larvae than P. pubescens-reared larvae when they were presented without plants. Predator handling times were affected by the amount of food in the caterpillar gut, with a slight trend depending on what plant species was present in the caterpillar gut.