GUT BACTERIA MEDIATE THE PERCEPTION OF CATERPILLARS BY PLANTS AND PARASITOIDS

Chewing insect herbivores cause massive damage during feeding bycrushing plant tissues with their mandibles, thus releasing a vast array of cues (such as salivry proteins) that may be perceived by the plant, which then mobilizes plant defenses. Among those cues are bacteria that are deposited during feeding by some herbivores such as beetles, which suppress plant defenses. We have new,compelling evidence from field-collected caterpillars that their gut bacteria play a critical role in suppressing induced plant defenses in response to herbivory, but the mechanisms appear to differ from other insects in that the bacteria affect the composition of salivary cues. We will test whether gut bacteria mediate the perception of caterpillars by their host plants and their naturalenemies. We will also identify specific bacteria responsible for any changes in perception.We will use two field-collected species: Helicoverpa zea and Spodoptera frugiperda, feeding on tomato and maize, and the parasitoid Cotesia marginiventris to test the hypothesis. These insects are each responsible for more than a billion dollars per year in control costs and damage. Toamto and maize are two of the most important crops grown worldwide.Completing these objectives will uncover the overlooked role of gut microbes in mediating plant-herbivore interaction