Know your insect: The structural backgrounds of regurgitation, a case study on Manduca sexta and Heliothis virescens (Lepidoptera: Sphingidae, Noctuidae)

Abstract

Insect herbivores often regurgitate on wounded sites while feeding on plants. Their regurgitant contains different kinds of elicitors that could trigger different plant responses. While feeding on the same host plant, Heliothis virescens and Manduca sexta caterpillars deposit different amount of regurgitant on the damage site (Peiffer and Felton 2009). According to literature data the foregut of regurgitating caterpillars is longer and more strongly musculated than that of not or rarely regurgitating caterpillars (Grant 2006). We compared the gross morphology of fore and midgut of the rarely regurgitating caterpillar of Manduca sexta with the more often regurgitating caterpillar of Heliothis virescens. The foregut of the rarely regurgitating caterpillar is longer than that of the regurgitating caterpillar, which contradicts the literature data.