Physiological adaptations of the insect gut to herbivory

Abstract

Plant biomass is the most abundant resource in terrestrial communities, and terrestrial green plants and the herbivorous (phytophagous) insects that feed on them account for more than half of all living species (Scudder 2009). Still, herbivory appears to have represented a challenge that most insect orders have not been able to adapt, since phytophagous insects are only represented in nine (Coleoptera, Lepidoptera, Diptera, Hymenoptera, Hemiptera, Orthoptera, Phasmida, Thysanoptera, and Collembola) of the 29 orders of insects. Nonetheless, once an insect group has overcome the initial difficulties and can exploit the resources provided by the plants, the herbivorous habit seems to have promoted diversification (Futuyma and Agrawal 2009).