Nearly half of all insects are herbivores, but their diets do not consist of only plant material. It is not uncommon for potentially harmful microorganisms to slip in during a feast. In a study published on January 19 in Cell Chemical Biology, researchers report that these insects use an ironic strategy to resist microbial infections. A bacterial species commonly found in the gut of the cotton leafworm and other moths secretes a powerful antimicrobial peptide, killing off competitors while defending its host against pathogens.