Grooming Keeps Insect Senses Sharp

Unlike humans who groom themselves primarily to keep up appearances, insects groom for survival, according to a new study. A team of researchers at North Carolina State University and the Russian Academy of Sciences has determined that a number of bugs, including the American cockroach, habitually clean their antennae to remove chemical residues that build up there (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1212466110). Insects use sensors on their antennae to find food and mates, as well as to avoid danger, and these findings “explain why they fastidiously groom, even in clean places,” says team leader Coby Schal, an entomologist at NC State. Using nerve cell recordings, the researchers showed that when cockroaches aren’t allowed to groom their antennae the insects can’t detect food odors such as geranyl acetate and sex pheromones such as periplanone-B with their usual sensitivity. Gas chromatography analysis unveiled that waxy long-chain alkyl compounds known as cuticular hydrocarbons are the main substance that accumulates on the ungroomed antennae. Insects secrete these chemicals as a protective coating to prevent dehydration and pathogen invasion. “Given the findings,” says biologist Susan M. Bertram of Canada’s Carleton University, “future research could explore insecticides that prevent grooming and thus constrain fitness in pest insects.”