Behaviour: Hungry caterpillars follow pheromones

The same scents that adult moths and butterflies use to attract mates are shown to attract caterpillars to food in this week’s Nature Communications. The study shows that, given the choice between normal food or food mixed with sex pheromone, the caterpillars opt for the pheromone-laced meal. This finding is surprising as sexually immature insect larvae such as caterpillars were thought not to respond to sex pheromones released by adult moths and butterflies.

Emmanuelle Jacquin-Joly and colleagues make these observations in cotton leafworms, caterpillars that feed on a wide range of plants including cotton and tobacco. They find that the caterpillars of both sexes are attracted to a female pheromone, which indicates that this signal is not used as a sex pheromone by larvae. It is possible that the caterpillars use this scent as a shortcut to find food in the wild, the authors suggest, since adult moths have a more complex olfactory system that may be better equipped to identify suitable plants.