An olfactory receptor detecting caterpillar frass governs competition avoidance in a moth

The tobacco hawkmoth uses olfaction to localize suitable host plants for oviposition. Recent findings suggest that the moth not only decides based on odors emitted by host plants, but also can sense odors emitted from frass of conspecific larvae already present on this host plant. By avoiding oviposition in the presence of frass odors, the female moth avoids conspecific competition for its offspring. Using the novel genetic tool CRISPR/Cas9 we could identify the olfactory receptor detecting these frass odors and hence, governing the moth’s competition avoidance.