The female rove beetle (Aleochara curtula) emits a sex pheromone which males can detect from a distance. This sex pheromone elicits a grasping response from males and subsequent mating. Once the male has mated with a female he transfer a spermatophore and also an antiaphrodisiac pheromone. Once the female has mated she is unreceptive to other males, but unfortunately for the other males she will still produce the sex pheromone. Once a male graps onto an already-mated female he can detect the antiaphrodisiac pheromone and will cease his behavior, but this has already been a costly endeavor.
In a recent publication from Animal Behaviour (click here for the full article), the authors examined the ability of males to avoid previously mated and thus unreceptive females. The male rove beetle is attracted to the sex pheromone even at a distance which is emitted from both appropriate and inappropriate partners, but he cannot distinguish between them until he has grasped them and can sense the antiaphrodisiac pheromone. What is stopping the males from repeatedly approaching the same inappropriate females? The rove beetles use cuticular hydrocarbons to recognize each other and the authors found that females have greater individual variation in this signature. Furthermore they found, that males were able to learn the individual signature of a female and associate this with their experience of her mating status. This is turn allows the male to waste less energy approaching inappropriate mates.