Anti-perfume – the male butterfly’s gift to his partner

Pieris butterflies are not like all other butterflies. Both sexes agree about sex. In a dissertation about olfactory communication, Johan Andersson, a scientist at the Royal Institute of Technology in Stockholm (KTH), Sweden, presents exciting new findings about a joint effort that provides an alternative view of the theory of sexual selection.

The Western man gives his partner an engagement ring when he wants to show the world that this woman is spoken for. When mating, the male white-winged rape-seed butterfly instead gives his partner methyl salicylate-a turn-you-off odor that serves the same purpose. The next male butterfly needs only a second to realize that the race is run and flies on to the next female.

The idea of a so-called anti-aphrodisiac has been known for some time, but it is only now that it is possible to show how the system works in its entirety, exactly what substances are involved and above all that the whole thing is a collaborative effort between male and female and not a conflict.

This will call into question the theory of sexual selection that is based on the idea that sex is a conflict between the male’s and the female’s different strategies in mating. The male attempts to fertilize as many females as possible, and the female, who is making a greater commitment in mating, is more frugal in her selection and must therefore protect herself from bad propositions.

Anti-aphrodisiacs benefit both. The male, of course, because no other males will mount the female while the substance is active, but the female also has time to lay her eggs in peace. The time she needs for this has proven to be exactly the time the anti-aphrodisiac is in effect.

What good is this knowledge? It is indeed pure research, but already applications lie just around the corner. Pieris butterflies, or rather their larvae are a major pest in many kinds of plant cultivation. The larvae eat cabbage, rape-seed, and turnips, and today fields are sprayed with various pesticides to kill these larvae. In the future it might be enough to expose the butterflies to the natural turn-off substance. There wouldn’t be many offspring made, at least not right there.