Parasitic Wasps Find Hosts by Odor

February 16, 2005

Parasitic wasps tap into an intimate butterfly communication system to sniff out appropriate host butterflies before hitching a ride with them to their egg-laying sites, according to a Brief Communication in the February 16, 2005 Nature. The wasp, Trichogramma brassicae, distinguishes between the aromas of newly mated and virgin female Pieris brassicae butterflies in order to parasitize freshly laid eggs.

During mating, the male butterfly passes an anti-aphrodisiac to the female, making her less attractive to other males, but this tactic allows the wasp to sniff out the female, and successfully ambush her egg-laying. Monika Hilker and colleagues studied the wasps' responses to male, mated female and virgin female butterflies. Their results show that the wasps are more attracted to mated than to virgin females, and respond to the anti-aphrodisiac benzyl cyanide.

The authors say that this hijacking strategy may occur frequently in nature and may encumber the evolution of sexual communication between hosts.

Abstract © 2005 Nature

“Butterfly anti-aphrodisiac lures parasitic wasps,” Nina E. Fatouros, Martinus E. Huigens, Joop J. A. van Loon, Marcel Dicke, Monika Hilker, Nature, February 16, 2005

Monika Hilker (Institute of Biology, Freie Universität Berlin)