BROOD-MATE AVOIDANCE IN THE PARASITIC WASP BRACON-HEBETOR SAY

The parasitic wasp Bracon hebetor suffers severe inbreeding depression . This study examined two behavioural mechanisms that minimize mating between close relatives. First, the majority of males and females were unwilling to mate immediately upon emergence. Receptivity to mating s lowly increased with age of the adult. By the time most individuals we re willing to mate, the majority of wasps had dispersed from the natal site. Second, females tended to avoid mating with brood-mates when gi ven a choice between a male that developed on the same host and one th at developed on a different host. Experiments using eye-colour mutants and broods composed of relatives and non-relatives indicated that fem ales discriminated against male brood-mates on the basis of environmen tal cues. Females consistently mated with brothers and non-brothers if they developed on another host, but tended to reject brothers and non -brothers from the same brood as themselves. Females maintained the ab ility to recognize brood-mates for at least 5 days after eclosion.