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Abstract

In polyandrous species, males seek to maximize their reproductive output by monopolizing their mate.
Often the male transfers substances to the female that suppress her sexual receptivity or antagonize
the behavior of competing males; both are usually transferred in seminal fluids and represent forms of
chemical mate guarding. In moths, more long-range female sex pheromones have been identified than
in any other animal group, and males often display with close-range sex pheromones, yet odor-based
post-copulatory mate guarding has not been described in moths so far. We tested the hypothesis that
the male sex pheromone in the noctuid moth Heliothis virescens perfumes the female and functions
as an anti-aphrodisiac. Indeed, virgin females perfumed with male pheromone extract, or with its
main component, mated significantly less than control virgin females, and this effect persisted for two
successive nights. This chemical mate guarding strategy was disadvantageous for H. virescens females,
because the reproductive output of twice-mated females was significantly higher than that of oncemated
females. Since the female and male sex pheromones are biosynthetically related in this and
other moth species, chemical mate guarding may also impose selection pressure on the long-range
female sex pheromone channel and consequently affect the evolution of sexual communication.