The effects of dietary pyrrolizidine alkaloids on the developmental biology and reproductive behavior of the salt marsh moth Estigmene acrea (Dru.) (Lepidoptera: Arctiidae)

The growth and development of the androconial organs of Estigmene are diet (PA) dependent. Males that ingest PAs have coremata that develop more quickly. The coremata of PA-fed males were shown to be approximately twice as large as controls and housed twice as many scales, sockets, and trichogen cells for pheromone production and release. PAs also shorten the pupal stage of male Estigmene by 72 hours.; The morphogenetic effects of ingested PAs can be triggered by a secondary PA metabolite called retronecine. All ingested alkaloids are funneled through this critical metabolite and it appears to be a key player in PA morphogenesis. Retronecine is effective whether ingested or injected into the hemolymph.; PAs are the precursors for the male courtship pheromone hydroxydanaidal and that PAs also have profound behavioral effects on the males. PA fed males inflated their coremata more frequently than males devoid of PAs. PA- males rarely showed this behavior. PAs had no apparent effect on female calling behavior.; Taken together these results illustrate that access to PAs has a profound effect on Estigmene and its mating system. A significant remaining question is how does access to PAs influence female mate choice? In previous work with Creatonotus gangis researchers focused on mate choice between males within an artificial lek (in a greenhouse). They concluded that females did not choose males with larger coremata and higher levels of hydroxydanaidal. They based this on the observation that females mated with the first male that they encountered. My results suggest that female mate choice may operate on another level. I present a model for how sexual selection takes place in Estigmene. In the model access to PAs controls alternate mating strategies in the males and females and result in the unusual sex role reversal seen in this species.