Emergence, mating, and postmating behaviors of the oriental beetle (Coleoptera : Scarabaeidae)

In a previous field-trapping study of the oriental beetle, Exomala oriental is (Waterhouse), by using synthetic sex pheromone on golf course fairways, numerous males were observed and trapped during the hours of peak mating ac tivity. However, very few beetles were observed in the same areas when synt hetic pheromone was absent. To investigate the hypothesis that mating in na ture occurs cryptically within vegetation at the soil surface, laboratory s tudies on female emergence and pheromone release, male emergence and mate-l ocating, and female and male mating behaviors were conducted Mate acquisiti on and copulation occurred on the soil surface near the female emergence si te, with both sexes engaging in pheromone-mediated behaviors after having e merged from the soil. A highly stereotyped female pheromone release, or cal ling, behavior was observed consisting of insertion of the female's head in to the soil and elevation of the tip of her abdomen into the air Bioassays conducted in a wind tunnel that simulated a turf fairway environment showed that walking and flying were both important in the upwind response of male s to females. Mating and copulation occurred without an obvious complex cou rtship, but observations of postmating behaviors suggested that mate guardi ng occurs.