The German cockroach is a gregarious species, and the male courtship behavior is mediated by the female's contact sex pheromone. The sexes usually congregate around food, shelter, or at a deposition site of aggregation pheromone, so no long distance searching is necessary for contact. In this study, we demonstrate that sexually receptive males not only detect the heterosexual odor, but also prefer the odors of virgin females over that of mated females. Sexually receptive females can also detect the heterosexual odor, but show no preference between the odors of either sex, nor do females exhibit a differential response to mated and virgin males. Sexually receptive virgin females not only increase locomotion to find mates, but also exhibit a calling behavior which releases a volatile sex pheromone. The longer a female does not sense the conspecific odor, the more frequent calling behavior is displayed. We suggest that German cockroach females increase locomotion and calling frequency as a secondary strategy when sexually receptive virgin females do not encounter males.
Calling behavior, Odor preference, Secondary strategy
