Interspecific attractivity of female sex pheromone components ofPeriplaneta americana.

Female sex pheromones ofPeriplaneta americana, P. australasiae, andBlatta orientalis elicit locomotion and upwind orientation in conspecific males. Interspecific attraction between these species was observed in a wind tunnel assay for most species combinations, with the exception ofP. australasiae males not being attracted toP americana females. The role of twoP. americana sex pheromone components, periplanone-A (PA) and periplanone-B (PB) in male attraction was analyzed. PA induced locomotion in males of all three species, with highest threshold concentration inP. americana. PB was effective inP. americana andB. orientalis, but not inP. australasiae. Experiments with mixtures of both components confirmed an inhibitory influence of PB onP. australasiae males when it was added to PA in a ratio of 3∶1 or higher. SinceP. americana andP. australasiae have been found to be syntopous, and their daily mating periods overlap, the female sex pheromone ofP. americana is discussed as an isolating factor between both species.