Abstract
Males of
Periplaneta americana respond to the sex pheromone secreted by females with increased locomotion and positive chemo-orientation. Both sexes orient toward aggregation pheromone without an increase in locomotion. Immediately following removal of one antenna males exhibit ‘circus’ movements, but after 2 days orient toward pheromones; a bi-modal mechanism of chemo-orientation is proposed. Cockroaches turn away from air currents, but orient toward air currents carrying sex or aggregation pheromone, suggesting the possibility of up-wind orientation. Antennae deflect upward and outward when pheromone is first perceived; the head then moves toward the pheromone source. Following removal of one antenna, the pattern of head and antennal movement changes in a manner which enhances the sweeping of the intact antenna.