ROLE OF VIBRATIONAL SIGNALS IN MATING-BEHAVIOR OF SPISSISTILUS-FESTINUS (HOMOPTERA, MEMBRACIDAE)

Mating behavior of the threecornered alfalfa hopper, Spissistilus festinus (Say), was investigated to determine the possible role of vibrational signals in mate recognition, attraction, and courtship. Isolated males frequently emitted a vibrational call consisting of a frequency and amplitude modulated wave train that was punctuated with several chirps, whereas isolated females infrequently emitted a simpler spontaneous call. However, when placed on a plant with a male, females readily emitted their call in response to signaling males. These vibrational signals were found to mediate mate recognition and attraction in the absence of other possible kinds of signals (e.g., visual, tactile, or olfactory). When individual males and females were placed on separate plants, vibrational exchanges followed by searching behavior in males occurred only when the petioles of the plants were in contact. Moreover, playback of male or female song to the respective opposite sex resulted in calling and searching behavior in males and response calls from females. Males and females continued to exchange calls during courtship, but other modes of intersexual communication may be important before copulation. These results provide the first experimental evidence for any treehopper species that mating behavior is mediated by substrate-borne vibrational communication.