Calling-song function in male haglids (Orthoptera: Haglidae, Cyphoderris).

We studied the response of males to the singing of nearby male conspecifics in two species of the orthopteran genus, Cyphoderris, primitive relatives of crickets and katydids in Alberta. Lone male Cyphoderris buckelli stridulating in a large cage made a phonotactic approach to a nearby speaker broadcasting conspecific calling song. But in field experiments no phonotaxis to song broadcasts occurred. Calling male Cyphoderris monstrosa were exposed in the field to playback of a synthetic calling song at a typical conspecific pulse rate, relayed broadcast of their own call, and low-frequency audio noise. We tested whether a C. buckelli field singer would alter his calling song in response to the singing of a nearby male conspecific. The pulse rate of C. monstrosa varies linearly with temperature. There was no significant change in duty cycle for males exposed to synthetic song or to rebroadcast of their own song, whereas males reduced their acoustic output in the presence of noise. Male C. monstrosa responded to the song of a conspecific male broadcast nearby with only a non-significant increase in chirp duty cycle. The marking and recapture studies of C. buckelli reveal an almost complete absence of site fidelity in this species. Most males move to different singing locations on successive nights in a fashion consistent with choosing random bearings and traveling random distances