Communication with substrate-borne vibrational signals between conspecific males and females was compared in the red-shouldered stink bug, Thyanta pallidovirens, and a closely related species, T. custator accerra. These species are sympatric in the southwestern United States, and distinguishing the two species using morphological characteristics can be difficult. Mating behaviour and vibrational signals were recorded from sexually mature adults on the membrane of a loudspeaker, and on a bean plant. Spectral and temporal characteristics of signals were analysed and related to insect behaviour.
The sequence of mating behaviour and phases of vibrational communication were similar for each species, although the repertoire and song parameters differed. Males and females of T. pallidovirens each produced two different songs. Females of T. custator accerra also emitted two different songs, while males emitted four different signals. Copulating pairs of T. custator accerra produced a copulation song. The female songs of both species were comparable in structure and function, as was one of the male signals. Males of both species emitted a signal which immediately preceded copulation; although the function of this song appeared to be similar in both species, structural properties differed between species. The other two male songs of T. custator accerra and the copulation song had no counterpart in the T. pallidovirens repertoire. These differences in vibrational communication, combined with differences in male-produced pheromone, are probably important factors in maintaining reproductive isolation in these closely related species.
Species 1: Hemiptera Pentatomidae Thyanta pallidovirens (red shouldered stink bug)
Species 2: Hemiptera Pentatomidae Thyanta custator accerra
Keywords: substrate-borne communication, mating behaviour
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