Substrate-borne vibrational signals of the Consperse stink bug (Hemiptera: Pentatomidae)

There is increasing evidence that short-range reproductive behaviors of phytophagous pentatomid bugs are mediated by vibrational signals. These signals have not yet been examined for bugs in the genus Euschistus, which contains several species native to the Americas. Substrate-borne vibrational signals (songs) were recorded from both sexes of the Consperse stink bug, Euschistus conspersus Uhler, an economically important agricultural pest in western North America. Females produced two songs (FS-1 and FS-2), each consisting of a series of frequency-modulated pulses with a pulse duration of 352 ± 105 (mean ± SD) and 163 ± 36 ms, respectively. Males produced four distinct songs, two composed of frequency-modulated pulses (MS-1 and MS-3), one consisting of narrowband pulses (MS-2), and one composed of a series of 1–6 short pulses, many of which were fused to form distinct pulse trains (MS-4). For both males and females, songs consisting of very short, frequency-modulated pulses (FS-2 and MS-3), with a mean pulse duration <170 ms, were emitted when the other member of the pair was silent. Songs made up of longer, frequency-modulated pulses (FS-1 and MS-1) were produced spontaneously and in response to songs from conspecifics. Pulses of MS-2 were produced by a male once a duet with a female had been initiated. This song had no frequency modulation and a longer mean pulse repetition time than MS-1. The two female songs and three of the male songs (MS-1, MS-2, and MS-3) were produced during the calling phase of mating behavior. Pulse trains of MS-4 were emitted during close-range courtship. During copulation males produced intermittent pulses of MS-1, the function of which is unknown. Dominant frequencies of all songs ranged from 102 to 136 Hz, comparable with those of other pentatomid songs. Although there were superficial similarities in the song structures of E. conspersus when compared with those of other pentatomid species, the song repertoire of E. conspersus was distinct and unique.