Acoustic signals in the communities of Bryodemini (Orthoptera: Acrididae: Oedipodinae): segregation of communication channels through the temporal divergence of acoustic activity peaks and the emergence of the dusk chorus

摘要

The sounds produced by four sympatric species of Bryodemini from South Siberia during flight displays are described. In spite of distinct interspecific differences in signal temporal pattern, Bryodema luctuosum, Bryodemella holdereri and Angaracris barabensis sing during daytime, whereas B. tuberculatum dilutum usually demonstrates only short and sharp peak of acoustic activity after sunset sometimes forming so-called dusk chorus. Since the abundance of Bryodemini usually is remarkably high, it can be assumed that during flight displays acoustic signals of different species suffer mutual interference even though they differ distinctly from each other in temporal pattern. Apparently, this is the reason for temporal shift of B. tuberculatum dilutum acoustic activity peak and the emergence of dusk chorus in this species.