Recognition of acoustic signals in sympatric grasshopper species
V.Yu. Vedenina, R.D. Zhantiev
Biological Faculty, Moscow State University
Calling songs of 12 species inhabiting three different biotops of Kursk reserve were recorded and analyzed by measuring temporal and frequency song parameters. The signals differed in many temporal, and sometimes, frequency parameters. In behavioural experiments, females of three species Chorthippus albomarginatus, Ch. parallelus and Ch. dorsatus responded not only to conspecific but also to heterospecific songs. The response frequency to conspecific songs ranged from 74 to 89 %, to the heterospecific songs - from 0 to 49 %. The analysis of female responses to artificial songs showed that Ch. parallelus females use echeme structure (the presence of discrete impulses) and amplitude modulation of the echeme to recognize the conspecific song; in Ch. dorsatus females, the presence of two parts in the song as well as subdivision of the first part into the echemes with separate pulses were found to be essential in their recognition process. It is suggested that Chorthippus females do not use a single key characteristic but employ the entire complex of temporal parameters.