On Some Peculiarities of Mechanisms of Phonotaxis Selectivity in the Cricket Gryllus bimaculatus

It is shown that positive phonotaxis of female crickets Gryllus bimaculatus is characterized by a band-pass tuning to the pulse repetition period (PRP) in the male communicative calling song; this feature can be provided by two neuronal mechanisms--high-frequency (HFF) and low-frequency (LFF) filters. With elevation of temperature, PRP becomes shorter. The tuning of phonotaxis to this parameter changes correspondingly. It is suggested that this coupling is provided by differences in properties of LFF and HFF with respect to the environmental temperature as well as to the sound pressure level (SPL) of the signal. In behavioral experiments on a Y-maze labyrinth, the tuning of the female phonotaxis selectivity to PRP in a model calling song was determined for 20 and 25°C at 70 dB SPL and for SPL changing from 70 to 85 dB at 20°C. At an increase both of temperature and of SPL, the optimum of the phonotaxis tuning shifted towards the lower values of PRP. The agreement of the results of this study with the above-exposed hypothesis indicates in favor of possible existence in the cricket of neuronal mechanisms that are different in their characteristics with respect to temperature and signal intensity.[PUBLICATION ABSTRACT]