Phonotaxis in Male Field Crickets: The Role of Flight Experience, Serotonin and Octopamine Neurotransmission

Insect phonotaxis is influenced by various external and internal factors related to the environment and to the inner states of an organism. Previously, we found that flight, a natural behavior common among insects, significantly enhances the subsequent phonotactic response of female crickets (Gryllus bimaculatus) via serotonergic mechanisms. It is known that phonotaxis is also present in male crickets. However, the natural factors influencing phonotaxis in males and the neurochemical mechanisms behind these effects remained unknown. Our goal was to clarify these points and to compare phonotaxis of freely moving male and female crickets using a recently developed experimental paradigm. First, we found that freely moving male and female crickets demonstrate similar phonotactic response, quantitatively evaluated based on the time that animals spent near the source of calling song, their average distance to it and the number of approaches to it. We also found that the experience of previous flight increased phonotaxis in male crickets as it does in females. Also, as in females, this effect was associated with serotonergic neurotransmission. Thus, the manifestation of phonotactic behavior in freely moving male and female crickets, as well as the behavioral and monoaminergic modulation of phonotaxis in both sexes, appear to be quite similar in our experimental paradigm.