Many animals use sound for communication, particularly for highly species-specific mating calls, as in birds and insects. In crickets, females ready to mate show an easily measurable behavior of turning toward the source of an appropriate mating call. Insects also have accessible single nerve cells that permit testing for the neuronal mechanisms of whole behavior patterns. Particular single nerve cells in parts of the brain of female crickets have been found to respond physiologically to key features of the male calling pattern. In this project a synthesized call is used to see how changes in the call pattern change behavioral responsiveness of the females, and specific explorations and lesions of nerve cells in the brain are used to determine the neural circuit underlying the response to the call. Hormonal effects also modulate the responsiveness of females as they become mature, and this model system allows a novel approach to test directly the effects of a particular hormone on the neural mechanisms underlying the auditory response behavior. This work on an accessible, novel model system will provide important comparisons with other hormonally-modulated communication, and provides groundwork for examining the molecular mechanisms for these modulating actions. The impact of this work will be not only on auditory neuroscience, but on work relating neural mechanisms to behavioral plasticity and development in general, and on understanding breeding in insect populations.