P-32 Evaluating phonotaxis variability and selective processing of its underlying neural elements in an insect model

Buller Hall Hallways

Selective phonotaxis exhibited by female Acheta domesticus and Gryllus bimaculatus has been documented in multiple studies. While some females are finely tuned and attracted to calling songs with syllable periods matching those of the natural calls of the male, other females respond phonotactically to calls with a wider range of syllable periods. Multiple studies have also provided evidence supporting the importance of prothoracic auditory neurons such as L3/AN2 in the selective phonotaxis of female crickets. We have developed a neuronal model, which includes the contralateral omega 1 neuron inhibiting a source of delayed inhibition as well as a source of selective excitation onto the L3. The inhibition by ON1 is downregulated by Juvenile Hormone III and PTX, which increases selectivity to syllable period, and is upregulated by histamine, which leads to decreased selectivity. Testing this model has included prothoracic injections of JHIII, histamine and PTX followed by an assessment of phonotaxis and L3’s selective responses using electrophysiology. The model so far remains valid as we continue to test it. Preliminary data shows the effect of H -7 (a kinase inhibitor) on phonotaxis before and after injection parallels the effect of L3’s response. Additionally, exposure to males, decreases selectivity in females. Electrophysiology of L3’s response in exposed females is currently being evaluated.