PROJECT SUMMARY The overarching goal of the Asahina lab is to understand the neurogenetic mechanisms by which animals ad- just tactics during social behaviors in a context-dependent manner. To this end, they study agonistic interac- tions between Drosophila melanogaster fruit flies. Flies choose between different types and intensities of social behaviors based on both internal and external conditions (e.g., feeding status, mating status, outcomes of pre- vious interactions). Powerful tools for manipulating gene and neuronal function in Drosophila with high preci- sion provides a unique platform for understanding the neurogenetic mechanisms underlying this rich behavioral flexibility. One major finding from the Asahina lab during the past 4 years is that a specific subset of octopamin- ergic neurons suppress aggression, and that the transcriptional regulator nervy controls the expression of genes necessary for these neurons to function as an aggression “brake”. They also characterized the genetic origins of the functional differences between three male-specific aggression-promoting neurons. With the ability to genetically control previously characterized aggression-promoting neurons and their development of novel computational methodologies for characterizing agonistic interactions at fine resolution, goals of the Asahina lab over the next five years are to: 1) elucidate how animals establish dominant-submissive hierarchies based on experience, and 2) characterize the neuronal and genetic mechanisms by which deficits in specific nutrients modulate behavioral tactics during competition for food. The first goal will be pursued by building upon their recent finding that the dominant-submissive relationship can override experimental activation of aggression- promoting neurons. They will test the prediction that experience-dependent modulation of aggressive behav- iors is implemented by an uncharacterized neuronal or molecular mechanism. The second goal is inspired by their finding that amino-acid deprivation dramatically increases aggression in both male and female flies, but only when live yeast is present in the environment. They will elucidate how specific nutrition deficits alter the function of aggression-controlling neuronal and genetic modules. These studies build upon strengths of the lab in genetics and advanced behavioral quantification, plus their ingenuity in developing novel behavioral para- digms for addressing longstanding questions in the field of animal behavior, most importantly: how do animals strategically choose between behavioral options? Theoretical analyses have predicted that animals must have evolved sophisticated mechanisms to integrate information and calculate costs and benefits associated with a particular behavior during agonistic interactions. However, experimental systems to quantitatively characterize the neural bases of these behavioral choices have remained elusive. The proposed experiments provide entry points for ...