Maria de la Paz Fernandez, Ph.D.


Robust innate behaviors are attractive systems for genetically dissecting how environmental cues are perceived and integrated to generate complex behaviors. In mammals and insects, pheromones strongly influence social behaviors such as aggression and mate recognition. Prior studies suggest that the suboesophagueal ganglion (SOG), the brain region that processes information about taste, helps Drosophila males decide whether to mate or fight. Moreover, it was recently found that Tetanus toxin-mediated inactivation of Gr68a-expressing neurons or leads to a significant reduction in male courtship performance, while CheB42a mutant males attempt to copulate with females earlier and more frequently than control males. In male competitive assays we found that these proteins also have opposite effects in aggression: CheB42a mutant males get stuck in the fencing step, displaying a 4 fold increase in their latency to fight while Gr68a-Gal4/ UAS-TNT males exhibit the highest aggression levels described so far. These mutant males very often display high intensity features of aggression like boxing or tussling, rarely seen in pairs of wily type flies, and also attempt to copulate with other males, frequently skipping the early steps or the courtship ritual. Together, these data indicate that the gustatory pathway involving Gr68/CheB42a is required for a normal behavioral response to male cuticular hydrocarbon pheromones that modulate aggressive behavior. Moreover, in preliminary experiments we found that poxn mutant males �which completely lack taste bristles- do not display any feature of aggressive behavior. These results suggest that sensory inputs mediated and/or processed by the tarsal receptors or SOG contribute to the regulation of male-male aggression and provide insight into how diverse behavioral choices are initiated in response to specific sensory cues.

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