Courtship in Drosophila melanogaster offers a powerful experimental paradigm for the study of innate sexually dimorphic behaviors [1, 2]. Fruit fly males exhibit an elaborate courtship display toward a potential mate [1, 2]. Females never actively court males, but their response to the male's display determines whether mating will actually occur. Sex-specific behaviors are hardwired into the nervous system via the actions of the sex determination genes doublesex (dsx) and fruitless (fru) . Activation of male-specific dsx/fru(+) P1 neurons in the brain initiates the male's courtship display [3, 4], suggesting that neurons unique to males trigger this sex-specific behavior. In females, dsx(+) neurons play a pivotal role in sexual receptivity and post-mating behaviors [1, 2, 5-9]. Yet it is still unclear how dsx(+) neurons and dimorphisms in these circuits give rise to the different behaviors displayed by males and females. Here, we manipulated the function of dsx(+) neurons in the female brain to investigate higher-order neurons that drive female behaviors. Surprisingly, we found that activation of female dsx(+) neurons in the brain induces females to behave like males by promoting male-typical courtship behaviors. Activated females display courtship toward conspecific males or females, as well other Drosophila species. We uncovered specific dsx(+) neurons critical for driving male courtship and identified pheromones that trigger such behaviors in activated females. While male courtship behavior was thought to arise from male-specific central neurons, our study shows that the female brain is equipped with latent courtship circuitry capable of inducing this male-specific behavioral program.
Paper commented on Archer R. Brain wiring explains sex differences in Drosophila behaviour. Journal of Experimental Biology 2016 219: 3675 doi: 10.1242/jeb.130369.
Movie promoting this research 'The Fe-male Brain'
- neural circuits
- reproductive behaviours
- brain sex differences