Evolution of Mechanisms that Control Mating in Drosophila Males.

Genetically wired neural mechanisms inhibit mating between species because even naive animals rarely mate with other species. These mechanisms can evolve through changes in expression or function of key genes in sensory pathways or central circuits. Gr32a is a gustatory chemoreceptor that, in D. melanogaster, is essential to inhibit interspecies courtship and sense quinine. Similar to D. melanogaster, we find that D. simulans Gr32a is expressed in foreleg tarsi, sensorimotor appendages that inhibit interspecies courtship, and it is required to sense quinine. Nevertheless, Gr32a is not required to inhibit interspecies mating by D. simulans males. However, and similar to its function in D. melanogaster, Ppk25, a member of the Pickpocket family, promotes conspecific courtship in D. simulans. Together, we have identified distinct evolutionary mechanisms underlying chemosensory control of taste and courtship in closely related Drosophila species.

Ahmed OM ，Avila-Herrera A ，Tun KM ，Serpa PH ，Peng J ，Parthasarathy S ，Knapp JM ，Stern DL ，Davis GW ，Pollard KS ，Shah NM ... -  《Cell Reports》

Genetic and neural mechanisms that inhibit Drosophila from mating with other species.

Genetically hard-wired neural mechanisms must enforce behavioral reproductive isolation because interspecies courtship is rare even in sexually naïve animals of most species. We find that the chemoreceptor Gr32a inhibits male D. melanogaster from courting diverse fruit fly species. Gr32a recognizes nonvolatile aversive cues present on these reproductively dead-end targets, and activity of Gr32a neurons is necessary and sufficient to inhibit interspecies courtship. Male-specific Fruitless (Fru(M)), a master regulator of courtship, also inhibits interspecies courtship. Gr32a and Fru(M) are not coexpressed, but Fru(M) neurons contact Gr32a neurons, suggesting that these genes influence a shared neural circuit that inhibits interspecies courtship. Gr32a and Fru(M) also suppress within-species intermale courtship, but we show that distinct mechanisms preclude sexual displays toward conspecific males and other species. Although this chemosensory pathway does not inhibit interspecies mating in D. melanogaster females, similar mechanisms appear to inhibit this behavior in many other male drosophilids.

Fan P ，Manoli DS ，Ahmed OM ，Chen Y ，Agarwal N ，Kwong S ，Cai AG ，Neitz J ，Renslo A ，Baker BS ，Shah NM ... -  《-》

Evolution of a central neural circuit underlies Drosophila mate preferences.

Seeholzer LF ，Seppo M ，Stern DL ，Ruta V ... -  《-》

A Drosophila gustatory receptor essential for aversive taste and inhibiting male-to-male courtship.

Moon SJ ，Lee Y ，Jiao Y ，Montell C ... -  《-》

Drosophila pheromone-sensing neurons expressing the ppk25 ion channel subunit stimulate male courtship and female receptivity.

Vijayan V ，Thistle R ，Liu T ，Starostina E ，Pikielny CW ... -  《PLoS Genetics》