The importance of increasing brain complexity for the evolution of novel social behaviors.

性冲突（SC）塑造了生殖行为的演变。它表现在男性特征，限制女性生殖选择，产生选择女性的反适应。进化生物学家提出，SC导致适应-反适应的循环，产生复杂的性互动，除了刺激效果外几乎没有其他目的。这对研究性行为背后的神经回路很有意义，因为它表明这些回路不仅是为了刺激反应而进化的，而且还有被另一种性别劫持的调制层。这个项目将在果蝇中测试这一假设，其中SC是有据可查的，尖端的神经发生学工具允许功能性神经元回路解剖。我们的数据表明，女性神经元可以提前女性射精，一种准备女性再次交配的行为。这些神经元的一个身份不明的人口的男性精液肽的目标，以延迟射精，显示劫持的神经元电路的精子喷射，而不是刺激反应。我将使用交叉遗传学工具结合光遗传学和RNA干扰来定义男性性肽靶向的女性神经元。为了定义电路的刺激反应部分，我将使用候选基因和转录组学方法来识别检测男性存在并提前射精的女性感觉受体。通过解剖在SC下进化的神经元回路，我将测试SC对产生大脑复杂性的假设影响。

Sexual conflict (SC) shapes the evolution of reproductive behaviours. It manifests itself in male traits that limit female reproductive choices, generating selection for female counter-adaptations. Evolutionary biologists proposed that SC causes cycles of adaptation-counteradaptation producing complex sexual interactions with little purpose other than stimulatory effectiveness. This is of interest for studies of the neuronal circuit underlying sexual behaviours because it suggests that those circuits have not only evolved for stimulus–response but also have layers of modulation resulting from their hijacking by the other sex. This project will test this hypothesis in Drosophila melanogaster, where SC is well documented and cutting-edge neurogenetic tools allow functional neuronal circuit dissection. Our data indicate that female neurons can advance female ejaculate ejection, a behaviour preparing females for remating. An unidentified population of these neurons are targeted by the male seminal fluid peptides to delay ejaculate ejection, showing hijacking of the neuronal circuit for sperm ejection instead of a stimulus-response. I will use intersectional genetic tools combined with optogenetics and RNA interference to define the female neurons that are targeted by male sex peptide. To define the stimulus-response part of the circuit, I will identify female sensory receptors that detect the presence of males and advance ejaculate ejection, using candidate gene and transcriptomics approach. By dissecting a neuronal circuit that has evolved under SC, I will test the hypothetical impact of SC on generating brain complexity.