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

性冲突（SC）影响着生殖行为的进化。它表现在男性特征上，这些特征限制了女性的生殖选择，从而产生了对女性反适应的选择。进化生物学家提出，SC引起适应-反适应循环，产生复杂的性相互作用，除了刺激效果之外没有什么目的。这对性行为背后的神经回路的研究很有意义，因为它表明，这些回路不仅是为了刺激-反应而进化的，而且由于它们被异性劫持而产生了多层调节。该项目将在黑腹果蝇中测试这一假设，其中SC有很好的记录，尖端的神经遗传学工具允许功能性神经回路解剖。我们的数据表明，雌性神经元可以促进雌性射精，这是一种为雌性交配做准备的行为。一种未知的神经元群被男性精液肽靶向延迟射精，显示出劫持了精子射精的神经元回路，而不是刺激反应。我将使用交叉遗传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。为了定义回路的刺激-反应部分，我将使用候选基因和转录组学方法，识别检测雄性存在并提前射精的雌性感觉受体。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.