OPUS: MCS: Mechanisms and evolution of premating reproductive isolation along a speciation continuum

进化生物学的一个核心问题是，一万亿种生命--无论是活的还是灭绝的--是如何以及为什么出现的。物种形成--新物种的形成--可以在两组生物体由于行为(例如，歌曲)或外表(例如，颜色)等相关特征的差异而不再识别对方为配偶时进行。这项研究量化了调节女性配偶识别和偏好的行为和神经机制，以了解物种形成是如何进行的。研究人员将测量雌性对同一物种分化种群的雄性(物种形成前阶段)和两个密切相关物种的雄性(物种形成后阶段)的反应，从而跨越物种水平分化的连续体。研究人员将首先进行行为研究，以确定相关特征在每个阶段的求爱和交配成功中的力量和作用。接下来，女性的反应将与大脑中与视觉、听觉和求爱相关的区域的激活模式联系起来。沿着物种形成连续体对大脑求偶区域神经失活模式的研究解决了物种形成是逐渐进行还是突然进行的知识缺口。这项研究建立在17年对新热带红眼树蛙的遗传和行为研究的基础上，以了解早期物种形成的机制和过程。它支持不同的学生在现场和实验室体验科学，并在K5年级水平的丰富计划中为大约120名学生创建主动学习内容(82%的少数族裔学生服务不足，60%的学生免费/减少午餐)。最后，这项研究促进了美国和哥斯达黎加研究生物学家之间的国际合作。这项合作研究为信号分歧、女性识别和神经活动模式的演变以及这些因素对生殖隔离和物种形成的影响提供了新的和令人兴奋的见解。这项研究有两个具体目的。目的1通过女性偏好分析和神经激活模式来检验女性对发散线索的反应，以检验特征发散的递增是否会导致持续的或全有或全无的神经反应。目标2测试不匹配的线索如何改变神经活动反应模式，解决不匹配的线索是否削弱/破坏求爱反应。神经反应将使用免疫组织化学和显微镜进行测量。这两个目标结合在一起，确定了对于刺激求爱行为非常重要的特征(S)如何调节神经活动功能，从而为最大程度的生殖隔离是如何演变提供了机械性的洞察。计算模型将使用模拟数据探索信号分化和女性反应(行为和神经活动)之间的动态关系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A central question in evolutionary biology is how and why a trillion forms of life, both living and extinct, have emerged. Speciation—the formation of new species— can proceed when two groups of organisms no longer recognize each other as mates due to differences in relevant traits such as behavior (e.g., songs) or appearance (e.g., coloration). This research quantifies the behavioral and neural mechanisms that mediate female mate recognition and preference to understand how speciation proceeds. Researchers will measure female response to males from differentiated populations of the same species (pre-speciation stage) and to males of two closely related species (post-speciation stage), thus spanning a continuum of species-level differentiation. Researchers will first conduct behavioral studies to identify the strength and role of relevant traits in courtship and mating success at each stage. Next, female response will be linked to activation patterns in the regions of the brain associated with visual, acoustic and courtship processing. Examination of neural de-activation patterns in the courtship region of the brain along the speciation continuum addresses a gap in knowledge of whether speciation proceeds gradually or abruptly. This research builds upon 17 years of genetic and behavioral studies of the Neotropical red-eyed treefrog, Agalychnis callidryas, to understand the mechanisms and processes of early-stage speciation. It supports diverse students to experience science in the field and in the lab, and creates active-learning content for ~120 students in an enrichment program at the K5 grade level (82% underserved minority, 60% Free/Reduced Lunch). Finally, this research fosters international collaboration between U.S. and Costa Rican research biologists.This collaborative research provides new and exciting insights into the evolution of signal divergence, female recognition and neural activity patterns, and the consequences of these factors for premating reproductive isolation and speciation. This research has two specific aims. Aim 1 examines female response to divergent cues through both female preference assays and neural activation patterns to test whether incremental increases in trait divergence result in a continuous or all-or-none neural response. Aim 2 tests how mismatched cues alter neural activity response patterns, addressing whether mismatched cues weaken/break courtship response. Neural response will be measured using immunohistochemistry and microscopy. Combined, these two aims identify how the trait(s) that are important for stimulating courtship behavior modulate neural activity function, and thus provide mechanistic insight into how premating reproductive isolation evolves. Computational modeling will explore the dynamic relationship among signal differentiation and female response (behavior and neural activity) using simulated data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.