Social Learning and Sexual Selection in Field Crickets

这一建议解决了进化生物学中的一个核心概念，即通过性选择来起源和维持生物多样性。通过雌性选择的性选择可以加速分化种群的生殖隔离，其在推动雄性装饰物精心制作和维护中的作用得到理论和经验的支持。性选择的所有理论框架都依赖于女性偏好和男性装饰物的遗传基础。然而，一些非遗传因素已经引起了研究人员的注意，因为它们对性选择的强度和方向有潜在的巨大影响。其中之一最近引起了人们的注意：女性择偶的可塑性。择偶是一个过程，通过这个过程，雌性会评估可供选择的雄性的吸引力，并决定与谁交配。择偶可塑性是指个体择偶行为受环境因素影响的灵活性。这一建议关注的是从同种个体那里学习到的社会信息是如何促成这种配偶选择的灵活性的，而我最终感兴趣的是配偶选择的变化是如何反馈到改变男性特征的选择压力的。我的研究将使用昆虫系统，因为尽管昆虫被广泛用作性选择研究的模型，但关于社会学习如何影响昆虫的配偶选择和性选择的信息缺乏。我将利用波利尼西亚蟋蟀Teleogryllus oceanicus进行这一富有成果的调查。我将研究社会学习配偶选择可塑性的种群水平变化，其遗传基础和对个体的适应性影响，以及其对男性特征的性选择压力的更广泛含义。我在加州大学河滨分校（University of California, Riverside）的博士后研究发现，雌性蟋蟀可以保留雄性蟋蟀的吸引力信息，并利用这些信息改变随后的交配决定。在此基础上，我的第一个目标是调查在整个种群范围内择偶可塑性的变化程度。理论论证表明，在新环境中的创始种群将被选择表现出更大程度的适应性表型可塑性。新建立的种群的社会环境预计会随机变化，我将测试一个假设，即更新建立的种群（通过种群遗传数据推断）显示出更大程度的社会介导的配偶选择可塑性。其次，我将进行一个定量的遗传交配实验，通过改变雌性的交配行为来检测雌性对不同社会环境的反应倾向的遗传变异。我的分析将检测不同遗传背景的女性是否对社会经验表现出不对称的行为反应。这将揭示选择作用于社会介导的配偶选择可塑性的潜力，这取决于其加性遗传变异的大小。第三，我将在该领域研究社会介导的配偶选择可塑性的适应性后果。这一分析将为社会影响如何改变野生动物的性选择压力提供关键的见解，这一点迄今为止还没有在实证研究中得到解决。最后，我将发展性选择的定量遗传模型，其中包括社会介导的配偶选择可塑性，以测试这种可塑性如何改变性选择的结果。这些理论模型将解决相反的假设，即经验介导的择偶可塑性可以加强或削弱性选择，并将探讨择偶可塑性的选择是否可以推动种群间生殖障碍的进化。

This proposal addresses a central concept in evolutionary biology regarding the origin and maintenance of biological diversity through sexual selection. Sexual selection via female choice can accelerate reproductive isolation in diverging populations, and its role in driving the elaboration and maintenance of male ornaments is supported theoretically and empirically. All theoretical frameworks for sexual selection rely on the genetic basis of female preferences and male ornaments. However, a number of non-genetic factors have captured the attention of researchers because of their potentially large effects on the strength and direction of sexual selection. One of these has recently gained attention: plasticity in female mate choice. Mate choice is the process by which females evaluate the attractiveness of available males and make a decision about who to mate with. Mate choice plasticity refers to flexibility in individual mating behavior that is influenced by environmental factors. This proposal focuses on how social information learned from conspecifics contributes to such flexibility in mate choice, and I am ultimately interested in how changes in mate choice feed back to alter selection pressure on male traits. My research will use an insect system, because although insects are extensively used as models in sexual selection studies, information about how social learning affects insect mate choice and sexual selection is lacking. I will pursue this fruitful avenue of inquiry using the Polynesian field cricket Teleogryllus oceanicus. I will investigate population-level variation in socially-learned mate choice plasticity, its genetic basis and fitness effects on individuals, and its broader implications for sexual selection pressure on male traits. My postdoctoral work at the University of California, Riverside has established that female crickets can retain information about the attractiveness of calling males and use that information to alter subsequent mating decisions. Given this foundation, my first goal is to investigate the extent to which mate choice plasticity varies on a population-wide scale. Theoretical arguments suggest that founding populations in new environments will be selected to exhibit a greater degree of adaptive phenotypic plasticity. The social environment of newly-founded populations would be expected to vary stochoastically, and I will test the hypothesis that more recently founded populations (inferred using population genetic data) show a greater degree of socially-mediated mate choice plasticity. Second, I will perform a quantitative genetic mating experiment to detect genetic variation in the tendency of females to respond to different social environments by altering their mating behavior. My analysis will detect whether females of different genetic backgrounds show asymmetrical behavioral responses to social experience. This will reveal the potential for selection to act on socially-mediated mate choice plasticity, which depends on the magnitude of additive genetic variation for it. Third, I will examine fitness consequences of socially-mediated mate choice plasticity in the field. This analysis will lend key insights into how social effects alter sexual selection pressure in the wild, which has not been addressed in empirical studies to date. Finally, I will develop quantitative genetic models of sexual selection that incorporate socially-mediated mate choice plasticity, to test how such plasticity alters the outcome of sexual selection. The theoretical models will address the opposing hypotheses that experience-mediated plasticity in mate choice can strengthen vs. weaken sexual selection, and will explore the question of whether selection on mate choice plasticity can drive the evolution of reproductive barriers between populations.