DISSERTATION RESEARCH: Mechanisms of Female Mate Choice in a Coercive Mating System

强迫交配系统中交配后选择的机制。凯伦·S·奥伯哈斯米歇尔·J·索伦斯当性胁迫，有时被称为强迫交配在一个物种中盛行时，雌性对个体交配尝试的结果控制有限。然而，它们可能进化出其他方法来确定与它们交配的雄性，或者真正使它们的卵受精的雄性。帝王蝶的交配尝试通常涉及漫长的地面斗争，在此期间，雄性有时会强迫雌性交配。雌性可能会利用这种斗争来评估雄性的质量并相应地调整它们的抵抗力水平(交配前的选择)，或者她们可能会倾向于使用高质量的雄性精子(交配后的选择)。雌性交配后的配偶选择可能是推动雄性生殖策略进化的重要选择力量，在强迫是常见交配策略的物种中尤其重要。在一项初步研究中，几乎没有证据支持帝王蝶交配前雌性选择的存在。针对这一主题的研究将在实验室和野生种群中继续进行。交配后选择的研究将解决这样的假设，即雌性将精巢大小作为雄性交配史的指标，并倾向于使用精子，偏向于以前交配过的雄性。精巢大小是雄性交配成功的可靠、诚实和可检测的信号，先前的研究已经证明雄性交配成功是可遗传的。因此，雌性可能受益于根据这一线索选择精子，因为交配成功应该传递给她们的儿子。拟议的实验设计将有偏见的精子使用的影响与精子竞争力的潜在混杂影响分开。

Mechanisms of Post-Copulatory Choice in a Coercive Mating SystemDr. Karen S. OberhauserMichelle J. SolensyWhen sexual coercion, sometimes called forced copulation, is prevalent in a species, females have limited control over the outcome of individual mating attempts. However, they may evolve other means of determining the males with which they mate, or the males that actually fertilize their eggs. Mating attempts in monarch butterflies typically involve a lengthy ground struggle during which males sometimes force females to mate. Females may use this struggle to assess male quality and adjust their level of resistance accordingly (precopulatory choice), or they may bias sperm use in favor of high quality males (postcopulatory choice). Postcopulatory mate choice by females could be an important selective force driving the evolution of male reproductive strategies, and should be especially important in species in which coercion is a common mating strategy. In a preliminary study, there was little evidence to support the existence of precopulatory female choice in monarch butterflies. Studies addressing this topic will be continued in both laboratory and wild populations. Studies of postcopulatory choice will address the hypothesis that females use spermatophore size as an indicator of male mating history, and bias sperm use in favor of males that have mated previously. Spermatophore size is a reliable, honest, and detectable signal of male mating success, and previous work has demonstrated that male mating success is heritable. Thus, females may benefit by selecting sperm based on this cue since mating success should be transmitted to their sons. The proposed experimental design separates the effect of biased sperm use from the potentially confounding effect of sperm competitiveness.