DISSERTATION RESEARCH: Cryptic Female Choice and Sperm Competition in a Novel Vertebrate Model

许多物种的雌性在繁殖季节与多个雄性交配。对这种行为的一种解释是，它有助于交配后的配偶选择。雌性在交配后的选择是可以检测到的，因为不是所有雌性的配偶都有平等的父权；因为这个过程是隐藏的，所以被称为隐性女性选择。例如，雌性可能会将特定雄性的精子运送到受精地点附近的储存地点，这可能导致父权偏向这些雄性。雌性的隐性选择对性选择的强度和方向、交配系统的进化以及导致物种形成的雌性和雄性生殖特征的共同进化有着深远的影响。然而，交配后雌性选择的隐蔽性使其极难记录。pi已经开发出一种用荧光颗粒标记活精子的方法，以便在体内观察精子的命运。通过观察精子储存的位置和哪些精子使卵子受精，就有可能测量出女性隐秘选择的程度。这项工作将以吊带蛇为对象进行，这种方法可能对许多物种都很有价值。pi将开发和试点一个适合高中生物学生的基于探究的综合讲座、实地和实验室单元。该项目建立在pi为中学生开发的成功模块的基础上。pi还打算通过培训至少两名PCR，基因分型和亲子分析的本科生来维持他们对本科生研究机会的承诺。

Females of many species mate with multiple males in a breeding season. One explanation for this behavior is that it facilitates mate choice after copulation. Female choice that occurs after copulation is detectable because not all the female's mates have equal paternity; it is called cryptic female choice because the process is hidden. For example, females may transport sperm from particular males to storage sites near where fertilization occurs, which could result in paternity biased towards those males. Cryptic female choice can have profound effects on the strength and direction of sexual selection, the evolution of mating systems, and the coevolution of female and male reproductive traits that leads to speciation. However, the cryptic nature of postcopulatory female choice has made it extremely difficult to document. The PIs have developed a method to label live sperm with fluorescent particles so that the fate of the sperm can be observed in vivo. By observing both where sperm are stored and which sperm fertilize eggs, it will be possible to measure the extent of cryptic female choice. The work will be conducted with garter snakes and the methods are likely to be valuable for many species.The PIs will develop and pilot an integrated inquiry-based lecture, field and laboratory unit appropriate for upper-level high school biology students. This program builds on a successful module that the PIs developed for middle-school students. The PIs also intend to sustain their commitment to undergraduate research opportunities by training at least two undergraduates in PCR, genotyping, and paternity analysis.