Reproductive Tactics in an Androdioecious Crustacean - Laboratory and Field Tests of a Model for the Maintenance of a Mixed Mating System

几十年来，异种有性繁殖一直吸引着进化生物学家的兴趣，因为能够通过自交或无性繁殖产生后代的个体比异种繁殖具有直接的优势。混合交配系统(包括自交和异交)为确定这两种繁殖模式的选择优势提供了一种极好的方法。混合交配的一种形式，雄雄异体(雄性两性)，特别有趣，因为理论上的治疗表明这种混合应该是进化上不稳定的。最近发现的一种甲壳类动物(Eulimnadia Texas Ana)表现出一种持久的雄雄异体。在之前的一次资助中，我们实施了一种综合的方法来研究雄雄异体，使用遗传学、细胞学、生理学、行为学和生态学的研究来量化两个种群中的模型参数。尽管这些项目被证明是卓有成效的，但仍然存在许多问题。目前的提案将通过两个综合项目来解决这些问题。(A)将使用结合行为和遗传研究的实验室测试来进一步探索该模型的两个参数。(B)现场收集，估计雄性与两性的相对存活率、近亲繁殖衰退和雄性交配成功，以估计自然生境中模型的四个参数中的三个。将在新墨西哥州的Jornada LTER现场收集两组现场数据(来自自然填充的池塘和来自人工填充的数据)。从实地和实验室研究中收集的数据将被用来估计四个模型参数，这些参数将被用来测试模型预测每个池塘中发现的性别类型比例的能力。这些试验的结果将使我们对该系统中异交的维持有一个全面的了解，这将进一步加深我们对交配系统进化的总体理解。更广泛的影响：两家私人投资机构都坚定地致力于学生培训，并致力于旨在为阿克伦地区的高中和本科生带来探究式科学体验的项目。这项拟议的研究将指导研究生和本科生，他们将获得现代基因技术方面的培训，并通过现场经验得到丰富。

Outcrossing sexual reproduction has intrigued evolutionary biologists for decades, for the individual that can produce offspring by self-fertilization or asexually has an immediate advantage over outcrossers. Mixed mating systems (with both self-fertilization and outcrossing) provide an excellent way to identify the selective advantage of both modes of reproduction. One form of mixed mating, androdioecy (males + hermaphrodites), is particularly interesting because theoretical treatments suggest such a mixture should be evolutionarily unstable. A recently discovered crustacean (Eulimnadia texana) exhibits a persistent form of androdioecy. In a previous grant, we implemented an integrative approach to the study of androdioecy, using genetic, cellular, physiological, behavioral, and ecological studies to quantify the parameters of a model in two populations. Although these projects proved quite fruitful, many questions remain. The current proposal will address those questions with two integrated projects. (a) Laboratory tests that combine behavioral and genetic studies will be used to further explore two of the model's parameters. (b) Field Collections, that estimate relative male to hermaphrodite survival, inbreeding depression and male mating success to estimate three of the four parameters of a model in natural habitats. Two sets of field data will be collected (data from naturally-filled ponds and from artificially-filled) at the Jornada LTER site in New Mexico. Data collected from both the field and laboratory studies will be used to estimate the four model parameters, which will in turn be used to test the ability of the model to predict the proportions of sex types found in each pond. The results of these tests will provide a thoroughly integrative understanding of the maintenance of outcrossing in this system, which will further our understanding of mating system evolution in general. Broader Impacts: Both PIs have strong commitments to student training and are on projects designed to bring inquiry-based science experiences to high school and undergraduate students in the Akron area. The proposed research will mentor graduate and undergraduate students who will gain training in modern genetic techniques, and be enriched by field experiences.