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，异交有性生殖一直引起进化生物学家的兴趣，因为能够通过自交受精或无性繁殖后代的个体比异交者具有直接的优势。混合交配系统（包括自交受精和异种杂交）提供了一种很好的方法来识别两种繁殖模式的选择优势。混合交配的一种形式，雄性异雄（雄性+雌雄同体），是特别有趣的，因为理论治疗表明，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（ulimnadia texana）表现出一种持久的雄性异雄性形式。在之前的一项资助中，我们实施了一种综合方法来研究雄性雄性，使用遗传、细胞、生理、行为和生态研究来量化两个种群的模型参数。尽管这些项目证明相当富有成效，但仍存在许多问题。目前的建议将用两个综合项目来处理这些问题。(a)结合行为和遗传研究的实验室测试将用于进一步探索该模型的两个参数。(b)野外收集，估计雄性与雌雄同体的相对存活率、近亲繁殖的减少和雄性交配的成功，以估计自然生境中一个模型的四个参数中的三个。将在新墨西哥州的Jornada LTER站点收集两组现场数据（来自自然填充的池塘和人工填充的池塘的数据）。从实地和实验室研究中收集的数据将用于估计四个模型参数，这些参数将反过来用于测试模型预测每个池塘中发现的性别类型比例的能力。这些测试的结果将为这个系统中异交的维持提供一个彻底的综合理解，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：这两个pi都对学生培训做出了强有力的承诺，并致力于为阿克伦地区的高中生和本科生带来探究性科学体验的项目。拟议的研究将指导研究生和本科生，他们将获得现代遗传技术方面的培训，并通过实地经验得到丰富。

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.