Maintenance of An alternative Reproductive Strategy in the Swordtail Xiphophorus Multilineatus

多线剑尾剑尾鱼（剑尾剑尾鱼）维持一种可选择的生殖策略智力优势——同性和同一物种的个体被期望以相似的方式解决生存和繁殖的问题。然而，同一物种的雄性不仅看起来非常不同，而且生存和繁殖的策略也非常不同。这些差异被称为“替代性生殖策略”。该项目的主要目的是研究在同性个体中发现的有趣的行为和形态多样性的维持。通常提出三种机制来维持不同的生殖策略：负频率依赖选择，生态因素的变化，以及不同亚种群之间雌性对不同类型雄性的偏好的变化。本研究将测试这些不同机制在剑尾鱼（xiphohorus multilineatus）中的相对重要性及其相互作用。这个物种代表了一个独特的系统，在这个系统中，研究维持替代生殖策略的机制，因为这个物种的替代生殖策略的遗传基础是已知的，并且可以通过检查雄性的大小和色素模式来了解它的基因组成。本项目将在受控的实验室实验中，通过检查两种不同相对频率下的相对受精成功率（早熟和潜行交配的球鞋和晚熟和求偶的闪光），确定多线X.的替代生殖策略是否通过负频率依赖选择得以维持。这个项目将确定在自然亚种群中，捕食的变化（在某些地方，高捕食率选择小雄性，而在其他地方，低捕食率选择大雄性）和雌性偏好的变化（一些种群对大雄性有强烈的雌性偏好，而其他种群则没有）如何影响两种雄性的受精成功。最后，将使用分子技术研究亚种群之间的基因流动程度，因为了解这些种群是否在交换基因，以确定亚种群之间捕食和/或雌性偏好的差异是否可以在全球种群水平上维持不同的生殖策略，这一点很重要。B)更广泛的影响-该项目产生的更广泛的影响将包括在俄亥俄大学培养一名博士后（Co-PI），一名研究生和几名本科生。此外，这项研究将建立一项长期合作，旨在研究实地（在墨西哥，一旦Co-PI返回他的国家）和实验室（在俄亥俄大学）的鱼类种群，最终促进原产国进化研究的发展。

MAINTENANCE OF AN ALTERNATIVE REPRODUCTIVE STRATEGY IN THE SWORDTAIL Xiphophorus multilineatusA) Intellectual Merit - Individuals of the same sex and same species are expected to solve the problems of surviving and reproducing in a similar way. However, males of the same species can not only look very different, but have very different strategies for surviving and reproducing. These differences are known as alternative reproductive strategies". The main objective of this project is to examine the maintenance of the intriguing diversity of behaviors and morphologies found within individuals of the same sex. Three mechanisms are commonly proposed to maintain alternative reproductive strategies: negative frequency-dependent selection, variation in ecological factors, and variation in female preference for different types of males between subpopulations. This study will test the relative importance of these different mechanisms and their interactions in the swordtail fish Xiphophorus multilineatus. This species represents a unique system in which to examine the mechanisms maintaining alternative reproductive strategies since the genetic basis for the alternative reproductive strategies in this species are known, and it is possible to know a male's genetic makeup by examining his size and pigment patterns. This project will determine if the alternative reproductive strategies in X. multilineatus are maintained by negative frequency dependent-selection by examining the relative fertilization success of the two strategies (sneakers that mature early and sneak copulations and flashers that mature late and court females) under different relative frequencies in controlled laboratory experiments. This project will determine how variation in predation (high predation selects for small males in some places while low predation selects for large males in others) and variation in female preference (some populations have strong female preferences for large males, others do not) across natural subpopulations influences the fertilization success of the two types of males. Finally, the degree of gene flow between the subpopulations will be studied using molecular techniques, as it is important to know if these populations are exchanging genes to determine whether the differences in predation and/or female preferences across subpopulations could be acting to maintain the alternative reproductive strategies at the global population level.B) Broader Impact - The broader impacts resulting from this project will include the training of one postdoctoral fellow (Co-PI), one graduate student and several undergraduate students at Ohio University. In addition, this research will establish a long-term collaboration designed to study fish populations in the field (in Mexico, once the Co-PI returns to his country) and in the lab (in Ohio University), ultimately stimulating the development of evolutionary studies in the country of origin.