DISSERTATION RESEARCH: Proximate Mechanisms of Aggression in Role Reversed Species

杂交，即两个独立而独特的物种的繁殖，有可能在杂交后代相当健康时将两个物种合并为一个，或者在杂交后代表现不佳时保持物种分离。在巴拿马西部，热带滨鸟的种类范围，被称为北水仙花和荆水仙花相遇，它们形成了一个杂交区。豺龙表现出交配角色的颠倒，雌性通过争夺包含雄性后宫的领地来控制获得配偶的机会，而雄性则提供所有的亲代照顾。具有如此独特的交配系统的物种之间杂交的不寻常情况提供了一个窗口，从女性的角度来研究物种特定的交配界限为什么以及如何失败。遗传和实验证据表明，物种之间攻击行为的差异可以解释杂交模式。更具侵略性的物种的雌性产生了大多数杂交后代。提出的研究采用技术来评估基因的表达，以检查杂交物种之间的攻击行为的变化。这项研究解决了生态学、进化论和行为学中的一个基本问题——行为差异的遗传基础是什么？这可以1)提高我们对物种形成中重要行为机制的理解，2)深入了解雄性和雌性之间行为差异的遗传机制。对科学和研究的理解将通过在巴拿马实地与当地学龄儿童和生态游客举行的讲习班进行交流。在最近分化的物种之间，交配行为可能阻碍或促进生殖隔离。理论和经验证据表明，雌性择偶和雄性竞争都是如此，但人们对两者的相对作用知之甚少。女性的攻击性直到最近才被认为是一种适应性行为，其潜在机制与男性的相比如何尚不清楚。了解雌性竞争表型进化意义的关键一步是确定其潜在的基因组机制。本研究的目的是通过识别导致攻击行为一致变化的候选基因簇，阐明雌性竞争性表型的分子基础。本研究将攻击性分析与转录组学方法相结合，以角色反转的方式解决这个问题，杂交了中美洲的北方蓝芋花（jackana spinosa）和荆芥花（J. Jacana）。这个项目在理解表型随着角色逆转物种分化而变化的机制方面是新颖的，它可以促进我们对生物体如何响应和适应不断变化的环境选择的理解。通过识别潜在的攻击性基因在角色逆转的女性和男性之间是如何不同地表达的，这项研究将扩展在众所周知的男性主导系统中发展起来的性选择理论的一般原则。此外，该项目还研究了野生、自由生活、非模式生物复杂行为特征的遗传基础，这对于理解自然条件下生态相关表型的进化至关重要。

Hybridization, the breeding of two separate and distinct species, has the potential to merge two species into one when hybrids are fairly healthy, or keep the species separate when hybrids fare poorly. In western Panama, where the species ranges of the tropical shorebirds known as Northern Jacanas and Wattled Jacanas meet, they form a hybrid zone. Jacanas exhibit mating role reversal where females control access to mates by competing for territories encompassing a harem of males, and males provide all parental care. The unusual circumstance of hybridization between species with such a unique mating system offers a window into examining why and how species-specific boundaries to mating fail, from a female perspective. Genetic and experimental evidence suggests that differences in aggressive behavior between the species may explain patterns of hybridization. Females of the more aggressive species produce the majority of hybrid offspring. The proposed research employs techniques to assess the expression of genes to examine variation in aggressive behavior between the hybridizing species. This research addresses a fundamental question in ecology, evolution, and behavior what is the genetic basis of behavioral differences? This can 1) improve our understanding of the behavioral mechanisms important in species formation, and 2) provide insight into the genetic mechanisms underlying behavioral differences between males and females. Understanding of science and research will be communicated through workshops with local school aged children and ecotourists at the Panamanian field site.Between recently diverged species, mating behavior can either impede or promote reproductive isolation. Theoretical and empirical evidence demonstrates this for female mate choice and male competition, but little is known about the relative roles of each. Female aggression has only recently been recognized as an adaptive behavior, and how its underlying mechanisms compare to those of males is not well understood. A key step towards understanding the evolutionary significance of the competitive phenotype in females is determining its underlying genomic mechanisms. The goal of the proposed research is to elucidate the molecular basis of the female competitive phenotype by identifying clusters of candidate genes whose differential expression is responsible for consistent variation in aggressive behavior. This study combines aggression assays with a transcriptomic approach to address this question in role reversed, hybridizing Northern Jacanas (Jacana spinosa)and Wattled Jacanas (J. jacana) in Central America. This project is novel with respect to understanding the mechanisms by which phenotypes change as role reversed species diverge, which could advance our understanding of how organisms respond and adapt to changing environmental selection. By identifying how the genes underlying aggression are differentially expressed between role reversed females and males, the proposed research will expand upon general principles in sexual selection theory that have been developed in well-known male-dominant systems. Furthermore, this project investigates the genetic underpinnings of complex behavioral traits in wild, free-living, non-model organisms, which is vital for understanding the evolution of ecologically relevant phenotypes under natural conditions.