DISSERTATION RESEARCH: Proximate Mechanisms of Aggression in Role Reversed Species

杂交是两个不同且不同物种的育种，当杂交体相当健康时，有可能将两个物种合并为一个物种，或者当杂交体状况不佳时，使两个物种保持分离。在巴拿马西部，被称为北水雉和肉垂水雉的热带鸻鹬物种在此交汇，形成了一个混合区。水雉表现出交配角色逆转，雌性通过竞争包含雄性后宫的领地来控制与配偶的接触，而雄性提供所有的父母照顾。具有如此独特交配系统的物种之间杂交的不寻常情况为从雌性角度研究物种特异性交配界限为何以及如何失败提供了一个窗口。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。 更具攻击性的物种的雌性会产生大多数杂交后代。拟议的研究采用评估基因表达的技术来检查杂交物种之间攻击行为的变化。这项研究解决了生态学、进化和行为中的一个基本问题：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的行为机制的理解，2）深入了解男性和女性之间行为差异背后的遗传机制。 将通过与巴拿马实地现场的当地学龄儿童和生态游客举办研讨会来传达对科学和研究的理解。在最近分化的物种之间，交配行为可能会阻碍或促进生殖隔离。理论和经验证据证明了女性择偶和男性竞争的这一点，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。了解雌性竞争表型的进化意义的关键一步是确定其潜在的基因组机制。拟议研究的目标是通过识别候选基因簇来阐明女性竞争表型的分子基础，这些候选基因的差异表达导致攻击行为的一致变化。这项研究将攻击性测定与转录组学方法相结合，通过角色逆转、杂交中美洲的北水雉（Jacana spinosa）和肉垂水雉（J. jacana）来解决这个问题。该项目在理解角色逆转物种分化时表型变化的机制方面是新颖的，这可以增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。通过确定角色逆转的女性和男性之间攻击性基因的差异表达，拟议的研究将扩展在众所周知的男性主导系统中发展的性选择理论的一般原则。此外，该项目研究了野生、自由生活的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.