Phenotypic and genetic integration of personality and growth under competition in the sheepshead swordtail, Xiphophorus birchmanni

Competition for resources including food, physical space, and potential mates is a fundamental ecological process shaping variation in individual phenotype and fitness. The evolution of competitive ability, in particular social dominance, depends on genetic (co)variation among traits causal (e.g., behavior) or consequent (e.g., growth) to competitive outcomes. If dominance is heritable, it will generate both direct and indirect genetic effects (IGE) on resource-dependent traits. The latter are expected to impose evolutionary constraint because winners necessarily gain resources at the expense of losers. We varied competition in a population of sheepshead swordtails, Xiphophorus birchmanni, to investigate effects on behavior, size, growth, and survival. We then applied quantitative genetic analyses to determine (i) whether competition leads to phenotypic and/or genetic integration of behavior with life history and (ii) the potential for IGE to constrain life history evolution. Size, grow...包括食物、生存空间以及潜在配偶在内的资源竞争，是塑造个体表型与适合度变异的核心生态过程。竞争能力（尤其是社会支配地位）的演化，取决于与竞争结果存在因果关联（如行为）或由竞争结果导致（如生长）的性状间的遗传（共）变异。若支配地位具备可遗传性，则会对资源依赖型性状同时产生直接遗传效应与间接遗传效应（indirect genetic effects, IGE）。此类间接遗传效应预计会施加演化约束，因为竞争获胜者获取资源必然以失败者的损失为代价。我们通过调控伯奇曼剑尾鱼（Xiphophorus birchmanni）种群内的竞争强度，探究其对行为、体型、生长与存活的影响。随后我们采用数量遗传分析，旨在解答两个问题：其一，竞争是否会引发行为与生活史的表型整合及/或遗传整合；其二，间接遗传效应（IGE）制约生活史演化的潜在可能性。体型、生长……