Ontogenetic habitat shifts are predicted to increase the fitness and survival of individuals by allowing effective utilization of spatially distributed resources. Evidence supports nutritional requirements and predation pressure as drivers of habitat shifts. Likewise, intraspecific interactions are thought to lead to ontogenetic habitat shifts, however, empirical evidence is lacking. Here, we test if intraspecific male–male interactions are responsible for ontogenetic habitat shifts in Xanthagrion erythroneurum, a damselfly that undergoes developmental colour change. The juvenile males are yellow and change colour to red with sexual maturity. Field observations showed that the proportion of juvenile males is higher in adjacent woods than in primary mating arenas by ponds. We measured male–male interactions by the pond and in the woods, predicting the habitat switch would reduce male antagonistic interactions such as male aggression and male–male mating attempts. We showed that juvenile males receive less aggression in woods than at the pond mating arena. We conclude that lower population density and lower male encounter rates in the woods reduce the cost of male aggression for juvenile males. Our study provides evidence that stage-dependent habitat choice resulting from intrasexual antagonistic interactions may drive ontogenetic habitat shifts.

中文翻译：

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个体发生栖息地的变化减少了代价高昂的雄性-雄性互动

个体发生栖息地的变化预计将通过有效利用空间分布的资源来提高个体的适应度和生存率。证据支持营养需求和捕食压力是栖息地变化的驱动因素。同样，种内相互作用被认为会导致个体发生栖息地的变化，然而，缺乏经验证据。在这里，我们测试了种内雄性-雄性相互作用是否是 Xanthagrion erythroneurum（一种经历发育颜色变化的豆娘）个体发育栖息地变化的原因。幼年雄性为黄色，随着性成熟而变色为红色。野外观察表明，邻近树林中的幼鱼比例高于池塘边的初级交配场所。我们在池塘和树林里测量了男性与男性的互动，预测栖息地转换将减少雄性对抗性相互作用，例如雄性攻击性和雄性-雄性交配尝试。我们表明，与在池塘交配场所相比，幼年雄性在树林中受到的攻击较少。我们得出结论，较低的人口密度和较低的森林中雄性遭遇率降低了雄性对少年雄性的攻击成本。我们的研究提供的证据表明，由性内拮抗相互作用导致的阶段依赖性栖息地选择可能会推动个体发生栖息地的变化。我们得出结论，较低的人口密度和较低的森林中雄性遭遇率降低了雄性对少年雄性的攻击成本。我们的研究提供的证据表明，由性内拮抗相互作用导致的阶段依赖性栖息地选择可能会推动个体发生栖息地的变化。我们得出的结论是，森林中较低的人口密度和较低的雄性相遇率降低了雄性对少年雄性的攻击成本。我们的研究提供的证据表明，由性内拮抗相互作用导致的阶段依赖性栖息地选择可能会推动个体发生栖息地的变化。