Developmental plasticity for male secondary sexual traits in a group of polyphenic tropical butterflies

Many organisms alter their investment in secondary sexual traits to optimise the fitness trade-off between reproduction and survival. Though seasonal variation in the expression of sexual traits is evident (e.g. conspicuous breeding plumage in birds), little attention has been given to short-lived organisms that inhabit relatively stable environments throughout their own lifetime but are exposed to strong environmental variation across generations. Some insects have evolved seasonal polyphenism to cope with intergenerational variation in environmental selection, yielding alternative phenotypes better suited for the environment in which they occur. Here we use mycalesine butterflies, which express distinct seasonal forms in response to wet-dry seasonal environments, to explore whether seasonal polyphenism extends to secondary sexual traits. Sex pheromones, which are produced by androconial patches on the wings of males, are a key determinant of mating success in these species. Through a ...

诸多生物会调整其在第二性征（secondary sexual traits）上的资源投入，以优化繁殖与存活间的适合度权衡（fitness trade-off）。尽管性征表达的季节变化已被广泛观测到（例如鸟类醒目的繁殖羽），但学界对一类短命生物的研究仍较为匮乏：这类生物在自身生命周期中所处的环境相对稳定，却会面临跨世代的强烈环境波动。部分昆虫演化出了季节多型性（seasonal polyphenism）以应对环境选择的世代间差异，进而产生更适配所处生境的替代表型。本研究以眼蝶亚科（Mycalesinae）蝴蝶为研究模型，这类蝴蝶会响应干湿季环境呈现出截然不同的季节型，借此我们可探究季节多型性是否同样适用于第二性征。雄性翅膀上的香鳞斑（androconial patches）所分泌的性信息素（sex pheromones），是决定该类物种交配成功率的核心因素。Through a ...