How does the timing of weapon loss influence reproductive traits and trade-offs in the insect Narnia femorata?

A longstanding goal of evolutionary biology is to understand among-individual variation in resource allocation decisions and the timing of these decisions. Recent studies have shown that investment in elaborate and costly weapons can result in trade-offs with investment in testes. In this study, we ask at what point plasticity in resource allocation to these different structures ceases during development, if at all? Furthermore, can individuals tailor their reproductive behavior to accompany structural changes? We experimentally addressed these questions in the insect Narnia femorata, quantifying resource reallocation across development for the first time, using a phenotypic engineering approach. To investigate whether allocation plasticity diminishes throughout ontogeny, we induced weapon loss at a range of different developmental stages and examined subsequent testes mass and reproductive behavior. We found that relative testes mass increased as weapon investment decreased, implying a..., ,进化生物学领域一项长期以来的核心研究目标，是解析个体间资源分配决策的差异及其决策时机。近期研究显示，对结构复杂且成本高昂的武器结构的资源投入，会与睾丸发育的资源投入形成资源权衡（trade-off）。本研究旨在探究两个核心问题：其一，针对上述两类结构的资源分配可塑性，在发育过程中会于何时停止（若确实存在该停止节点的话）；其二，个体能否调整其繁殖行为以匹配结构层面的变化？本研究以昆虫足肢猎蝽（Narnia femorata）为实验对象，首次采用表型工程（phenotypic engineering）方法量化了发育全过程中的资源重分配情况。为探究资源分配可塑性是否会随个体发育逐渐减弱，我们在多个不同发育阶段诱导武器结构脱落，并随后检测了睾丸质量与繁殖行为。研究发现，随着对武器结构的资源投入减少，相对睾丸质量会随之升高，这表明……