Data from: Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf-footed cactus bug, Narnia femorata

The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium-quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high-quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection.

武器与睾丸的大小，对于雄性繁殖成功率而言至关重要。然而，这些性状的表型往往存在极高的变异性。因此亟需采用更完整的生物体研究视角，同时探究这两类性状的变异来源，并使用模拟自然环境的发育条件开展实验。本研究以叶足仙人掌蝽（Narnia femorata，半翅目：缘蝽科）为实验对象，在三种天然发育日粮条件下，探究了其武器与睾丸大小的变异组分。研究结果表明，发育日粮对武器与睾丸的表型表达及体型缩放关系均具有显著影响。值得注意的是，取食中等质量日粮的雄性个体虽拥有发达的武器，但其睾丸相对较小，这暗示了复杂的资源分配策略。此外，我们还发现，在高质量日粮条件下，睾丸大小与体质量的遗传力、进化潜力以及加性遗传变异均达到最高水平。该结果表明，在每年可获取该高质量日粮的短暂窗口期内，这些性状对选择压力的响应能力可能会得到增强。综合来看，本研究结果说明，营养环境的正常季节性波动，可能对性选择性状的表型表达以及这些性状响应选择的能力，均发挥着重要作用。