A costly chemical trait: phenotypic condition dependence of cuticular hydrocarbons in a dung beetle

Chemical traits are increasingly recognised as important cues used in mate choice. For example, the cuticular hydrocarbons (CHCs) of insects have been shown to influence mating success in a range of taxa. Less is known, however, about how CHCs are expressed in proportion to an individual’s condition, and consequently whether CHCs can function as condition dependent signals of quality. We investigated this question using the dung beetle, Onthophagus taurus. CHCs are subject to sexual selection in this species through mate choice. A dietary manipulation revealed condition dependence of CHC expression for both sexes: dietary restriction decreased overall CHC production and altered the composition of CHCs. Furthermore, CHC production was associated with a measure of condition in beetles fed a limited diet but not those fed ad libitum. These results implicate a resource cost to CHC production that is likely to result in trade-offs with other fitness components in this species, as these respo...

化学特征作为择偶过程中的关键信号，正日益受到学界的广泛关注。例如，昆虫的表皮碳氢化合物（cuticular hydrocarbons, CHCs）已被证实可在多个类群中影响个体的交配成功率。然而，学界对表皮碳氢化合物的表达如何随个体生理状态发生变化，以及其能否作为依赖于个体状态的质量信号，仍缺乏深入了解。本研究以牛蜣螂（Onthophagus taurus）为实验对象，针对该问题展开探究。该物种中，表皮碳氢化合物已被证实通过择偶过程受到性选择的作用。通过饮食操控实验，研究发现两性的表皮碳氢化合物表达均存在状态依赖性：饮食限制会降低表皮碳氢化合物的总合成量，并改变其组分构成。此外，在饲喂受限日粮的牛蜣螂个体中，表皮碳氢化合物的总合成量与一项状态衡量指标呈显著相关，但在自由采食的个体中未观察到此关联。上述结果表明，表皮碳氢化合物的合成本身存在资源成本，这可能使得该物种在该合成过程与其他适合度相关性状间存在权衡，正如这些[...]