Data from: Differential aging of bite and jump performance in virgin and mated Teleogryllus commodus crickets

Evolutionary theories of aging state that the force of natural selection declines with age, resulting in trait senescence. However, sexual selection theory predicts that costly traits that signal mate value should increase in expression as survival prospects decline. Mortality rates and fertility tend to show strong signatures of senescence, whereas sexual signalling traits increase with age, but how the expression of traits such as whole-organism performance measures that are subject to both sexual and non-sexual selection should change with age is unclear. We examined the effects of both a key life-history event (mating) and diet quality (male and female optimal diets) on aging in two whole-organism performance traits (bite force and jump take-off velocity) in male and female Teleogryllus commodus crickets. We found no evidence for diet effects on any of the measured traits. Aging effects were more evident in females than in males for both jumping and biting, and constitute a mix of senescence and terminal investment patterns depending on sex/mating class. Sex and mating therefore have important implications for resource allocation to performance traits, and hence for aging of those traits, and interactions between these two factors can result in complex changes in trait expression over individual lifetimes.

衰老的进化理论指出，自然选择压力随年龄增长而减弱，进而引发性状衰老（trait senescence）。然而，性选择理论（sexual selection theory）预测，传递配偶质量信号的高成本性状，其表达量应随生存前景的下降而提升。死亡率与生育率通常呈现显著的衰老特征，而性信号性状（sexual signalling traits）则随年龄增长而增强；但对于同时受性选择与非性选择作用的整体有机体性能指标（whole-organism performance measures）这类性状，其表达量随年龄的变化规律仍不明确。本研究以澳洲铃蟋（Teleogryllus commodus）的雌雄个体为研究对象，探究了关键生活史事件（交配）与日粮质量（diet quality，即雌雄最优日粮）对两种整体有机体性能性状——咬合力（bite force）与起跳速度（jump take-off velocity）——的衰老过程的影响。本研究未发现日粮对任一被测性状存在影响的证据。咬合力与起跳性能的衰老效应在雌性个体中均较雄性更为显著，且其衰老模式与终端投资（terminal investment）策略的组合因性别与交配状态而异。因此，性别与交配状态对性能性状的资源分配具有重要影响，进而影响这些性状的衰老过程；且二者的交互作用可导致性状表达量在个体生命周期内呈现复杂的动态变化。