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.

衰老的进化理论认为，自然选择力随年龄增长而衰退，最终引发性状衰老。然而，性选择理论预测，传递配偶价值的高成本性状，其表达水平应随个体生存前景的下降而升高。死亡率与繁殖力通常表现出显著的衰老特征，而性信号性状则随年龄增长而增强；但诸如整体有机体性能指标这类同时受性选择与非性选择作用的性状，其表达量如何随年龄变化仍尚不明确。我们以澳洲黑蟋蟀（Teleogryllus commodus）的雌雄个体为研究对象，选取两项整体有机体性能性状——咬合力与跳跃起跳速度，探究了关键生活史事件（交配）与日粮质量（雌雄最优日粮）对其衰老过程的影响。研究发现，日粮对所有被测性状均无显著作用。雌性的跳跃与咬合力衰老特征较雄性更为显著，且其衰老模式依性别与交配类群的不同，同时兼具性状衰老与终端投资两种特征。由此可见，性别与交配状态对性能性状的资源分配具有重要意义，进而影响这些性状的衰老进程；二者的交互作用可导致个体一生中性状表达量呈现复杂的动态变化。