Data from: Ontogenetic timing as a condition-dependent life history trait: high-condition males develop quickly, peak early and age fast

Within-population variation in ageing remains poorly understood. In males, condition-dependent investment in secondary sexual traits may incur costs which limit ability to invest in somatic maintenance. Moreover, males often express morphological and behavioural secondary sexual traits simultaneously, but the relative effects on ageing of investment in these traits remain unclear. We investigated the condition-dependence of male life history in the neriid fly Telostylinus angusticollis. Using a fully factorial design, we manipulated male early-life condition by varying nutrient content of the larval diet and, subsequently, manipulated opportunity for adult males to interact with rival males. We found that high-condition males developed more quickly and reached their reproductive peak earlier in life, but also experienced faster reproductive ageing and died sooner than low-condition males. By contrast, interactions with rival males reduced male lifespan but did not affect male reproductive ageing. High condition in early life is therefore associated with rapid ageing in T. angusticollis males, even in the absence of damaging male-male interactions. Our results show that abundant resources during the juvenile phase are used to expedite growth and development and enhance early-life reproductive performance at the expense of late-life performance and survival, demonstrating a clear link between male condition and ageing.种群内部的衰老差异至今仍未得到充分解析。对于雄性个体而言，对次级性征（secondary sexual traits）的条件依赖型投资可能会产生相应成本，进而限制其体细胞维持（somatic maintenance）的投入能力。此外，雄性往往会同时表达形态与行为层面的次级性征，但这些特征的投资对衰老的相对影响仍不明确。我们以细足水蝇（Telostylinus angusticollis）为研究对象，探究了雄性生活史（life history）的条件依赖性。通过全因子实验设计（fully factorial design），我们通过改变幼虫饲料的营养含量调控雄性早期发育状态，并在此后调控成年雄性与同性竞争者互动的机会。研究发现，发育状态较佳的雄性个体发育速度更快，且在生命早期即可达到繁殖峰值，但相较于发育状态较差的雄性，其生殖衰老更快，寿命也更短。与之相对，与竞争者的互动虽缩短了雄性的寿命，但并未影响其生殖衰老进程。因此，即便不存在具有伤害性的雄性间互动，细足水蝇雄性的早期高发育状态仍与快速衰老相关。本研究结果表明，幼体阶段充足的资源会被用于加速生长发育、提升早期繁殖性能，却以后期性能与存活为代价，清晰揭示了雄性发育状态与衰老之间的直接关联。