Department of Biology, Bucknell University, Lewisburg, PA, USA.
Department of Natural Resources Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.
Proc Biol Sci. 2022 Jul 13;289(1978):20220139. doi: 10.1098/rspb.2022.0139.
Determinants of individual variation in reallocation of limited resources towards self-maintenance versus reproduction are not well known. We tested the hypothesis that individual heterogeneity in long-term 'somatic state' (i) explains variation in endocrine and behavioural responses to environmental challenges, and (ii) is associated with variation in strategies for allocating to self-maintenance versus reproduction. We used relative telomere length as an indicator of somatic state and experimentally generated an abrupt short-term reduction of food availability (withdrawal of food supplementation) for free-living seabirds (black-legged kittiwakes, ). Incubating male kittiwakes responded to withdrawal by increasing circulating corticosterone and losing more weight compared to continuously supplemented controls. Males with longer telomeres increased time in directed travel regardless of treatment, while experiencing smaller increases in corticosterone. Males with longer telomeres fledged more chicks in the control group and tended to be more likely to return regardless of treatment. This study supports the hypothesis that somatic state can explain variation in short-term physiological and behavioural responses to challenges, and longer-term consequences for fitness. Male kittiwakes with longer telomeres appear to have prioritized investment in self over investment in offspring under challenging conditions.
个体将有限资源重新分配用于自我维持还是繁殖的变化的决定因素尚不清楚。我们检验了以下假设：个体长期“躯体状态”（i）的异质性解释了对环境挑战的内分泌和行为反应的变化，（ii）与自我维持与繁殖之间资源分配策略的变化有关。我们使用相对端粒长度作为躯体状态的指标，并对自由生活的海鸟（黑腿海鸥）进行了实验性的短期食物供应突然减少（停止食物补充）。与持续接受补充的对照组相比，正在孵卵的雄性海鸥对这种减少做出了反应，表现为循环皮质醇增加和体重减轻更多。端粒较长的雄性无论接受何种处理，定向旅行的时间都增加，而皮质醇的增加幅度较小。在对照组中，端粒较长的雄性孵化出的雏鸟更多，而且无论接受何种处理，它们更有可能返回。这项研究支持了这样一种假设，即躯体状态可以解释个体对挑战的短期生理和行为反应的变化，以及对适应度的长期影响。在具有挑战性的条件下，端粒较长的雄性黑腿海鸥似乎更倾向于将资源优先用于自我，而不是用于后代。
