Ton Riccardo, M Gillings Max, Pacheco-Fuentes Hector, Stier Antoine, Griffith Simon C
School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia.
Cavanilles Institute of Biodiversity, University of Valencia, Valencia, Valencian Community, Spain.
Biol Lett. 2025 Aug;21(8):20250199. doi: 10.1098/rsbl.2025.0199. Epub 2025 Aug 6.
Identifying the physiological mechanisms underpinning inter-individual differences in performance and fitness remains a key challenge in organismal biology. Variation in mitochondrial aerobic metabolism has been suggested to underlie inter-individual variation in performance, but this remains seldom tested, partly because of the need to use terminal sampling for assessing mitochondrial parameters. To fill this knowledge gap, we investigated whether inter-individual variation in mitochondrial aerobic parameters measured from less-invasively taken samples (i.e blood cells) would correlate with both anaerobic and aerobic metrics of flight performance in house sparrows (). We predicted that mitochondrial aerobic metabolism should correlate with aerobic but not anaerobic metrics of flight performance. As expected, we found no evidence for a relationship between mitochondrial metabolism and the energy required to take-off (i.e. anaerobic), but flight duration to exhaustion (i.e. aerobic) correlated positively with both cellular mitochondrial respiration rates and oxidative phosphorylation efficiency, a proxy of mitochondrial efficiency to convert nutrients into ATP. Our results, therefore, support the idea that inter-individual variation in mitochondrial aerobic metabolism could underlie variation in aerobic performance and suggest that the nucleated blood cells of birds (and potentially other non-mammalian vertebrates) may be a relevant biological sample to test those links.
确定构成个体在性能和适应性方面差异基础的生理机制，仍然是生物生物学中的一项关键挑战。线粒体有氧代谢的变化被认为是个体在性能方面差异的基础，但这一点很少得到验证，部分原因是需要采用终末取样来评估线粒体参数。为了填补这一知识空白，我们研究了从侵入性较小的样本（即血细胞）中测得的线粒体有氧参数的个体间差异，是否与家麻雀飞行性能的无氧和有氧指标相关。我们预测线粒体有氧代谢应与飞行性能的有氧指标相关，而与无氧指标无关。正如预期的那样，我们没有发现线粒体代谢与起飞所需能量（即无氧）之间存在关联的证据，但耗尽前的飞行持续时间（即有氧）与细胞线粒体呼吸速率以及氧化磷酸化效率均呈正相关，氧化磷酸化效率是线粒体将营养物质转化为ATP效率的一个指标。因此，我们的结果支持了这样一种观点，即线粒体有氧代谢的个体间差异可能是有氧性能差异的基础，并表明鸟类（可能还有其他非哺乳动物脊椎动物）的有核血细胞可能是测试这些联系的一个相关生物样本。
