Institut Pluridisciplinaire Hubert Curien, Département Ecologie, Physiologie et Ethologie, CNRS-UDS, UMR 7178, Strasbourg, France.
PLoS One. 2010 Oct 1;5(10):e13104. doi: 10.1371/journal.pone.0013104.
The diversity of longevities encountered in wildlife is one of the most intriguing problems in biology. Evolutionary biologists have proposed different theories to explain how longevity variability may be driven by bad genes expression in late life or by gene pleiotropic effects. This reflexion has stimulated, in the last ten years, an active research on the proximal mechanisms that can shape lifespan. Reactive oxygen species (ROS), i.e., the by-products of oxidative metabolism, have emerged as the main proximate cause of ageing. Because ROS are mainly produced by the mitochondria, their production is linked to metabolic rate, and this may explain the differences in longevity between large and small species. However, their implication in the sex difference in longevity within a species has never been tested, despite the fact that these differences are widespread in the animal kingdom.
METHODOLOGY/PRINCIPAL FINDINGS: Mitochondrial superoxide production of hemolymph immune cells and antioxidant and oxidative damages plasma levels were measured in adult male and female B. albopilosa at different ages. We found that female spiders are producing less mitochondrial superoxide, are better protected against oxidative attack and are then suffering less oxidative damages than males at adulthood.
CONCLUSIONS/SIGNIFICANCE: In tarantulas, once reaching sexual maturity, males have a life expectancy reduced to 1 to 2 years, while females can still live for 20 years, in spite of the fact that females continue to grow and moult. This study evidences an increased exposure of males to oxidative stress due to an increase in mitochondrial superoxide production and a decrease in hemolymph antioxidant defences. Such a phenomenon is likely to be part of the explanation for the sharp reduction of longevity accompanying male tarantula maturity. This opens several fundamental research roads in the future to better understand how reproduction and longevity are linked in an original ageing model.
野生动物的长寿多样性是生物学中最引人入胜的问题之一。进化生物学家提出了不同的理论来解释长寿的可变性如何可能是由晚年不良基因表达或基因多效性引起的。这种思考在过去十年中激发了对塑造寿命的近端机制的积极研究。活性氧（ROS），即氧化代谢的副产品，已成为衰老的主要近端原因。由于 ROS 主要由线粒体产生，因此它们的产生与代谢率有关，这可以解释大、小物种之间寿命的差异。然而，尽管这些差异在动物界广泛存在，但它们在物种内的性别差异与长寿之间的关系从未被检验过。
方法/主要发现：在不同年龄的成年雄性和雌性 B. albopilosa 中测量了血淋巴免疫细胞的线粒体超氧阴离子产生和抗氧化和氧化损伤血浆水平。我们发现，雌性蜘蛛产生的线粒体超氧阴离子较少，对氧化攻击的保护更好，因此在成年期比雄性遭受的氧化损伤更少。
结论/意义：在狼蛛中，一旦达到性成熟，雄性的预期寿命缩短到 1 到 2 年，而雌性仍然可以活 20 年，尽管雌性仍在继续生长和蜕皮。这项研究表明，由于线粒体中超氧阴离子产生的增加和血淋巴抗氧化防御的减少，雄性蜘蛛暴露于氧化应激的风险增加。这种现象可能是雄性狼蛛成熟时寿命急剧缩短的部分原因。这为未来更好地理解生殖和长寿如何在一个原始的衰老模型中联系起来开辟了几条基础研究道路。
