Stier Antoine, Delestrade Anne, Zahn Sandrine, Arrivé Mathilde, Criscuolo François, Massemin-Challet Sylvie
Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, Strasbourg, France,
Oecologia. 2014 Jul;175(3):791-800. doi: 10.1007/s00442-014-2946-2. Epub 2014 May 8.
The short favorable period of time available for the growth in seasonal environments could constrain the resources allocation between growth and other life-history traits, and the short-term fitness benefits of increased growth rate may prevail over other functions. Accelerated growth rates have been associated with long-term deleterious consequences (e.g., decreased lifespan), and recently oxidative stress (the imbalance between pro-oxidants generation and antioxidant defenses) has been suggested as a mediator of these effects. Here, we examined the impact of elevation on growth rate and self-maintenance parameters (resting metabolism, oxidative damage, and antioxidant defenses) of coal tit chicks (Periparus ater). We predicted that the shorter favorable season at the higher-elevation site could lead to a reallocation of resources towards growth at the expense of self-maintenance processes. We found that chicks at high elevation grew significantly faster in terms of body mass and body size. Chicks from the high-elevation site presented higher resting metabolism, higher oxidative damage level, but similar antioxidant defenses, compared to low-elevation chicks. Interestingly, the chicks exhibiting the better antioxidant defenses at 7 days were also those with the highest resting metabolic rate, and the chicks that grew at the faster rate within the high-elevation site were those with the highest levels of oxidative damage on DNA. Our study supports the idea that increasing elevation leads to a higher growth rate in coal tit chicks, possibly in response to a shorter favorable season. In accordance with life-history theory, a bigger investment in growth was done at the expense of body maintenance, at least in terms of oxidative stress.
在季节性环境中，可供生长的有利时间较短，这可能会限制生长与其他生活史特征之间的资源分配，而且生长速率提高带来的短期适应性益处可能会超过其他功能。加速的生长速率与长期的有害后果（如寿命缩短）有关，最近氧化应激（促氧化剂生成与抗氧化防御之间的失衡）被认为是这些影响的介导因素。在此，我们研究了海拔对煤山雀雏鸟（Periparus ater）生长速率和自我维持参数（静息代谢、氧化损伤和抗氧化防御）的影响。我们预测，海拔较高地点较短的有利季节可能会导致资源重新分配，以牺牲自我维持过程为代价来促进生长。我们发现，高海拔地区的雏鸟在体重和体型方面生长明显更快。与低海拔雏鸟相比，高海拔地区的雏鸟具有更高的静息代谢、更高的氧化损伤水平，但抗氧化防御能力相似。有趣的是，7日龄时抗氧化防御能力较好的雏鸟也是静息代谢率最高的雏鸟，而在高海拔地区生长速度较快的雏鸟是DNA氧化损伤水平最高的雏鸟。我们的研究支持了这样一种观点，即海拔升高会导致煤山雀雏鸟生长速率提高，这可能是对较短有利季节的一种响应。根据生活史理论，至少在氧化应激方面，生长方面的更大投入是以身体维持为代价的。
