Reproductive versus ecological advantages to larger body size in female snakes, Vipera aspis
Reproductive versus ecological advantages to larger body size in female snakes, Vipera aspis
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DOI：
10.1034/j.1600-0706.2000.890310.x
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发表时间：
2000-06-01
期刊：
影响因子：
3.4
通讯作者：
Lourdais, O
中科院分区：
文献类型：
--
作者：
Bonnet, X;Naulleau, G;Lourdais, O
体型可以通过生态因素（生态选择）或生殖输出的变化（性或繁殖力选择）影响生物体的微进化适应性。已发表的关于爬行动物性别二态性的研究通常集中在雄性的性选择力量上，隐含的假设是雌性繁殖力选择的强度（因此，对雌性体型的总体选择）可能在谱系中相对一致。在本文中，我们探讨了在自由放养的雌性肉冻蝰蛇（Vipera aspis）中，较大的体型在多大程度上增强了生态属性（例如食物摄入、生长、生存）和繁殖输出（繁殖频率、产仔数、后代大小、后代生存能力）。这些动物的繁殖频率低于每年一次，这使我们能够直接比较雌性动物在专注于“生态”挑战（尤其是建立能量储备）和繁殖挑战（产仔）的年份。由于雌蛇腹部空间有限，无法容纳幼蛇，因此我们预计繁殖力应取决于体型。然而，我们的数据表明，较大的体型对生态属性（例如摄食率和“繁殖成本”）的影响比对繁殖产出本身的影响更一致。事实上，在中等体型的情况下，总生殖产出最大化。这些结果表明，物种间和物种内雌性体型的差异（以及性别二态性程度）可能是由两性体型差异的生态和生殖后果驱动的。
Body size can influence an organism's microevolutionary fitness either via ecological factors (ecological selection) or changes in reproductive output (sexual or fecundity selection). Published studies on sexual dimorphism in reptiles have generally focussed on sexual-selective forces on males, under the implicit assumption that the intensity of fecundity selection in females (and hence, overall selection on female body size) is likely to be relatively consistent among lineages. In this paper, we explore the degree to which larger body size enhances ecological attributes (e.g., food intake, growth, survival) and reproductive output (reproductive frequency, litter size, offspring size, offspring viability) in free-ranging female aspic vipers, Vipera aspis. The less-than-annual reproductive frequency of these animals allows us to make a direct comparison between females in years during which they concentrate on "ecological" challenges (especially building energy reserves) versus reproductive challenges (producing a litter). Because female snakes have limited abdominal space to hold the clutch (litter), we expect that fecundity should depend on body size. However, our data show that larger body size had a more consistent effect on ecological attributes (such as feeding rates and "costs of reproduction") than on reproductive output per se. Indeed, total reproductive output was maximised at intermediate body sizes. These results suggest that variation in female body size among and within species (and hence, in the degree of sexual dimorphism) may be driven by the ecological as well as reproductive consequences of body size variation in both sexes.