Shine Richard
School of Biological Sciences, A08, University of Sydney, 2006, N.S.W., Australia.
Oecologia. 1980 Jul;46(1):92-100. doi: 10.1007/BF00346972.
Many theoretical models of life-history evolution rely on the existence of trade-offs between current fecundity and probable future fecundity and survival. Such "costs" of reproduction have been demonstrated only rarely. Field and laboratory studies on six species of Australian scincid lizards show that gravid females are more vulnerable to predation than are non-gravid females, primarily because (i) they are physically burdened (running speeds are reduced by 20 to 30%), and (ii) they bask more often (in some species). However, food intake is not reduced in gravid animals. A review of published literature suggests that reproductive trade-offs are widespread among reptiles, but the nature of the reproductive "costs" may vary widely among related species. Within the range of annual survivorship rates of most lizard species, trade-offs between fecundity and survival are likely to be the main evolutionary determinants of optimal levels of "reproductive effort". Trade-offs between fecundity and bodily growth are less likely to be significant.
许多生活史进化的理论模型都依赖于当前繁殖力与未来可能的繁殖力和生存之间存在权衡取舍这一假设。这种繁殖的“成本”仅在极少数情况下得到证实。对六种澳大利亚石龙子蜥蜴进行的野外和实验室研究表明，怀孕的雌性比未怀孕的雌性更容易被捕食，主要原因是：（i）它们身体负担较重（奔跑速度降低20%至30%），以及（ii）它们更频繁地晒太阳（在某些物种中）。然而，怀孕动物的食物摄入量并未减少。对已发表文献的综述表明，繁殖权衡在爬行动物中很普遍，但繁殖“成本”的性质在相关物种中可能有很大差异。在大多数蜥蜴物种的年生存率范围内，繁殖力与生存之间的权衡可能是“繁殖努力”最佳水平的主要进化决定因素。繁殖力与身体生长之间的权衡不太可能很显著。
