Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA.
Ecology. 2010 Oct;91(10):3016-26. doi: 10.1890/09-1149.1.
Conditions experienced early in life can influence phenotypes in ecologically important ways, as exemplified by organisms with environmental sex determination. For organisms with temperature-dependent sex determination (TSD), variation in nest temperatures induces phenotypic variation that could impact population growth rates. In environments that vary over space and time, how does this variation influence key demographic parameters (cohort sex ratio and hatchling recruitment) in early life stages of populations exhibiting TSD? We leverage a 17-year data set on a population of painted turtles, Chrysemys picta, to investigate how spatial variation in nest vegetation cover and temporal variation in climate influence early life-history demography. We found that spatial variation in nest cover strongly influenced nest temperature and sex ratio, but was not correlated with clutch size, nest predation, total nest failure, or hatching success. Temporal variation in climate influenced percentage of total nest failure and cohort sex ratio, but not depredation rate, mean clutch size, or mean hatching success. Total hatchling recruitment in a year was influenced primarily by temporal variation in climate-independent factors, number of nests constructed, and depredation rate. Recruitment of female hatchlings was determined by stochastic variation in nest depredation and annual climate and also by the total nest production. Overall population demography depends more strongly on annual variation in climate and predation than it does on the intricacies of nest-specific biology. Finally, we demonstrate that recruitment of female hatchlings translates into recruitment of breeding females into the population, thus linking climate (and other) effects on early life stages to adult demographics.
早期生活条件可以以生态重要的方式影响表型，具有环境性别决定的生物就是一个很好的例子。对于具有温度依赖性性别决定（TSD）的生物，巢温的变化会引起表型变化，从而影响种群增长率。在空间和时间上变化的环境中，这种变化如何影响表现出 TSD 的种群早期生命阶段的关键人口参数（群体性别比例和幼体补充）？我们利用一个为期 17 年的彩绘龟（Chrysemys picta）种群数据集来研究巢植被覆盖的空间变化和气候的时间变化如何影响 TSD 种群的早期生活史人口统计学。我们发现巢覆盖的空间变化强烈影响巢温与性别比例，但与卵窝大小、巢捕食、总巢失败或孵化成功率无关。气候的时间变化影响总巢失败和群体性别比例，但不影响捕食率、平均卵窝大小或平均孵化成功率。一年中的总幼体补充主要受气候独立因素、巢数和捕食率的时间变化影响。雌性幼体的补充由巢捕食的随机变化和年度气候以及总巢产量决定。总体人口统计学更多地取决于气候和捕食的年度变化，而不是巢特异性生物学的复杂性。最后，我们证明雌性幼体的补充转化为繁殖雌性进入种群的补充，从而将早期生命阶段的气候（和其他）效应与成年人口统计学联系起来。
