FEMALE TURTLES FROM HOT NESTS - IS IT DURATION OF INCUBATION OR PROPORTION OF DEVELOPMENT AT HIGH-TEMPERATURES THAT MATTERS
FEMALE TURTLES FROM HOT NESTS - IS IT DURATION OF INCUBATION OR PROPORTION OF DEVELOPMENT AT HIGH-TEMPERATURES THAT MATTERS
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DOI：
10.1007/bf00377078
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发表时间：
1989-01-01
期刊：
影响因子：
2.7
通讯作者：
GEORGES, A
中科院分区：
文献类型：
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作者：
GEORGES, A
在自然巢的淡水龟与温度依赖性的性别决定的平均日温度是一个贫穷的预测孵化的性别比例时，巢温波动。为了解释这一点，开发了一个模型，该模型假设当超过一半的胚胎发育发生在性别决定的阈值温度以上时，雌性将从卵中出现，而不是从超过一半的时间超过阈值的卵中出现。该模型与以前公布的数据是一致的，特别是解释的现象，即最好区分男性和女性之间的巢平均温度降低巢温度的变化增加。该模型，如果通过对照实验验证，有重要的意义，我们了解温度依赖性的性别决定在自然巢。平均巢温和“在阈值以上花费的时间”都是孵化期性别比的不良预测因子。旨在调查纬度趋势和种间差异的阈值温度的研究将需要考虑纬度和种间变化的昼夜波动幅度在巢温，以及影响这些波动幅度的因素，如巢深的变化。此外，任何因素，修改发育速度和温度之间的关系，可以预期影响孵化的性别比在自然巢，特别是当巢温度接近阈值。
Mean daily temperature in natural nests of freshwater turtles with temperature-dependent sex determination is known to be a poor predictor of hatchling sex ratios when nest temperatures fluctuate. To account for this, a model was developed on the assumption that females will emerge from eggs when more than half of embryonic development occurs above the threshold temperature for sex determination rather than from eggs that spend more than half their time above the threshold. The model is consistent with previously published data and in particular explains the phenomenon whereby the mean temperature that best distinguishes between male and female nests decreases with increasing variability in nest temperature. The model, if verified by controlled experiments, has important implications for our understanding of temperature-dependent sex determination in natural nests. Both mean nest temperature and "hours spent above the threshold" will be poor predictors of hatchling sex ratios. Studies designed to investigate latitudinal trends and inter-specific differences in the threshold temperature will need to consider latitudinal and inter-specific variation in the magnitude of diel fluctuations in nest temperature, and variation in factors influencing the magnitude of those fluctuations, such as nest depth. Furthermore, any factor that modifies the relationship between developmental rate and temperature can be expected to influence hatchling sex ratios in natural nests, especially when nest temperatures are close to the threshold.