Elphick Melanie J, Shine Richard
Biological Sciences A08, The University of Sydney, NSW 2006, Australia, , , , , , AU.
Oecologia. 1999 Mar;118(4):431-437. doi: 10.1007/s004420050745.
Most theoretical models for the evolution of temperature-dependent sex determination (TSD) rely upon differential fitness of male and female offspring incubated under different thermal regimes. However, there are few convincing data on this topic. We studied incubation effects in a lizard species (Bassiana duperreyi, Scincidae) with genotypic sex determination, so that we could separate effects due to incubation temperatures from those due to offspring gender. We incubated eggs under two different fluctuating-temperature regimes that simulated hot and cold natural nest-sites. The effects of our incubation treatments on phenotypes of the hatchling lizards (morphology and locomotor performance) differed between the sexes. Females emerging from eggs exposed to the "hot nest" treatment (diel cycling, 23-31°C) were larger, and ran faster, than did their sisters from the "cold nest" treatment (16-24°C). Males showed a smaller and less consistent phenotypic response than females. These incubation-induced responses were relatively stable during the first few weeks of life post-hatching, at least in captive lizards maintained under laboratory conditions. These kinds of sex differences in the phenotypic responses of hatchling reptiles to incubation conditions provide a plausible basis for the evolution of temperature-dependent sex determination in reptiles.
大多数关于温度依赖型性别决定（TSD）进化的理论模型都依赖于在不同温度条件下孵化的雄性和雌性后代的适应性差异。然而，关于这个话题的令人信服的数据很少。我们研究了一种具有基因型性别决定的蜥蜴物种（杜氏滑蜥，石龙子科）的孵化效应，以便我们能够将孵化温度的影响与后代性别的影响区分开来。我们在两种不同的波动温度条件下孵化卵，这两种条件模拟了炎热和寒冷的自然巢穴。我们的孵化处理对孵化出的蜥蜴幼体的表型（形态和运动性能）的影响在性别之间存在差异。从暴露于“热巢”处理（昼夜循环，23 - 31°C）的卵中孵化出的雌性比来自“冷巢”处理（16 - 24°C）的姐妹更大，跑得更快。雄性表现出比雌性更小且不太一致的表型反应。这些孵化诱导的反应在孵化后生命的最初几周内相对稳定，至少在实验室条件下饲养的圈养蜥蜴中是这样。孵化出的爬行动物对孵化条件的表型反应中的这种性别差异为爬行动物温度依赖型性别决定的进化提供了一个合理的基础。
