Shine Richard
Biological Sciences A08, University of Sydney, NSW 2006, Australia.
J Exp Zool A Comp Exp Biol. 2006 Jun 1;305(6):524-35. doi: 10.1002/jez.a.291.
Pregnant females modify their thermoregulatory behaviour in many species of viviparous (live-bearing) reptiles, typically maintaining higher and more stable body temperatures at this time. Such modifications often have been interpreted as adaptations to viviparity, functioning to accelerate embryonic development and/or modify phenotypic traits of hatchlings. An alternative possibility is that similar maternal thermophily may be widespread also in oviparous species and if so, would be a pre-adaptation (rather than an adaptation) to viviparity. Because eggs are retained in utero for a significant proportion of development even in oviparous reptiles, maternal thermophily might confer similar advantages in oviparous as in viviparous taxa. Experimental trials on montane oviparous scincid lizards (Bassiana duperreyi) support the pre-adaptation hypothesis. First, captive females (both reproductive and non-reproductive) selected higher temperatures than males. Second, experimentally imposing thermal regimes on pregnant females significantly affected their oviposition dates and the phenotypic traits (body shape, running speed) of their hatchlings. Thus, as for many other behavioural correlates of pregnancy in viviparous reptiles, maternal thermophily likely may have already been present in the ancestral oviparous taxa that gave rise to present-day viviparous forms.
在许多胎生（卵胎生）爬行动物物种中，怀孕的雌性会改变其体温调节行为，通常在这个时候保持更高且更稳定的体温。这种改变常常被解释为对卵胎生的适应，其作用是加速胚胎发育和/或改变幼体的表型特征。另一种可能性是，类似的母体嗜温性在卵生物种中可能也很普遍，如果是这样，那它将是对卵胎生的一种预适应（而非适应）。因为即使在卵生爬行动物中，卵在子宫内也会保留相当一部分发育时间，母体嗜温性在卵生类群中可能会带来与卵胎生类群类似的优势。对山地卵生石龙子蜥蜴（Bassiana duperreyi）进行的实验试验支持了这一预适应假说。首先，圈养的雌性（包括生殖期和非生殖期）选择的温度高于雄性。其次，对怀孕雌性施加不同的热环境会显著影响它们的产卵日期以及幼体的表型特征（体型、奔跑速度）。因此，就像在胎生爬行动物中许多其他与怀孕相关的行为一样，母体嗜温性可能在产生当今胎生形式的祖先卵生类群中就已经存在了。
