Abstract Early developmental temperatures influence the physiology and behavior of reptiles, with important consequences for their fitness and survival. For example, many viviparous lizards are cold adapted which may restrict their activity times during the reproductive season, increasing their susceptibility to global warming. However, it is unclear if and how lizards with different reproductive modes (oviparity vs. viviparity) can respond to rising temperatures by modifying their life-history traits. We examined the effect of developmental temperatures on hatchling behavior and learning in viviparous and oviparous populations of the lizard Saiphos equalis to test whether their reproductive behavior can buffer against rising temperatures. Gravid females from both populations were subjected to current or projected end-of-century (future) thermal environments to evaluate differences in the exploratory, foraging and antipredator behavior, and spatial learning ability of their offspring. We found that viviparous lizards were more exploratory and had a less-pronounced antipredator response than oviparous lizards. Regardless of the mode of reproduction, elevated temperatures reduced the exploratory behavior of hatchling lizards. Elevated temperatures also reduced the foraging efficiency of oviparous, but not viviparous, hatchlings. Finally, future-gestated oviparous hatchlings were more likely to choose the correct refuge and made fewer mistakes in a spatial learning task; however, we found only weak evidence of spatial learning in S. equalis . Our results suggest that although global warming is likely to have a negative impact on phenotypic traits, in S. equalis , some of these effects may be ameliorated by maternal behavior and/or physiological responses during pregnancy, particularly in viviparous populations. Significance statement Computational modeling studies suggest that live-bearing lizards (viviparous) are more vulnerable to global warming compared with egg-laying ones (oviparous). However, there is little experimental evidence showing that viviparous species are indeed at a greater risk of extinction. Using a lizard species that has both oviparous and viviparous populations, we tested the effect of high developmental temperatures (projected for 2100) on the behavior and learning of their offspring. We found that elevated temperatures had a stronger negative effect on egg-laying lizards by producing hatchlings with lower foraging efficiency. Our results suggest that viviparous mothers can ameliorate some of the effects of global warming on their offspring. Moreover, our study suggests that if live bearers are indeed more vulnerable to global warming, it is likely not due to maladaptive behavior in offspring, but rather, to other causes that affect pregnant females.

中文翻译：

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早期热环境对双峰繁殖蜥蜴行为和学习的影响

摘要 早期发育温度影响爬行动物的生理和行为，对其健康和生存产生重要影响。例如，许多胎生蜥蜴是冷适应的，这可能会限制它们在繁殖季节的活动时间，从而增加它们对全球变暖的敏感性。然而，目前尚不清楚具有不同繁殖模式（卵生与胎生）的蜥蜴是否以及如何通过改变它们的生活史特征来应对温度升高。我们在蜥蜴 Saiphos equalis 的胎生和卵生种群中检查了发育温度对孵化行为和学习的影响，以测试它们的繁殖行为是否可以缓冲温度升高。来自这两个种群的妊娠雌性受到当前或预计的世纪末（未来）热环境的影响，以评估其后代在探索、觅食和反捕食行为以及空间学习能力方面的差异。我们发现，与卵生蜥蜴相比，胎生蜥蜴更具探索性，并且具有较不明显的抗捕食者反应。无论繁殖方式如何，升高的温度都会减少幼蜥的探索行为。升高的温度也降低了卵生但不是胎生的幼体的觅食效率。最后，未来怀孕的卵生幼龟更有可能选择正确的避难所，并且在空间学习任务中犯的错误更少；然而，我们在 S. equalis 中只发现了空间学习的弱证据。我们的研究结果表明，尽管全球变暖可能对 S.equalis 的表型性状产生负面影响，但其中一些影响可能会通过怀孕期间的母体行为和/或生理反应得到改善，尤其是在胎生种群中。意义声明 计算模型研究表明，与产卵的蜥蜴（卵生的）相比，活的蜥蜴（胎生）更容易受到全球变暖的影响。然而，几乎没有实验证据表明胎生物种确实面临更大的灭绝风险。我们使用具有卵生和胎生种群的蜥蜴物种测试了高发育温度（预计为 2100 年）对其后代行为和学习的影响。我们发现升高的温度对产卵蜥蜴产生更强的负面影响，因为它会产生觅食效率较低的幼龟。我们的研究结果表明，胎生母亲可以减轻全球变暖对其后代的一些影响。此外，我们的研究表明，如果活生生的母猪确实更容易受到全球变暖的影响，这可能不是由于后代的适应不良行为，而是由于影响怀孕女性的其他原因。