Parent-offspring conflicts are widespread given that resources are often limited. Recent evidence has shown that availability of water can trigger such conflict during pregnancy in viviparous squamate species (lizards and snakes) and thus questions the role of water in the evolution of reproductive modes. Here, we examined the impact of water restriction during gravidity in the oviparous form of the bimodal common lizard (Zootoca vivipara), using a protocol previously used on the viviparous form. Females were captured in early gravidity from six populations along a 600 m altitudinal gradient to investigate whether environmental conditions (altitude, water access and temperature) exacerbate responses to water restriction. Females were significantly dehydrated after water restriction, irrespective of their reproductive status (gravid vs. non-reproductive), relative reproductive effort (relative clutch mass), and treatment timing (embryonic development stage). Female dehydration, together with reproductive performance, varied with altitude, probably due to long term acclimation or local adaptation. This moderate water-based intergenerational conflict in gravid females contrasts sharply with previous findings for the viviparous form, with implications to the evolutionary reversion from viviparity to oviparity. It is likely that oviparity constitutes a water-saving reproductive mode which might help mitigate intensive temperature-driven population extinctions at low altitudes.

中文翻译：

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母子对水的冲突及其以生殖双峰蜥蜴的卵生形式Zotoca vivipara的缓解

鉴于资源通常有限，父母与子女之间的冲突十分普遍。最近的证据表明，水的可利用性会在怀孕期间引起胎生鳞状物种（蜥蜴和蛇）的这种冲突，从而质疑水在生殖方式演变中的作用。在这里，我们检查了卵在双峰普通蜥蜴（Zootoca vivipara）的卵形妊娠过程中水分限制的影响。），使用先前在胎生形式上使用的协议。从六个种群中沿600 m的垂直梯度捕获了雌性，以调查环境条件（海拔，用水和温度）是否加剧了对水分限制的反应。禁水后雌性动物的脱水明显，不论其生殖状态（重度与非生殖状态），相对生殖力（相对离合器质量）和治疗时机（胚胎发育阶段）如何。女性脱水以及生殖能力随着海拔的升高而变化，这可能是由于长期适应或局部适应所致。妊娠雌性的这种温和的水生代际冲突与先前关于胎生形式的发现形成鲜明对比，涉及从胎生到卵胎的进化回归。产卵可能是一种节水繁殖方式，可能有助于减轻低海拔地区密集的温度驱动的种群灭绝。