The study of energy allocation is essential in understanding the regulation of major life history traits. It is often assumed automatically that the limitation of an energy budget or higher allocation to a single trait affect all life history traits. This assumption was inherently included in influential models of ontogenetic growth. We aim to challenge this perspective by focusing on growth in lizards. Summarizing the results of a series of long-term manipulative experiments in the Madagascar ground gecko ( Paroedura picta ), we show that although growth is generally assumed to be highly plastic in reptiles and other ectothermic vertebrates, it is at least in this species largely canalized and does not seem to be affected by energy limitations under several experimental conditions. Diet restriction, resulting in lower allocation to fat storage and reproduction, and the allocation to energetically demanding traits such as reproduction in both sexes and tail regeneration had little if any effect on structural growth. We document that sexual size dimorphism does not emerge in the ontogeny of the studied species directly due to differential allocation to structural growth in males and females. Instead, sex-specific growth trajectories are driven by a signaling of ovarian hormones as the key proximate mechanism shaping sex-specific allocation decisions during ontogeny. We suggest that the large degree of canalization of the structural growth can reflect hierarchy in energy allocation with the structural growth being prioritized to investment in other traits. The prioritized allocation to structural growth can reflect selective advantage of reaching a final, optimal size for a given sex as fast as possible.

中文翻译：

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能量视角的局限性：蜥蜴生长中的生活史决定

能量分配的研究对于理解主要生活史特征的调节至关重要。通常自动假设能量预算的限制或对单个特征的更高分配会影响所有生活史特征。这一假设固有地包含在有影响力的个体发育模型中。我们的目标是通过关注蜥蜴的生长来挑战这一观点。总结马达加斯加地面壁虎 (Paroedura picta) 的一系列长期操纵实验的结果，我们表明，虽然一般认为爬行动物和其他变温脊椎动物的生长具有高度可塑性，但至少在这个物种中，它主要被运河化并且在几个实验条件下似乎不受能量限制的影响。饮食限制，导致脂肪储存和繁殖的分配较低，而对能量要求较高的性状（如两性繁殖和尾部再生）的分配对结构生长几乎没有影响。我们记录了由于雄性和雌性结构生长的差异分配，性别大小二态性不会直接出现在所研究物种的个体发育中。相反，性别特异性生长轨迹是由卵巢激素信号驱动的，这是在个体发育过程中形成性别特异性分配决策的关键近似机制。我们认为，结构性增长的大运河化程度可以反映能源配置的等级，结构性增长优先于其他特征的投资。