Steroid hormones are crucial regulators of life-stage transitions during development in animals. However, the molecular mechanisms by which developmental transition through these stages is coupled with optimal metabolic homeostasis remains poorly understood. Here, we demonstrate through mathematical modelling and experimental validation that ecdysteroid-induced metabolic remodelling from resource consumption to conservation can be a successful life-history strategy to maximize fitness in Drosophila larvae in a fluctuating environment. Specifically, the ecdysteroid-inducible protein ImpL2 protects against hydrolysis of circulating trehalose following pupal commitment in larvae. Stored glycogen and triglycerides in the fat body are also conserved, even under fasting conditions. Moreover, pupal commitment dictates reduced energy expenditure upon starvation to maintain available resources, thus negotiating trade-offs in resource allocation at the physiological and behavioural levels. The optimal stage-specific metabolic shift elucidated by our predictive and empirical approaches reveals that Drosophila has developed a highly controlled system for ensuring robust development that may be conserved among higher-order organisms in response to intrinsic and extrinsic cues.

类固醇激素是动物发育过程中生命阶段过渡的关键调节剂。然而，通过这些阶段的发育过渡与最佳的代谢动态平衡相结合的分子机制仍然知之甚少。在这里，我们通过数学建模和实验验证证明，蜕皮甾类激素诱导的从资源消耗到养护的代谢重塑可以是成功的生命史策略，从而最大程度地提高果蝇的适应性在不断变化的环境中的幼虫。具体地说，蜕皮类固醇诱导蛋白ImpL2可以防止幼虫commitment入后引起循环海藻糖的水解。即使在禁食条件下，脂肪体内储存的糖原和甘油三酸酯也可以保存。此外，p的承诺指示饥饿时减少能源消耗以维持可用资源，从而在生理和行为水平上就资源分配进行权衡取舍。我们的预测和经验方法阐明了最佳的阶段特异性代谢变化，这表明果蝇已经开发出高度控制的系统，以确保在响应内部和外部线索时，高阶生物体中可以保守的稳健发育。