Organisms trade-off limited resources between life-history traits to maximize fitness. In particular, costs associated with reproduction are balanced against somatic maintenance and this can result in age-dependent changes in the optimal allocation of resource to reproduction. Changes in the allocation of resources to reproduction with age were considered in the facultatively parasitic blowfly Lucilia sericata (Diptera: Calliphoridae), using biochemical analysis of lipids in the body and ovary, and lipid and protein in individual eggs. Resource allocation to reproduction, measured as lipid content in the ovary, declined over time. This decline was associated with the production of fewer and smaller eggs per batch. The lipid content of the residual body did not change. A decrease in lipid and increase in protein contents of individual eggs over time, although statistically significant, were relatively slight, suggesting that age-related changes in nutritional allocation to individual eggs were more subtle than changes in egg batch number or size. This study highlights the insights to be gained from considering both biochemical measures of nutritional allocation, and observable measures of reproductive effort, when evaluating how females balance allocation across competing life-history traits. Future work should explore how allocation patterns might vary under conditions of resource constraint and whether age-dependent allocation in laboratory flies is representative of that found in wild populations.

中文翻译：

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兼性体外寄生虫绿蝇绿蝇（美根）（丽蝇科）生殖分配的年龄依赖性变化

生物体在生活史特征之间权衡有限的资源，以最大限度地提高适应性。特别是，与生殖相关的成本与体细胞​​维持相平衡，这可能导致生殖资源的最佳分配随年龄而变化。在兼性寄生绿蝇绿蝇中考虑了繁殖资源分配随年龄的变化（双翅目：Calliphoridae），对体内和卵巢中的脂质以及单个卵中的脂质和蛋白质进行生化分析。以卵巢中的脂质含量衡量的生殖资源分配随着时间的推移而下降。这种下降与每批鸡蛋产量越来越少和较小有关。残留体的脂质含量没有变化。随着时间的推移，单个鸡蛋的脂质含量下降，蛋白质含量增加，尽管具有统计学意义，但相对较小，这表明单个鸡蛋的营养分配与年龄相关的变化比鸡蛋批次数量或大小的变化更微妙。这项研究强调了从考虑营养分配的生化指标和生殖努力的可观察指标中获得的见解，在评估女性如何在相互竞争的生活史特征之间平衡分配时。未来的工作应探讨在资源有限的条件下分配模式如何变化，以及实验室果蝇中年龄依赖性分配是否能代表野生种群中的分配模式。