Does it pay to delay? Flesh flies show adaptive plasticity in reproductive timing.
Does it pay to delay? Flesh flies show adaptive plasticity in reproductive timing.
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拖延有好处吗？
DOI：
10.1007/s00442-010-1805-z
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发表时间：
2011
期刊：
影响因子：
2.7
通讯作者：
Hahn,DanielA
中科院分区：
文献类型：
--
作者：
Wessels,FrankJ;Kristal,Ross;Netter,Fleta;Hatle,JohnD;Hahn,DanielA
生活史可塑性在生物体中普遍存在。然而，一个重要的问题是它是否具有适应性。大多数生活史时间可塑性模型预测，动物一旦在恶劣条件下达到最低营养阈值，将加速发育或繁殖时间。繁殖的适应性延迟并不常见，特别是在短命物种中。适应性生殖延迟的例子存在于经历强烈种间差异的哺乳动物种群中（例如，捕食）和种内（例如，竞争。但是，是否还有其他环境因素可能引发生殖时间的适应性延迟？我们表明，短寿命的肉蝇Sarcophaga crassipalpis将延迟繁殖营养不良的条件下，即使它已经达到了最低营养阈值的繁殖。我们测试这种延迟策略是否是一种适应性反应，允许清道夫的时间，通过实验提供补充蛋白质脉冲（早，中，晚）在整个生殖延迟期，以找到更多的资源。接受额外蛋白质的苍蝇产生更多更大的蛋，证明了延迟的好处。此外，通过使用稳定同位素跟踪脉冲中碳的分配，我们发现，接受早期脉冲的果蝇比接受后期脉冲的果蝇将更多的碳纳入卵子和体细胞组织中。这些结果表明，生殖延迟在S. crassipalpisis符合适应性阈值后可塑性，营养相关的生殖策略，以前没有报道在无脊椎动物物种。
Life-history plasticity is widespread among organisms. However, an important question is whether it is adaptive. Most models for plasticity in life-history timing predict that animals, once they have reached the minimal nutritional threshold under poor conditions, will accelerate development or time to reproduction. Adaptive delays in reproduction are not common, especially in short-lived species. Examples of adaptive reproductive delays exist in mammalian populations experiencing strong interspecific (e.g., predation) and intraspecific (e.g., infanticide) competition. But are there other environmental factors that may trigger an adaptive delay in reproductive timing? We show that the short-lived flesh flySarcophaga crassipalpiswill delay reproduction under nutrient-poor conditions, even though it has already met the minimal nutritional threshold for reproduction. We test whether this delay strategy is an adaptive response allowing the scavenger time to locate more resources by experimentally providing supplemental protein pulses (early, mid and late) throughout the reproductive delay period. Flies receiving additional protein produced more and larger eggs, demonstrating a benefit of the delay. In addition, by tracking the allocation of carbon from the pulses using stable isotopes, we show that flies receiving earlier pulses incorporated more carbon into eggs and somatic tissue than those given a later pulse. These results indicate that the reproductive delay inS. crassipalpisis consistent with adaptive post-threshold plasticity, a nutritionally linked reproductive strategy that has not been reported previously in an invertebrate species.