Cold-seeking behaviour mitigates reproductive losses from fungal infection in Drosophila.
Cold-seeking behaviour mitigates reproductive losses from fungal infection in Drosophila.
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DOI：
10.1111/1365-2656.12438
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发表时间：
2016-01
期刊：
影响因子：
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通讯作者：
Priest NK
中科院分区：
文献类型：
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作者：
Hunt VL;Zhong W;McClure CD;Mlynski DT;Duxbury EM;Keith Charnley A;Priest NK
动物必须调整它们的生活史策略，以适应当时的条件，并对环境中的危险做出反应。感染致命病毒的动物面临着一个艰难的选择：是分配更多资源用于繁殖并承受更高的死亡率，还是减少繁殖，以期提高免疫力并推迟繁殖。然而，用于调节生活史特征变化的策略在很大程度上是未知的。本文研究了黑腹果蝇（Drosophila melanogaster）在感染罗伯特绿僵菌（Metarhizium robertsii）时的温度偏好，以及温度偏好对生活史性状的影响。我们测量了不同病原菌条件下果蝇的温度偏好。我们在不同的温度条件下对寄主和病原菌进行了多次适应度测定。从这些数据中，我们估计了健康的标准测量，并使用特定年龄的方法来测试健康权衡，这些权衡被认为是生活史策略差异的基础。我们发现真菌感染的果蝇寻求更低的温度，这有助于它们生活史策略的适应性转变。受感染动物喜欢的较低温度对病原体是有害的，因为它增加了对感染的抵抗力。但是，它并没有为受感染动物提供特定的净效益，因为无论动物是否被感染，较低的温度都会增加终生的繁殖成功率和存活率。相反，我们发现寻求寒冷对受感染动物有利，因为它增加了它们晚期的生殖产出，但代价是它们早期的生殖产出。相比之下，幼稚对照蝇更喜欢温暖的温度，以优化早期繁殖，但代价是后期的繁殖产出。这些发现表明，受感染的动物表现出与健康动物截然不同的生殖策略。温度偏好可以促进策略的转变，但并非没有不可避免的权衡。
Animals must tailor their life‐history strategies to suit the prevailing conditions and respond to hazards in the environment. Animals with lethal infections are faced with a difficult choice: to allocate more resources to reproduction and suffer higher mortality or to reduce reproduction with the expectation of enhanced immunity and late‐age reproduction. However, the strategies employed to mediate shifts in life‐history traits are largely unknown. Here, we investigate the temperature preference of the fruit fly, Drosophila melanogaster, during infection with the fungal pathogen, Metarhizium robertsii, and the consequence of temperature preference on life‐history traits. We have measured the temperature preference of fruit flies under different pathogen conditions. We conducted multiple fitness assays of the host and the pathogen under different thermal conditions. From these data, we estimated standard measures of fitness and used age‐specific methodologies to test for the fitness trade‐offs that are thought to underlie differences in life‐history strategy. We found that fungus‐infected fruit flies seek out cooler temperatures, which facilitates an adaptive shift in their life‐history strategy. The colder temperatures preferred by infected animals were detrimental to the pathogen because it increased resistance to infection. But, it did not provide net benefits that were specific to infected animals, as cooler temperatures increased lifetime reproductive success and survival whether or not the animals were infected. Instead, we find that cold‐seeking benefits infected animals by increasing their late‐age reproductive output, at a cost to their early‐age reproductive output. In contrast, naive control flies prefer warmer temperatures that optimize early‐age reproductive, at a cost to reproductive output at late ages. These findings show that infected animals exhibit fundamentally different reproductive strategies than their healthy counterparts. Temperature preference can facilitate shifts in strategy, but not without inevitable trade‐offs.