Bigger is better: changes in body size explain a maternal effect of food on offspring disease resistance.
Bigger is better: changes in body size explain a maternal effect of food on offspring disease resistance.
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DOI：
10.1002/ece3.2709
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发表时间：
2017-03
影响因子：
2.6
通讯作者：
Little TJ
中科院分区：
文献类型：
--
作者：
Garbutt JS;Little TJ
环境变化引发的母体效应（例如，营养或拥挤）可以影响后代-寄生虫相互作用的结果，对宿主和寄生虫造成适合度后果。除了脊椎动物中抗体转移的经典例子之外，几乎没有研究过近似机制，因此，母体对感染的适应性影响的意义没有得到很好的解决。我们试图确定为什么当甲壳类动物Daphnia magna暴露于口腔感染性细菌病原体时，食物应激的母亲生下的后代显示出低感染率。这些更具抵抗力的后代在出生时也更大，并且以较低的速度进食。因此，降低的抗病性可能是由于缓慢喂养后代摄入较少的细菌孢子，或者因为它们的较大尺寸允许更大的免疫投资。为了区分这些理论，我们进行了一项实验，测量了身体大小，摄食率和易感性，并能够表明身体大小是导致易感性改变的主要机制：较大的水蚤不太可能被感染。与我们的预测相反，还有一种趋势是快速喂养的水蚤不太可能被感染。因此，我们的研究结果解释了母体环境效应如何改变后代的抗病能力（尽管体型），并突出了在喂食时遇到寄生虫的宿主中喂食率和易感性之间关系的潜在复杂性。
Maternal effects triggered by changes in the environment (e.g., nutrition or crowding) can influence the outcome of offspring–parasite interactions, with fitness consequences for the host and parasite. Outside of the classic example of antibody transfer in vertebrates, proximate mechanisms have been little studied, and thus, the adaptive significance of maternal effects on infection is not well resolved. We sought to determine why food‐stressed mothers give birth to offspring that show a low rate of infection when the crustacean Daphnia magna is exposed to an orally infective bacterial pathogen. These more‐resistant offspring are also larger at birth and feed at a lower rate. Thus, reduced disease resistance could result from slow‐feeding offspring ingesting fewer bacterial spores or because their larger size allows for greater immune investment. To distinguish between these theories, we performed an experiment in which we measured body size, feeding rate, and susceptibility, and were able to show that body size is the primary mechanism causing altered susceptibility: Larger Daphnia were less likely to become infected. Contrary to our predictions, there was also a trend that fast‐feeding Daphnia were less likely to become infected. Thus, our results explain how a maternal environmental effect can alter offspring disease resistance (though body size), and highlight the potential complexity of relationship between feeding rate and susceptibility in a host that encounters a parasite whilst feeding.