Climate change may have diverse and complex impacts on species interactions, destabilizing food webs and ecosystem services. The effects of warming on the top‐down biological control of crop pests have been considerably less studied than bottom‐up effects through crop physiological changes. We studied the effect of a 2°C warming in the laboratory and in wheat fields on the predation and metabolism of Harmonia axyridis on wheat aphids using molecular gut content analysis. We also measured the effects of warming on the predation rate and functional response of H. axyridis on each aphid species in the laboratory, as well as on DNA degradation rate. Field densities of Sitobion avenae and Rhopalosiphum padi, the two most abundant wheat aphid species, were increased by 2 and 2.5 times, respectively, under experimental warming, but densities of H. axyridis were not. Field predation rate of H. axyridis on these two aphid was found to be about 25% lower under elevated temperature. This could have been due to faster prey digestion, since degradation of the preferred aphid species, Sitobion avenae, was 1.5 times faster under elevated temperature. However, the functional response of H. axyridis larvae on these two species was 1.5 times higher under warming over the range of prey densities tested (50–250 over 24 h). The total predation rate of H. axyridis larvae on a mixture of S. avenae, R. padi and Schizaphis graminum aphid prey was also increased by 1.4 times, but consumption of R. padi aphids was increased while that of S. graminum was decreased under warming. Overall, our results show that global warming could strongly increase pest outbreaks and destabilize biological pest control, which would likely result in accrued yield losses. Read the free Plain Language Summary for this article on the Journal blog.

中文翻译：

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瓢虫捕食和新陈代谢的增加并不能抵消实验变暖下田间蚜虫种群增长的增加

气候变化可能对物种相互作用、破坏食物网和生态系统服务的稳定产生多样化和复杂的影响。与通过作物生理变化产生的自下而上的影响相比，变暖对作物害虫自上而下的生物控制的影响的研究要少得多。 我们在实验室和麦田中研究了 2°C 变暖对捕食和代谢的影响异色瓢虫使用分子肠道内容分析对小麦蚜虫进行研究。我们还测量了变暖对捕食率和功能反应的影响异色异色线虫实验室中每种蚜虫的情况以及 DNA 降解率。 场密度为燕麦和稻瘟病菌，两种最丰富的小麦蚜虫物种，在实验变暖的情况下分别增加了 2 倍和 2.5 倍，但密度异色异色线虫不是。田间捕食率异色异色线虫发现在升高的温度下，这两种蚜虫的感染率降低了约 25%。这可能是由于更快的猎物消化，因为首选的蚜虫物种退化了，燕麦，在高温下速度提高了 1.5 倍。然而，功能反应异色异色线虫在测试的猎物密度范围（24 小时内 50-250 个）内，这两个物种的幼虫数量在变暖条件下增加了 1.5 倍。总捕食率异色异色线虫幼虫在混合物上燕麦链霉菌,指鹳和禾谷裂霉蚜虫的猎物也增加了1.4倍，但消耗量指鹳蚜虫数量有所增加，而禾谷链霉菌随变暖而减少。 总体而言，我们的结果表明，全球变暖可能会严重增加害虫爆发并破坏生物害虫控制的稳定性，这可能会导致累计产量损失。 阅读免费的通俗易懂的语言总结这篇文章发表在《期刊》博客上。