Herbivorous insects have more difficulty obtaining proteins from their food than do predators and parasites. The scarcity of proteins in their diet requires herbivores to feed voraciously, thus heavily damaging their host plants. Plants respond to herbivory by producing defense compounds, which reduce insect growth, retard development, and increase mortality. Herbivores use both pre‐ and postdigestive response mechanisms to detect and avoid plant defense compounds. Proteinase inhibitors (PIs) are one example of plant compounds produced as a direct defense against herbivory. Many insects can adapt to PIs when these are incorporated into artificial diets. However, little is known about the effect of PIs on diet choice and feeding behavior. We monitored the diet choice, life‐history traits, and gut proteinase activity of Helicoverpa armigera larvae using diets supplemented with synthetic and natural PIs. In choice experiments, both neonates and fourth‐instar larvae preferred the control diet over PI‐supplemented diets, to varying degrees. Larvae that fed on PI‐supplemented diets weighed less than those that fed on the control diet and produced smaller pupae. Trypsin‐specific PIs had a stronger effect on mean larval weight than did other PIs. A reduction of trypsin activity but not of chymotrypsin activity was observed in larvae fed on PI‐supplemented diets. Therefore, behavioral avoidance of feeding on plant parts high in PIs could be an adaptation to minimize the impact of this plant's defensive strategy.

中文翻译：

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类特异性，合成和天然蛋白酶抑制剂对棉铃虫棉铃虫生活史特征的影响。

与食肉动物和寄生虫相比，草食性昆虫从食物中获取蛋白质的难度更大。饮食中蛋白质的稀缺要求食草动物大量进食，从而严重破坏其寄主植物。植物通过产生防御化合物来对草食动物做出反应，从而降低昆虫的生长，延缓发育并增加死亡率。草食动物同时使用消化前和消化后反应机制来检测和避免植物防御化合物。蛋白酶抑制剂（PIs）是作为对草食动物的直接防御而生产的植物化合物的一个例子。当将它们掺入人工饮食中时，许多昆虫可以适应PI。然而，关于PI对饮食选择和喂养行为的影响知之甚少。我们监测了人的饮食选择，生活史特征和肠道蛋白酶活性日粮中的棉铃虫幼虫，使用合成和天然PI补充饮食。在选择实验中，无论是新生儿还是四龄幼虫，都在不同程度上偏爱对照饮食而不是补充PI的饮食。以补充PI饮食喂养的幼虫的体重比以对照饮食喂养的幼虫轻，并且产生的smaller更小。胰蛋白酶特异性PI对其他幼体PI的平均幼虫体重影响更大。在补充PI饮食的幼虫中，胰蛋白酶活性降低，但胰凝乳蛋白酶活性未降低。因此，避免在PI较高的植物部分上进食的行为可能是一种适应措施，可最大程度地降低该植物防御策略的影响。