When animals are faced with a life-threatening challenge, they mount an organism-wide response (i.e. Plan A). For example, both the stress response (i.e. fight-or-flight) and the immune response recruit molecular resources from other body tissues, and induce physiological changes that optimize the body for defense. However, pathogens and predators often co-occur. Animals that can optimize responses for a dual challenge, i.e. simultaneous predator and pathogen attacks, will have a selective advantage. Responses to a combined predator and pathogen attack have not been well studied, but this paper summarizes the existing literature in insects. The response to dual challenges (i.e. Plan B) results in a suite of physiological changes that are different from either the stress response or the immune response, and is not a simple summation of the two. It is also not a straight-forward trade-off of one response against the other. The response to a dual challenge (i.e. Plan B) appears to resolve physiological trade-offs between the stress and immune responses, and reconfigures both responses to provide the best overall defense. However, the dual response appears to be more costly than either response occurring singly, resulting in greater damage from oxidative stress, reduced growth rate, and increased mortality.

中文翻译：

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动物有 B 计划：昆虫如何应对捕食者和病原体的双重挑战

当动物面临危及生命的挑战时，它们会发起全生物体的反应（即计划 A）。例如，压力反应（即战斗或逃跑）和免疫反应都从其他身体组织中募集分子资源，并诱导优化身体防御的生理变化。然而，病原体和捕食者经常同时发生。能够优化对双重挑战（即同时捕食者和病原体攻击）的反应的动物将具有选择优势。对捕食者和病原体联合攻击的反应尚未得到很好的研究，但本文总结了现有的昆虫文献。对双重挑战的反应（即计划 B）会导致一系列生理变化，这些变化不同于压力反应或免疫反应，而不是两者的简单总和。这也不是一种反应与另一种反应的直接权衡。对双重挑战的反应（即计划 B）似乎解决了压力和免疫反应之间的生理权衡，并重新​​配置了这两种反应以提供最佳的整体防御。然而，双重反应似乎比单独发生的任何一种反应都更昂贵，导致氧化应激造成更大的损害、生长速度降低和死亡率增加。