Kairomones are chemical signals that mediate interspecific interactions beneficial to organisms that detect the cues. These attractants can be individual compounds or mixtures of herbivore-induced plant volatiles (HIPVs) or herbivore chemicals such as pheromones, i.e. chemicals mediating intraspecific communication between herbivores. Natural enemies eavesdrop on kairomones during their foraging behaviour, i.e. location of oviposition sites and feeding resources in nature. Kairomone mixtures are likely to elicit stronger olfactory responses in natural enemies than single kairomones. Kairomone-based lures are used to enhance biological control strategies via the attraction and retention of natural enemies to reduce insect pest populations and crop damage in an environmentally friendly way. In this review, we focus on ways for improving the efficiency of kairomone use in crop fields. First, we highlight kairomone sources in tri-trophic systems, and discuss how these attractants are used and detected by natural enemies searching for hosts or prey. Then we summarise some examples of field application of kairomones (pheromones versus HIPVs) in recruiting natural enemies. We highlight the need for future field studies to focus on the application of kairomone blends rather than single kairomones which currently dominate the literature on field attractants for natural enemies. We further discuss ways for improving kairomone use through attract and reward technique, olfactory associative learning, and optimisation of kairomone lure formulations. Finally, we discuss why the effectiveness of kairomone use for enhancing biological control strategies should move from demonstration of increase in the number of attracted natural enemies, to reducing pest populations and crop damage below economic threshold levels and increasing crop yield.

中文翻译：

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探索基于Karomone的自然敌人的觅食行为，以增强生物控制：审查。

Kairomones是介导种间相互作用的化学信号，对检测线索的生物有益。这些引诱剂可以是草食动物诱导的植物挥发物（HIPV）或草食动物化学物质（如信息素）的单独化合物或混合物，即介导草食动物之间种内连通的化学物质。天敌在觅食行为（即产卵位置和自然界的觅食行为）中偷听海藻酮。与单一的海洛酮相比，海洛酮混合物在天敌中可能引起更强烈的嗅觉反应。基于海洛酮的诱饵用于通过吸引和保留天敌来增强生物防治策略，以环保的方式减少害虫的数量和对农作物的损害。在这篇评论中，我们专注于提高在农作物田中使用海洛酮的效率的方法。首先，我们重点介绍三营养系统中的海洛酮来源，并讨论天敌寻找寄主或猎物如何使用和检测这些引诱剂。然后，我们总结了海洛酮（信息素与HIPV）在招募天敌方面的野外应用实例。我们强调未来的田间研究需要着重于海洛酮掺混物的应用，而不是目前在有关天敌的田间引诱剂的文献中占主导地位的单一海洛酮。我们进一步讨论了通过吸引和奖励技术，嗅觉联想学习以及对海洛酮诱剂配方进行优化来改善海洛酮使用的方法。最后，