Tian Zhiqiang, Wang Yuanyuan, Sun Tao, Hu Xiaoyun, Hao Wanting, Zhao Te, Wang Yanan, Zhang Lei, Jiang Xingfu, Turlings Ted C J, Li Yunhe
State Key Laboratory of Crop Stress Adaptation and Improvement, State Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Life Sciences, Henan University, Kaifeng 475004, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; College of Agriculture and Forestry Science and Technology, Weifang Vocational College, Weifang 262737, China.
Curr Biol. 2025 Jul 7;35(13):3001-3010.e4. doi: 10.1016/j.cub.2025.04.066. Epub 2025 May 21.
Parasitoids of herbivores exploit inducible plant volatiles to find plants with potential hosts from a distance, whereas at close range they typically use host-derived cues to pinpoint and identify suitable hosts. Here, we show, however, that the egg parasitoid Trichogramma japonicum assesses host egg quality far more efficiently by remotely using oviposition-induced plant volatiles (OIPVs). In olfactometer assays, female T. japonicum wasps showed a strong preference for the odor of rice plants carrying 2-day-old eggs of the rice leaf folder Cnaphalocrocis medinalis over the odor of plants with younger or older eggs, a preference that correlated with higher parasitism rates. In accordance with the preference-performance hypothesis, the offspring of T. japonicum showed superior performance in 2-day-old eggs, including shorter development times and higher eclosion rates. Volatile analysis revealed significantly increased emission of D-limonene and α-pinene from plants with 2-day-old eggs, and we found that synthetic versions of these two monoterpenes were highly attractive to the wasp. Knockout rice plants deficient in D-limonene and α-pinene synthesis lost their appeal to the wasps, but attraction could be restored by dispensing synthetic versions of the attractants alongside the knockouts. These findings reveal a novel and highly efficient host-assessment strategy in egg parasitoids, whereby plant-provided cues inform the wasps about host quality from afar. This discovery is illustrative of the clever strategies that have evolved out of plant-insect interactions and offers fresh ideas to optimally exploit plant traits for biocontrol approaches against C. medinalis, a major rice pest.
植食性动物的寄生蜂利用植物诱导产生的挥发性物质从远处找到有潜在寄主的植物，而在近距离时，它们通常利用寄主来源的线索来精准定位并识别合适的寄主。然而，我们在此表明，卵寄生蜂日本赤眼蜂通过远程利用产卵诱导的植物挥发性物质（OIPVs）能更高效地评估寄主卵的质量。在嗅觉仪试验中，日本赤眼蜂雌蜂对带有稻纵卷叶螟2日龄卵的水稻植株气味表现出强烈偏好，相较于带有较年轻或较老卵的植株气味，这种偏好与更高的寄生率相关。根据偏好 - 表现假说，日本赤眼蜂的后代在2日龄卵中表现出更优的性能，包括发育时间更短和羽化率更高。挥发性物质分析显示，带有2日龄卵的植株中D - 柠檬烯和α - 蒎烯的释放量显著增加，并且我们发现这两种单萜类化合物的合成版本对这种黄蜂具有高度吸引力。缺乏D - 柠檬烯和α - 蒎烯合成能力的基因敲除水稻植株对黄蜂失去了吸引力，但在基因敲除植株旁边喷洒合成引诱剂可以恢复其吸引力。这些发现揭示了卵寄生蜂一种新颖且高效的寄主评估策略，即植物提供的线索能让黄蜂从远处了解寄主质量。这一发现说明了植物 - 昆虫相互作用中演化出的巧妙策略，并为优化利用植物特性以生物防治主要水稻害虫稻纵卷叶螟提供了新思路。
