Finding a suitable oviposition site is a challenging task for a gravid female fly, because the hatched maggots have limited mobility, making it difficult to find an alternative host. The oriental fruit fly, Bactrocera dorsalis, oviposits on many types of fruits. Maggots hatching in a fruit that is already occupied by conspecific worms will face food competition. Here, we showed that maggot-occupied fruits deter B. dorsalis oviposition and that this deterrence is based on the increased β-caryophyllene concentration in fruits. Using a combination of bacterial identification, volatile content quantification, and behavioral analyses, we demonstrated that the egg-surface bacteria of B. dorsalis, including Providencia sp. and Klebsiella sp., are responsible for this increase in the β-caryophyllene contents of host fruits. Our research shows a type of tritrophic interaction between micro-organisms, insects, and insect hosts, which will provide considerable insight into the evolution of insect behavioral responses to volatile compounds.

寻找合适的产卵地点对于怀孕的雌性苍蝇来说是一项具有挑战性的任务，因为孵化的蛆虫的流动性有限，很难找到替代宿主。东方果蝇Bactrocera dorsalis 可在多种水果上产卵。在已经被同种蠕虫占据的水果中孵化的蛆将面临食物竞争。在这里，我们表明蛆占据的水果可以阻止B. dorsalis产卵，并且这种阻止是基于水果中 β-石竹烯浓度的增加。结合细菌鉴定、挥发物含量定量和行为分析，我们证明了B. dorsalis的卵表面细菌，包括Providencia sp。和克雷伯氏菌属导致寄主果实 β-石竹烯含量增加。我们的研究显示了微生物、昆虫和昆虫宿主之间的一种三营养相互作用，这将为昆虫对挥发性化合物的行为反应的演变提供相当多的见解。