Parasitoids and their injection components indirectly alter plant responses via their caterpillar host, affecting later-arriving parasitoids

Abstract: Plant responses to insect feeding mediate interactions with other community
members. Since plants perceive herbivory through damage patterns and salivary components, changes in these herbivore traits may alter herbivore induced plant mediated interactions. Upon parasitism, many parasitoids inject a combination of polydnavirus and venom into their host. In doing so, the host’s behaviour and physiology are modified. We investigated the ecological consequences of parasitism and its associated injection components on the plant volatile response, and consequently the attractiveness of these plants to later-arriving parasitoids. Our findings reveal that parasitoid- or even injection component-induced modifications can cascade through plant-mediated interactions, highlighting an underappreciated mechanism shaping multitrophic communities. These modulating effects deserve attention in future studies that investigate the dynamics of plant-arthropod communities.