Third and fourth trophic level composition shift in an aphid–parasitoid–hyperparasitoid food web limits aphid control in an intercropping system

Understanding how resource diversification affects ecological interactions, food web structure and ecosystem functioning is essential in both fundamental applied ecology. While plant strategies (either in-field or around-field) are often proposed agricultural landscapes as practices to improve the biological control of herbivores by natural enemies, results remain variable unsure. Here, we studied effect an practice (the intercropping leguminous crops within cereal fields, increasingly common but with inconsistent on control) aphid a aphid–parasitoid–hyperparasitoid for 2 years. We report that was not increased mixed nor parasitoid diversity complexity. Nevertheless, provision alternative hosts fields led functional community composition shift, favouring generalist species over specialist ones. Moreover, observed higher hyperparasitism rate suggesting secondary parasitoids were favoured resources, which may have disrupted primary parasitoids. Synthesis applications. This study demonstrates shift top-down fourth trophic level can impact efficiency herbivores. These highlight necessity fine-scale mechanisms webs be able set up efficient methods support biodiversity associated services landscapes.