Species diversity and food web structure jointly shape natural biological control in agricultural landscapes

Land-use change and agricultural intensification concurrently impact natural enemy (e.g., parasitoid) communities and their associated ecosystem services (ESs), i.e., biological pest control. However, the extent to which (on-farm) parasitoid diversity and food webs mediate landscape-level influences on biological control remains poorly understood. Here, drawing upon a 3-year study of quantitative parasitoid-hyperparasitoid trophic networks from 25 different agro-landscapes, we assess the cascading effects of landscape composition, species diversity and trophic network structure on ecosystem functionality (i.e., parasitism, hyperparasitism). Path analysis further reveals cascaded effects leading to biological control of a resident crop pest, i.e., Aphis gossypii. Functionality is dictated by (hyper)parasitoid diversity, with its effects modulated by food web generality and vulnerability. Non-crop habitat cover directly benefits biological control, whereas secondary crop cover indirectly lowers hyperparasitism. Our work underscores a need to simultaneously account for on-farm biodiversity and trophic interactions when investigating ESs within dynamic agro-landscapes. Yang, Liu, Zhu et al. analyzed a dataset of 3-year parasitoid-hyperparasitoid trophic networks from 25 different agro-landscapes. Using path analysis, they uncover how species diversity and food web structure shape ecosystem functionality.

Automated summary

This study analyzed a 3-year dataset of quantitative parasitoid-hyperparasitoid trophic networks from 25 different agro-landscapes to evaluate the impacts of landscape composition, species diversity, and trophic network structure on ecosystem functionality. The research found that functionality is primarily dictated by (hyper)parasitoid diversity, with its effects modulated by the generality and vulnerability of the food web. The study underscores the importance of considering on-farm biodiversity and trophic interactions when investigating ecosystem services within dynamic agro-landscapes.