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 causality leading to the 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.

The study contained a 3-year study of quantitative parasitoid-hyperparasitoid trophic networks from 25 different agro-landscapes along with a gradient of crop and non-crop habitats. We assess the cascading effects of landscape composition, species diversity and trophic networks structure on ecosystem functionality (i.e., parasitism, hyperparasitism). General linear model (GLM) analysis with multiple model selection inference were first performed to assess the direct effects of explanatory variables belonging to the same groups (such as landscape composition, species diversity, quantitative food web metrics) on each response variable. Linear mixed effect model (LMM) analysis then helped assess the direct effects of combinational predictors belonging to three groups: landscape composition, species richness and diversity, and food web features, on ESs and EDSs. Path analysis with structural equation models (SEMs) further reveals causality leading to the biological control of a resident crop pest, i.e., Aphis gossypii. Functionality is dictated by (hyper)parasitoid diversity, with its effects modulated by two key metrics of food web generality and vulnerability. Non-crop habitat cover directly benefits biological control, whereas secondary crop cover indirectly lowers hyperparasitism.

We analyzed a dataset of 3-year parasitoid-hyperparasitoid trophic networks from 25 different agro-landscapes. Using path analysis, we uncover how species diversity and food web structure shape ecosystem functionality. Locaiton: the northern China