Interactions between natural enemies and pollinators: combining ecological theory with agroecological management

Interspecific interactions are major drivers shaping ecological communities. Nevertheless, understanding how and to what extent they affect ecosystem functioning remains a key challenge for both fundamental and applied ecology. In the context of agricultural biodiversity loss, sustaining populations of organisms that provide essential ecosystem ser- vices is crucial but remains challenging. Interactions among beneficial organisms may explain such results, as they impact organisms' fitness. These effects could accumulate when scaled up to the population level, modifying community structure and functioning. Interactions could also affect organisms' foraging behaviour and consequently their efficiency. Here, we review and synthesize the knowledge of the effect of interactions within and between two groups of ecosystem services providers: natural enemies and pollinators, respectively providing biological control of pests and crop pollination services. We show that intra-guild predation, competition and resource partitioning are common interactions structuring natural enemy communities, and may affect their effectiveness to control pests. Nevertheless, actual evidence in complex systems and long-term studies are still missing, and application in agricultural settings is only at its beginning. Similarly, competi- tion and resource partitioning among pollinators is a recent focus of ecological research. Studying facilitative interactions is clearly missing. Finally, while we show that interactions between natural enemies and pollinators can theoretically hap- pen in natura due to the use of similar resources and habitats, this question remains poorly addressed. We discuss future research perspectives to better capture the complexity of biodiversity effects on ecosystem functioning, and propose guide- lines to the implementation of more efficient multi-service schemes in agroecological landscapes.