Multiple global change impacts on parasitism and biocontrol services in future agricultural landscapes

Parasitoids are a significant mortality factor in the population dynamics of many arthropods involved in key ecological processes such as herbivore-plant and predator-prey interactions. Parasitoids are therefore widely used in biocontrol programs. Global change phenomena influence these natural and anthropocentric roles of parasitoids and here we review the effects of the main drivers and their interplay. Land use intensification modifies landscape structure and elevates agroecosystem loads of fertilisers and pesticides creating risks for parasitism and loss of biocontrol services. Climate change can affect parasitoids directly, affecting physiology and survival, or indirectly via phenological and other effects (plant chemistry, herbivore-induced plant volatiles HIPVs) on their hosts, endosymbionts and plants. Biological invasions have the potential to modify native host-parasitoid systems and elevate risk of novel pest dynamics, requiring restoration of biocontrol. The interplay between these global change drivers may thus exacerbate the overall risk to parasitism in future agricultural landscapes. To make more accurate predictions, future studies could focus on the impact of interacting global change drivers on parasitoids and the biocontrol services they provide. Moreover, host and parasitoid specificity appear to be a key driver in assessing the effects of global change on parasitoids.