Hyperparasitoids as new targets in biological control in a global change context

Abstract

Agricultural and forest insect pests generate important yield losses worldwide. Global-change is expected to increase pest outbreaks and their impact on human-managed ecosystems. Pest control performed by natural enemies is also likely to be influenced by global-change. Yet, pests and their natural enemies are part of complex food-webs and interact with other species, notably at upper trophic levels (e.g. hyperparasitoids, predators). These interactions have to be considered as important facets of food-web structure, functioning, and pest control efficiency. Relatively recent evidence suggests that global-change may translate to modifications in upper-trophic level abundance, phenology, and geographic range. The combination of these shifts at different trophic-levels may ultimately threaten ecosystem services such as biological pest control, yet these shifts have largely been overlooked. Little information is available on hyperparasitoid ecology and therefore little is known about the potential impact of climate change on these species. Improving our knowledge on this topic is important if we aim at adopting biological control programs in the near future. In this overview, we first emphasize that hyperparasitoids may have huge potential to disrupt biological control in natural and agricultural settings. We then stress that this disruption may increase in frequency and magnitude in the near future due to global-change. We finally propose that hyperparasitoids may become new targets in biological control and recommend different methods to control them, or limit their impact.