Many predatory beneficials are able to utilise alternative food sources when prey is limited. If they manage to ensure their development and reproduction in this way, they could gain a competitive advantage over other species. This factor may allow immigrated or introduced exotic species to displace native ones.
Beneficials such as predators and parasitoids, which are used for biological pest control, can also harm non-target organisms. To be able to assess the environmental risks before the release of such beneficials, it is important to know the physiological and behavioural factors constituting the host- or prey spectrum.
New species in an ecosystem can exert an influence on native species either directly through competition, or indirectly through changes in food sources. They can also alter the balance between native species and their natural enemies.
Macroorganisms are a common means of protecting plants from pests. International guidelines define how they are to be used. Agroscope evaluates the potential environmental risks of such macroorganisms on behalf of the Federal Office for Agriculture.