The association between the exotic species Raoiella indica Hirst and the predator Amblyseius largoensis (Muma) may cause displacement of the native species Oligonychus pratensis (Banks)

Introduced herbivores often alter predator–prey dynamics between native organisms. We investigated whether the exotic mite Raoiella indica can interfere in the predation relationships between the predator Amblyseius largoensis and the native herbivorous mite Oligonychus pratensis and be favored as a result. Populations of A. largoensis were established in laboratory, one reared with exotic prey and another with native prey. For each population, of A. largoensis were evaluated for: egg-to-adult developmental time, oviposition rate, and feed conversion efficiency (FCE) of females. Also, to observe the interaction with prey, behavioral tests were conducted, evaluating the time to the first attack, oviposition site preference, and prey preference consumption. Regardless of prey offered, there was no prey effect on immature developmental time or female oviposition rate. However, A. largoensis showed superior FCE feed on exotic (11.4%) over native prey (3.9%). Both A. largoensis populations preferred to prey on eggs of native species and also tended to choose oviposition sites containing native prey eggs. Those reared on exotic prey attacked their first prey in less time than those reared on native prey. Therefore, the presence of R. indica affects both predator population growth and the feeding preference for native prey, which causes a risk of displacement of O. pratensis .