Consuming Parasitized Aphids Alters the Life History and Decreases Predation Rate of Aphid Predator

SIMPLE SUMMARY: Intraguild predation is a common phenomenon between predators and parasitoids. Despite numerous studies on the performance of intraguild predators by consuming on intraguild prey, the entire two-sex life table and predation rates of intraguild predators fed on intraguild prey remain poorly known. In this study, we investigated the effect of parasitized Myzus persicae aphids by Aphidius gifuensis (Ashmead) on the entire two-sex life table and predation rates of Aphidoletes aphidimyza (Rondani). Our results showed that feeding on parasitized aphids did not influence the survival rates of immature A. aphidimyza individuals but significantly increased the development time of A. aphidimyza individuals and markedly reduced their longevity. The predation rate of immature A. aphidimyza individuals was also adversely affected by feeding on parasitized aphids. These results provide basic data for the potential use of A. aphidimyza in combination with A. gifuensis in M. persicae control programs. ABSTRACT: Intraguild predation interactions have substantial theoretical and practical implications for the dynamics of natural competitor populations used for biological control. Intraguild predation on parasitized aphids not only has a direct, negative effect on the parasitoid species, but it may indirectly influence the predator’s development, survival, reproduction and predation rates. In this study, we used two-sex life table theory, life table parameters and predation rates of Aphidoletes aphidimyza (Rondani) to compare when its populations fed on aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) that were either unparasitized or parasitized by Aphidius gifuensis (Ashmead) (Hymenoptera: Braconidae). Our results showed that individuals of A. aphidimyza were capable of completing their development and attaining maturity when they fed on parasitized aphids. Although feeding on parasitized aphids did not influence the survival rates of immature A. aphidimyza, it did significantly slow their development and extended their longevity, thereby reducing the fecundity and predation rates of A. aphidimyza. These findings may be pivotal for better understanding the sustained coexistence of predators with parasitoids in the biological control of aphids.