How Do Host–Parasitoid Interactions Shape the Effectiveness of Anagyrus aberiae as a Biological Control Agent?
Simple Summary Delottococcus aberiae is an invasive mealybug that has become an important pest of citrus crops in eastern Spain, causing damage that reduces fruit quality and economic value. To help control this pest, a parasitic wasp, Anagyrus aberiae, was introduced from the mealybug’s area of origin in South Africa in 2019. However, little was known about how this natural enemy attacks the pest and how effective it may be under different conditions. In this study, we examined which life stages of the mealybug are most suitable for the parasitoid, how parasitism affects mealybug reproduction, and the ability of the parasitoid population to grow and respond to different pest densities. The parasitoid was able to attack all tested stages of D. aberiae but strongly preferred adult females. Parasitized female mealybugs produced fewer eggs than unparasitized control ones, and females already laying eggs stopped doing so within two days after parasitism. The parasitoid also showed a strong capacity for population growth and parasitized more mealybugs as host density increased, although this response slowed at high densities. These findings provide valuable information for improving biological control strategies against D. aberiae and for guiding future research on this host–parasitoid system.