Plant Domestication Affects the Oviposition Behavior and Performance of Ganaspis kimorum, a Parasitoid of Drosophila suzukii

Abstract

The domestication syndrome refers to a suite of phenotypic changes that differentiate domesticated organisms from their wild relatives. Although such changes can influence plant-herbivore interactions, their effects on herbivores' natural enemies remain less explored. In highbush blueberries (Vaccinium corymbosum L.) (Ericales), domestication has resulted in larger fruits with reduced phenolic content, thereby enhancing the performance of the invasive spotted-wing drosophila (Drosophila suzukii Matsumura, Diptera: Drosophilidae). This study investigated how blueberry domestication affects the oviposition behavior and performance of Ganaspis kimorum Buffington (Hymenoptera: Figitidae), a larval endoparasitoid of D. suzukii. To assess oviposition behavior, gravid G. kimorum females were observed for 10 min on D. suzukii-infested wild diploid, wild tetraploid, and domesticated berries, and their on- and off-berry behaviors were recorded. Parasitoid performance was evaluated based on adult emergence rates, development time, and tibial length from infested wild and domesticated berries. Physical and chemical fruit traits, such as berry size, sugar content (°Brix), and total defensive phenolic content, were also quantified across domestication levels. Results showed that blueberry domestication significantly affected G. kimorum behavior and performance. Notably, female wasps spent more time searching on wild diploid berries as host number increased compared with other genotypes. However, offspring performance was higher in domesticated berries. Domesticated fruits were larger, less sweet, and contained lower phenolic content than wild berries. Thus, although G. kimorum readily oviposits in infested wild berries, these serve as suboptimal hosts for larval development. These findings highlight the impact of domestication on tri-trophic interactions and provide insights into the suitability of non-crop hosts for supporting biological control agents of D. suzukii.