Confused by domestication: incongruent behavioral responses of the sunflower moth, Homoeosoma electellum (Lepidoptera: Pyralidae) and its parasitoid, Dolichogenidea homoeosomae (Hymenoptera: Braconidae), towards wild and domesticated sunflowers

Due to domestication, agricultural plants and their wild ancestors encompass a wide range of variation, which is useful for identifying promising plant attributes that promote parasitoid activity. We examined the behavioral responses of the sunflower moth, Homoeosoma electellum Hulst and its major parasitoid, Dolichogenidea homoeosomae Muesebeck to agricultural and wild sunflowers. We found that female moths preferred to land on, and lay more eggs on agricultural plants. While female parasitoids preferred to land on infested agricultural sunflowers, they foraged poorly on them. Parasitoids spent 74% more time foraging on wild flowers than on agricultural flowers, and they probed for a significantly longer period of time for host larvae on wild flowers. As a result, each individual female parasitized 25.7% ± 0.06 more larvae on wild flowers than on agricultural flowers with the same larval density. Also, parasitoids probed for hosts four times longer on wild flowers than on agricultural flowers, while resulting parasitism levels were 19 times higher, indicating that parasitoids were more efficient on wild flowers. Agricultural flowers are about four times larger than wild flowers, and the increase in flower size correlated with higher moth oviposition but lower parasitoid efficiency. Our results show that changes to plant attributes through domestication can disrupt host–parasitoid interactions and limit the ability of parasitoids to control insect pests effectively.