Reproductive Traits of Ontsira mellipes (Hymenoptera: Braconidae), a North American Parasitoid, as a Novel Biological Control Agent for Exotic Anoplophora glabripennis (Coleoptera: Cerambycidae)

Authors: Wang, Xingeng; Aparicio, Ellen

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2020
Publication Date: 7/22/2020
Citation: Wang, X., Aparicio, E.M. 2020. Reproductive traits of Ontsira mellipes (Hymenoptera: Braconidae), a North American parasitoid, as a novel biological control agent for exotic Anoplophora glabripennis (Coleoptera: Cerambycidae). Journal of Economic Entomology. https://doi.org/10.1093/jee/toaa160.
DOI: https://doi.org/10.1093/jee/toaa160

Interpretive Summary: The Asian longhorned beetle (ALB) is a high-risk invasive insect pest native to China and Korea that attacks various hardwood trees. First detected in the late 1990s in North America, it is the subject of extensive ongoing quarantine and eradication efforts. The beetles can be difficult to detect, especially in large forested areas, and new introductions are possible. Biological control is a valuable option for reducing established and incipient populations in areas where intensive management methods such as chemical control are prohibitively expensive and/or environmentally undesirable. Ontsira mellipes is a North American parasitoid wasp that readily attacks ALB. To evaluate the potential of this parasitoid for biological control of ALB, we investigated aspects of its biology on ALB. Young female wasps had the highest number of mature eggs and their number increased with the wasp’s body size. Wasps laid more eggs and produced more and larger offspring on large ALB hosts than on small hosts. Our study suggests that large ALB larvae and young female wasps should be used for optimal rearing and/or field release of this parasitoid.

Technical Abstract: Ontsira mellipes Ashmead (Hymenoptera: Braconidae) is a gregarious ectoparasitic larval parasitoid of wood-boring cerambycids. Native to North America, O. mellipes readily attacks the invasive Asian longhorned beetle Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), and thus has the potential for novel association biological control of this exotic beetle. This study investigated some aspects of the parasitoid’s reproductive traits, including egg maturation dynamics, host size preference and suitability in association with A. glabripennis. Results showed that female O. mellipes emerged with a substantial portion of its lifetime complement of mature eggs. Mature egg load reached a peak 4–6 d post-eclosion, and mature egg load also increased with female’s body size. Oviposition prompted production of more mature eggs in young female wasps. The parasitoid did not show a significant preference for large over small hosts in a choice test. Offspring survival, developmental time and sex ratio were not affected by host size. However, clutch size increased with host size and female wasps that developed from the large host had a larger body and consequently higher mature egg load than those reared from the small host. Neither longevity or total number of parasitized hosts over a female lifetime were affected by female’s body size, but life-time fecundity, in terms of total number of offspring produced, increased with the female’s size. These results may have important implications for improving rearing and field-release protocols as well as understanding the ecological mechanisms underlying host size selection in gregarious parasitoids.