1a. Objectives (from AD-416):
Objective 1: Investigate key biotic factors influencing the spatial and temporal dynamics of wood-boring pest (including ALB and EAB) populations in their native range, focusing on exploration and quarantine service for effective, host-specific natural enemies (parasitoids) for biocontrol. Subobjective 1a - Explore for parasitoids of ALB and EAB in the pests’ native range (Asia). Subobjective 1b - Evaluate the role of the key natural enemies in regulating the spatial and temporal dynamics of ALB and EAB in the area of collection in Asia. Subobjective 1c - Evaluate the host specificity of parasitoids discovered for introduction to North America for ALB and EAB control. Subobjective 1d - Quarantine services to support research on exotic insect pests and their natural enemies. Objective 2: Conduct field releases and evaluate impacts of extant (indigenous) and previously introduced parasitoids on populations of wood-boring beetles such as EAB and ALB in the United States, while elucidating factors that influence successful establishment of introduced biological control agents, such as climate adaptation, release methodology, genetic variation in founder populations and risk-spreading (diapause) strategy. Objective 3: For newly discovered parasitoids of ALB, EAB and other invasive pests, and based on studies of life histories and reproductive biology, develop effective rearing technologies for these natural enemies, focusing on optimizing host stage, host substrate complex, temperature, photoperiod and relative humidity. Subobjective 3a - Characterize the reproductive biology, risk-spreading (diapause) strategy and key life history parameters of most promising parasitoid species. Subobjective 3b - Determine the optimal host stage and host-substrate complex in association with host density and host-to-parasitoid ratio. Subobjective 3c - Determine the optimal environmental conditions for adult parasitoid survival, oviposition and progeny development including diapause induction and termination.
1b. Approach (from AD-416):
Using the approaches relevant to the knowledge base of the targeted pests and their natural enemies, we will conduct foreign explorations for new natural enemies from the pests’ native home (Northeast Asia) and construct life tables of the target pest populations to evaluate the impact of the natural enemies on the pests’ population dynamics in Northeast Asia. After selecting the most promising (or efficient) natural enemies, we will test the selected natural enemies against non-target wood-boring insects in North America to delineate their host range for biological control introduction against the target pests. Upon regulatory approval for environmental releases of the discovered natural enemies in North America, we will conduct field experiments to assess their establishment, dispersal and impacts on the target pests’ population in the U.S. Laboratory studies will also be conducted to collect information on the parasitoid’s biology, risk-spreading and reproductive strategy and life history and to develop efficient rearing methods for mass-production of the introduced natural enemies for biological control releases. In addition, this project will provide quarantine services, host range data and mass-rearing technologies for natural enemies of high priority plant pests to state and federal agencies.
3. Progress Report:
Due to the critical vacancy for the Asian longhorned beetle (ALB) project and lack of operational funds for the emerald ash borer (EAB) project, no substantial progress was made in the investigation of ALB and EAB natural enemies in their native ranges including northeast China, Korea and the Russian Far East (Objective 1a – 12 month milestones). However, substantial progresses were made in the following (12-month) milestones. ALB RESEARCH: We determined the reproductive biology and critical life history parameters (longevity, fecundity, and sex ratio) of a North American native braconid parasitoid (Ontsira mellipes) using larvae of laboratory-reared Asian longhorned beetles (Objective 3a). Our study has shown that this North American native parasitoid can successfully attack and reproduce on ALB larvae and mass-rearing procedures for this parasitoid may be developed using the new association host for development of effective biocontrol programs against ALB. EAB RESEARCH: We discovered and described a new species of the emerald ash borer egg parasitoid (Oobius primorskyensis) previously collected from the Russian Far East, and determined the host range of this new egg parasitoid (Objective 1c). This new species is morphologically very similar to the previously introduced EAB egg parasitoid (O. agrili) from Northeast China. The two species together constitute a cryptic species complex of EAB egg parasitoids in northeast Asia. Further laboratory study reveals that there are distinctive differences in the reproductive biology and progeny dormancy pattern between the two species and the two egg parasitoid species may be complementary to each other in reducing EAB egg densities in the U.S. (Objective 3a). Based on these data, we have submitted the petition to USDA APHIS for regulatory approval of environmental releases of this new parasitoid in the U.S. for EAB biocontrol. In cooperation with university and state cooperators, we also selected and established 14 new study sites in Maryland (5), Massachusetts (3), Michigan (4), and Virginia (2), where over several thousands of previously introduced parasitoids (Tetrastichus planipennisi, Spathius galinae, and Oobius agrili) were released at each site for EAB biocontrol. QUARANTINE SERVICE: We provided essential quarantine services for two other ARS research projects at the Beneficial Insects Introduction Research Unit as well as several ARS cooperators (Objective 1d). These activities included receipts of a total of 131 permitted consignments, consisting of 16,607 pest specimens, and 1,298 parasitoids in 10 genera, and sending 31 outgoing shipments with 17,913 pest specimens, and 331,563 parasitoids in five genera. In addition, four identification requests were provided to the ARS Systematic Entomology Laboratory.
1. Discovery of a new emerald ash borer biocontrol agent. The emerald ash borer (EAB) is a serious invasive forest pest that has been detected in 27 U.S. states and killed hundreds of millions of ash trees since it was first detected from Michigan in 2002. Classical biocontrol via introduction of a diverse complex of co-evolved natural enemies from the pest’s native range (Northeast Asia) may be the only viable option for effective long-term management of EAB in North America natural forests. ARS researchers in Newark, Delaware discovered and described a new species of EAB egg parasitoid previously collected from the Russian Far East. This species is new to science and described as Oobius primorskyensis. Further laboratory study reveals that this new species shows distinctive differences in the reproductive biology and progeny dormancy pattern from the previously introduced EAB egg parasitoid (O. agrili) and may be more suitable for introduction against EAB in Northeast U.S. This new egg EAB parasitoid is currently being evaluated by USDA APHIS for environmental releases as a biocontrol agent and may help improve the efficacy of the current EAB biocontrol programs and increase the survival and recovery of North American ash trees.
5. Significant Activities that Support Special Target Populations:
Duan, J.J., Bauer, L., Abell, K.J., Ulyshen, M.D., Van Driesch, R. 2015. Population dynamics of an invasive forest insect and associated natural enemies in the aftermath of invasion: implications for biological control. Journal of Applied Ecology. DOI: 10.1111/1365-2664.12485.
Hoban, J., Duan, J.J., Hough-Goldstein, J. 2016. Effects of temperature and photoperiod on the reproductive biology and diapause of oobius agrili (Hymenoptera: Encyrtidae), an egg parasitoid of emerald ash borer (Coleoptera: Buprestidae). Environmental Entomology. 45(3):726-731. doi: 10.1093/ee/nvw034.
Golec, J.R., Duan, J.J., Hough-Goldstein, J., Aparicio, E.M. 2016. Life history, reproductive biology, and larval development of Ontsira mellipes (Hymenoptera: Braconidae), a newly associated parasitoid of the invasive Asian longhorned beetle (Coleoptera: Cerambycidae. Journal of Economic Entomology. 109(4):1545-1554. doi: 10.1093/jee/tow122.
Peterson, D.L., Duan, J.J., Yaninek, S.J., Ginzel, M.D., Sadof, C.S. 2015. Growth of larval agrilus planipennis (Coleoptera: Buprestidae) and fitness of tetrastichus planipennisi (Hymenoptera: Eulophidae) in blue ash (Fraxinus quadrangulata) and green ash (F. pennsylvanica). Environmental Entomology. doi: 10.1093/ee/nvv122.
Jennings, D.E., Duan, J.J., Bauer, L.S., Schmude, J.M., Wetherington, M.T., Shrewsbury, P.M. 2016. Temporal dynamics of woodpecker predation on the invasive emerald ash borer (Agrilus planipennis) in North America. Agricultural and Forest Entomology. 18:174–181.
Jennings, D.E., Duan, J.J., Bean, D., Gould, J., Rice, K.A., Shrewsbury, P.M. 2016. Monitoring the establishment and abundance of introduced parasitoids of emerald ash borer larvae in Maryland, U.S.A. Biological Control. 101:138–144.
Wang, X., Jennings, D.E., Duan, J.J. 2015. Trade-offs in parasitism efficiency and brood size mediate parasitoid coexistence, with implications for biological control of the invasive emerald ash borer. Journal of Applied Ecology. 52(5):1365-2664 doi: 10.1111/1365-2664.12487.
Wang, X., Liang-Ming, C., Yang, Z., Duan, J.J., Gould, J.R., Bauer, L.S. 2015. Natural enemies and their impacts on emerald ash borer populations in its native range, with new records of parasitism by two species of beetles. The Canadian Entomologist. 148(3):329–342.
Wang, X., Wei, K., Qi-Yang, Z., Jennings, D.E., Duan, J.J. 2016. Biotic and abiotic drivers of phenotypic plasticity of wing Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (hymenoptera: bethylidae). Scientific Reports. doi: 10.1038/srep26408.
Watt, T.J., Duan, J.J., Tallamy, D.W., Hough-Goldstein, J., Ilvento , T.W., Yue, X., Ren, H. 2016. Reproductive and developmental biology of the emerald ash borer parasitoid Spathius galinae (Hymenoptera: Braconidae) as affected by temperature. Biological Control. 96:1–7.
Yao, Y., Duan, J.J., Hopper, K.R., Moltern, J.L., Gates, M.W. 2016. A new species of oobius trjapitzin (hymenoptera:encyrtidae) from the russian far east that parasitizes eggs of emerald ash borer (coleoptera:buprestidae). Annals of the Entomological Society of America. 109(4):629-638. doi: 10.1093/aesa/saw022.