Biology and life history of Atanycolus cappaerti (Hymenoptera: Braconidae), a north american larval parasitoid attacking the invasive Emerald Ash Borer (Coleoptera: Buprestidae)

Authors: Duan, Jian; Schmude, Jonathan

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2016
Publication Date: 12/1/2016
Citation: Duan, J.J., Schmude, J.M. 2016. Biology and life history of Atanycolus cappaerti (Hymenoptera: Braconidae), a north american larval parasitoid attacking the invasive Emerald Ash Borer (Coleoptera: Buprestidae). Florida Entomologist. 99(4):722-728.

Interpretive Summary: Understanding the biology and life history of insect natural enemies (predators and parasitoids) is critical to the development of effective biological control programs against agricultural and forest arthropod pests. The parasitic wasp (Atanycolus cappaertie) is a native North American natural enemy that has recently been found attacking the invasive emerald ash borer (Agrilus plannipennis), which has killed tens of millions of North American ash trees since it was discovered in 2002 in US. To facilitate the development of effective rearing protocols for mass production of this native natural enemy against the emerald ash borer, we investigated its biology and life history using the emerald ash borer larvae as rearing hosts under normal rearing conditions in the laboratory. Our study showed that this parasitic wasp took approximately 20 days to complete a single generation (from egg to adult) under the laboratory rearing conditions for non-dormant populations. For dormant populations, however, this parasitic wasp will take much longer to complete a generation, because the dormant larval stage would not resume development to adults until they were chilled at 2 – 4°C for approximately 2 – 4 months. These findings suggest that the dormant populations of this parasitic wasp would only have one generation per year whereas the non-dormant population may have 2 – 3 generations per year and can be continuously cultured in the normal laboratory rearing condition. This information is useful to the development of effective rearing programs for mass production of this parasitic wasp for biological control of emerald ash borers in the US.

Technical Abstract: Atanycolus cappaerti Marsh and Strazanac is a native North American parasitoid that has been found to parasitize the emerald ash borer, Agrilus planipennis Fairmaire, a serious invasive pests of North American ash trees (Fraxinus spp.). To facilitate the development of potential augmentative biocontrol of A. planipennis, we investigated the biology and life cycle of A. cappaerti when reared with larvae of A. planipennis at 25 ± 2 ºC, 65 ± 10% RH and 16:8 (L:D) hr photoperiod in the laboratory. Our study shows that newly emerging adults of A. cappaerti have a median survival time of 9 - 11 wks, and females live approximately two weeks longer than males. The weekly progeny production by female parasitoids peaked at wk 3 after emergence, with a mean of 5.4 progeny per female. Throughout their life span, female parasitoids produced a mean (±SE) of 28 (±3.07) progeny. Atanycolus cappaerti larvae molt five times to reach the 6th instars in silk cocoons in a median of 8.3 d. Approximately 43% of the 6th instars continued development to adult wasps and the rest diapaused. The median developmental time from eggs to adults for non-diapaused parasitoids was approximately 20 d. For diapaused A. cappaerti, however, the developmental time is much longer as larvae enter obligatory diapause in 6th instars. The median time for diapause-terminated larvae to develop to the adults is approximately 28 d. These findings should be useful for development of potential mass-rearing protocol for augmentative biocontrol of A. planipennis with A. cappaerti.