|KONGPHINITBUNJONG, KITIPHONG - Chiang Mai University|
|De Guzman, Lilia|
|TARVERE, MATTHEW - Bayer Cropscience|
|Chen, Yanping - Judy|
|CHANTAWANNAKULA, PANUWAN - Chiang Mai University|
Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2016
Publication Date: 8/12/2016
Citation: Kongphinitbunjong, K., De Guzman, L.I., Rinderer, T.E., Tarvere, M., Frake, A.M., Chen, Y., Chantawannakula, P. 2016. Responses of Varroa-resistant honey bees (Apis mellifera L.) to Deformed Wing Virus. Journal of Asia-Pacific Entomology. doi: 10.1016/j.aspen.2016.08.008.
Interpretive Summary: The parasitic mite Varroa and associated diseases are major factors adversely affecting health of honey bees, which play an essential role in pollination of our food crops. One sustainable solution to solve bee health problems is to select breeding stocks that are resistant to parasites and diseases. We conducted studies to evaluate the ability of three Varroa-resistant honey bee stocks to resist the infection of a honey bee virus, Deformed wing virus (DWV), which is transmitted by the Varroa mite and causes wing deformities and mortality in emerging adult bees. Our results demonstrated differential resistance to DWV infection by the three stocks of honey bees, suggesting that breeding for DWV resistance may help protect honey bees from the serious impact of DWV infection. The information obtained from this study will be of interest to people who work in bee industry and bee research societies.
Technical Abstract: The impact of Deformed wing virus (DWV) on Apis mellifera is magnified by Varroa destructor parasitism. This study compared the responses of two Varroa-resistant honey bee stocks [Russian honey bees (RHB) and an outcross of Varroa Sensitive Hygienic bees (POL)] to DWV infection to that of Italian honey bees (IHB) known for their susceptibility to Varroa. Two-day old larvae were fed DWV lysate in different concentrations diluted by PBS: undiluted DWV lysate (D1), D1:100, and D1:1,000. Unfed larvae and those fed PBS only served as negative controls. Thereafter, combs with the test larvae were exposed to a common environment during their development using host colonies. About 30% of the test brood was removed by the host colonies regardless of honey bee stock or DWV concentration. For the levels of DWV in brown-bodied pupae, our analyses showed variation among the different DWV concentrations within POL only. DWV level in POL fed high DWV concentration (D1) significantly increased to about 104 fold the levels of the unfed bees (control), which probably contributed to the decrease in the survival and median longevity (LT50) of D1-fed POL. Overall, all test bees weighed >110 mg. However, weights of newly emerged D1-fed POL were similar to that of the two controls and DWV-fed bees. Within IHB, however, D1-fed IHB showed significant reductions in weight, days of survival and LT50 despite the low (102 fold) increase in DWV levels. Within RHB, the DWV levels were also similarly low (up to 102 fold increase) among bees fed different DWV concentrations and did not affect the weights of newly emerged adults. In contrast to IHB and POL, RHB fed DWV and PBS survived longer than the unfed bees. POL and RHB had a lower proportion of bees with deformed wings but was not different from that of IHB. Regardless of stocks, bees fed the highest DWV concentration (D1) supported the highest wing deformation. Our results demonstrate differential resistance or tolerance to DWV infection by the three stocks of honey bees. Thus, it is possible that breeding for DWV resistance or tolerance may help protect honey bees from the serious impact of DWV infection.