|Khongphinitbunjong, Kitiphong - Chiang Mai University|
|De Guzman, Lilia|
|Tarver, Matthew - Former Ars Employee|
|Chen, Yanping - Judy|
|Chantawannaku, Panuwan - Chiang Mai University|
Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2016
Publication Date: 8/30/2016
Citation: Khongphinitbunjong, K., De Guzman, L.I., Rinderer, T.E., Tarver, M.R., Frake, A.M., Chen, Y., Chantawannaku, P. 2016. Responses of Varroa-resistant honey bees (Apis mellifera L.) to Deformed wing virus. Journal of Asia-Pacific Entomology. 19:921-927.
Interpretive Summary: The health of honey bees continues to decline due to a myriad of factors, including pathogens and parasitic mites. Among the many pathogens that infect honey bees, viruses are considered to be a major threat to honey bee colonies [1,2]. At least 24 viruses have been isolated and characterized from honey bees, Apis mellifera [3,4]. However, the most common viruses are Acute bee paralysis virus (ABPV), Black queen cell virus (BQCV), Chronic bee paralysis virus (CBPV), Deformed wing virus (DWV), Kashmir bee virus (KBV), Sacbrood virus (SBV) and Israeli acute paralysis virus (IAPV). Infections by IAPV and DWV are thought to be associated with Colony Collapse Disorder (CCD) and the death of millions of colonies worldwide, respectively [5,6]. DWV is the most ubiquitous virus which has been detected in the European and Asian honey bees (A. cerana, A. florea and A. dorsata) [3,7-10]. It is a single-stranded, positive-sense RNA virus belonging to the family Iflaviridae . This virus infects all stages of honey bees [12,13] and can be transmitted vertically and horizontally [14,15].
Technical Abstract: The negative impact of Deformedwing virus (DWV) on European honey bees Apis mellifera is magnified by Varroa destructor parasitism. This study compared the responses of two Varroa-resistant honey bee stocks, pure Russian honey bees (RHB) and out-crossed Varroa Sensitive Hygienic bees, Pol-line (POL) to DWV infection to that of Varroa- susceptible stock, Italian honey bees (IHB). Two-day-old larvae were fed with DWV lysate in different concentrations: undiluted DWV lysate (D1), D1:100, and D1:1000. The unfed larvae served as negative control. Combs containing test larvae were exposed to a common environment during their development using host colonies. Our results showed that only POL displayed variation in DWV levels when fed different DWV concentrations. POL fed highest concentration of DWV inoculum had the highest increase in DWV level than those fed low concentrations and unfed POL. This high increase in DWV level probably contributed to the decrease in the survival and median longevity (LT50) of D1-fed POL. Weights of newly eclosed D1-fed POL were similar to those of the two controls and DWV-fed bees. However, within IHB, D1-fed bees showed significant reductions in weight, days of survival and LT50. Regardless of the concentrations of DWV inoculum, the DWV levels were similarly low within RHB; adult bees had similar weights. Overall, larvae fed D1 had the highest rate of wing deformation. POL and RHB had numerically lower proportions of bees with deformed wings. This study suggests that RHB showed some degree of resistant to DWV as shown by no reduction on weight and numerically lower proportion of wing deformity when compared with the other bee stocks.