|OLDROYD, BENJAMIN - University Of Sydney|
|De Guzman, Lilia|
Submitted to: Australian Journal of Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2012
Publication Date: 5/1/2013
Citation: Rinderer, T.E., Oldroyd, B.P., Frake, A.M., De Guzman, L.I., Bourgeois, A.L. 2013. Responses to Varroa destructor and Nosema ceranae by several commercial strains of Australian and North American honey bees (Hymenoptera: Apidae). Australian Journal of Entomology. 52(2):156-163.
Interpretive Summary: The potential impact of varroa on Australian beekeeping and agriculture depends in part on the levels of resistance to this parasite expressed by Australian commercial honey bees. The responses of seven lines of Australian honey bees to varroa were compared to the responses of a stock of Italian honey bees from the United States known for its susceptibility to varroa and two stocks known for their resistance to varroa, Russian honey bees (RHB) and a stock expressing the Varroa Sensitive Hygiene trait (VSH). While the RHB and VSH honey bees in the trial displayed resistance to the parasitic mite, the Australian and Italian honey bees were quite susceptible. Almost all of them died in the course of the 7 month experiment. All stocks and line supported high numbers of Nosema ceranae although none of them seemed to be adversely effected by this parasite. It is recommended that Australian beekeeping import and establish resistant stocks of honey bee prior to the arrival of varroa.
Technical Abstract: The potential impact of varroa (Varroa destructor, Anderson & Trueman. 2000) on Australian beekeeping and agriculture depends in part on the levels of resistance to this parasite expressed by Australian commercial honey bees (Apis mellifera). The responses of seven lines of Australian honey bees to V. destructor were compared to the responses of a stock of Italian honey bees from the United States known for its susceptibility to V. destructor and two stocks known for their resistance to V. destructor, Russian honey bees (RHB) and a stock expressing the Varroa Sensitive Hygiene trait (VSH). The experiment began in May with uniform colonies having uniform infestation of V. destructor. V. destructor infestations measured as the percentage of adult bees infested in the Australian lines and the Italian stock rose from less than 10% in August to over 25% in October. From August to November, 44% of both the Australian and Italian colonies died while strongly exhibiting symptoms of Parasitic Mite Syndrome. In contrast, RHB and VSH colonies displayed comparative resistance to V. destructor. Their infestation rates rose from about 5% in August to 10% (RHB) and 14% (VSH) in October. Likely some of this increase resulted from invasion pressure by mites from the dying Australian and Italian colonies. During the August to November period, 4.4% of the RHB and 14.3% of the VSH colonies died. In comparisons of the seven Australian lines, only non-significant and trivial differences were found for infestation and mortality rates. All Australian lines were highly susceptible to V. destructor. Additionally, evaluations of rates of Nosema ceranae infections were made throughout the course of the experiment. Although high levels of infection were found across all stocks and lines, no stock or line exhibited an adverse effect from N. ceranae infection.