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United States Department of Agriculture

Agricultural Research Service

Title: Evaluating pure Africanized honey bees and hybrid crosses for colony health and resistance to varroa mites in a subtropical climate

Authors
item Adamczyk, John
item Elzen, Patti - DECEASED
item Cox, Robert

Submitted to: Subtropical Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2009
Publication Date: September 26, 2009
Citation: Adamczyk Jr, J.J., Elzen, P.J., Cox, R.L. 2009. Evaluating pure Africanized honey bees and hybrid crosses for colony health and resistance to varroa mites in a subtropical climate. Subtropical Plant Science. 61:24-30.

Interpretive Summary: Different honey bee, Apis mellifera L., breeds were evaluated for overall health and for resistance to the parasitic mite, Varroa destructor Oud. in the subtropical Lower Rio Grande Valley (LRGV) in south Texas. Breeds examined that have shown genetic resistance to varroa mites were honey bees carrying the Hygienic or SMR/VSH trait (SMR), from Far East Russia (RUS), and the local feral Africanized Honey Bee (AHB). In addition, RUS and SMR crossed with AHB to produce hybrids were also examined. All of these varroa mite resistant breeds were evaluated against the varroa mite susceptible European (Italian) honey bee breed. To estimate the health of a colony, the number of adults and the amount of honey produced was recorded monthly. In addition, varroa mite populations in a hive were estimated by counting the number of dead mites. Typically, the AHB, SMR, and SMR x AHB hybrid breeds produced more adults and honey compared to the Italian breed. Surprisingly, the pure RUS breed had high levels of varroa mites with the fewest adults and low honey production, suggesting that this breed will not perform well in the LRGV. In contrast, while varroa mite populations were somewhat lower than the pure RUS breed, the RUS x AHB hybrid breed clearly had the most adults and eventually produced the most honey compared to all other breeds, including the pure AFB breed. In addition, the SMR x AHB hybrid had the lowest varroa mite populations compared to all breeds, including the pure SMR breed. Both AHB hybrid breeds appeared to be very healthy and contain the fewest varroa mites, but were still as aggressive as the pure AHB breed and very difficult to manage.

Technical Abstract: Different honey bee, Apis mellifera L., breeds were evaluated for overall health and for resistance to the parastic mite, Varroa destructor Oud. in the subtropical Lower Rio Grande Valley (LRGV) in south Texas from June 2005 through October 2006. Breeds examined that have shown genetic resistance to varroa mites were honey bees carrying the Hygienic or SMR/VSH trait (SMR), from Far East Russia (RUS), and the local feral Africanized Honey Bee (AHB). In addition, RUS and SMR crossed with AHB to produce hybrids were also examined. All of these varroa mite resistant breeds were evaluated against the varroa mite susceptible to European (Italian) honey bee breed. To estimate the health of a colony, the number of adults and the amount of honey produced was recorded monthly. In addition, varroa mite populations in a hive were estimated using a mite-fall count onto a stick board. Typically, the AHB, SMR, and SMR x AHB hybrid breeds produced more adults and honey compared to the Italian breed. Surprisingly, the pure RUS breed had high levels of varroa mites with the fewest adults and low honey production, suggesting that this breed will not perform well in the LRGV. In contrast, while varroa mite populations were somewhat lower than the pure RUS breed, the RUS x AHB hybrid breed clearly had the most adults and eventually produced the most honey compared to all other breeds, including the pure AFB breed. In addition, the SMR x AHB hybrid had the lowest varroa mite populations compared to all breeds, including the pure SMR breed. The fact that these two hybrid breeds performed better than the corresponding pure breeds suggests that heterosis (i.e. hybrid vigor) was observed. Both AHB hybrid breeds appeared to be very healthy and contain the fewest varroa mites, but were still as aggressive as the pure AHB breed and very difficult to manage.

Last Modified: 9/20/2014
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