| The exciting potential of remote feral bee colonies for Varroa coexistence |
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Third European Congress
on Social Insects The exciting potential of
remote feral bee colonies for Varroa coexistence When varroa mites first became a problem, concerned parties immediately turned (A) to the use of chemicals as a control measure. That happened, despite earlier abundant evidence that chemical treatments: 1) are at best a short term measure, 2) result in an intense pressure that can lead to resistant mites, 3) keep susceptible bee strains in the gene pool, 4) can have both lethal and sublethal effects on bee colonies (e.g.,queen failure), 5) may damage favorable microfauna, 6) result in ever higher costs, and 7) may lead to residue problems in wax and honey. Seemingly, all those reservations have been borne out. Mechanical procedures (B) against varroa have gained some following, including: 1) periodic destruction of infested drone brood (labor intensive), 2) small cell size foundation, 3) screen bottom boards, and 4) mineral oil (of questionable value). Breeding programs (C) have become more prominent, involving detection, selection, and propagation of favorable traits. In the USA we now have hygienic and SMR/Russian bees under continuing development. During the past few decades, after varroa arrival, feral colonies in remote areas (D) experienced a catastrophic decline, followed by resurgence in population density. A deliberate programmed effort could have been instituted upon first varroa arrival in the United States (that is, establish experimental apiaries and wait for "survival of the fittest"), but that didn't happen. Some individuals have now begun to exploit the potential that feral colonies provide. (By feral, I include managed colonies in remote areas that have had no treatment against varroa mites.) John Kefuss and colleagues, for example, have had success with Apis mellifera intermissa queens from Tunisia and their naturally mated descendants. Erik Osterlund in Sweden promoted a mix (the "Elgon" stock) between Buckfast bees and the east African mountain bee, A. m. monticola. Some selected bee strains (at times along with the use of small cell size foundation) have proved promising. Of special interest is the fact that some strains of Elgon bees exude an odor that apparently repels varroa mites, a trait that would likely not have become apparent in a chemical treatment regime. In the Santa Barbara area we instituted two programs; 1) deliberate introduction of varroa to a large offshore, uninhabited, island, as well as 2) monitoring varroa impact on bee colonies next to or within isolated wilderness areas or nature preserves. Results were mixed. Feral colonies composed of mixed genetic traits have survived for several years, but colonies of genetically uniform bees perished in an island ecosystem. Feral colonies located remote from beekeeper activity could now have strains quite resistant to varroa mites and should be investigated. References Harbo, J.R. and J.W. Harris. 2003. An evaluation of commercially produced queens that have the SMR trait. Am. Bee J. 143:213-216. Kefuss, J., J. Vanpoucke, J. D. de Lahitte, and W. Ritter. 2004. Varroa tolerance in France of Intermissa bees from Tunisia and their naturally mated descendants: 1993-2004. Am. Bee J. 144: 563-568. Osterlund, E. 2001. The Elgon bee and varroa mites. Am. Bee J. 141: 174-177. Wenner, A.M. and R.W. Thorp. 2002. Collapse and resurgence of feral colonies after Varroa arrival. Pp. 159-166 in Proceedings of the 2nd International Conference on Africanized Honey Bees and Bee Mites (E.H. Erickson Jr., R.E. Page Jr., and A.A. Hanna, eds.). The A.I. Root Co., Medina, OH. See also: (http://www.beesource.com/pov/lusby/meetlusby.htm) |