This Article was written as an assignment for the Apprentice Level Beekeeper course through the University of Montana. I put a lot of work into the paper and felt like is full of useful information, prompting me to post it here. I hope you enjoy and encourage your comments and input. Where you a beekeeper before Varroa, I sure wasn’t and would LOVE to hear want you have to say.
The History of Varroa and its relationship with Apis mellifera
Varroa destructor is public enemy number one. If this is news to you and you manage honey bee colonies I would suggest to stop reading now and go kill the mites that are in your hives. This article is about how Varroa destructor and Apis mellifera, the western honey bee, met and how from their meeting place they spread to the North America.
To understand how they met I wish we understood why they did in the first place. Varroa’s host before it started to also infest A. mellifera was A. cerana, the Eastern honey bee, which is managed in southern Asia for crop pollination and honey production (1). Varroa’s shift to also infest managed A. mellifera colonies may have taken as much as 100 years since their introduction to the area, but since then they have spread world wide with the exemption of only a few places (2). It was only up until 2000 that science thought that the Varroa mite that infested A. mellifera colonies worldwide was Varroa jacobsoni and not Varroa destructor (2) and because of that lack of understanding I am going to assume that is was I can’t find information as to why V. destructor made the jump to A. mellifera.
All though we don’t understand how Varroa made the jump to A. mellifera from A. cerana we know it happened in southern Asia. This is important to think about because Varroa and A. mellifera where never in the same region of the world until human moved them (3). The genus Apis may have originated in Europe, not Africa, then spread south to Africa and east to Asia. When in Africa it gave raise to A. mellifera and when in Asia A. cerana rose. This would mean as described my Keith Delaplane, at ESA 2019 in South Carolina, the break between A. cerana and A. mellifera is older than thought (3). Knowing this might be key to how realistic we need to be when we setting goals and how serious we need to be when breading for resistance, or tolerance, in our managed bees.
History out of Asia and to the USA
In a 1975 edition of The Hive and the Honey Bee, printed in 1987, only mentions Varroa, then called Varroa jacobsoni, in the pest and diseases chapter as a pest found on the A. mellifera in southern Asia and the USSR (4). Being that this edition was printed 1987 and not extensively revised until 1992. It gives me the impression that we weren’t ready for it while in 1987 it was already in Europe for almost ten years (5).
According to an interactive map on http://www.wblomst.com Varroa first took the world by land spreading east into Africa before Europe. Once it reaches Europe it than jumped to south America. It getting to Europe first was to the benefit of beekeepers in north America as they started to developed miticide to control it that we quickly adopted.
In October 1987 Varroa was found in 19 of Florida’s 67 counties in It is thought to have been brought into Florida illegally from south America bases on generic treating by Professor Roger A. Morse of Cornell. After its introduction it spread beekeeper to beekeeper through the sale or movement of packages, nucs, and full sizes hives and within two years it spread to most states and by 1995 they were documented everywhere in the continental United States (6,7).
But “documented” doesn’t mean it actually took eight years to spread. The 1992 revised edited of The Hive and the Honey Bee says to sampling one a year is common practice (8), while now it is common to sample at lease some hives every time, you’re in the apiary, and we still can’t convince some people to sample. I think the spread could have been faster thought.
Once here we only had only had fluvalinate, in the form of Apistan®, as the only legal acaricide (8). Since than fluvalinate has become ineffective for the control of Varroa (2). On Vita Parma’s web site (9) they blame the mis-use of pyrethroids which altered the biological processes of the mite.
Since the Varroa invasion we have developed different methods to control Varroa such as Pyrethroids, organophosphates, essential oil and organic acids have been use along with physical controls like the removal of drone brood all with there pros and cons. For example there may be issues with the synergistic effects of the miticides and other chemicals that the bees were once tolerant of, while drone brood removal is extremal labor intensive.
Other action started to be taken in 1997 when Russian queens where brought in to the US and bread for their ability to control varroa. Russia, then the USSR, was the first region to have Varroa infestation and because of the lack of access chemical controls they (the bees) started to build some kind of tolerance or resistances (2).
A Look Forward
It isn’t going to get better until it gets worst. Varroa isn’t just a parasite now it has teamed up with viruses and become more of a parasitoid benefiting not by keeping its host, our bees, alive but by killing the colony spreading by become a robbing lure to strong healthy colonies (9). Also, there is another mite on the way, Tropilaelaps spp. has found A. mellifera as a host with only few working on understanding its biology (10).
- J.S Pettis et al. (2015). The hive and the Honey Bee. Chapter 27 Diseases and Pest of Honey Bees. Page 852 – 856. Dadant & Sons, Inc
- Delaplane, Keith (2019). EAS Conference “What Bees in Nature Can Teach us About Colony Health”
- J.S Pettis et al. (1975). The hive and the Honey Bee. Chapter 21 Diseases and Enemies of the Honey Bee. Page 652. Dadant & Sons, Inc
- Connor, Larry. (2015) “Varroa Control Past and Future”. American Bee Journal. September 1, 2015 excerpt. Web. Nov 26,2019: https://americanbeejournal.com/varroa-control-past-and-future/
- (1992). The Hive and the Honey Bee
- Peck DT, Seeley TD (2019) Mite bombs or robber lures? The roles of drifting and robbing in Varroa destructor transmission from collapsing honey bee colonies to their neighbors. PLoS ONE 14(6): e0218392. https://doi.org/10.1371/journal.pone.0218392
- McAfee, Alison. (2019) Another Mite to Fight: Varroa isn’t the only mite that has jumped hosts to Western honey bees. American Bee Journal. Volume 156 NO 12