EAS at Cornell: Genetic Selection Comes of Age

EAS 2002 at Cornell University: Genetic Selection Comes of Age

Dr. Malcolm T. Sanford

http://apis.shorturl.com

Dr. Roger Morse, who some consider Dean Emeritus of U.S. beekeeping, and long-time supporter of the Eastern Apicultural Society (EAS) would have been proud. Sitting at the same banquet table were seven of his students, along with his widow Mary Lou. One, Dr. Michael Burgett of Oregon State University, was about to formally receive the third Roger A. Morse Award for outstanding achievements in the field of apicultural extension, teaching and regulatory activities given by the Eastern Apicultural Society (EAS) at his alma mater, Cornell University, where Dr. Morse was professor of entomology and apiculture for over three decades. Beyond the considerable contributions of the man the students called “Doc,” it would be difficult to overestimate what Cornell University has meant to modern beekeeping. Not only is it home to the Dyce® creamed honey process and laboratory where many workshops are scheduled, but it also boasts one of the largest collections of apicultural literature in the world, currently housed at the Mann library on campus. It is more than fitting, therefore, that this institution in the Finger Lakes region of New York served as host for EAS 2002.

The Eastern Apicultural Society of North America, Inc. (EAS) is an international non-profit educational organization founded in 1955 for the promotion of bee culture, education of beekeepers, and excellence in bee research. EAS is the largest non-commercial beekeeping organization in the United States, perhaps in the world.¹ It meets once a year at rotating venues, usually on the east coast of the United States.

A key element of EAS is that it caters to those with a deep interest in apiculture, most of whom are not commercial beekeepers. Thus, it carries on the tradition of the legion of dedicated amateurs, such as L.L. Langstroth, who are responsible for advancing the craft in so many ways over the last 300 years. This year, for example, the Chairman of the Board, Kim Flottum, chose to honor a philosopher, Dr. Richard Taylor, who lives just up the road from Cornell in upstate New York. Dr. Taylor is so well known he needs no introduction other than to say he has dedicated much of his writing life to promoting his own particular brand of the joy of beekeeping. An invitation to EAS at Cornell by Dr. Taylor himself and a description of his famous honey house appear in the May 2002 Bee Culture.

It is apparent from the tenor of beekeeping meetings over the last few years that much of the joy of the craft expressed so eloquently by Dr. Taylor has been lost to many beekeepers who must daily actively protect their bees from a variety of organisms, including tracheal mites, small hive beetles, brood diseases, viruses, and most damaging of all, the Asian brood mite, Varroa destructor. This year, however, the dedicated amateurs of EAS are leading the way toward a paradigm shift, by informing themselves about the prospect of using the honey bee’s innate defenses to help it survive through genetic selection, rather than chemical intervention. In the process, it is palpably clear that they are seeking to recover some of the unabashed enthusiasm that they once had for taking up one of humankind’s oldest activities.

One sign of this was the Society’s selection of Dr. Orley R. “Chip” Taylor of the University of Kansas for the James. I. Hambleton Award. Dr. Taylor’s talk was appropriately entitled, “What We Know and Don’t Know About the Honey Bee Mating System.” Much is known about queens, according to Dr. Taylor. They take one to two mating flights, generally lasting about 15 minutes, and in the process, mate with 6 to 17 drones within one to one and half kilometers from their hive. There is less good information about drones, which Dr. Taylor discussed in some detail. For several years in collaboration with others, he used radar and drones traps in an attempt to discover how these “flying gametes” behave in order to find queens. Their activities center around what are called drone congregation areas or DCAs.

According to Dr. Taylor, drones show strong directional fidelity to DCAs and visit many during their daily flights. Older drones fly longer distances from DCAs, which helps contribute to maximum genetic diversity. DCAs are often found associated with structural landscape features; they do not form in featureless terrain. In the final analysis, drone availability is a function of distance and number, Dr. Taylor said. But although DCAs are important entities in their own right, ironically and surprisingly, few if any actual matings take place in them.

Dr. Taylor concluded with the provocative statement that the Varroa mite had done a favor to bee breeders by removing feral honey bees from the natural environment. Thus, it is now easier to control the genetics of a honey bee colony than it was in the past. The downside, however, is that there is much less genetic diversity to work with than previously. Whether in the long run this severe narrowing of the honey bee’s genetic diversity will be good for bee breeders, in spite of the increased control they are offered in the mating process, remains unknown.

Dr. Medhat Nasr of Rutgers University also addressed the mating situation. In a theme that was to be repeated several times, he said that drones were a vital part of any breeding program and an effort should be made to propagate them. The loss of feral colonies resulting in a reduction in the number of drones available for queens to mate with is leading to early supersedure. Contemporary queens examined by Dr. Nasr have only an average of 3 million sperm, much less than the normal complement of around 5 million; 7 to 9 million being optimum. The reason so many sperm are needed is that as each egg descends into the queen’s oviducts, several are released, and since only one actually accomplishes the fertilization, the rest are discarded and lost in the process. Another important issue is that nutrition plays an important role in drone rearing because sperm number is determined in the larval stage.

Besides inadequate sperm, Dr. Nasr says early supersedure is the result of stress caused by beekeeper management and chemical treatments, especially the increased use of coumaphos (CheckMite+®). Unfortunately, coumaphos is an organophosphate, which attacks the nervous system. This seems to be a problem because coumaphos molecules build up in wax and the ventral nervous system of the queen is continually in contact with more and more of this material as she crawls over the comb. This result, according to Dr. Nasr is that many queens appear to be “walking on fire.”

Breeding for control of Varroa destructor (the new name for Varroa jacobsoni) was the title of a well-attended and keynote symposium at EAS. Dr. Marla Spivak of the University of Minnesota discussed two directions this kind of breeding might take: 1) limiting survival of Varroa mites on adults and/or 2) limiting mite survival in bee brood. Unfortunately, she said there is no good way to measure survival on adult bees based either on the number of mites that fall to the bottom board and whether or not they are damaged. Thus, the second option is much more promising.

Survival on brood is dependent on several variables, but most important are reducing the post-capping time to emergence or limiting mite reproduction in affected cells. The former is not promising, according to Dr. Spivak, since only about 1.4 mites are produced by each female on the average; most models involve the mother mite producing three or four.

Two ways to limit mite survival in brood is to stop reproduction and/or develop hygienic bees that uncap and remove affected brood. The latter trait is useful, Dr. Spivak says. Hygienic bees, however, only detect and remove about sixty percent of affected individuals, and the mother mite may escape during the removal process. In addition, the trait’s effectiveness declines with infestation level, and heavily mite-infested colonies of hygienic bees can and do collapse. Thus, Dr. Spivak concluded, a suite of treatments will be necessary, which will include hygienic behavior, although the trait cannot be relied on alone as an effective treatment.

Dr. John Harbo of the Baton Rouge, LA Bee Laboratory described his breeding efforts, which have resulted in stock that shows suppressed mite reproduction (SMR). This trait has been discussed in other articles in this magazine and I reviewed it in the December 2001 Bee Culture.² It has most of the things a breeder is looking for, including being measurable, heritable and additive. It is only a trait, however, according to Dr. Harbo, and not a population of bees. Thus, it must continually be conserved in populations. The mechanism for this trait is not known, but Dr. Harbo conjectures that it could be related to insufficient matings by males and females in the cell.

Tom Glenn of Glenn Apiaries in Fallbrook, California discussed the transition of his breeding efforts from open mating to instrumental insemination.³ He concurred with Dr. Nasr that the use of coumaphos is one reason for increased, early supersedure of queens. The time has come, according to Mr. Glenn, for beekeepers to “get off the pesticide treadmill.” Commercial beekeepers must accept a certain amount of contamination as they are caught in a price vs cost trap Mr. Glenn said, so the future lies in the committed, amateur beekeeper, who will no longer tolerate chemical treatment, and who must lead the way in the brave new world of “stewardship” of honey bees through genetic selection for tolerance to pests and diseases.

Beekeepers can facilitate selection in a number of ways, according to Mr. Glenn, who quoted the well-known saying, “A small group of committed citizens can change the world.” They can help accomplish this by influencing the genetics of a bee population one hive at a time, as every colony is a possible participant. In addition, he urged those present to take up queen rearing themselves, for he said there is no better time than now to engage in an activity that is considered one of the most intricate and interesting the beekeeping craft has to offer. Another plus at EAS is that the meeting also offered hands-on experience in queen rearing and so participants got both theory and practice. At the very least, Mr. Glenn urged beekeepers to continually ask and demand that queen producers provide a product in tune with their desires and philosophy.

In a separate presentation Mr. Glenn described the genetic solution to most problems as being a continuous process. He said that three levels of genetic contribution exist, as do cards in a deck: 1) individual bee (ace of spades), 2) colony (a dealt hand) and 3) the total population (full deck). The goal is to stack the deck with extra aces (desirable genes), which can then be expressed (shown) at the individual level (in the hand). The aces are those traits currently being discovered by scientists, including hygienic behavior (Dr. Spivak), SMR (Dr. Harbo), tracheal mite resistance (Dr. Bob Danka), and those being introduced into the North American bee population through Russian bees (Dr. Rinderer). The bottom line, Mr. Glenn said, is that most of these (aces) traits exist in the bees currently managed in the United States, but unfortunately they are being suppressed by chemical treatment and thus not allowed to show (express) themselves.

Sue Cobey of The Ohio State University concluded the symposium with a call to arms for what she calls “responsible beekeeping.” Step by step beekeepers are emerging from the “hype” and “hyperbole” of crisis management, which has resulted in maintaining susceptible bees (chemical treatment) to a more mature situation, where they can let the honey bee rely more on its own devices she said. This parallels the biological relationship that is also building between honey bees and Varroa mites, one that is characterized by constant change not only in mite/bee populations, but in both the beekeepers’/scientist’s knowledge of this relationship. An example is the current work showing that as many different flavors or “haplotypes” of Varroa exist, as apparently there are species/races of bees. All this is leading, Ms. Cobey said, to a much more “professional” approach that will benefit honey bee and beekeeper alike.

Sprinkled throughout the EAS meeting were other topics of current interest. The tracheal mite is still on the minds of many beekeepers as it should be, according to Dr. Nasr, who sees this organism as a major culprit leading to winter loss. Dr. Diana Sammataro of the Tucson Bee Laboratory discussed the mite’s biology. It is found in all three castes, the “k-wing” symptom is not as reliable as that of crawling bees in early spring issuing from colonies with lots of honey, and at least 25 (preferably 50) individuals must be dissected to determine infestation level. Menthol and formic acid both control the mites by fumigation, which is highly temperature dependent.

Grease (oil) patties are also being used to treat tracheal mites. According to Dr. Sammataro, these change the “flavor” of susceptible, young bees, causing the mites to move ever onward in a futile attempt to find a suitable host. Control strategies include treatments mentioned above; especially important is eliminating older bees (especially drones) in the fall as they are most infested (move colonies to rid them of old foragers and drones), and encouraging a round of brood production to get young, emerged winter bees prior to first frost.

Dr. Gard Otis of Canada’s University of Guelph, Ontario discussed what he called the winter bee - protein connection. Winter bees are designed to be “on hold” throughout the cold season and, therefore, nutrient storage is needed so they can commence brood rearing activities as the active season approaches. Dr. Otis analyses of the large storage proteins (vitellogenin and lipophorin) in bees show significant trends in colonies correlating with presence of winter bees, suggesting the importance of getting these proteins into the colony early on. There is much to be learned here, he concluded, including best ways to measure protein content and the cost effectiveness of feeding bees pollen substitute.

Those treating Varroa mites with hard chemicals are having a difficult time, according to Dr. Patti Elzen of the Weslaco Bee Laboratory. Resistance to both fluvalinate (Apistan®) and now coumaphos (CheckMite+®) means that beekeepers must begin to emulate those in other realms of agriculture who practice resistance management. Unfortunately, the only way to favor mite susceptibility is to stop using a chemical class after resistance is established. This means that when there is resistance to a pyrethroid such as fluvalinate, all others of the same class (e.g. flumethrin) will no longer function. The best way to minimize resistance development is to reduce pesticide selection pressure on mites by using materials only when necessary, and removing them from the hive as soon as possible, according to instructions on the label.

A specific strategy for resistance management in Varroa mites according to Dr. Elzen is to: 1) sample the yard and only treat when a threshold population is reached, 2) apply the resistance test developed by Dr. Jeff Pettis at the Beltsville, MD Bee Laboratory to ensure materials are effective⁴, and 3) rotate materials by using coumaphos (CheckMite+®) for two years followed by a one-time use of fluvalinate (Apistan®), and 4) leave the treatments on only as long as the label says.

Those wishing to use a more biotechnical rather than chemical approach to Varroa control were accommodated by presentations by Drs. Burgett and Zachary Huang⁵ (Michigan State University) on drone trapping and Dr. Tom Webster (University of Kentucky) on the use of screened bottom boards. He concluded that more mites appear to fall during hot weather, making these more effective at high temperatures, and that their use should help slow development of Varroa resistance to chemicals. He also provided ideas on how mites could be more easily counted (smaller and/or especially marked sticky boards).

Mr. Tony Jadczak, bee inspector in the state of Maine, discussed the current pest/disease situation with respect to commercial pollinators. Maine is unique being the “end of the line” for these outfits, as more converge on the blueberry fields each year in search of pollination contracts. The state is a veritable “mixing pot” of bees as many are offloaded at one particular location, euphemistically named the “airstrip,” an abandoned runway. This large pool of bees provides Mr. Jadczak a unique insight into the current disease and pest status of beekeeping operations. Last year an estimated 50,000 colonies from about ten states were sampled and 12.7 percent of those examined had American foulbrood. They were burned. Florida and Georgia had the most infested colonies; outfits from these states also generally had detectible levels of small hive beetle. In addition, Mr. Jadczak encountered coumaphos resistance in a large operation in time to prevent an already serious loss of bees from becoming truly catastrophic. In the course of over twenty years of bee inspection in Maine, Mr. Jadczak’s job has changed from that of protecting the beekeeping industry to ensuring adequate pollination is available to growers of an ever-expanding blueberry crop.

Every year the EAS conference is attracting more quality presentations from the best and brightest researchers and innovators in beekeeping. At Cornell, it also hosted a contingent of international speakers from Canada, Mexico and Brazil. Dr. Ernesto Guzman provided a perspective on the impact of the African honey bee in Mexico; it is responsible in great part for a 50 percent decline in honey production, and Dr. David DeJong, former Cornell student now at the University of São Paulo, Brazil, provided the same for his country, where the bee is now considered an asset instead of a liability. This year’s event also featured presentations on other bees that are being studied for their pollination ability, including bumble bees (Dr. Marion Ellis, University of Nebraska) and squash bees, Peponapis sp. (Ms. Roberta Glatz, a New York beekeeper). Dr. Ellis’ project, called “Bumble Boosters,” employs a teaching by doing philosophy in conjunction with information sharing (networking). Students from forty high schools across Nebraska are involved.⁶

Finally, the meeting was highlighted by Cornell’s own Dr. Tom Seeley, who spoke on the dance language of honey bees and how it relates to honey bee society, which he characterized as a “honey factory.” The famous dances of the bees are used to both increase the number of foragers (waggle dance) and turn up the honey-processing rate (tremble dance).⁷

If the above presentations weren’t enough, the week-long EAS meeting at Cornell University was also jam-packed with hands-on workshops, the ever- popular short course and Master beekeeper examination, and honey and bee product competitions. Finally, the bee display (exposition) rivaled that of any other North American bee meeting, with over 25 vendors represented from Georgia to Canada. The organizers of next year’s meeting are looking to guidance from the successes of EAS 2002 at Cornell. They hope to see everyone in August 2003 in the great State of Maine.