APIS Volume 15, Number 8, August 1997
In this issue
- Following Up Varroa Treatments
- Brood Pheromone: The Revolution Continues
- Smoking Bees: Alarm and Varroa Control
- Pollen Flow: As Important as Honey Flow
- Honey Promotion: A Neglected Activity?
FOLLOWING UP VARROA TREATMENTS
My recent journey to Europe suggests that beekeepers must not become complacent concerning Varroa treatment. Unfortunately, the effectiveness of the current material Apistan is so foolproof that U.S. beekeepers tend not to follow up with inspections to determine a subsequent infestation level. As a result of the same situation, many in Italy and France were taken by surprise when their standard procedures began to falter as mites became resistant. There are many possible reasons treatments could fail. These include improper application, emergence of resistance and product formulation failure.
In Florida there have been several revealing incidents. Recent bee kills blamed on pesticides, tracheal mites, viruses and diseases, when investigated closely, appeared to be caused by large undetected infestations of Varroa. The beekeeper apparently had treated the colonies, but did not determine how effective it was. These occurrences, common sense and evidence found elsewhere suggest that failing to follow up Varroa treatment by confirming the size of the resultant mite level is a prescription for disaster.
One of the problems with inspections has been that treatment thresholds for Varroa mites have not been strictly defined (see April 1992 APIS). Thus, it is difficult to determine what the effectiveness of a treatment should be. Dr. Keith Delaplane at the University of Georgia recently published some information on treatment levels based on a 300-bee "ether roll test." He and Dr. Mike Hood in South Carolina found that Varroa-infested colonies installed as packages in April had highest colony survival, highest colony populations and no secondary brood disease symptoms by December when treated with Apistan in August (American Bee Journal, Vol 137, pp. 571-573, August 1997). August treatment was called for based on about 15 mites in an ether roll or a natural drop (not using pesticides) of about 117 mites on a sticky board overnight (about 19 hours). The authors also state that these thresholds are different in other parts of the country, citing California (August: 1-2 mites in an ether roll; 20-200 on a miticide-assisted sticky board), Michigan (summer: more than ten mites on a non-miticide assisted sticky board for 24 hours), and Nebraska (August: more than six mites in an ether roll). In Florida an official treatment level has yet to be defined, but Mr. Laurence Cutts, chief apiarist recommends treatment if more than 20 mites are found in an ether roll.
The ether roll detection technique is universally used in Florida by commercial beekeepers. Although only a crude test and quite variable, it is simple, one-step and produces immediate results. For information on Varroa detection using this technique, a video I produced continues to be available. It is VT 249, Detecting Varroa Mites, available by sending me a blank VHS video tape.
BROOD PHEROMONE: THE REVOLUTION CONTINUES
We are continuing to find out more about the pheromonal revolution described in the June 1997 APIS. Royal pheromone was one of the first of these substances to be identified. A pheromone is a chemical given off by one individual that controls the behavior of another of the same species. Much of the work on royal pheromone, sometimes called "queen substance," was done by French researchers. Now another, Dr. Yves Le Conte (see my letter from France dated July 9, 1997), at the INRA station in Montfavet, has identified what he calls "brood pheromone." Like royal pheromone, this is a "primer" chemical. That means it indirectly results in changes by influencing hormonal production of the endocrine system. It is the same process resulting in the irrevocable decision at the third day of larval life that determines whether it becomes a queen or worker.
Brood pheromone keeps workers from developing their ovaries (CR Acad. Sci. Paris, Sciences de la vie/Life Sciences, 317, pp. 511-5, 1994), something originally thought to be totally under control of royal pheromone. It also helps workers recognize queen cells (Chemoecology 5/6,1:6-12, 1994-5) and stimulates development of the worker hypopharyngeal glands that produce royal and worker jelly to feed larvae (CR Acad. Sci. Paris, Sciences de la vie/Life Sciences: 319, pp. 769-72, 1996).
Brood pheromone is a mixture of 10 simple fatty aliphatic esters. These are emitted by the brood in large amounts as the cells are capped, and in different concentrations varying with the age of the larva. Evidence has been found for specific actions for three of these chemicals. Methyl stearate produced best acceptance of queen cups, methyl lineolate caused more royal jelly to be deposited in queen cups, and methy palmitate produced heavier larvae (J Econ. Entomol. 88(4): pp. 798-804, 1995). The practical results of this include the possibilities of increasing the amount of royal jelly a colony provides during queen rearing. Placement of the queen rearing bar also affected the amount of jelly deposited; that closer to the comb bottom produced larger, heavier larvae.
At the present time, methyl palmitate is perhaps the ester of most significance in brood pheromone with reference to Varroa. It appears to be used by mites to find host larvae. Other work by Dr. Le Conte and his students include looking at mite pheromones within the Varroa population that might help control its population (see my letter from France, March 23, 1997).
SMOKING BEES: ALARM AND VARROA CONTROL
A most-often-asked question by the novice is how smoke works in calming a colony so the beekeeper can manipulate it with less chance of being stung. There have been several stock answers. One is that smoke makes the insects "think" their tree or house is on fire. Therefore, workers engorge themselves with honey in case they have to abandon the nest. This process makes them calmer (some say more "content"). And when their abdomens are distended after taking on honey, it is thought workers find it more difficult to sting intruders.
There is, however, another answer that is less anthropomorphic. Worker honey bees produce "alarm pheromone" when disturbed. In contrast to the royal and brood pheromones, the reaction to this substance is much quicker and more direct. Thus, it is called a "releaser" as opposed to a "primer" chemical. Alarm pheromone is also volatile and smells like bananas (isopentyl acetate) or blue cheese (2-heptanone). Smoke introduced into a colony masks the odor of these alarm signals and the bees fail to communicate with each other that they are threatened by an intruder.
P. K. Visscher and colleagues have put the latter hypothesis to the test (J. Insect Behavior 8:11-18, 1995). They used an electroantennograph, which translates chemical signals from the antenna into electrical signals that are transcribed on paper. Use of smoke caused antennae to be 50 percent less sensitive to both alarm pheromones. This effect was reversible, however, and antennal response returned to normal in 10 to 20 minutes. The investigators also tested floral odor and found the same responses, suggesting that smoke has a more generalized effect, and is not specific for alarm pheromones.
Other uses of smoke are also possible in a bee colony. Most recently, that from tobacco has been reported to reduce Varroa populations. Unfortunately, this natural material is difficult to control, and the exact dosage that kills mites but doesn't harm bees is unknown. "Smoking" Dr. Frank Eischen, working at the Weslaco Bee Laboratory, has taken this idea to another level (USDA ARS Agricultural Research, August 1997). So far, he has treated bees with the smoke of over 40 plants. The technique is to take cages with 300 to 400 mite-infested bees, expose them to smoke for 60 seconds while covered in plastic, and then count the number of mites that fall off. Most smokes don't kill the mites, it seems, they are simply knocked off the bees. If not caught by a sticky board, the mites, like the bees, "pick themselves up, dust themselves off and do it all over again." It is not clear, Dr. Eischen says, whether the mites are confused or just irritated. Two materials that show the most promise are smoke from creosote bush and dried grapefruit leaves.
Dr. Eischen emphasizes that this smoke treatment is only experimental at the present time; he does not yet recommend the process. There are too many unknowns. And other drawbacks to this technology exist. Mites in the brood are not killed, and so the smoke treatment must be repeated several times as bees and mites emerge. It becomes important, therefore, to determine what chronic smoking with tobacco or other plants might do to a colony. Given recent debates about the effects of smoking in humans, the prognosis is not good. Too much smoke can also contaminate hive products. There is evidence that heavily smoking honey supers when removing them from a colony can give the resultant honey an off flavor.
Finally, there remain questions about disrupting the delicate balance of honey bee social structure, which relies on pheromones for internal control as described above and elsewhere. Now we know that smoke can interfere with the releaser alarm pheromone, albeit only temporarily. What might it do to the more long-term, and perhaps more significant, primer pheromone communication that takes place within a honey bee colony?
POLLEN FLOW: AS IMPORTANT AS HONEY FLOW
All beekeepers know about nectar flows; they look forward to them with eager anticipation. Most nectar-producing plants have been cataloged and written about extensively. There is, however, another side to the nutritional coin in beekeeping. There will be no honey if protein is not available to developing bees. Thus, flow of pollen is just as important, if not more so, than that from nectar. R. Nabors recently published an analysis of pollen flows in Portageville at the University of Missouri Delta Center Experiment Station (American Bee Journal, Vol. 137. pp. 215-216, March, 1997).
His analysis from three colonies showed a pollen flow in April (maple and dandelion), July (various agricultural crops) and September (goldenrod and ragweed). Although the dates correlated with the traditional plants present at the time, the study did not give information about specific plants and how much they might have contributed to the protein supply.
Given this set of data, the author suggests that the time pollen supplement/substitute would most benefit a colony would be early March, mid-May and August in the region. The time to trap pollen corresponds to April through early May and September. It pays to know these flows, which can vary greatly depending on region, the author concludes, to determine when supplemental feeding might be needed (see February 1992 APIS).
Besides timing and quantity, the quality of the pollen flow these days needs much more examination. It appears to be the most vulnerable part of the flower to environmental contamination and serves as a magnet for things like heavy metals, as shown by Dr. Jerry Bromenshenk at the University of Montana (see May 1994 APIS). Adverse conditions can also quickly erode its viability; studies in preservation of collected pollen provide abundant evidence of its ephemeral nutritional value. Pollen is plant sperm. Recent investigations on non-viability of sperm in animals from alligators to humans, thought to be the consequences of chemical contamination in both air and water, may also apply to that of plants. Though not as vulnerable as other kinds of sperm, being housed in a tough outer shell, pollen is nevertheless still a far more fragile commodity than honey.
Lack of pollen and consequent inadequate nutrition has been implicated in many conditions that have defied description. Although not proven to everyone's satisfaction, "disappearing disease", "autumn collapse", "May disease" and others may be directly related to protein and thus, pollen deficiency. Some pollen is even toxic to colonies. A feeding study done in the Florida's Panhandle was inconclusive concerning whether or not pollen deficiency had some impact on bee colony loss originally attributed to tracheal mites, but the symptoms were certainly similar to those conditions mentioned above. (M. Sanford and W. Johnson, Bee Science, Vol. 1, pp. 72-77, January 1991).
Perhaps the most innovative use of pollen and protein monitoring occurs in Australia. There gross nitrogen is measured to determine whether bee colonies should be moved into and out of eucalyptus groves, notorious for poor pollen flows (G. Kleinschmidt and A. Kondos, Australasian Beekeeper, Vol. 81, pp. 5-6, 1979). For more information on this important aspect of bee nutrition see the July 1990 APIS.
HONEY PROMOTION: A NEGLECTED ACTIVITY?
September is National Honey Month. As part of this national promotion effort, the National Honey Board has published the official proclamation by Secretary of Agriculture Dan Glickman on its web page (http://www.nhb.org/). The Board has also developed a press and media kit that it will distribute free to beekeepers (tel 800/553-7162). For other Board activities see the Honey Board thread on the APIS world wide web site (http://www.ifas.ufl.edu/~mts/apishtm/threads/nhboard.htm).
Honey promotion by North American beekeepers appears to be only in its infancy. One doesn't have to be in Europe, especially France, long to see the remarkable difference in this effort. The level of honey promotion on a local level is astounding. It takes many forms, from roadside stands to honey fairs and tastings. Practically every town has its "Maison du miel."
The Parisian variety of this is well described by Dr. Mark Winston in the April 1997 Bee Culture, pp. 21-22. He discusses in detail the store decor and tasting facilities complete with silver spoons. Honey from all regions of France was represented along with special varieties from other parts of Europe. Dr. Winston also details the vertical integration he saw in that store. It's the same that almost every French beekeeper has developed. Most not only sell monofloral varieties of honey, but also honey-laced nougat, spice bread and mead. In a variation on the theme of monofloral sources, the Parisian "Maison du Miel" also sells propolis from certain sources. This is just one of the creative ideas the French have come up with to sell honey. Another I reported on in the July 1997 issue of this newsletter is honey made in the middle of Paris on top of one of its most spectacular tourist attractions, the Opera.
Professional beekeepers associations in southern France have organized themselves into associations (syndicats) with the special mission of promoting honey. As part of this, the red label program has been developed to give the consumer the finest quality product available (see my letter from France, February 22, 1997). These associations, along with local chambers of agriculture, sponsor honey tastings and other events or fetes. They also collaborate in printing and distributing slick brochures in which honey is prominently included as one of the products of the region. One enterprising beekeeper I met had inserted his name and address into a leaflet published by the local tourist office. As I was leaving France, my host agency, ADAPI, was developing a brochure called "The Honey Route of the Var," which also was in the process of being adapted for the World Wide Web and stand-alone computer kiosks.
Perhaps the most interesting promotional activity to one with any beekeeping background is a museum. There are quite a few of these in France and Europe. To take advantage of the reputation of beekeeping and honey, they are often called "ecomuseums." Some are noncommercial, but most are tied in with selling local bee products. Mr. Gilles Ratia of the APISERVICES consulting group is in the process of putting a list of these on the Internet. As Dr. Winston concludes: "...we have a lot to learn from the French about how to appreciate, and especially how to market, honey and other bee products."
Sincerely,
Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (352) 392-1801, Ext. 143 FAX: 352-392-0190
http://www.ifas.ufl.edu/~entweb/apis/apis.htm
INTERNET Address: MTS@GNV.IFAS.UFL.EDU
©1997 M.T. Sanford "All Rights Reserved
