Bees Healthy (And On Their Own Six Feet)- Part I
American Bee Journal (February) Vol. 148 (2): 119-123
Dr. Malcolm T. Sanford
It is now apparent that many causes might be responsible for Colony Collapse Disorder (CCD). The list includes everything from the conventional (effects of sublethal pesticides to poor nutrition to the standard litany of diseases and pests) to the sublime (cellular telephones). It is not surprising, therefore, that a growing number of those involved with colony losses are looking at concept of how to maintain a healthy colony. Indeed, the major USDA program recently rolled out in response to CCD announced that “$4 million will be available in Fiscal Year 2008 for a 4-year Coordinated Agricultural Project (CAP) to research ways to improve the health and protection of honeybees, which are facing serious threats that have the potential to heavily impact the nation's food supply.”1
This is not a new concept of course. Some fourteen years ago an Article in these pages (American Bee Journal, June, 1993, pp. 431-434) by Jost Dustmann discussed the natural defense mechanisms protecting the health of the honey bee. It asked a provocative question: when is a social organism like the bee colony sick? And concluded the presence of pathogens in a colony, single bees, food or wax does not mean a colony is sick. Only when the number of diseased or dead bees, larvae or pupae exceeds a certain limit and normal, functioning of the colony is disturbed, is a colony deemed sick.
The article discussed ten main defense mechanisms honey bees have against diseases and pests:
1. Cleaning or grooming behavior of adults. Some call this "hygienic behavior." It is the basis for several breeding programs in the U.S. This pattern includes: (a) single infected bees reacting quickly by dying soon and removing themselves as a source of infection and/or (b) sister bees quickly identifying abnormal (diseased) individuals (adults, larvae and pupae) and eliminating them from the population. Hygienic behavior is shown to be effective against American foulbrood, nosema, chalkbrood, sacbrood and paralysis. The article also indicated it will probably be involved in resistance to Varroa mites in European bees as has been observed in Asian species.
2. Quickly regenerating losses of population. This is extremely effective as removal of diseased individuals can be compensated for in a short time. The ability to replace bees rapidly generally outstrips even the greatest current threat to populations, the Varroa mite.
3. Continuous rotation of bee generations. Brood followed by adults followed by brood is analogous to crop rotation in commercial agriculture, where the growing of one crop is often followed by sowing another. The article suggested a good example of this is tracheal mite infestation, which cannot keep up with replacement of bees by a colony in normal times. There is also evidence of active movement of mites into older bees. However, when older bees live longer, the mites may get the upper hand.
4. Swarming. A major defense is building new wax combs after bees swarm from their old colony. This appears to be a predominant strategy of African honey bees, which not only swarm, but also abandon (abscond from) their nests.
5. Restricting disease to either larvae or adults. This strategy ensures that if larvae are diseased, adults are not and vice versa. Both stone brood and Varroa are exceptions to this rule.
6. Control of fertility and population control. More in evidence in Varroa infestations, the mite's preference for drone brood deflects parasites away from workers. In addition, the heavier cappings on affected drone brood, if left intact, ensure no mites will emerge.
7. Immune reactions. Bactericidal molecules (peptides) are formed in individual bees and consumption of foreign materials (phagocytosis) by blood (hemolymph) cells has also been observed.
8. Stinging and biting. The first is self-evident. Biting has been shown to be a defense mechanism against Varroa, but found at low levels in European bees.
9. Proventriculus and peritrophic membrane. The former structure prevents entry of foreign organisms (bacteria, pathogens) from the crop or honey stomach into the digestive system. The latter lines the digestive tract, protecting it from rough materials and also preventing entry of bacteria and fungi into the hemolymph.
10. Antibiotic substances. An extremely important aspect of the honey bee's defenses, these chemicals can be found in honey (called "inhibine"), stored pollen and propolis (flavonoids, terpenes). These substances have also been implicated in human health concerns, including the use of diluted honey as a surgical dressing and consumption of propolis as preventative medicine.
The article concluded with another question: How can the beekeeper manage bees without interfering with the above natural strategies? There are five recommendations:
1. Selecting and breeding bees that have the necessary defense mechanisms already in place. Controlled mating is seen as essential.
2. Ensuring the environment provides enough of the right food for bees. If not, then the beekeeper must feed both carbohydrate (sugar) and protein (pollen substitute/supplement).
3. Determining the beehive is the right size with reference to colony size and management practices. Establishing artificial swarms that build new combs and uniting young colonies with older ones established the year before ensure rotation of bees and wax. Routinely replacing old combs is something every beekeeper should consider.
4. Keeping bees without using drugs. In general, the article concluded that medical treatment of a colony will interfere with the natural defense mechanisms discussed above. This is especially true for antibiotics, which cannot eradicate infections, but only mask symptoms, leading to sometimes huge reservoirs of disease ready to break out at any moment. At the time there was considered one exception to this, the use of a registered pesticide to control Varroa.
Expect to see many folks get on this healthy honey bee bandwagon in the future. Dr. Marla Spivak at the University of Minnesota is as usual ahead of the curve. She rolled out “Healthy Bees: A Course For Keeping Bees Healthy (and on their own six feet),” just as CCD was becoming an issue. This pioneering project was several years in the making and takes advantage of the considerable advances in computer technology and the World Wide Web. It is one of only two courses available via the University of Minnesota’s Extension Learning Management System.2
The course takes many of the concepts above and puts them into a nicely designed format that is not only easy to use and comprehend, but also has some exceptional design concepts. It looks at the bee colony as a “super-heroine.” “A bee colony is a collection of female workers with amazing capabilities. As an individual, each bee has an immune system, which gives her physiological defenses against diseases and parasites. As a colony, they have collective defenses against these villains. It is this colony-level response of thousands of individuals that turns them into a super-heroine.”
The strengths of the super-heroine include: strength in numbers, good queens, brood in all stages, and presence of drones, adequate food and new comb, all relating to the concepts presented in Jost. Dustmann’s article. The course helps one discover in an innovative way the best strategies beekeepers can use to “help the bees help themselves.”
The villains seeking to destroy the super-heroine are a fantastic lot, each with their own level of evil and lists of powers and weaknesses. Here’s where the artwork shines in this course. We see them in all their glory in animated graphics.
As we scan right, we see in order, the Liquifier, The Shifty Debilitator, the Montezuma’s Silent Revenger, the Destructors, the Micro-Congestors and the Writhing Menace.
Each villain is accompanied a list of steps, which reveal the characteristics of the disease/pest and its potential management. Finally, one can take a test to determine how well the material was absorbed.
As one proceeds through the course, it is possible to track progress. When all the sections or modules are completed, one can be awarded the coveted Warrior’s Certificate.
The course contains various resources, including extensive articles entitled: Comb Replacement, Testing and Breeding for Hygienic Behavior, Technique for Finding Tracheal Mites (video segment), Sampling and Treating for Varroa Mites. Finally references are listed as well as a number of supporting frequently-asked questions (FAQs). Especially good are the numerous images of honey bees, brood and disease symptoms found throughout the materials, including a special screened bottom board and the animated sequence showing how Varroa transfers to adults.
This course costs $25.00, but one gets the rights to use it for four (4) years once registered. Not only does one get to go back over the material again and again, and there’s much more there than first meets the eye, but it should also be extremely useful for attracting the attention of youngsters. What better way to get them interested in beekeeping than sitting down and going through this course with its animated villains and their effects on the Hive’s Angels? To register, access the URL listed below.3