Nancy Ostiguy, Associate Professor, Penn State
Whether or not you have experienced Colony Collapse Disorder, you are probably thinking that the bees are trying to tell us something: what we beekeepers have been doing is not working. Common complaints include colonies building up too slowly in the spring, queens needing replacement with increasing frequency, less honey production, and colonies not living as long as they did in the past. Beekeepers are not alone in thinking that honey bees are in trouble. In 2007, the National Academy of Sciences reported a worldwide decline in pollinators (Berenbaum et al. 2007), which is leading to a decline in pollination services (Biesmeijer et al. 2006). Our concern is justified: pollinators, and honey bees in particular, are critical for the pollination of food crops. Taken together, pollinator contributions to agriculture have an estimated worth of over $194.6 billion per year (Gallai et al 2008). All this is telling us that if we are to continue to have fruits and vegetables in our diet – let alone a diverse ecosystem – we need to change how we are managing our honey bees.
Starting with our use of terramycin for American Foulbrood control, and continuing through the use of various pesticides for Varroa and Small Hive Beetle control, we beekeepers and researchers have been looking for magic bullets to solve the honey bee’s problems. Solutions addressing honey bee health that have claimed to be simultaneously easy, cheap and effective have failed. I believe these “magic bullets” have only masked the problems they were purported to “solve.” Not only do the problems remain but their solutions, I believe, are among the causes of our current bee losses. We need to face the reality that the potential for developing the perfect solution is about as likely as the chance for that proverbial snowball to survive.
The first magic bullet, the pesticide (meaning: pest killer) Terramycin®, was introduced for American Foulbrood control. But we beekeepers decided this was okay because we all know that antibiotics are good and only bad things are harmed by antibiotics. [More on this fallacy later.] This introduction of pesticides into beekeeping opened the door to all manner of magic bullet colony “treatments”. When varroa control became necessary, the idea of a chemical solution was an easy sell. Our continuing search for magic bullets has lead us to an amazing place. Today we have Terramycin-resistant American Foulbrood, and Apistan®- and CheckMite+®- resistant varroa. We use Guardstar®, a permethrin with known high toxicity to honey bees, to control Small Hive Beetle in our apiaries, and viruses, as evidenced by deformed wing bees, run rampant through colonies. We find the antibiotic tylosin (Tylan®) in honey (Adams et al. 2007, Thompson et al. 2007). Wax, honey and pollen all contain measurable pesticide residues. We find the pesticides Apistan® and CheckMite+® in honey (especially honey consumed by bees overwinter, unpublished data), and these are also the most common pesticides detected in beeswax (Frazier et al. 2008). Despite this growing disaster we continue use to look for single, simple solutions while wondering why our bees are dying, our colonies are not building up well in the spring, and our honey production is down. Maybe it is time to remind ourselves that insanity is doing the same thing over and over again expecting the result to be different.
There is no better time than now to step back, remind ourselves of our ultimate goal, and ask whether our strategy is working to achieve it. Our goal is simple. We want long-lived and productive – in other words, sustainable – colonies. As evidenced by the unprecedented level of colony loss since the introduction of varroa mites in 1987 it is clear that our present strategies for colony management are not working. We need a new set of strategies.
What should those strategies be? Let’s tackle that question by breaking our goal down into concrete, measurable objectives. Good strategies will be those that help us meet our objectives.
Colony productivity can be assessed by honey production, colony strength and foraging rate. An estimate of colony strength and predictive information about honey production and pollen storage can be obtained from measuring only foraging rate.
Colony longevity is easily measured. The elements that contribute to high colony longevity – a healthy, long-lived and productive queen, low disease and parasitism rates, low individual bee death rates and low drones to workers ratio – provide additional details that are critical to our understanding why and how a colony dies. We can evaluate colony management success via measurements of all of these elements.
Now that we know our goal, and how to measure whether we are moving nearer to, or further away, from it, we can ask what our bees need in order that we can reach our goal.
The problem we face with bee colony health today is analogous to the problem we faced with human “colony” health – i.e., cities – in the middle of the nineteenth century. Let’s seek guidance by looking at what we did to achieve the dramatic improvements in human health beginning in 1850. We purified drinking water, decreased workplace hazards, improved housing, provided vaccinations, and cleaned up the environment. We were also taught to do some things personally - eat well, drink plenty of water, practice good hygiene, exercise, get regular physicals, reduce stress, stay away from sick people, and stay home from work or school when sick. All of our successful strategies can be characterized by one pithy slogan, coined one hundred years earlier by Benjamin Franklin: An ounce of prevention is worth a pound of cure.
Let’s try applying these ideas to bees, bearing in mind three things: (1) what happens to the individual bee affects the whole colony, (2) what happens to a colony will affect a neighboring colony, and (3) everything is connected. Bees are our ‘workers;’ we need to provide them with a safe, healthy work and living environment. We could consider ourselves lucky that they cannot unionize; but then if they could, maybe we would have addressed bee health problems sooner!
Are our bees eating well?
During the summer months most colonies experience a dearth of nectar and pollen. We know that short bouts of starvation (more than fasting for a single day or two) cause problems for humans, including decreased longevity and increased susceptibility to disease. Consider feeding your bees when the dearth is long – even if it is of ”normal” length.
Honey bees are generalist pollinators. When we put bees on a single crop, where even the weeds are scarce, there is only one source of nectar or pollen. Parents know that there is no need to worry about their child’s desire to eat only oranges and hotdogs today as long as the child’s weekly diet is diverse enough to contain all the necessary nutrients. Consider the diversity of forage resources when placing your colonies. We need to advocate more ”weeds” and wild/unmanaged areas when we bring our bees in for pollination. Growers want healthy colonies; their management decisions impact our colonies. We need to locate our apiaries were the diversity of forage is high.
Are our bees drinking plenty of clean water?
If you are like most beekeepers, you think even less about water sources than forage. Water should be plentiful and clean. The water source should not be contaminated with bacteria; even bacteria that is not known to cause bees to become ill may be problematic because of the adverse impact of varroa mites on the bee’s immune system (Yang and Cox-Foster 2005).
Chemicals, including pesticides, may be present in the water. Changes in agricultural practices over the last 30 years have increased the likelihood that agricultural runoff, containing pesticides and other potentially harmful chemicals, will be the only source of water for many bees working a pollination contract. We need to begin thinking about providing bees with potable water.
Do we give our bees a physical?
When was the last time you gave your colonies a physical? Do you monitor for pests and diseases or wait to see who survives winter? Mites play a critical role in colony health and survivorship; so knowing how severe the mite infestation is will determine if you are going to meet your goals of colony longevity and productivity. The most important component of disease and pest monitoring is doing it. The most common methods for varroa monitoring are (1) stickyboards placed beneath the screened bottom, (2) powdered sugar shakes, and (3) ether rolls. The most reliable method is a 3-day stickyboard using petroleum jelly (unpublished data). Do not use vegetable oil! Mites can walk several inches through petroleum jelly: vegetable oil is not even a challenge! While the 3-day sticky board is the most reliable monitoring technique, that reliability is irrelevant if you do not use it. Monitoring your colonies is like exercise: pick a method that works for you and that you will continue for the long haul.
Does your state have a honey bee inspection program, or are you left on your own to figure out when American Foulbrood or other diseases are present? Learn everything you can about bee diseases by talking to veteran beekeepers and taking classes. Helping your bees practice good hygiene depends upon you knowing your bees. Consider advocating with your local and state beekeeping associations for an apiary inspection program that will help you help your bees. Healthy bees are in everyone’s best interest.
Do we practice good bee hygiene?
Are we doing the best we can to help the bees practice good hygiene? We should not limit what we do to buying hygienic queens and selecting for hygienic behavior in our own colonies. Help your bees by ventilating hives to keep moisture from accumulating, replacing bottom boards with screens so that at least some mites can fall out of the colony onto the ground rather than climbing back on the bees from the bottom board, and reducing the number of hive bodies so as not to exceed the ability of the colony to control wax moth, hive beetles or other pests.
Are you collecting the wax scraped from your colonies, or are you dropping it on the ground for wax moth and small hive beetle? The moths and beetles might thank you but the bees would prefer that you remove all wax outside the hives.
Are your hive bodies and frames in good repair, or do pest have multiple entrances into the hive? Can water drip into your colony through cracks or splits are the corners? Do your bees have to fight the outside elements inside the hive? Better health is related to homes in good repair.
Disease rates can be influenced by your management of hive frames. Is the wax in your hives less than 2-3 years old, or is it a potential source of American Foulbrood spores and chemical contaminants? Are you moving disease and mites around your colony by moving frames of brood and/or bees between colonies? Never move a frame from a weak or sick colony to a healthy colony. If you need to move bees and/or brood from a healthy to a weak colony, use the opportunity to recycle your old frames, putting a new frame into the healthy colony.
Are you giving your bees a continuous supply of terramycin or tylosin for American Foulbrood control? Continuous exposure to an antibiotic aids the development of antibiotic resistance. Antibiotics kill beneficial bacteria as well as pathogens. You may be killing the beneficial bacteria bees need for good health. While little is known about beneficial bacteria in honey bees, when we have looked in other organisms beneficial bacteria have been found.
Can your bees propolize the inside of the hive body, thereby using the antibacterial properties of propolis to maintain colony health; or, is the wood inside the hive body smooth? Consider roughing the inside of your hive bodies. Talk with the producers of hive equipment and ask them to avoid the use of smooth finished wood on hive interiors. According to proponents of top bar hives, bees propolyze the interior of these colonies (personal communication). Consider switching the type of your hive equipment.
Are you using drone brood removal, especially in the spring, to control varroa? Providing drone comb early in the spring can be an effective mean to reduce mite populations. Taking this simple preventative measure may be sufficient to make other mite control tactics unnecessary!
What are we doing to to reduce bee crowding?
Are you helping your bees identify their hive, or are they confusing their home with nearby hives? Drifting is enhanced by similar hive features and close colony proximity. Feral honey bees are less likely to drift – unintentionally enter another colony’s hive – because colony to colony distances and unique hive features assist bees in finding their hive. The hive of feral colonies differs in physical characteristics and location:i.e., tree shape and height, shape and direction of the hive entrance in the tree, type and spacing of surrounding trees and other plants, ground topography are all different. Colors, shapes and relative placement of physical features on the hives all help the bees locate the correct colony.
While quantity of forage is probably the largest determinant of the distance between two feral colonies, disease and parasite transmission also increases with decreased separation, resulting in the selective elimination of colonies that are spatially nearby. If you have multiple hives on a single pallet, your colonies are living under conditions as far from natural conditions as it is possible. If one colony is sick, the other colonies on that pallet are – or soon will be – sick. The closer the proximity of your colonies, the greater the risk of colony to colony transmission of disease and parasites. Consider increasing the distance among colonies and/or reducing the number of colonies per apiary. It might be slightly less convenient to work your colonies when they are spread-out, but reaching the goal of greater colony longevity will be more readily attained.
Have you ever had to ask at the front desk of your hotel for your room number when you returned from dinner? Our apiaries tend to be like hotel rooms – so identical that being anything other than in top form can cause the bees to wander around confused. For many years we have known that placing colonies in a line increases drifting (50-59%) towards the end colonies (Jay 1966). Placing colonies in concentric circles, at least 1 meter apart, with entrances all facing south was found to lead to extremely low drifting rates – 0.1-3% (unpublished data). How are the hives in your apiary arranged? Are your hive bodies identical? Consider painting hive bodies different colors or painting different shapes on the exterior. Maybe different colors/shapes on the lids would be the easiest distinctive characteristic to include in your operation.
Are we reducing bee stress or increasing it?
Are your bees in a highly managed or monocrop ecosystem? Low floral diversity and quantity may result in stress. Bees evolved as generalist pollinators: monocrop or low floral diversity ecosystems make it difficult for them to be the generalists they evolved to be. When we control the land surrounding our apiaries, we can plant polliator friendly crops, trees, shrubs and other plants. Consider talking to the landowner(s) surrounding your apairy about how he/she can help honey bee health by providing floral diversity. Consider talking to the growers where your colonies are located, asking for more unmanaged areas where weeds are allowed to grow and provide forage diversity.
Because droughts are usually associated with higher temperatures, the stress caused by lack of water is intensified. Little can be done to prevent droughts, but their impacts can be mitigated by providing water for the bees whenever natural sources are lacking or contaminated.
Putting bees on the back of truck to haul them to various pollination contract location is stressful; the high loss of queens reported by migratory beekeepers is an indicator of this stress. Even if you move your bees only short distances, the stress will increase any problems already existing in the colony. Consider talking with growers about permanent or semi-permanent placement of your colonies. Changes in land management practices may be necessary to ensure sufficient forage, but with healthier colonies the quantity and quality of the pollination per colony will improve and fewer colonies may be needed in each location.
Are we helping our bees avoid spreading diseases and parasites?
Are you moving bees and brood among your colonies? Disease and parasities are spread from bee to bee and from colony to colony. While we have little direct impact on bee to bee spread our management practicies can have a tremendous influence on colony to colony spread. Moving frames of bees and/or brood between colonies increases the risk of colony to colony transmission of disease and parasites. Moving a frame from a strong to a weak colony should be low risk, but it may not lead to the intended outcome – a healthier colony. A strong colony is not necessarily a disease/parasite-free colony: what is important is that the number of infected bees be small compared to the toal bee population. Moving healthy people in with sick people doesn’t make the sick healthy: it makes the healthy sick! In the same way, adding healthy brood/adults into weak colonies may not have the desired effect of improving the weak colony. Similarly, it is nearly a certainty that moving frames from a weak to a strong colony will introduce disease and pests into the stronger colony, weakening both and hindering your goal of sustainable colonies. Beekeepers have known for many years that merging two or more weak colonies results in a single weak colony: further evidence that both the presence of disease/parasites and the proportion of sick to health bees are important in determining colony health. From a colony health perspective, it may be a waste of time and effort to move frames of bees among colonies.
Are you increasing or decreasing the chance of your bees drifting or robbing? Drifting and robbing are significant routes for colony to colony disease and parasite spread. As mentioned earlier, drifting is not a significant problem with feral honey bees because individual bees are unlikely to inadvertently enter another colony’s hive. Distance and the distinctive features of each colony’s hive help bees, even the most navigationally challenged, find the correct colony. Robbing is likely to be the primary means of disease and parasite spread among feral colonies. Even so, robbing is less frequent in feral colonies compared to managed honey bee colonies because distances between colonies limit the number of colonies/bees that can participate in a robbing event. For our convenience we create apiaries – reducing the distance among colonies – and use identical looking hives – eliminating distinctive characteristics between colony hives. This means the rate of drifting and robbing we experience are under our control. How close together are your colonies? If you have colonies on the same pallet or touching in any way, the probability of individual bees entering the wrong hive is high. Consider increasing the distance between colonies and arranging them in a random, non-linear fashion. As mentioned above, we obtained extremely low drifting rates when colonies were placed in concentric circles 1 meter apart with hive entrances all facing south. Do your colonies look identical? There would be fewer confused hotel guests if the décor of each floor differed and the doors to each room were distinct. Consider increasing the unique visual characteristics of your hives.
Do you know where your drones are? Colonies need drones when virgin queens need to take their mating flights; after that, drones are no longer necessary. Limiting drone populations (and limiting the production of drones to your healthest colonies) will reduce the risk of drones moving disease and parasite among colonies.
Are we isolating our sick bees?
It is critical to differentiate between healthy and sick colonies. If a colony is weak and you don’t know why, it is only prudent to assume that an illness is the cause, that the illness can be transmitted to your other colonies, and that you should to act to isolate the weak colony. To do otherwise is to jeopardize your healthy colonies. Consider using entrance reducers when a colony is first becoming weaker than other colonies.
It is hard to decide when a colony is dying and we can do nothing to prevent it. Determine in advance the criteria you will use to decide when a colony needs to be removed/eliminated. For the health of your other colonies you need to be able to make this assessment early enough to limit the spread of disease and parasites. If you have decided to isolate sick/weak colonies, an ideal ”sick bay” should be located at least 3-5 miles from healthy colonies in order to prevent robbing. If a ”sick bay” is not available then consider being ruthless for the sake of your other colonies.
A Sustainable Beekeeping Management Plan
Beekeeping is not a one-size fits all activity. Keeping in mind that your conditions differ from mine, here is a description of how we are attempting to achieve the goals of productive and sustainable colonies.
This plan is a work-in-progress because we have not achieved the level of colony sustainability we desire. Each winter we re-evaluate our success and change our plan as needed. Still, following this plan we have developed a set of colonies that have survived, untreated by pesticides or antibiotics, for seven years and counting.
Next month’s CAP columnist is Dr. Marla Spivak at the University of Minnesota.
I wish to thank Lee S. Finn for his comments and critical reading of this manuscript.