3.4: Wintering Honey Bees - Biology

3.4: Wintering Honey Bees - Biology

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First, ensure that the bees have enough honey stores to get through the winter, generally considered to be 60-90 lbs of capped honey (one deep or two mediums of wall-to-wall capped honey) in this area for a typical sized colony in standard Langstroth equipment; if your hives are still light in mid-September, feed them with 2:1 syrup (up until mid-October) to get them up to that weight. Mouse guards need to go on by early September.

Wrapping hives with black tar paper can help, but is not absolutely necessary (it’s also not a detriment); as someone said, it provides solar gain in the early spring, but has negligible insulation value. A wind break can also help, but is not necessary; a friend of mine uses sections of stockade fence that he bought at Home Depot; my hives are on the south side of a stand of red cedar trees, which provide a natural wind break.

Ventilation is key if you are using standard Langstroth equipment. It doesn’t have to be a lot – the standard notch in an inner cover is enough, even with a solid bottom board and a small lower entrance. Top insulation is critical, between the inner cover and the outer cover; otherwise the moisture in the air in the hive will condense inside the top, drip down on the bees and kill them; the ideal insulation is rigid foam insulation (1″ or 2″ thick) cut to the size of an inner cover; Homasote does not do the job. I alternatively use quilt boards, but they are a bit more complicated. The foam insulation and the notched inner cover accomplish; Michael Palmer, a highly respected commercial beekeeper in northern Vermont, demonstrates this set-up on YouTube in Keeping Bees in Frozen North America starting at about 54:40, though the entire presentation is worth watching.

Finally, I don’t want to reignite the debate about Varroa, but for anyone who might care, if you focus on the above steps and your colonies either abscond by late fall or don’t make it through the winter, you almost certainly will have lost them due to varroa and the viruses they vector. Randy Oliver describes this issue in Understanding Colony Buildup And Decline: Part 1 – Varroa and Late Season Collapse, which was published in the American Bee Journal. Monitor mites using an alcohol wash and consider your treatment options if the count is more than 3% at this time of year.

Overwintering honey bees: biology and management

Factors regulating overwintering behavior are not well understood.

Multiple stressors can affect overwintering success.

Recommendations to improve overwintering success.

In temperate climates, honey bees (Apis mellifera) survive the winter by entering a distinct physiological and behavioral state. In recent years, beekeepers are reporting unsustainably high colony losses during the winter, which have been linked to parasitization by Varroa mites, virus infections, geographic location, and variation across honey bee genotypes. Here, we review literature on environmental, physiological, and social factors regulating entrance, maintenance, and exit from the overwintering state in honey bees in temperate regions and develop a testable model to explain how multiple factors may be acting synergistically to regulate this complex transition. We also review existing knowledge of the factors affecting overwintering survival in honey bees and providing suggestions to beekeepers aiming to improve their colonies’ overwintering success.

Fall Preparation

Preparation of the colony for winter must begin in late summer or early fall. In northern climates, preparation usually starts in August/September, though it may begin earlier depending on the location. Beekeepers must ensure that there are enough food stores for the entire winter and that the colony is healthy and strong. One of the leading causes of colony death during the winter is lack of food. Generally, there should be about 90 pounds of honey reserves for a colony in the North, because bees will not be able to forage in the winter. If there is not enough honey stored in the supers for the winter after the removal of surplus honey by the beekeeper, the hives can be supplemented with a mixture of high fructose heavy corn syrup or, better yet, sugar syrup (2 parts sucrose sugar:1 part water by volume) in the fall. Bees will store the syrup as a substitute "honey" for use throughout the winter. Colonies that have enough honey or stored sugar syrup to survive winter will pass the "lift" test. To conduct a lift test, attempt to lift the colony with one hand using the handle on the back of the bottommost super. If the hive is difficult to rock forward with one hand, then it likely has enough food reserves to survive winter. If the hive is easy to lift, then it probably needs more food.

Some colonies may be located in areas that experience a fall nectar flow from goldenrod, aster, or other fall-blooming plants. This flow may allow the bees to store enough reserves, but honey production should be monitored carefully by the beekeeper during this time. The best way to learn about local honey flows in your area is to contact a horticulturalist at a local county or state Extension center or mentor with an experienced beekeeper from your immediate area. An alternative to supplementing with syrup is to supplement weak colonies with extra honey from stronger colonies. Care must be taken if this path is chosen because diseases may be spread from one colony to another through infected honey or frames.

Beekeepers must also ensure that the honey stores are properly located within the hive. Brood should be located in the bottom hive body (brood box, or deep super) and surrounded by cells filled with pollen. The pollen-filled cells, in turn, should be surrounded by cells filled with capped honey. A typical colony will naturally create this brood/pollen/honey pattern.

Most races of bees cover stored pollen with honey, often sealing the honey, making it hard to measure the amount of pollen stored within a colony. Late summer and early fall bees can be fed abundant protein and store many food reserves in their body to feed to late winter and early spring brood.

Bees will cluster around the queen in the bottom brood box as temperatures drop. The center of the cluster is maintained at approximately 95°F while brood is present. As winter progresses, the cluster of bees will move up through the colony as a unit, slowly eating through their honey stores. It is important that food stores are available above and beside the cluster. Because wintering clusters tend to move up in the nest, remove any queen excluders that are still on the hives after the last nectar flow. Otherwise, the queen can be trapped below the excluder as the cluster migrates upward throughout winter.

Sugar Syrup Recipe

Basic ingredients: White granulated sugar, water

Warning – Do not use brown or raw sugars as they contain impurities.

Thick Sugar Syrup: 1 Kg of granulated sugar to 630 ml of water (2 lb sugar to 1 pt of water)

Thin Sugar Syrup: 1 Kg of granulated sugar to 1L of water (2 lb sugar to 2 pt of water)

There is no need to boil the mixture but heating the water helps. Stir regularly to dissolve all the sugar. When fully dissolved the mixture is clear and a very pale straw colour.

If syrup is stored for any length of time then a black fungal growth may appear. This can be prevented by adding a little thymol. Thymol does not dissolve readily in water but a solution can be made up in a small sealable bottle. Fill it to one third with thymol crystals* and top the bottle up with surgical spirit. Add 2.5 ml. of this solution to 4.5 l. of sugar syrup or half a teaspoon to a gallon of syrup.

I use 30lb honey buckets to mix and serve the syrup.

Bee Informed: Warming and Swarming

You may be noticing that wild honey bees are more noticeable foraging in your landscapes, but that doesn’t mean there hasn’t been busy bee activity all winter long.

If you are located in the colder regions of the U.S., wild honey bee colonies just hunker down and cuddle. They do not hibernate, and mortality can be high with older bees dying off over time. But if a wild colony has set up home in a sunny spot, protected from wind and flooding (Fig. 1), activity never stops inside the comb. Assuming the queen is healthy, and the colony has plenty of stored honey and pollen accessible to them, they will shiver their way through the winter months. Quite literally, the worker bees cluster around the queen and shiver to maintain an internal colony temperature significantly higher than the outside ambient temperature.

Under subtropical, tropical, and mild winter conditions, egg laying and brood rearing slows down, but doesn’t stop. As the spring days lengthen, and temperatures increase, plants generating new sources of pollen and nectar stimulate the rearing of brood (baby bees). Bees forage for food and water to regulate temperature and liquefy crystalized honey to feed the brood. With the successful rearing of young and emergence of worker bees, the colony will eventually become overcrowded. This necessitates swarming.

What is honey bee swarming?

When it comes to colonies and queens, there can be only one. The queen bee in an active hive is rarely seen outside and hardly ever needs to fly. She stays deep inside the comb, is cared for by the worker bees, and continually lays eggs. Honey bee queens produce a pheromone that inhibits the production of new queen bees.

But as colonies become increasingly crowded the message fails to make it to all the bees, or older queens begin to produce lower levels of the pheromone. Uninhibited worker bees create larger elongated rearing cells called queen cups. Once eggs in the queen cups hatch the larvae are given special care and are fed with a food called royal jelly. Worker bees tending the existing queen give her less food, and egg production slows as the queen loses body weight, which will ultimately help her to fly. When new queens are almost ready to emerge from the queen cups, the old queen takes most of the workers and departs. The traveling mass of bees is called a “swarm”.

Before leaving, the workers fill their stomachs with honey, and this is the only food the swarm has to sustain activity until they find a new home site in which to establish their new colony. The old queen, being a weak flyer will often land suddenly, and often not far from the original hive. Resting swarms can be found clustered on the ground, on a fence post, a tree limb, or the side of a building (Fig. 2), and workers will quickly surround the queen to regulate her temperature. Since swarming bees are focused on finding a new home, they are not generally defensive and rarely pose any danger to humans or other animals. Swarming is common during spring and continues throughout the year while pollen and nectar sources support growing colonies. This is greatly influenced by environmental conditions. In the low desert southwest, plants are already blooming, and bee experts report that wild honey bee swarming began weeks earlier than usual.

While the old queen takes a mini break several hundred scout bees will leave the swarm and explore the surroundings in search of a new home site. When a scout discovers an appealing location, the scout will perform recruitment dances to persuade the other bees to investigate the site. What follows is a literal debate over several days, all communicated in dance. After multiple site visits and a veritable dance-off between scout bees they reach a consensus regarding the new location. The scouts then guide the swarm to the chosen site, which can be several miles from the original colony. A swarm needs to build a new hive before the honey reserves in the workers’ stomachs is depleted. If the weather is not favorable and/or food sources are unavailable, the swarm can starve and suffer significant mortality.

Once settled, workers will start building a new comb. The queen will start laying eggs, and workers will carry out all other duties for the colony including foraging, cleaning, hive building, guard duty, comb ventilator, and nanny for the brood.

Back in the original hive, the first queen to emerge will sting and kill other emerging queens. The old hive usually has enough food reserved to last the colony for a while, but it is important to start building up the number of worker bees once more. The new virgin queen will mature after several days and fly out to seek drones in areas called “drone aggregations”. She will mate multiple times with several drones and will store sperm for the remainder of her lifetime. After mating, she will return to the hive and start laying eggs, slowly building up the colony.
Sometimes newly emerged virgin queens will leave the hive with a group of workers in another swarm, called an
“after swarm”, and this can occur repeatedly until the old hive is depleted and dies off.

If a cluster of bees suddenly appears on a wall, on a branch of a tree or on the ground and remains exposed, this is most likely a resting swarm. Swarming bees will not have yellow or orange pollen evident in pollen baskets on their hind legs, and swarms will not be seen moving in and out of cavities. Swarms will often move on in a few days without intervention and although not defensive, they can sting if disturbed. It is best to observe the swarm from a distance and hope they do not find suitable nesting sites close to or in your home or building.

What to do when you see a swarm?

It is best to leave swarms alone if they are in a spot that does not have much human traffic passing close by, e.g., a swarm on a wall that can be cordoned off using caution tape. But if a swarm is in the way of people in a location that cannot be avoided, seek the help of an experienced professional to remove swarms. If swarms are disturbed, they will disperse within a local area and this can cause people to panic.

Have staff or contacted pest management professionals who can respond rapidly to wild honey bee swarms when necessary. Local beekeepers or beekeeping associations often help. Most states have their own beekeeper’s association, and many are active on social media. Some beekeepers will collect swarms and use them to start new hives. Information for the Arizona Beekeepers Association can be found at The website provides a list of beekeepers that might be able to assist with bee removal.

Compared to swarms, established colonies in and around homes, schools, and other buildings pose greater risks to people (Fig. 3 and 4).

Wild honey bees can become pests because of sting incidents, defensive bee attacks, and the structural damage and annoyance that their foraging and nest-building activities can cause. The chances of people getting stung in such situations are much higher once brood are being reared.

Bees and combs should be removed by professionals who have appropriate personal protective equipment.

Most honey bees observed in the landscape are foraging bees from established colonies looking for water, nectar or other sugary, sweet-smelling substances. If you observe bees passing in and out of a cavity, this indicates the presence of a colony within.

Honey bees and other pollinators are important and desirable elements in our natural environment. But wild honey bees can sometimes interfere with our activities or interests. When this happens the best course of action is to take an integrated pest management (IPM) approach.


Nice job Rusty. Last year I went into winter with 31 hives and had 29 survive. This year I went into winter with 50 hives and I have 15 surviving. I live in Genesee county in Michigan and we had some very long, very cold spells this year. That, combined with a very dry summer last year causing some weak hives going into winter, spelled doom for my girls this year. The sad thing is I saw it coming too late.

In early October when there should have been a lot of brood for the winter bees there wasn’t. I should have realized earlier in fall that there weren’t enough bees to raise a lot of bees for winter. I fed like crazy starting in September but to no avail. I believe during the dry late summer period the queens shut down laying more so than normal. During the normal goldenrod flow it was also dry. Often I would pick some of the blossoms and find them crumbling in my hand because of dryness. This is normally an important flow for my bees that just didn’t produce last year. Maybe if I had been more prescient and started feeding earlier I could have made a difference. Hopefully, I learned something.

That is so sad, especially after having such a great winter the year before. It’s a good example of how bees and beekeepers are at the mercy of the weather and the local climate. So even when beekeepers do everything right, mother nature comes along just to prove a point–or so it seems. I trust you will be re-building your colonies? Hope so.

I haven’t heard from you in while. Hope all (else) is well.

Thanks for all the helpful info . . . I’ve been thinking about that Warré quilt and why we don’t use it on Langstroths. Meanwhile (also in the NW) trying to balance ventilation and dryness with warmth. Your approach sounds great I can’t wait to try it.

I’m still really excited about the Warré quilts. As I said in my post, it made an unbelievable difference inside my hives. Everything was dry and toasty under the quilt even though the inside of the telescoping cover was drenched every time I opened the hives. And the quilts are easy to make and easy to work around. I’m surprised they didn’t catch on years ago.

Great website. Lots of good information on here and you sure have spent a lot of time amassing it.

I have some comments from the other side of the spectrum concerning your wintering methods and success. None of this should be taken as criticism, just my perspective and a desire for balance.

It’s obvious that we beekeepers (as a whole) keep striving for a 100% overwintering survival rate without considering that in naturally reproducing biological systems 100% survival is not only impossible, it’s genetically counterproductive. If wild colonies had anywhere near the success rate you were able to induce with your colonies, the world would be knee deep in honeybees. That die-off is a necessary and natural requirement for continued strengthening of any species. The world is not benevolent. Not everyone or everything gets to live and, though harsh, this evolutionary process has been immensely useful.

So, from that biological fact, a 100% survival rate is equally unlikely as a near 100% death rate, assuming nothing catastrophic occurred. I’m betting that a natural time-weighted average survival rate of about 50% is more realistic. But, when humans get involved we can short cut that process a little and baby the creatures we “use”, increase their survival rate, and we feel we are either saving money or more successful, or likely both. To that end we come up with all sorts of “fixes” for problems that, in reality, did not exist and, in turn, other problems unlooked for pop up as a result of those “fixes”. Like, say, the way commercial queens tend to be reared thousands upon thousands of queens that are nearly genetically identical 100’s of queens from the same colony, all surviving. The shallowing of the genetic pool that big commercial queen breeders use (because it is the only economical way to do so) is stunning. Nothing good can come from this practice, I assure you. Look at the survival rate and longevity of the commercial queens . . . not good. On the other hand, I’ve had feral queens that produced very well into their 4th and even 5th years! I’ve heard rumors of the occasional commercially bred queen lasting that long, but I’ve never met anyone that witnessed it.

I guess I’m rambling on a little too much here, but it’s late and my long windedness gets worse the more tired I get. To close, bees die. As for my methods, I let the bees build their own comb (no foundation), I try to provide a cavity that is as natural as possible within the confines of my scientific curiosity and convenience, I don’t feed them unless I have to and when I do I don’t enjoy it, I don’t treat at all, and for my lack of effort I get 50 to 100 lbs of surplus honey per colony and between a 50% and 80% survival rate (even for nucs) with a small, statistically insignificant apiary of 10 to 20 full size colonies left in the cold to fend for themselves. I doubt that it’s possible to get a 100% survival rate with my no-treatment, sink-or-swim method. When I lose a colony through no obvious fault of my own, GREAT! Good riddance! Weakness removed.

That’s a well-thought out and well-written comment. Thank you. I agree for the most part and have, myself, occasionally written about in-breeding, gene pool suppression, and the perils of over-management. No argument.

On the other side of the coin, I like to experiment and see how far I can push the envelope. I always end up learning something. But I actually have another purpose in writing the overwintering pieces.

From what I’ve read, approximately 80% of new beekeepers quit within the first two years of starting. They usually quit after losing all their bees during the winter. They get discouraged and decide it isn’t worth it.

I believe that a world with many beekeepers is good for the bees, the environment, and for environmental awareness. If the new beekeepers stay in, a number of them will make contributions to the art and science of beekeeping–maybe large, maybe small, we don’t know.

So if I can help some of the newbies make it through that first and second year, then perhaps they won’t give up. By that time, they will have developed their own beekeeping philosophies and will go off their own and develop their own techniques.

I just try to give folks a sample of what can be done. I try to offer multiple suggestions and let them take it from there.

I definitely have two types of readers. The first group is interested in the science. They want to know about nutrition, pollination ecology, reproduction, and environmental toxins. The second group–by far the larger–just wants to know how to get through the next beekeeping day. So I try to mix up the posts, not only for them but for me. It’s kind of fun.

So there you have it: I can be long-winded too. I appreciate your comments and welcome more of them in the future. Please come back.

I will vouch for this post. Year later, I am a newb starting my first two hives this April. I am combing all of the posts and filling my brain with bee info. I think I have the initial process down. I’m already looking towards winter. Thank you so much for this website.

Best comment ever. I feel too new to contribute to this conversation, but I’m taking notes for future reference because it’s in line with where my thinking is headed (which is usually a lonely place).

Ken opens the door to a really important conversation. In my view we could realistically attribute something like 85% of the problems in beekeeping today to sloppy genetic management. Sadly, this is taught almost everywhere you look.

The art of animal husbandry has historically been one that seeks first and foremost to care for the bloodlines, the carefully raised strains, the *populations*. This entails, always, selective breeding. Only the best of each generation are allowed to make the new generations, sending only the best genetic material down to all the future generations.

This mirrors natures, where the weaker tend not to reproduce, and the strongest reproduce in far greater numbers. Thus thus strains healthiest and best suited to the present environment flourish, keeping the population as a whole healthy, while those unsuited to the environment for whatever reason are steadily winnowed out.

If you remove this *process* the result is an ever weakening population. And sooner or later nature will catch up, and remove those individuals unsuited to the environment.

Today, the effort to maintain every single hive has lead to almost total abandonment of any such process. Even the weakest individuals are treated and mollycoddled through the winter, and the following year their drones spread their inadequate genes into the next generation.

Treatment, generally, can be seen to be a kind of poisoning.

These are hard words for a novice to hear (and for many professional beekeepers too). Yet I think this plain truth should be taught from the beginning, and the alternative path shown. Always raise more colonies than you need, don’t treat, and allow nature to sort the strong from the weak. Or, get more proactive, and learn about the signs by which mite tolerance can be recognised culling non-tolerant queens and replacing them with new and better suited ones raised from your mite-tolerant and thriving colonies.

To do otherwise is to be part of the great error of modern beekeeping, the perpetual destruction of the natural emergence of mite-tolerance and bursting, self-sufficient health.

Mosquitoes carry malaria which they transmit to humans by biting them and sucking their blood. They are similar to varroa mites which transfer viral diseases to honey bees by biting them and sucking their hemolymph. Instead of treating humans for malaria, should be have let them all die in hopes of creating a malaria-resistant human? This might work after millions and millions perish, but is it the best thing? Is it the best management philosophy?

Among other things, your system attacks the victim rather than the vector. Humans are victims of malaria and honey bees are victims of the viral infections. Your system allows the victims to die and the vectors (mosquitoes and varroa mites) to thrive. There has to be a better way.

In addition, if we allow mass die-offs of honey bees in order to find the genetically perfect population, we will have a short-term pollination deficit until varroa-resistant honey bees are the norm. This could be a few years or many years. How do you plan to feed the world in the interim? How many days are you, personally, willing to go without food?

Although it is crucial to have breeders work on these problems and develop more resistant strains, we need productive fields in the meantime. So, although it is not ideal, we must keep our less-than-perfect bees working. And dead bees don’t work.

Not all beekeepers are bee breeders, but there is a vital role for both. It is up to the beekeepers to keep our food, textile, drug, and industrial crops coming in while we wait for the bee breeders to do their magic. To do otherwise could be tragic.

I fully agree with you about using Quilt box. This also help me overwinter 3 hives successfully, including one hive this is very weak and I thought would not make it.
This is my second year using a quilt box and I have not losses since using quilt boxes. I use a medium as a quilt box, the box consists of burlap topped with crumpled up newspapers. I noticed too in winter the newspaper absorbed moisture very well, keeping the hive warm and dry.

I live in northern New Jersey and came thru a rather harsh and cold winter.

This is our first time ever of having hives. We have two, one is weak, one is strong. We got both colonies at same time from same company. We live in a very rural area of south central Missouri. We are surrounded by forest, hay fields and cattle. Pesticides aren’t a concern. What is a concern is the cell phone tower near by. I read long before we even thought about beekeeping that the signals from these towers interferes with a bees navigational system thus causing the bee to not find its way back to the hive. In doing so, this is what is causing colony collapse.
Any comments?

Some folks theorized that cell phone signals interfere with honey bee navigation, but scientific experiments have not been able to prove this. In any case, it does not cause colony collapse disorder. Colonies that live hundreds of miles from the nearest cell tower also get colony collapse–a fact that eliminates it as a cause.

A recent study showed that if you leave your cell phone on and store it in your hive, the bees become agitated. But if you are not doing this, your bees should be fine.

Having a weak colony and a strong colony is not unusual. There can be any number of reasons for a weak colony, including the queen’s health and genetics, pathogens, predators . . . or sometimes just luck.

If you are worried about the weaker colony, you can take a frame or two of brood from the strong colony and add it to the weak one. (Be sure not to move the queen.) This normally doesn’t affect the large one but it may boost the smaller one enough to to get it “over the hump.” This technique called “equalizing” is one I use often and it can save a questionable hive.

Rusty, I am wondering what is your configuration for overwintering? This wil be my first winter with the bees and have had a great spring/summer so far. I am in Vancouver BC so my weather is not to far off yours. I started with a package in April, had a swarm in June, caught it and started a 2nd colony. Both colonys did well and grew to 4 boxes (2 deeps and 2 mediums on #1 and 3 deeps and 1 medium on #2) I harvested recently and removed both the top mediums. I am wondering your thoughts on overwintering with 3 deeps or 2 deeps and a medium. here in the Pacific North West (yes we call it that here too, which I always thought was weird, shouldn’t it be the Pacific South west)

You know, I’ve always wondered about that. I’m always afraid to write Pacific Northwest when I’m addressing a Canadian. It does indeed seem like it should be the Pacific Southwest. At least we got the Pacific part right.

I like to overwinter my bees in a hive that fits the colony size. At times, I’ve overwintered single deeps. Many times I’ve overwintered one deep and one medium. I think the ideal is a double or triple deep, but there is no point if the boxes are empty or nearly so. Last year I overwintered two nucs, each in a single deep with five frames of bees, pollen, and honey and five frames of foundation. I stacked these with double screens so they could share warmth.

So if you have three deeps or two deeps and a medium full of bees, you should have no trouble.

Our winters are not that cold, so as long as the bees have plenty of food and good ventilation (that is, the interiors are not wet), they can do fine. Our temperatures will not kill the bees as long as they are dry and have food. Check frequently for moisture. If it collects under the cover and drips back on the cluster, you have to add ventilation. In late December or early January check to see that the colony is in contact with the food supply. Sometimes you have to move frames of honey closer to the bees, especially toward the end of winter.

I’ve noticed you don’t wrap your hives during the winter, and I assume it’s because your mild Pacific Northwest weather doesn’t make the extra weatherproofing necessary. What are your thoughts on hive wrapping? How cold is too cold for bees?

I took your question and made it into yesterday’s post. Hope I answered your questions. As for “how cold is too cold for bees?” it’s hard to come up with a number. A good-sized colony with lots of food and a dry hive can keep themselves warm in amazingly cold weather. It’s almost always moisture that kills bees, not cold.

Think of it like this: If you are dry inside your winter clothes, you can survive in cold weather for a long time. If you fall in a creek wearing the same winter clothes, they do almost no good at all–you’ll freeze to death in no time. Same with bees.

You mention in your reply to Steve to check on the colony in late December or early January to check that they are in contact with the food supply, and assess moisture/ventilation. My hives are overwintering with 2 deeps and 1 medium each. I am concerned about pulling apart the hive in winter — if they are still in the 2nd deep, then I would have to move the medium to see what they are doing. This could mean smoking them and all around disrupting them, which I would rather not do in the winter. I know this would have to happen on a mild day, but if they are out and active on that mild day, doesn’t that tell me what I need to know in regards to their ability to access the food stores within their hives? If it isn’t mild enough for them to be active, then I shouldn’t be opening their hive, right?

I never tear apart a hive in winter. I tip up the moisture quilt and inch or two and look inside. If the bees are all clustered around the top bars with no more room to move up, I give them candy. If I can’t see the bees, that means they are in contact with food somewhere down there and they are good to go with no further intrusion.

You don’t have to go into the hive looking for them. If you can hear them, you know they are there. If they are not clustered at the top, they are not out of food. Hearing but not seeing is a good thing in winter.

I never tear apart a winter hive unless I know it’s dead.

Thank you for clarifying, Rusty. I mis-understood your comment about checking. Just a little peek.

3.4: Wintering Honey Bees - Biology

I always put some into winter

Before we had varroa, when I had well over 100 colonies of bees I regularly put nuclei into winter. I did much of the pollination of apple orchards that were in my part of West Sussex at the time. I used to put strong 4-5 frame nucs into winter and found the survival rate was as good as the full colonies. I found they were amongst the strongest colonies in the spring, even though they mainly had minimal protection. They were good colonies to take to the orchards.

In those days there were a large number of WBCs in existence and I collected many for next to nothing, mainly because the floors had rotted or the lifts had fallen to bits and I was given the remains. That still left many brood boxes, so I made up a number of floors, similar to single walled hives, that I put the WBC brood boxes on. Plastic fertiliser sacks were used as quilts, with something waterproof for a roof, which could be anything from a sheet of corrugated iron to a paving slab! The nucs were wintered in these with no other protection, no packing and no division boards "to keep them warm".

I mention all the above because I have a lot of experience and success of wintering nucs pre-varroa. I learnt a lot too, especially that the old saying "the best packing for bees is bees" is spot on. Since varroa arrived it has become much more difficult because the mite and the viruses it vectors has shortened the lives of winter bees, meaning weaker or dead colonies in the spring. It is still possible to get nucs through the winter though and I still do, but I need to be more careful.

I use a lot of standard frame nucs for queen mating, which are worked quite hard, with flying bees and brood added or removed during the summer. At the end of the season they vary a lot in strength, depending on circumstances and if any queens have failed. What they usually have is a young queen, which means they are laying well, so providing the nuc with young bees that will last most of the winter.

Uniting of smaller nucs may be needed, or because you have some poor queens that you would normally cull. When uniting you must remember that two 3 frame nucs don't make one 6 frame nuc. There won't be as many bees as you think there should be. In normal circumstances I like to unite in August, to give the nuc time to settle down and get things where they want them. You can increase the number of bees in a nuc by adding a frame of sealed brood from a full colony.

I have some nuc boxes without floors. These allow me to unite nucs using the newspaper or shaking methods. I often leave these as double boxes during the winter, where they usually do well.

For wintering any colony there are a few things you need to have, but the smaller the colony, the more important they are.

    A good queen. If she is young she will lay well, where older ones may be backing off. I don't bother putting poor queens into winter if I can help it, otherwise I have to replace them in the spring. If a queen is showing signs of failure, then kill her, as she will probably die anyway and take the bees with her.

Since varroa has changed things I have successfully wintered nucs, often as small as three frames. I put 6 nucs into the 2014/15 winter that were quite weak, but I wanted to try to save the queens. I didn't expect any of them to survive, but they all did. I wouldn't suggest putting weak nucs into winter as a matter of course, but it shows what can be achieved if you prepare them as above.

So far I have only mentioned wintering established nucs, but towards the end of the season you can easily make up nucs to overwinter from your honey producing colonies using increase Method 4 . If the nucs are balanced well, with plenty of bees, sealed brood and gentle feeding they will soon be in the same state as an extablished colony. No harm will come to your full colonies if they have the required amount of brood, bees and stores.

Winter losses are greater than they were and the ordinary beekeeper with 3-5 colonies can expect to lose one or two. Putting one or two strong nucs into winter is a good way of making up losses before they happen.

The Honey Bee (Apis mellifera)

For illustrations to accompany this article see Insect Life-Cycles

Ants, bees and wasps are social insects. This means that they tend to live in colonies where all the individuals are of the same family, often the offspring of one mother. In the more highly organized societies there is a division of labour in which individuals carry out particular duties.

Structure. The bodies of bees are divided into head, thorax and abdomen, with three pairs of legs and two pairs of wings on the thorax. The fore and hind wings on each side are linked by hooks and grooves so that they move together in flight.

The mouth parts consist of a "tongue" or labium, which can be enclosed near the head by the labial palps and maxillae. Nectar, from the nectaries of flowers, can be drawn up the grooved surface of the labium, partly by capillary attraction and partly by the pumping action of muscles in the head. When not in use, these elongated mouth parts are folded back under the head, leaving the shorter, stouter mandibles free in front to chew pollen, manipulate wax, attack intruders etc.

The ovipositor through which the queen lays her eggs in the wax cell, is modified in the workers to form a sting.

Organization of the colony. There are four species of Apis, the honey-bee, one of which is Apis mellifera, the Western honey-bee, which is the commonest hive-bee in this country. There are three kinds of bee in a colony: in the summer, a few hundred drones or males, one egg-laying female, or queen, and from 20 to 80 thousand sterile females or workers. The mature queen is usually easily recognized by her large abdomen.

The Queen. A queen bee may live from two to five years and, except for a short period at the end of her life when one of her daughters takes over the colony, she is the only egg-laying female. All the members of the colony, whether drones or workers, are her offspring. She spends all her time laying eggs, perhaps up to 1500 a day, each one being placed in a wax cell made by the workers. The queen can feed herself but in the hive the nearest workers turn towards her, lick her body and feed her by regurgitating a special secretion of their salivary glands, called "royal jelly", on to their probosces from which the queen can absorb it.

The queen usually mates only once in her life (though second and third matings are known to happen) and stores the sperms received from the drone in a sperm sac in her abdomen. This store of sperms lasts her for the two or more years of egg-laying, a small quantity being released with each fertilized egg laid.

When the store of sperms is used up she may continue to lay eggs but they are all unfertilized and will become drones. By this time one of her daughters has been reared as a queen and is ready to take over the egg-laying.

Life history. Each egg is laid in one of the hexagonal wax cells and hatches into a tiny, white, legless larva. The larva feeds on substances deposited in the cell by the workers it grows, pupates in the cell, hatches as an adult bee and finally emerges from the cell into the hive. The eggs hatch after three to four days and by nine days are fully grown and ready to pupate. The workers put a capping over the cells at this time. Ten or eleven days later the capping is bitten away and the adult emerges. The times given above vary with changes of temperature and according to whether the bee is becoming a drone, worker or queen.

Drones. The drones, who live for about four to five weeks and do not work inside the hive, are fed by the workers or help themselves from the store of pollen and nectar in the combs. Their function is to fertilize a new queen. In the autumn, or when conditions are poor, they are turned out of the hive where, unable to find food for themselves, they soon die.

Workers. The workers are female bees whose reproductive organs do not function. Among many other tasks they collect food from outside the hive and store it, make the wax cells and
feed the developing larvae.

Origin of the three types of bee. The wax combs are built hanging vertically with a gap of about half an inch separating each one. The cells in each comb thus lie horizontally. The workers prepare three kinds of cell: worker cells about 5 mm across, drone cells about 6 mm across, and queen cells quite different from the others. The queen cells are larger and made individually, pointing downwards like small acorns from the surface or bottom of the comb. The relative numbers of these three kinds of cell seem to depend on the time of the year, the temperature, the abundance of food and condition of the colony. Normally, the worker cells predominate.

Eggs are laid by the queen in the brood area. This is where the temperature is about 32° C, kept so by the heat given out by the bees' bodies. The area varies, diminishing in the winter and expanding in the summer. The queen moves over the brood area, laying eggs indiscriminately in any of the three types of cell she encounters, by placing her abdomen in the cell and depositing a single egg. The eggs placed in the larger, drone cells, are not fertilized, and this results in the eggs developing into a male bee or drone. In the queen and worker cells, fertilized eggs are laid.

For the first three days after hatching, all the larvae are fed on a protein-rich, milky secretion, called royal jelly, which comes from the salivary glands of workers of a certain age. The grubs in queen cells continue to be fed on royal jelly for the rest of their lives, but those in drone or worker cells are "weaned" onto a mixture of dilute nectar and pollen. If a one-to-three-day old larva is transferred from a worker to a queen cell, it will receive the diet of royal jelly and develop into a queen. Thus, though there is no difference between the eggs and young larvae in queen and worker cells, their different treatment by the workers results in their becoming quite distinct types of bee.

Exactly what aspects of their feeding cause this is not known for certain. It may be the absence of pollen from the queen's diet, the cessation of royal jelly in the worker's diet, the super-abundance of food placed in the queen cells or a vitamin-like chemical fed to the queen larvae in the early stages. After three days, worker grubs cannot be reared as queens, even if they are placed in queen cells and fed on royal jelly.

Drones, then, develop from unfertilized eggs in wide cells, queens and workers from fertilized eggs which are fed differently as larvae.

Life of a queen. When a new queen emerges she is fed by the workers. She bites a hole in any other occupied queen cells that she finds and some observers believe she stings the occupants. In any event, the workers usually tear down the other queen cells that have been bitten into and destroy the occupants.

For a few days the queen leaves the hive for short flights lasting, at first, only a minute but gradually lengthening to about 15 minutes. During these flights she learns the geography of the district around the hive. On one of these flights she is pursued by drones, but not necessarily from her own hive in fact, they do not follow her from the hive but are already waiting outside. One of them catches the queen and mates with her, depositing in her vagina sperms which eventually find their way into her sperm sac. She now returns to the hive, and soon after begins to lay eggs.

From glands in her head, the queen produces a mixture of chemicals called pheromones (&lsquoqueen substance&rsquo). When the workers &lsquolick&rsquo her body, the pheromones suppress their fertility. When, at the end of her life, the queen ceases to produce these pheromones, some workers start to lay eggs which, being unfertilised, produce only drones. They do, however, start building new queen cells.

Division of labour. The tasks undertaken by a worker bee depend partly on its age and partly on the immediate needs of the colony. Generally speaking, the worker&rsquos life follows the course described below, although the times given are very approximate and in many cases may not apply.

After hatching, she is fed by other workers and spends a good deal of time standing still on the comb. She does, however, clean out cells from which bees have recently hatched by removing the cast larval cuticles. On the fourth day she feeds on honey from the store cells and eats a good deal of pollen. Between the third and fifth day she feeds older larvae by placing nectar, water and pollen in their cells.

The pollen that she eats is rich in protein and helps her salivary, brood food glands to become active, so that by the fifth day they can secrete the brood food or royal jelly which is fed to the younger larvae. After ten or twelve days these glands cease to function effectively but wax glands on the underside of her abdomen begin to secrete wax which the worker uses for comb-building and repair. By this time she is also beginning to leave the hive for short flights during which she learns the position of the hive and the topography of the surroundings.

Between the twelfth and twenty-first days these reconnaissance flights continue while in the hive, the worker collects pollen and nectar from the incoming field bees and stores it in the cells. She also processes the nectar and begins its conversion to honey, and cleans the hive by removing the dead bees and detritus from its floor.

After three weeks of hive duties the worker becomes a forager and spends the daylight hours collecting water, nectar, pollen and propolis (see below) and carrying it back to the hive. This work she may continue for about three weeks before she dies.

The "schedule" given above is by no means rigid, and observers have recorded bees doing several of the duties mentioned at the same time, as well as old bees performing "nurse" duties, and young bees foraging. Some of the duties may be missed out altogether. For example, only a few of the young foragers do duty as guard bees, protecting the hive from invasion by robber bees.

Food. The foraging workers collect nectar from the nectaries of flowers. The nectar is drawn off from the nectaries by the long labium. It is pumped up and swallowed into the honey sac, a region of the gut from which it can be regurgitated on reaching the hive. Nectar is a watery sugar solution when collected, but it is processed by the house bees to whom it is passed. These workers repeatedly swallow it, mix it with enzymes and regurgitate it. The enzyme action and the evaporation of water result finally in its conversion to honey. Nectar contains very little protein, and the pollen collected by the foragers makes up this deficiency.

Pollen is collected by combing off with the legs the grains which adhere to the bee's body after it has visited a flower. The pollen collected on the head, and removed by the front legs, is mixed with a little nectar and passed to the back legs which have combed pollen from the abdomen. The rows of bristles on the legs assist this combing action. The pollen press, in the joint between the tibia and tarsus of the hind legs, squeezes the pollen which is passed to it from the pollen comb of the opposite hind leg. The pollen and nectar paste is thus pushed by the press into the pollen basket on the tibia, where it is retained by the fringe of setae. All this may be done while the bee hovers in the air or while hanging from the flower. The forager returns to the hive with the two packs of pollen and pushes them off into an empty cell or into one with some pollen already in it.

The younger house bees then break up the pollen masses and pack them down into the cell. When the cell is full it may be covered with a little nectar and sealed over. Both pollen and honey sealed in the store cells are eaten by the bees in the winter months when no other food is available. Water is collected and used to dilute the nectar with which the larvae are fed, but there is no evidence of water being stored.

Propolis is a resinous substance that the bees collect from trees and sticky buds. They use it for sealing small cracks and gaps in the hive.

Swarming. When the size of the colony reaches a certain stage, usually in Spring or Summer when the nectar flow is at its greatest, the queen and a great many workers, leave the hive in a swarm. The swarm comes to rest in a great cluster on a tree branch or similar situation. Scout bees, who may have left the hive some days before, seek out a suitable situation for a new nest and return to the swarm and communicate this information, whereupon the whole swarm moves off to the new site. In the old hive, one of the new queens hatches out, mates, and takes over the colony that is left.

Senses and communication. The senses of touch and smell, particularly through the antennae, are very important to bees in finding sources of food, in identifying members of their own colony, and sometimes in finding their way home. Their compound eyes are sensitive to certain groups of colours though colour-blind to red. In the darkness of the hive they must depend on touch and smell to carry out their activities. They find their way to and from the hive by learning the landmarks in the vicinity and steering by the position of the sun.

A bee which has found a rich source of food will return to the hive and execute a dance on the surface of the comb. It takes the form of a figure eight with a straight section in the middle. The length of the straight section is proportional to the distance of the flowers from the hive, and the angle it makes with the vertical represents the angle between the position of the sun, the hive and the source of food. In addition. the dancer may make waggling movements of her body on the straight section, which indicates distance. Some of the foraging bees in the hive follow the dance, touching the dancer with their antennae. From time to time the dancer stops and, regurgitating a little of the nectar she has collected from the flowers, she feeds the attentive workers. The dance pattern, the taste of the nectar and sometimes the scent of the flowers on the dancer's body enable the workers to find the feeding ground from which the dancer ,has just returned.

Bee-keeping. Although humans cannot tame the honey bee they can exploit its activities. A hive is provided which can be opened and examined without unduly disturbing the colony. It is fitted with vertical wooden frames in which the bees can build their combs. The frames have, wired into their centre, a sheet of wax which is indented with a hexagonal pattern so that the workers build their combs within the confines of the frame, and each comb can then be removed separately. By means of a grid, through which the workers but not the queen can pass, the queen is kept in the lower section of the hive. As a result, the combs in the upper sections will contain no grubs but only pollen and nectar. It is from these "supers" that the honey is eventually removed by the bee-keeper. In the autumn and spring the bees are given sugar solution to compensate them for the honey taken from their winter store.

In addition to their value as honey producers, the part played by bees in pollination is very important. In apple orchards and clover fields, for example, the yields have been greatly increased by keeping a hive of bees in the locality. Efficient pollination leads to complete fertilization of all the ovules in an ovary, which subsequently develops into a perfect fruit. There are firms which hire out hives of bees to farmers and fruit growers during the flowering period of their crops.

For illustrations to accompany this article see Insect Life-Cycles

3.4: Wintering Honey Bees - Biology

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Planning for Varroa

We are in the middle of an epidemic of varroa mites (Varroa destructor). Varroa mites damage developing honey bees and transmit a number of deadly viruses, often leading to colony death. This deadly pest has become so widespread in the United States that they are present in virtually every honey bee colony, and can re-infest colonies quickly. If you are a beekeeper in the United States in 2017, your honey bee colonies are at risk from dying from varroa associated viruses

Those of us in beekeeping education have seen a rather upsetting trend with beginner beekeepers (who aren&rsquot enrolled in good classes): they start full of enthusiasm, but will lose all or most of their bees year after year, almost always to varroa. After about 3-4 years of steady losses, many quit beekeeping all together. If you consistently have high losses, you will continue to lose bees until you give varroa the respect it deserves. The beekeepers who succeed are those beekeepers who take varroa seriously, and make varroa control a regular part of their honey bee management.

The varroa mite is one of the most serious pests we have dealt with as beekeepers, but we can take actions to keep our bees safe from it, and there is no reason to lose all or most of your bees to varroa every year. While varroa mites WILL be in your hives this year, not every colony is doomed to die from the viruses that these mites transmit. If you keep the varroa population in check, the honey bees can remain healthy. It is when the varroa population gets out of control that the colony becomes profoundly sick from injury and disease, and is at a high risk of dying.

The information below is designed to explain the different tools that we have to manage varroa populations. Your goal as a beekeeper should be to develop a strategy at the beginning of the season that will use a variety of these tools, making sure that varroa mites never take over your colonies, and your bees stay healthy.

Varroa mite populations, when left unchecked, can grow quickly. Each female mite reproduces multiple times in her life, and each time she reproduces, she lays multiple daughters (and they all reproduce multiple times, and they all produce multiple daughters, and those daughters reproduce&hellip). All of this reproduction is occurring under capped brood cells, which means two things 1) the more capped brood we have, the faster varroa can reproduce, and 2) we can&rsquot see the population of varroa as it grows out of control. A honey bee colony can look very healthy and large, even when the population of varroa, hidden from our view, is about to explode.

Even with exponential growth it takes some time for varroa populations to get to dangerous levels. In the real world, they often grow all summer and peak right when winter bees are being raised (late summer / early fall). These winter bees have to survive a period of high stress, and can&rsquot handle the extra challenge of being bitten and filled with viruses. This is one of the reasons that varroa mites kill colonies so often in the fall/ early winter.

A colony that is heavily infested with varroa can act as a reservoir, and put other colonies around it at risk. When varroa mites take over a colony, bees will often drift or abscond, and neighboring bees will rob the weakened colony. When this happens, the mites very quickly get transmitted to other neighboring colonies. This means that your infested colony can affect the bees and beekeepers around you, or that your otherwise healthy colony can become reinfested quite quickly from a neighboring colony. Not only are the bees in an overwhelmed colony profoundly unhealthy, but they are a risk to other bees in their neighborhood.

So how do we keep the varroa population from getting out of control? Unfortunately, most of our bees don&rsquot naturally have strategies to keep mite populations down on their own (yet) - varroa mites are relatively new to our honey bees (they jumped over from a different bee species), and our bees haven&rsquot had enough time to evolve natural defenses. While breeders are working tirelessly to find bees that do have defensive strategies, as of 2017, most of the colonies in the United States don&rsquot have the ability to manage varroa populations by themselves. Left alone, the mite populations grow uncontrolled, and our bees get overwhelmed, very sick, and die. We don&rsquot have a silver bullet for managing varroa mites (if we had a perfect strategy, they wouldn&rsquot be a problem, and we could all go back to happy, easier beekeeping). However, even though we don&rsquot have a one-size-fits-all strategy, we aren&rsquot helpless. We do have a variety of tools that, if employed well, can help keep the population of varroa mites in check, so our bees and the bees around us can stay healthy.

There are three steps to keeping your bees safe from varroa infestation:

  1. Know the level of mites in your colonies,
  2. Know what level of mites is safe,
  3. Know what tools we have to keep mite populations at a safe level. A. Tools that break varroa reproduction (keeping a low mite population low) B. Tools to use if we have an infestation (bring a high population of mites down) (Easy, right?).

To keep our bees healthy, we want to monitor our colonies for this pest all season long, making sure that varroa populations never reach dangerous levels. Simultaneously throughout the season, we can use an integrated set of management strategies to help break the reproduction of varroa, preventing the population from taking off. Finally, we want to make sure that we have a plan in place and the tools on hand for if/when we notice an infestation.


There is a big difference between seeing varroa mites in your colony and monitoring for them - you could have a lot of varroa in your colony, but not actually see any mites when you inspect. This is a really important point that catches a lot of beekeepers. By the time you see mites, it is too late, and you are already at a high population. Remember, most of the varroa mites in a colony are under the capped brood, so they are out of view. You could be on the brink of a huge infestation, but not see mites, so you will not know your colony is safe from varroa by just looking. You have to use a monitoring tool such as an alcohol wash or sugar roll. These strategies allow you to sample bees to see some mites (representing the 1000s that can be in the hive).

The best way to monitor varroa mite populations is to use a sugar roll or alcohol wash, because these methods allow you to get a percent infestation. In both methods you take a known number of worker bees, dislodge the mites from them, and count the mites, calculating the mites per 100 bees (percent infestation).

* For more details and explicit instructions on how to perform a sugar roll visit

* For instructions on making your own sugar roll kit visit the Bee Informed Partnership website (

* To purchase a pre-made mite check kit visit

Ideally, you should monitor mites at least once/month. Mite populations can change quickly, and you never want to be caught off guard. Remember, mites have an exponential rate of population growth, meaning that the population can really take off. Even more importantly, you could get infested from nearby colonies, especially if a neighboring hive becomes heavily infested. As heavily infested colonies go downhill, the bees often abscond, entering neighboring healthy colonies, and your foragers can bring back mites from robbing out dying colonies. You could have low levels of varroa all summer long, and then suddenly suffer a huge infestation from neighboring colonies that goes downhill. Monitor more often in late summer/early fall when mite populations are at their highest, and your colonies are most at risk for re-infestation.


There are many factors that determine the safe level of mites in your colony, and thresholds are not set in stone. Monitor your colonies (recording their levels and how they survive) and to talk to extension agents and expert successful beekeepers in your area. If you consistently see that colonies with mite populations above a certain level do poorly, then that is your threshold. Be persistent, as thresholds can change over time as the mites or the viruses evolve. Our bees used to be able to handle a higher level of varroa mites without having problems, so you may see higher thresholds listed in older documents.

A safe level of 3% is a guideline, but there are other factors to take into consideration. For example, if you live in a northern climate with a tough winter, you want to make sure that you have varroa managed before your winter bees are developed, so those precious bees that survive the winter aren&rsquot full of cuts and viruses. You also have to keep in mind how much season is left and what is going on in your colony. If your bees have a break in raising brood, the varroa mites are not going to be reproducing. If you know your bees will still have a lot of brood for the next few months, you have to be aware that the varroa will have a lot of time to reproduce. Northern beekeepers have to work hard to make sure varroa populations are low in the late summer/ early fall to protect winter bees. Beekeepers in warm climates won&rsquot be fighting the clock as much, but can&rsquot count on a break from population growth in the winter.


We have two types of tools for managing varroa:

  1. Ones that are used all season to slow reproduction (management)
  2. Ones that are used when we recognize we have a problem /are above threshold (intervention).

None of our management tools completely prevent varroa or can completely remove varroa on their own, so you have to have a few in your toolbox. The best approach is to go in to the season with a management strategy, where you use a variety of tools in cooperation, and you use them all season long so you prevent the mite population from ever taking off. If the varroa population does take off (for example if a neighboring colony re-infests your colony), then you may have to use an emergency measure.

The Tools - Management 1.

1. Screened bottom boards

The idea behind screened bottom boards is that when phoretic mites fall off of bees, by just falling or by getting groomed off, they will fall through the screen and onto the ground, where they will be too far away from the bees to re-enter the hive. The effectiveness and cost of screened bottom boards is determined by the set-up. If the bottom is wide open, the mites will fall further (but the chance of a cold draft on your bees is much higher). If the screened bottom board has an inspection board employed, or is set on a solid surface, drafts will be much less of an issue, but screened bottom board will not be effective.

  • Does not remove that many mites. Best estimates are that screened bottom boards can cause a < 20% reduction in mite populations, so it has to be used conjunction with other tools.
  • May make the colony cooler during cold periods, which can affect brood rearing.
  • Does not work with some mite treatments that need the colony blocked off.

When screened bottom boards work best &ndash Most of the time. However, because their effects are so small, you will have to use other strategies as well, and those strategies may be sufficient even without a screened bottom board. Plenty of beekeepers use solid bottom boards and can manage varroa, so if you have solid boards and you are successfully managing varroa mites, it may not be worth it to switch.

How to use a screened bottom board &ndash Put it on the hive as a bottom board (yep, that&rsquos it).

2. Drone Comb removal

Varroa mites prefer drone brood, and at any one time, most of the varroa are under cappings. We can use these facts to our advantage and use drone cells like a trap &ndash we can add drone brood to attract the mites, and once the mites are in the capped drone pupae cells, we can remove them from the hive.

  • It takes a lot of energy for a colony to raise a full frame of drones. This energy could be used to raise young, draw wax, or bring in honey.
  • If you forget to remove the drone frame in time, you have just provided a lovely place for more mite reproduction.
  • It can only be used when the colony is naturally drawing wax and raising drones (not in the fall, or not on small colonies).

When drone comb removal works best &ndash On strong healthy colonies that would be raising drones anyway, and when you have a small enough number of colonies that you can visit each one multiple times on a schedule. Bees will not draw out wax if there is not sufficient nectar, so you can&rsquot put in a new drone frame in September as a last minute management strategy.

How to use drone brood removal - Purchase or make a frame that will promote the larger drone sized cells, and put it into the hive on the edge of the brood nest (between the brood and the outside honey frame). Make sure that the colony has sufficient room for honey storage and growth, so they don&rsquot just fill it with honey. Record the date that you put the drone comb into the colony, and remove it in three weeks. It should take about a week for it to get drawn out, the queen to lay in it, and the eggs to hatch (though this is variable), and then another week for the larvae to be capped. You have about a two week window while the cells are capped to remove the frame, and kill the larvae. Some people do this one time per year, other beekeepers will do this consistently through the summer. You can also just cut out/ remove large pieces of drone brood while you are in the colony for inspection &ndash feed it to your chickens &ndash they love it.

3. Breaks in the brood cycle

When varroa are in capped brood cells two things are happening: they are reproducing, and they are safely hidden away from grooming bees. If you can create a colony with no capped brood, then the varroa cannot reproduce during that time, and the mites that are left in the hive are all phoretic (running loose), and have a greater chance of falling to the ground and getting groomed by the bees. Many wild colonies (and colonies not well managed) can have success just because they have enough brood breaks from swarming to prevent varroa populations from ever reaching high levels.


When breaking the brood cycle works best &ndash When you have strong enough colony and/or enough time left in the season for the colony to handle the loss of workers/honey.

How to perform a break in the brood cycle &ndash Your colony may choose to use this varroa management strategy when it swarms. You can do this for them (skipping the part where you climb the tree, or cut them out of your neighbors soffit), by creating a swarm, moving the queen and capped bees into a nuc. There are many variations on breaking the brood cycle. Some beekeepers will simply remove all the capped and nearly capped brood &ndash using them for other hives (and dealing with the mites appropriately). Others will temporarily remove the queen and eggs, and later reintroduce her. One easy way is to make a nuc with the queen, and allow the original hive to make a new queen by itself. The nuc will grow slowly (not have so much brood to build up a big population of varroa), and the original colony will get a break from having capped brood as they create a queen.

4. Splits

Splitting colonies works to slow varroa by preventing a colony from having a high percentage of infested bees, using a principle similar to dilution. Varroa mites reproduce faster than bees, because each colony has only one reproductive bee (the queen), but many reproductive varroa. When you split a colony into many small colonies, each with their own queen, you allow for more bees to be raised. Remember that we measure mite load as percent infestation, or mites per 100 bees. When we split, we keep the same number of mites, but increase the number of bees, so the percent infestation drops.

  • Colonies have to have enough bees to raise workers/ get enough honey to survive the season.
  • Many beekeepers are limited by the number of colonies that they can manage.

When making splits works best &ndash When you have enough time for the colonies to build up sufficiently to make it through the winter. This often goes hand in hand with breaking the brood cycle. Making splits after the honey flow, and requeening with queen cells, causes a nice break in brood production at a time when you won&rsquot be needing so many workers.

How to make a split &ndash There are many ways to split colonies. The best way will determine the size of your colony, the time of year, and your needs. Many beekeepers make splits in the spring for swarm management, or in the late summer after the main honey flow. Splits can be made with various sizes (including nucs), and can be queened by introducing a mated queen, virgin, or cell, or by allowing the colony to requeen. Splits and breaks in the brood cycle often go hand in hand, and many beekeepers split colonies, and create a break in the brood cycle at the same time. One way to do this is to split the colony into two, keeping all the brood in the queenless colony (that will raise a new queen), and putting the queen into a colony with drawn comb so she can start laying. This gives both new hives a break in the brood cycle.

The Tools

Intervention Sometimes we can have colonies that are on screened bottom boards, have had drones removed, split and allowed to requeen, and our monitoring shows that the mite levels are still high. Maybe we live in an area where there are so many colonies with unmanaged levels of varroa that our pest pressure is too high for us to manage through other methods. Or maybe, we are just starting out in our beekeeping journey, and we don&rsquot have the understanding and experience to make splits or break the brood cycle. We need to include intervention tools at this point. There are three cases when chemical interventions are recommended:

  1. When you are unable to control varroa populations using only management strategies.
  2. You do not have the experience to safely and effectively perform strategies like splits or breaks in the brood cycle.
  3. When monitoring shows that varroa populations have already reached dangerous levels, and we need to quickly bring them down to prevent colony damage or death.

Note &ndash Early chemical treatments for varroa were quite harsh (neurotoxins), and many of them no longer work because the varroa mites have developed resistance. Furthermore, many beekeepers were adverse to put these treatments into their hives, because of damage to their bees, concerns about the chemicals in the wax, or build-up in the honey. In this article I focus only on the newer, &lsquosofter&rsquo chemicals, which are naturally derived, and most are labeled for organic use. I don&rsquot discuss amitraz (Apivar), which is a synthetic miticide that continues to be effective against the varroa mite.

Not all chemical tools are the same, and you need to choose the one that will reduce the varroa populations, and be appropriate to the context. Make sure that you are reading and following labels exactly, and are working with experts to make sure you are doing everything safely and effectively, before you head out to the bee yard.

When choosing an intervention tool, you must take the following factors into account:

  1. How early/late in the season is it (i.e. how much time do I have before my bees raise their winter brood)
  2. Are there honey supers on the colony (or will I expect them to be on before the treatment is complete
  3. How many times can I come back to visit this colony?

Some interventions are good only for affecting phoretic varroa mites (not in capped brood). These methods are only effective during the following two scenarios:

  1. When the colony is broodless (late fall &ndash winter, package installation)
  2. When you can return every week to apply it (to account for the mites that hatch out with the bees every week).

The applications that fall under this category are oxalic acid and powdered sugar. While both are applied at similar frequencies, and are similarly gentle on the bees, oxalic acid seems to be considerably more effective, so very few people recommend using powdered sugar, except during broodless periods.

Oxalic acid is a naturally found acid (it is what gives you that dry feeling in your mouth when you eat too much spinach). It works by affecting the mites that are loose in the hive, and is applied either by dribbling a low concentration solution in sugar water onto the cluster, or by using a vaporizer. You can use the table at to learn how to make a solution and apply the dribble, and any vaporizer that you purchase will have instructions for its safe use. Both methods kill phoretic mites equally well. The dribbling method is a bit quicker, but can&rsquot be used when it is cold out (30-55 degrees is ideal &ndash when the bees are loosely clustered). The vaporizer can be used all year, but requires extra equipment and extra safety precautions.

Powdered sugar is a naturally found chemical that is delicious on French toast. Even though it is delicious, it is still a chemical, and may damage the brood if you get it in uncapped cells. It is not labeled as a treatment for varroa, but many beekeepers will apply it by finely coating the bees with it using a sifter. Some people thinks that it works by causing the bees to increase grooming, and the mites lose their grip (the sugar is so fine, it interferes with their gripping ability). This will work much better if you have a screened bottom board. Many beekeepers use powdered sugar on a new package either when they install it, or after installation but before there is capped brood.

Oxalic acid dribble/drench or vaporizing only works on mites not in the brood. The upside of these methods is that they are relatively gentle on your bees. The downside is that unless you are using them in an exclusively broodless time, you would have to go in every week for three weeks to effectively cause a reduction in mite populations. You wouldn&rsquot want to use it if you already have really hive high levels of mites because in the three weeks that it takes to treat the colonies, the mites can continue to damage all of your developing bees.

Best use for oxalic acid and powdered sugar: Keep these tools in your back pocket for new colonies from packages (use after the colony is established in the hive, but not yet capped brood), and for broodless periods (fall/winter). Both are really cheap, and store well, so they are good to have on hand. Because these interventions seem to be so easy on the bees, many beekeepers use these automatically, to knock down the number of mites that would over winter with the colony. The fewer mites you have in the spring, the longer you have until the population of mites will skyrocket, so using oxalic acid in the late fall or early spring is highly recommended as part of your strategy.

Pre-Packaged interventions

Many manufacturers have developed delivery systems that make their product easy to apply, to keep the product in the hive until all the varroa are out and are affected, and control the amount applied to the colony. Three interventions fall under this category: two types of thymol and hop acids.

Thymol is the oil derived from the thyme plant (the herb). It seems to be very effective in controlling mites when used in sufficient concentrations (if you just plant thyme plants near your hives, they won&rsquot control varroa, though they will look nice). It is sold under two names: Api Life VAR and ApiGuard.

Api Life VAR comes in a wafer form, and has other essential oils mixed in (menthol, camphor, and eucalyptus). You do have to put multiple wafers in the colony to get the full dose (every 7-10 days), but they are easy and not disruptive to apply. ApiGuard is a crystal gel that is put in the colony a little tray, and lasts for two weeks. After two weeks, you put another tray on for a following two weeks. Make sure that you read the labels so that you get the timing right and apply them properly.

Best use for thymol: The biggest thing to worry about with thymol is the oil affecting the flavor of the honey. Do not use thymol when you have honey supers on. They also aren&rsquot effective against the mites unless it is warm enough, so these can&rsquot be used very early in the season. Most beekeepers use thymol in the late summer right after the honey supers come off (July). This is an excellent option for those who monitor and find a high level in late summer, or as a go-to treatment for beginners to use in late summer, as they are learning about integrated pest management.

Hop acids come from a plant that is used in beer. Like the thymol applications, Hop Guard II strips are designed to have a sufficient concentration to affect mites, without being too damaging to the bees, so you can&rsquot just use beer in your hive (though science has shown that you can have a beer after applying the strips). The labels indicate that you can use it up to three times per year, and most beekeepers who use it do these three applications right in a row. HopGuard II is not labeled for organic use because of the formulation.

Best use for HopGuard II: You don&rsquot want to use the same thing over and over, so this is good to have in rotation. The upside is that it can be used when honey supers are on. If you want to wait until the last minute to extract honey, but you are concerned about rising levels in your colony, or you want to drop the population in the spring, but don&rsquot want to wait to add supers, then Hop Guard II would be a good option.

Make sure that you use these long-delivery methods early enough to protect your winter bees, as they all have a really long time to be effective (3 &ndash 4 weeks). The most common mistake is to put them on too late, after your winter bees are already damaged. In years where we have a warm fall, many beekeepers think that they are lucky because they can &lsquoget a treatment in&rsquo before winter. In reality, the bees are already damaged, and they just wasted their money and harassed their bees without benefit. Give these interventions time to work, and make sure you pay attention to when you need honey supers on and when your winter bees will be raised.

Single applications that affect phoretic and non-phoretic varroa mites

The downside to everything listed above is that they do not get all the mites in capped cells, and so they take a long time to clear the colony of mites. Formic acid, sold under the name of Mite Away Quick Strips (MAQS) has a huge advantage in that it is designed to affect all the mites in a colony, including those reproducing in the capped cells, and it does so quickly (7 days).

Formic acid is naturally found in the hive (in very small quantities), and works by affecting the cuticle of the mite. It dissipates completely and quickly after use, so you can use it when honey supers are on, and it doesn&rsquot affect the honey. The best part about using the MAQS is that they work quickly. This is especially important when you find a colony that has a really high level of mites, or if you are getting late in the season. One 7-day application can cause a huge drop in the mite population very quickly. The down side, is that there is a temperature window that has to be followed, or you can damage your bees &ndash it is only labeled for use below 85 degrees.

Best use for formic acid (Mite Away Quick Strips): If you need to treat when you know you will have honey supers on. Because this method works so quickly, it is highly recommended to use MAQS if the varroa population in your colony is very high, or if it is getting late in the season. It can also be used as a ½ treatment, which has less risk of brood damage. You can use single strips during the summer to keep levels low (but use a full treatment if you need to knock populations back).

Watch the video: Οι 3 φάσεις που διαμαρτύρεται ο Σμυρναϊκός Βαθυλάκκου (May 2022).