Beekeeping in the Pacific Northwest during the month of May has a lot to do with what happens in April. When colonies swarm in April, they have time (May and early June) to rebuild their workforce and be prepared to glean the best nectar flow to make stores for winter. There are swarms in May, and if April is too cold and wet, May can be a major swarm month.
The old ditty—a swarm of bees in May is worth a load of hay, a swarm of bees in June is worth a silver spoon, a swarm of bees in July is not worth a fly—somehow does not and never did work for Oregon. If a colony swarms here in June, it is less likely to survive winter without help. May is still a month where it is critical to support your colonies and prevent swarming. If the colony does not swarm, it may be strong enough to not only get through winter but also make a surplus of honey for the beekeeper.
Swarming is the reproductive event for honey bees. Like any reproductive event, there is a lot of uncertainty. When a colony of bees swarm, the bees that stay in their old home must raise a queen and she must successfully mate and return to lay fertile eggs for that colony to continue. Raising a queen from an egg to a laying queen is a time-consuming event. There must also be time for the new queen to produce enough progeny so that there will be the foragers to collect winter stores and raise the bees to become the overwintering workforce that will keep the queen warm and fed until flowers return in spring. The swarm must find a new home, find food in the new location, and construct comb, so that their queen can restart her egg laying that will produce the workforce to collect winter stores and raise the progeny that will be the winter bees. It is easy to imagine how one or both of these colonies might fail. Swarming becomes an issue because it increases the likelihood of losing the colony. Swarm prevention requires an understanding of honey bee biology, especially their individual life cycle and their colony life cycle. Remember, swarming is a strong instinct and to be late with any preventive manipulation will probably result in swarming and perhaps loss of the colony left behind.
The queen in May is laying 1–2,000 eggs every day averaging 200,000 fertilized eggs plus a few unfertilized eggs during the laying season: March through October or November. The most-intense egg production occurs over spring and early summer. She is fat and heavy, and cannot fly.
Because the bees maintain a constant temperature within the brood nest, development is very constant. When a colony is raising lots of drones, the colony is thinking of queen mating and swarming. Lots of drones can also be the result of a laying worker. Look at the brood. There should be eggs, larvae, and pupae; drone brood should be separate, usually in the corners and top of the comb. Old frames can cause confusion, having larger cells or drone brood more randomly distributed over the frame if bees had to repair the comb. Laying workers often lay several (3 or more) eggs per cell and their abdomens are short, so most eggs are on the sides of a cell. This problem can only be turned around near the beginning of laying by a worker, and the only remedy that I have seen that works is the introduction of 1–2 brood frames with eggs and young larvae from a queenright colony.
Back to the swarm event. If the queen is to fly off with a swarm, she must first lose weight. So, when the colony decides that the time to swarm is near, they stop the queen from egg laying a week or so before they expect to depart. This means that in 3 days there will be no more eggs in the colony, and in 6 days all the larvae will be 3 days old or older. A larva at 3 days old can no longer become a queen. Before the queen is stopped from laying, the workers have been busy making queen cells (called swarm cells). The cells are usually placed along the lower edges of combs; for beekeepers, this is the bottom bar of a frame in standard Langstroth equipment. Eggs are laid in these queen cells over several days, so the larvae in these cells differ in age. There can be only a few of these cells or many. I have counted as many 50 in a single colony. The first queen to emerge from one of these cells will begin to kill the other queen pupae. Usually some are missed so multiple virgins may exist in a colony during this time. Some are killed during battles between virgin queens, but in my experience never all.
Just before these queens begin to emerge, the colony will produce a “prime” swarm including about 20–30% of the workers. When conditions are right, the workers coax the old queen out of the colony. The colony is now left with mature queen cells, some older larvae, and capped worker and drone brood. When virgin queens emerge, they need 3–4 days development time (cuticle hardening and muscle development) to be able to make mating flights. A virgin queen may make 1–2 flights to mate. After mating, she needs another 5–7 days to get the sperm into her spermatheca and develop her ovaries. When she does start to lay, she will begin slowly. Her first laying pattern will only be a small areas of eggs. This colony, even with the newly mated queen, will not make excess honey and may need to be fed to have enough stores for winter.
“After swarms” may occur when several virgin queens have emerged a few days before the prime swarm leaves. When the prime swarm has left, one or two of the virgin queens can leave the colony with a small number of workers. The function of after swarms has never become clear to me. Sometimes when more than one colony swarms at the same time in the same apiary, the swarms merge into a larger entity and will contain more than one queen.
After the colony swarms, a virgin queen must go on mating flights and return. Mating flights are hazardous for these small insects. Weather in spring is unpredictable and many predators (birds and other insects) are also flying, searching for prey. If the virgin is killed by bad weather or eaten, her colony will be queenless and without the resources (young open brood) to rear another queen. If the beekeeper has only the one colony, they are faced with starting over next year. Queens can be mail ordered. But it takes time and an already queenless, broodless colony does not have time. Currently, there are more local queen rearers, so the possibility may exist to get a mated queen quickly; generally though it can take at least a week or more for an ordered queen to arrive. Requeening in this situation is difficult since the colony has few young bees and no brood. Older worker bees are not likely to accept the new queen. Timing is also critical. A new queen needs 4–6 days in her introduction cage before she can be released. Longer is better because these are older bees and the probability of acceptance is already low.
If you have more than one colony, you can use open brood from a queenright colony to maintain the colony that swarmed. They can rear a queen from young brood if there are larvae less than 3 days old; however, time is against this being successful. So, how does one prevent swarming?
Swarm preparation begins when space in the colony is reduced and bees are crowded. Adding space can reduce the urge to swarm. One way to start before every cell is full of brood, honey, and pollen is a technique called checker boarding. This is taking empty frames and placing them between frames of honey and pollen. Start with empty frames on the outside edge of the box or super. If you remove frames, you will need a place to store these honey and pollen frames. Freezer space would be my recommended option. A second colony in need is another good option. It is a good idea to leave the brood nest alone. If the queen has no place to lay, an empty frame can be put into the brood nest for her to lay in. Another tactic to add space is to place a super with empty frames above the brood nest.
This is a good month to make new colonies or splits, basically artificial swarms, where frames of bees are transferred from a strong colony to another box making sure each box has some open brood. For the colony that bees and brood are transferred from, this would take the place of a swarm. The difference is you supply the newly mated queen for the split. Splits start by ordering or raising new queens. Two days before you expect new queens to arrive, make your split. You can use a nuc box (five deep frames is a standard nuc) or a single regular box. For a nuc, include two brood frames with lots of young bees if possible, an empty frame for the new queen to lay eggs in, and two food frames with both pollen and honey. Brood frames should be centrally placed together so you can place your caged queen between these two frames, empty frame next, and food on the outside. These bees should be held queenless for at least two days before introducing the caged queen. I have found the best success with queen acceptance happens if it takes the bees at least four days to release her. Make sure the candy plug is available to the bees in the nuc or single. Queen rearers generally put the correct amount of candy for a 4-day release. Even though you expect the queen to be released after four days, leave the unit alone for at least six days, then just check by pulling up the cage to see if she is released. If she is not, check the plug making sure it is open or nearly open, then gently put the cage back. If she is released and cage is empty (sometimes a worker or two may be inside), remove the cage but leave the colony alone. Bees are very nervous when they are queenless even after a new queen is placed into the colony. Too much disturbance at this stage may cause the workers to kill her. Give them another week, and then check for eggs and young larvae, by now these will belong to the new queen. When you are checking for eggs, you can reverse one of the frames that held the queen cage so the bees will correct the devits left by the cage. Sometimes if the devits are together the bees will build a bridge of comb between them connecting the frames.
You can also cage the queen to stop her laying and thus reduce population build up. I have never done this, as I do not like to cage a laying queen that is producing 1000-plus eggs each day. I expect this tactic to be rather hard on the queen. I would never hold a laying queen longer than a few days.
May is a good time to requeen. Have your new queens ordered before you start this process. A new queen is less likely to swarm. Most seasoned beekeepers will say, find the old queen (that you are replacing) and kill her. However, I would use a nuc and hold the old queen until the colony has accepted the new queen. In my early days of beekeeping, my requeening acceptance rate was not 100%. If you only have one or two colonies and a new queen is not accepted but you have killed the old queen, do you have a backup plan?
As in April, feeding may be critical in May. The weather is still unpredictable, so watch your colonies closely. The bees are building population rapidly, and the colony may only be able to bring in just enough food to last a few days; if the weather prevents foraging, the colony will starve. It is always the biggest and best colonies that are lost when this happens. May is the time of year that can be good for collecting swarms. So, if you have nuc boxes, have them handy. The first person to the swarm usually gets the swarm. Keep in mind, early swarms will need full-size boxes soon. You must have equipment ready to transfer the swarm into, unless you want give the swarm away or sell the bees. Don’t forget to feed the swarm.
May is the time of year when queen rearing in the Pacific Northwest can happen successfully. But it can also be cold, so I prefer to raise queens in a nuc box (5 frame) to be sure there are enough bees to keep a new queen or queen cell warm.
May is a good time to start checking for Varroa mites. There are several options for checking for mites and estimating their population. Probably the most common technique is the sugar shake. Use a pint jar with a screw-on ring and instead of solid top have a fitted screen (hardware cloth) with 8 squares per inch. Roll a sample of bees off the comb into the jar by placing the jar upright near the top bar and pressing the lip of the jar gently against the bees and move the jar in this position down the comb. The bees will roll into the jar. Be sure you find your queen and remove her on the frame and set aside, preferably in a nuc box, before you take your sample. When you feel you have collected about 300 bees (½–¾ cup of bees), place the screened lid on the jar. Add about a tablespoon of powdered sugar through the screen and shake the jar to coat the bees with the sugar. Then hold the jar upside down over a white or light colored tray or plastic container and shake to separate the mites from the bees through the screen. Water can be poured into the container to make the mites easier to see. If you have 3–6 mites in spring, the recommendation is to treat for mites; in fall, treatment is recommended if you count 6 or more for a 300-bee sample. There are several websites that will provide pictures and/or other methods of sampling. It is a good idea to follow your mite loads through the season whether or not you treat for mites. It is one more thing we need to understand our bee colonies better.