In the winter, the worker bees stop the Queen from laying for a period. It is too cold to keep the new eggs and larvae warm enough and in really cold climates, they have all that they can do to keep themselves warm.
That was not the case for our winter. I do not think that the worker bees actually stopped the Queen from laying. There were warm days in January that I was able to go into my hives (as the temp was above 60 degrees) and I still saw small amounts of brood (eggs, larvae and capped cells). They, of course, only let the Queen lay an amount that could be kept warm, in the event of really cold temps and yes, somehow they know when the winter will be cold, because brood in January does not happen every year. The bees keep the brood warm by clustering over the brood, vibrating and producing heat with their bodies and wings.
I was able to go into my hives at least once each month this winter. That is proof of a fairly warm winter.
By now, the end of March, the brood has increased along with the population in the hive. They know that with warmer temperatures, comes more flowers, more foods for them and soon we will be in the nectar flow. A time of year that a large number of high nectar producing plants and flowers are available. A time when there is such an abundance of nectar, that the bees store all the excess that they can get. A beekeeper is able to take some of the abundance that is stored in the hive as the bees will not be able to consume it all.
This is also a time when the population of the hive must be at peak. There is much work to do and everyone has their job. Sometimes the population gets so large that they do not have room for all the bees. This is when the bees might decide to swarm.
Swarming is a way that the bees re-populate
You've heard about swarming......it's when you see masses of bees flying in the air or you see a big glob of bees hanging from a tree. If you have never seen a swarm pouring out of the hive, you have missed a grand sight. The sound alone will make you stand in awe!!
When the bees actually comes out of the hive in a swarm, it has been planned for some time before they actually leave the hive. When things are beginning to get crowded in a hive, the workers and the Queen make a decision to swarm. Once that decision is made, it is hard to stop them.
At least 2 weeks before they swarm, the first thing that the worker bees do is find fresh eggs just laid by the Queen (1 or 2 day old eggs). The worker bees move this egg to the bottom of the brood frame. They do not only move one egg, but rather move many eggs, sometimes as many as 20 eggs. The worker nurse bees start feeding the egg Royal Jelly. Royal Jelly is a substance that only bees make and a Queen cell must only be fed Royal Jelly. They continue to feed the egg Royal Jelly until the egg hatches into a larvae and then through the pupae stage, all the while building the cell wall downward in the shape of a peanut. They stop feeding the egg when it is approximately 9 days old and close up the cell. The Queen bee will continue to develop for another 7 days. From egg to Queen bee is 16 days. The new Queen will emerge from the cell and usually start searching for other Queen cells. If she finds other Queen cells that have not emerged, she will sting the cell to kill the Queen inside. If 2 Queens emerge at the same time, a battle will ensue with the stronger Queen winning the battle.
There is a way that the beekeeper can control the swarm process so that his bees do not end up 40 feet up in a tree somewhere or take off to locations unknown. If the beekeeper is diligent about tending his/her hives in the early spring, a process called a "Split" can be done to alleviate the crowding and make the bees think that they have already swarmed. This "split" is a manual maneuvering of the hive to take the Queen and a large number of worker bees (usually 3-4 frames of bees and brood) and start another hive. This new hive is called a "Nuc" (nucleolus). As I said earlier, once a Queen and the workers are set on swarming, you will probably not stop them unless you create the appearance of them swarming and give the Queen room to lay more eggs. When the old Queen is in a new home with an ample number of bees, she will think that she has already swarmed. She will have plenty of room to start laying eggs again and she will grow that new colony.
On The Other Hand, If a Beekeeper does not pay attention......
Right before all the bees leave the hive, they gorge themselves with honey. They do not know when they will have food again. Days prior to the swarm, the worker bees stop feeding the Queen so that she will be light enough to be able to fly. To mate and to swarm are the only times that the Queen leaves the hive.
Where the Queen Lands, the Worker Bees Will Protect Her
Once they are out of the hive, where the Queen lands, the worker bees will also land to protect her. They will cluster together in a big ball of bees. Scout bees, (the older forager bees of the hive) will go out to find a new place to live. Again, if the beekeeper is at all prepared, he will have swarm traps out. These are prospective new homes for bee that swarm (yours or someone else's) . It could be an another hive that the beekeeper has out that he/she has baited with old comb frames or maybe some lemon grass essential oil. These are two things that will entice the scout bees and they in turn will encourage the other bees to make this a new home.
ARE SWARMS GOOD OR BAD?
This depends on the beekeeper. I actually think that swarms are good! This is their way of increasing the population of bees. Some bees are never caught again by a beekeeper and the swarm makes it's home in a hollowed out tree. These bees then become feral. If they are strong, healthy bees, they can become resistant to pests and diseases. If they are not strong and healthy, they can all die.
But either way, this is the way in which bees increase in number. Before the current ways of beekeeping, all hives swarmed. In some apiaries today, the beekeeper does not manipulate a hive that is about to swarm and the bees do what they would naturally do.