Colonies have a single queen. And when they don't they are queenless. This state is called queenlessness. There's nothing complicated about the definition of queenlessness!
But when it occurs it is an imminent threat to the future of the colony.
The existence of a colony depends on a constant growth and a renewal of resources. Given the short life cycle of the worker bee, simply maintaining the status quo requires a productive queen, laying efficiently so that dying workers are replaced. In fact, a healthy colony grows at a tremendous rate and the emergence of new bees greatly outstrips the loss of aging bees. The queen's 2,000 per day egg-laying productivity is crucial.
What are the causes?
There are a wide number of reasons why a colony can lose its queen.
Loss to disease
The queen is central to the colony but also as vulnerable to disease and pests as any other bee. She will have help, in the form of attendant worker bees, but there is never an absolute assurance that she will survive all threats.
Accidentally squashed by the beekeeper
This is a real risk when inspections take place. Extra precautions should be taken when handling frames, to lower the risk of killing the queen. For example, when examining a frame that may include the queen- and you will never know for sure unless you actually spot her - hold the frame over the box, so that if the queen falls from the frame she falls into the box below.
Killed by other members of the colony
The colony has an innate sense of how productive the queen is at all times, through the spread and detection of pheromones. If the colony believes the queen is under-performing she may be killed.
Killed during a mating flight
The mating flights that the queen makes early in her life are treacherous. There are many ways in which she may die and not return to the colony.
Killed by another queen
One queen killing another might seem like it will always leave a victor, hence leaving the colony with a queen. But it is also possible that two queens can fight to the death, with both of them dying.
Spotting the queen directly
Of course, one surefire way to know you your hive is not queenless...is to spot her! There are various ways to do this, directly.
If you are purchasing a package of bees it is simple to pay a small amount (often $5 or so) to have the queen marked. This places a small dot of paint on her abdomen which makes her easier to spot during inspections. A different color paint is used each year, so that the age of the queen is quite easy to determine in subsequent years.
The eagle-eyed beekeeper will locate the queen in various ways as he scans each frame. One will be the way workers line up as they are attending her.
As the colony grows over the summer, more boxes will be added. In a Langstroth, brood will be in the lower boxes, with honey being stored in upper boxes. This means the queen will generally be in the lower boxes of the colony. Note however, that nothing is guaranteed.
If a queen excluder is used then this limits the boxes in which she might be found. However, PerfectBee does not recommend the use of a queen excluder in the year a colony is established, when it is essential that the bees can continue their work unimpeded in the hope they can build sufficient reserves to survive the winter.
The critical timeline of queenlessness
If you have determined your hive is queenless, it's important to get a sense of how long this has been the case. The progress of brood from eggs to uncapped brood to capped brood and finally to adult bees offer the clues you need.
- If you see eggs, you have the most time to resolve queenlessness since it is clear the queen has been there recently. All being well, these eggs will turn to uncapped larvae and then to capped brood, before emerging as adults. That buys you some time.
- If you see no eggs but you do see uncapped brood, you have a little less time. Those larvae are still to be capped and then have time before they emerge as adult bees.
- If you see only capped brood then you have an emergency on your hands.
Finding eggs (assuming they are not from laying workers - see below) indicates that the queen was there within the last 3 days. That also means that there is a reasonably extended "pipeline" of bees on their way, to emerge as adults. Since you want to avoid a significant gap in the emergence of adult bees (to offset adult bees that die), the presence of eggs mean you have some time - but not much - in which to fix the situation.
For this reason, your hive inspections should usually include an effort to find eggs, to bring at least some peace of mind. An absence of eggs is a warning sign you should investigate.
Another important sign of queenlessness is the appearance of laying workers. However, by this stage it's very late in the game, since they don't become evident until 2-4 weeks after the queen was lost.
As workers, they will not have mated, so their only option is to lay unfertilized eggs. This of course results in drones. This production of only drones becomes a huge problem for the colony, since there are no workers to carry out the roles they fulfill, like foraging. The colony will soon die.
The following signs are clues of laying workers.
- The brood pattern may be spotty, without the consistency evident from a productive queen.
- Since workers have a shorter body than queens, they cannot reach the bottom and center of the cell when laying their eggs. Therefore eggs may be off-center.
- A significant clue is that workers often lay multiple eggs per cell.
As an aside, it is thought that colonies generally have a small number of laying workers, even when a queen exists, but generally in such tiny numbers that they create no problems. Here's a neat video of a laying worker "caught in the act".
Responding to queenlessness
There are two main ways to respond to queenlessness - let nature take its course and allow the bees to create another queen or introduce a mated queen.
Allow the colony to raise a new queen
Bees will often take the situation into their own hands when a queen is lost and create a new queen. The problem with this is that it takes time. Raising a queen from an egg takes 15 days. Then she will need to mate, which may take another five days or so (including the risk associated with her mating flights).
Another problem with this scenario is that the colony has a small window of opportunity. To raise a new queen, the colony needs two things - a fertilized egg and the ability to feed a larva royal jelly beyond its third day.
The fertilized egg must come from the (now departed) queen - so that starts the clock. If she lays an egg on her last day, the colony must identify the issue and elect to raise a queen before one of the larva is three days old. If they realize after that time, then they will have missed the opportunity for "continuous royal jelly" for a selected larva and no queen can be produced.
Introduce a mated queen
Given the time it takes to create a new queen, a common alternative is for the beekeeper to introduce a mated queen. These can be purchased in a queen cage, often with one or two workers with her. There is a significant risk of rejection by the colony. It is therefore important the queen is introduced in a cage, with a piece of candy at one end providing a "timer", of sorts. This is similar to the process many beekeepers use when establishing a colony from a package of bees.
When introducing the queen, carefully watch the reception she receives. If workers "attack" the cage and cannot be easily brushed off then the chances are they would not accept her. In such a situation, remove her for a day or two then try again.
Often, though, the colony is eager to receive a new queen and will accept her. When she is freed from her cage after a couple of days, she will become familiar with her new surroundings and then start laying.
Introduction of a mated queen can get you back to a queenright situation in about a week or less. If you caught queenlessness early enough, you stand a good chance of recovery to a healthy beehive.