Queen loss - defective queens
The loss of the queen is one of the most serious things that can happen to a honey bee colony. At best, it results in a long period without brood and if the workers have been unable to replace the queen it leads ultimately to colony death. Queens can die suddenly for a variety of reasons; the most common are being eaten by a predator or damaged by the beekeeper when opening the hive. In general, as long as eggs or very young worker brood are present in the colony then the bees will be able to rear a replacement queen. It is this principle that is used by beekeepers when they seek to divide a colony. This emergency queen replacement procedure is not quite the same as natural queen replacement due to supersedure or swarming.
Worker bees develop from fertilised eggs while drones develop from unfertilised eggs. Before they are laid the eggs can be fertilised using sperm stored in the queen's spermatheca. If the queen was poorly mated or if the supply of sperm runs out, the eggs that are laid can only develop into drone brood. The signs of this condition on the comb are characterised by the presence of drones in worker cells. In an effort to try and accommodate the much larger drones in the worker cells the cappings are raised well above the normal surface of the comb in a way that is easily recognisable. If the colony remains strong and has not been queenless for too long it is possible to remove the old queen and introduce a new queen into the colony. If this is not possible then putting a comb containing eggs into the colony once the old queen has been removed will give them the resources to raise a new queen but this will take much longer and is more likely to fail. If the time of year means that eggs are not available, then the queenless colony can be united with a queenright colony so that the bees are not wasted.
Under certain conditions normally sterile workers can also lay eggs. When colonies lose their queen and there is no brood in the colony some of the workers may develop functional ovaries and begin to lay eggs. The presence of the queen and also of brood in a colony produces pheromones that would normally inhibit this from happening. However, after a period of time without a queen all the brood will have hatched and the colony become broodless. Because the workers have never mated these unfertilised eggs can only develop into drones. The exception to this is the Cape bee (Apis mellifera capensis) which is a special case. The Cape bee is the only race or species of honey bees where fertile female eggs can be laid by worker bees under some circumstances. However, the consequences of this are not helpful. In these cases the worker bees take over another colony and start behaving as queen bees. Eventually the whole colony collapses from lack of worker input.
The signs of this condition on the comb are similar to those of the drone laying queen. The eggs of laying workers are smaller than those from a queen and because their abdomens are not long enough to reach the bottom of the cell the eggs may be attached to the sides of the cell. In some places there may be several eggs in one cell - although this can also be a sign that the number of workers is not sufficient to prepare the cells quickly enough to keep up with the queen when she is laying fast.
Laying workers are more likely to occur in African and Africanised bees. Colonies with laying workers are very difficult to requeen. If they are worth saving at all the worker bees can be shaken out of the hive onto the ground, and the hive and stand should be removed. The bees will then attempt to join another colony in the apiary.