The Queen Bee lays two kinds of eggs. She either lays a fertilized egg or an unfertilized egg. The unfertilized eggs develop into Drones (the lazy old male bee.) The fertilized eggs mostly become a Worker Bee (the ladies of the hive – the ones that collect pollen/nectar and sting!). But, the colony may suddenly decide that it needs a new Queen (the current Queen died, they want to swarm or the current queen is failing for some reason.) When this decision is made, the bees in the hive will choose 1 or more Worker eggs to become the new Queen(s), instead of a worker. What follows is how what was at first targeted to be a Worker Bee becomes a Queen instead.
All fertilized eggs (the eggs that become gals) hatch and move into the larva stage around Day 3. For the next 2 to 3 days, all are fed what Beekeepers refer to as Royal Jelly. This is a protein-rich substance made from nectar and pollen. All larva destined to become Worker Bees are weaned off of this substance and fed a diet that is mostly carbohydrates (nectar-based) for the remainder of their larva stage. But, when the Bees are raising a new queen, they choose a few of these larvae and do not wean them off of the Royal Jelly. The larvae continue to receive the high octane diet for the remainder of their larva stage. This added protein has many effects, the most noticeable being that the bee grows larger and fully develops the reproductive glands (all worker bees also have reproductive glands, but they never full develop given their reduced diet at this early stage.)
So, the queen spends 3 days as an egg and then spends another 5 days (give or take) in the larval stage. During the larval stage, she undergoes several changes, molting into a new form many times as she gets larger.
A bit after day 7.5, a final dose of Royal Jelly is put into the cell with the larva and the cell is capped. Now, the Queen begins to go through a fast transformation as a pupa. This is usually Day 8 to Day 16 or so, when she emerges (usually Day 17 or so). She is tended to by her retinue, but she will first go around and kill any other queens in the nest, even going so far as to open up other queen cells and sting the inhabitants. She spends 3 or 4 days walking about on the inside of the hive and gaining her strength.
For the next four days (Day 21 to Day 24), she begins to take Virgin Flights, where she goes out and gets a landmark on the hive (we call this “orienting” and it basically lets her eventually fly off, several miles away, and be able to return to the exact location of the hive/her home). She goes further and further out, each day. This is a high risk time for the hive and the beekeeper, as any number of bad things can happen to her during this outing (a bird may eat her, a human may spray her or maybe she gets caught in a down pour.)
On Day 25 (give or take), she returns as a fertilized queen and is ready to begin laying fertilized eggs. In truth, she may make several mating flights over the ensuing days, looking for the most handsome drones that she can find, sometimes as many as 3 or 4 miles from her home hive.
Anywhere from Day 26 to Day 40, she will begin laying eggs. It is most common to find eggs around Days 29 and 30, but later (and earlier!) dates have been recorded. Once she begins this part of her life, she will not leave the hive again unless the hive swarms or absconds. She is destined to spend the rest of her life laying eggs (sometimes as many as a thousand a day) for the hive.
Although I let my bees raise their own queens, Beekeepers over the ages have developed methods of raising many queens in confined locations, to either sell to other beekeepers or to use in their own hives. As you might imagine, having your hive without a laying queen for 30 days (see above) can really set it back a bit (although there is good evidence that this break in the brood cycle can have a disruptive effect on the Varroa mite.) So, having a queen ready can be a real benefit. Below are some notes on queen rearing, as I do hope to experiment with that one of these days.
Note: The general information above is good for the new beekeeper to get a basic understanding of, right from the start. The actual days (days as egg, days as larvae, etc…) is what beekeepers refer to as Bee Math. This will become critical to understand as one advances in the beekeeping hobby. More on that later:)