Queen cells: what you are looking at

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First, do nothing

You have lifted a frame and there they are. The reflex is to squash them, and it is the wrong one. Destroying queen cells has never been a way of stopping a swarm. Knock one lot down and the colony starts more, and it will often go earlier than it would have done anyway. 1

Knock them down twice and you risk the colony leaving with no provision at all for a new queen. The BBKA does not accept cell destruction on its own as reliable swarm control either. 5

So stop cutting. Nothing you do in the next hour will be as costly as the thing you were about to do.

Three reasons, and only one is a swarm

A colony builds queen cells for three separate reasons. To reproduce and swarm. To replace a queen it has decided is failing, which is supersedure. Or because it has suddenly lost her, which is an emergency. 1

Which programme the bees are running matters far more than what the cell looks like. Supersedure and emergency cells will not produce a swarm, and normally need nothing from you. But nine times out of ten, a beekeeper who opens a hive and finds queen cells is looking at swarming.

Where they sit, and how many

Position and number are the two clues you have before you touch anything. Neither is proof.

• Swarm cells hang straight down, usually along the bottom bars or in recesses in the side bars. Sometimes they sit on the comb face, and that is more likely when the colony is on a single brood box. There are rarely fewer than five or six. Ten to twenty is typical, and a hundred is possible. 1
• Supersedure cells are usually on the face of the comb, and there are usually only two or three of them, grouped together on the same frame.
• Emergency cells are built out of ordinary worker cells that already held an egg or a young larva. Some get remodelled into a full vertical cell, others keep a right angle bend halfway down. They look unimpressive beside a swarm cell and are easy to miss until the bees are off the frame. The idea that they produce a poor scrub queen is a myth.

The National Bee Unit describes a swarm cell the same way: long and drooping, around the bottom and the sides of the brood frames. Once those are capped, the old queen leaves with about half the adult bees. 4

A play cup is not a decision

Queen cups, play cups, practice cups. Same thing. Little acorn shapes, mostly on the bottom bars, and a normal part of a colony building up. They do not mean a swarm is coming. 1

What is inside is the question. Empty means nothing. An egg standing on end in a cup is worth noting and no more, because plenty of colonies do that several times a season and never swarm.

A charged cup is a different animal. That is a cup with a small larva sitting in a pool of royal jelly. The colony committed itself when the egg hatched on day three and the nurse bees began feeding it. A charged cup is almost always carried through to a sealed cell, so that is when the clock starts.

Drone brood is not a sign either. Healthy colonies raise drones from about the middle of March, and many of those colonies never try to swarm.

Has she already gone?

Everything from here depends on whether the old queen is still in the box. Take the evidence in order of worth. 2

• You see her. The best answer there is.
• Eggs standing on end. Laid within the last day, so she was here this morning.
• Eggs leaning over at about 45 degrees. Laid 24 to 48 hours ago.
• Eggs lying flat. Over 48 hours old and close to hatching. That settles nothing.
• No eggs anywhere. She has almost certainly gone, and the youngest larvae tell you roughly when. If she is still hanging in a bush nearby, she is collectable.

Two traps in that list. A late afternoon inspection can show standing eggs laid by a queen who left hours earlier. And a clipped queen can swarm without the colony losing many bees, so a full looking box proves nothing by itself.

Sealed or unsealed, and what it leaves you

Queen cells run to a timetable. The egg hatches on day three, the cell is sealed on day eight, and the queen emerges on day sixteen, eight days after sealing. Colonies usually swarm around the time the first cell is sealed, though some go earlier for no obvious reason. 1

Our queen cell calculator turns those day numbers into actual dates from the day you saw the cell, including how long to leave the colony alone afterwards.

So unsealed cells with larvae in them mean you have days rather than weeks, and you still have choices. Sealed cells mean the swarm may already have left.

The National Bee Unit draws a hard line there. Its method for swarm control without finding the queen only works while the cells still hold larvae. Sealed cells mean it is too late, because they suggest the colony may already have gone. 3

Worker brood gives you the calendar. Eggs hatch on day three and worker brood is sealed on day nine. So if there is no unsealed larva anywhere, only sealed brood, it is at least nine days since she left. A cast swarm is close, or has happened.

Reading an emerged cell

A cell a queen has walked out of usually still has its hinged lid attached at the tip. Sometimes the bees tidy up and reseal it, leaving a faint line round the end like a “tear here” strip. Look properly before you write a cell off as intact. 1

If there is a bee inside a cell, which way up she is tells you what she is. Head down is a worker who went in to clean and got sealed in by a tidy sister. Head up is a virgin queen.

Once the first virgin is out, a cast swarm normally follows two to four days later. That is your whole window. 2

When you genuinely cannot tell

Swarm cells are not always on the edges, supersedure cells are not always on the face, and the count can land awkwardly between the two. Cells on more than one frame lean towards swarming. Two or three on one comb face lean towards supersedure. Neither is certain. 1

Emergency cells are the one case that is never ambiguous. There will be no eggs in the hive at all, and the youngest brood tells you when she was lost.

If the cells are young and nothing is near sealing, you can defer the decision. Go back in two or three days. More new cells started means swarming, near enough for certain. No new cells means it was probably a supersedure.

If cells are sealed or close to it and you still cannot tell, split rather than guess. Leave the queen where she is. Move the cells, three or four frames of brood, and enough bees to cover them into a nuc box or above a split board.

What to do in the next hour

Less than you think. The evidence stays written on the combs for about three weeks after a swarm leaves, so you have time to be careful and none to be hasty. 2

• Go through every frame, both sides, and get the bees off the brood combs with a little smoke and a gentle shake. Cells hide in the bottom corners and hard against the side bars.
• Count them, and note where they are. Bottom bars or comb face, one frame or several.
• Sealed or unsealed? Then find the youngest brood while you are in there.
• Close up and fetch the kit you need, rather than improvising with the hive open.

If she is still there and the cells are unsealed, the answer is an artificial swarm. The National Bee Unit publishes a version that does not need you to find her. The brood box moves at least a metre aside. A new box of comb goes on the old site to catch the flying bees. One frame of eggs and young brood, with no queen cells on it, goes across into that new box. 3

After that, the inspection interval is what keeps you ahead. Every five days through the weeks of highest risk, and every seven to ten when it is lower. On a double brood box or brood and a half, cells usually start on the bottom bars of the upper box, so tilting it for a look underneath is a quick check between inspections. Not good enough to be your only one. 1

Clipping the queen’s wings stretches the safe gap to about a fortnight. Beekeepers disagree about it sharply, so treat it as a choice rather than as advice.