The Beekeeper’s Companion Since 1861
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Bees & Beekeeping: Present & Past

Finding Queen Cells That are Almost Invisible

- September 1, 2021 - Wyatt A. Mangum - (excerpt)

locating queen bee cells

One of my big bee management jobs begins toward the end of the swarm season. I inspect all my colonies to make sure each one has a laying queen. Definitely by the end of June when our spring nectar flow is winding down, I need to be finishing with my queen inspections. Especially for colonies that have swarmed, I want to be certain they have laying queens, not leaving to chance colony survival on the success of capricious mating flights.

My top-bar hives, which accumulate heavy surplus honey stored at the back of the hive, opposite the entrance end with the brood nest to the front, are easy to inspect. I open the hive from the entrance end and go right into the brood nest without having to move the surplus honey.

For my frame hives, many stacked tall with honey supers, off they come. Even before the time when one removes surplus honey supers later in the summer, I want to check for laying queens. For my proof of a functional queen, I want to see patches of larvae. Larvae indicate recent egg laying. Seeing only part of a ring of sealed brood could be the last brood from the former queen long gone with the swarm. The daughter queen could have failed to mate, leaving the colony hopelessly queenless (because by that time the colony has no young brood to raise another queen).

Large patches of sealed brood, especially with surrounding larvae, are acceptable evidence of a queen somewhere in the hive. Finding that, I start stacking the heavy supers. While the work is dreadfully laborious, I am trying to avoid a cryptic scenario that is bound to happen in some of my hives.

From swarming, some daughter queens will fail to mate as mentioned above. Even if the colony’s adult bee population has stabilized or rebounded somewhat, the bees replenished for a time from the leftover brood, the colony will eventually dwindle slowly during the long hot summer. From the entrance slot (for frame hives), plenty of bees may guard it. The entrance appearance can be quite misleading sometimes as the colony population decreases.

In the Southern summer heat, small hive beetle numbers increase. The bees at the hive entrance can mask deleterious symptoms beginning as the adult beetles invade the pollen bands in the brood nest and begin to ruin the combs. If the colony was originally strong, occupying several supers, the comb loss can be considerable, the cost expensive.

Sometimes by carefully watching the bees, one becomes aware of colonies with decreasing populations. For example, consider bee beards. As the summer heat of the day increases, the bees form clusters hanging from the entrances and wrapped across the hive fronts. By the time cooler mornings return, the bees will reenter the hives. When the bee beards become smaller, too quickly (compared to those of known queenright colonies of similar size), I become suspicious that the bees of those colonies are not being replaced, perhaps due to a queen problem. Correcting that cryptic problem before colonies succumb would reduce summer colony losses and save combs.

One colony began showing a rapid reduction in its afternoon bee beard size. It was at the end of the row in a rural apiary where I manage all the colonies in only medium-depth supers (see Figure 1). The colony had swarmed, which explained the bee reduction. Then I saw what Figure 2 shows, and the rest of my workday changed. The side of that brood comb jolted me with fascination as soon as I lifted the frame from the hive body.

Finding (and removing) all the queen cells was critical because missing one or more would allow the colony to continue swarming, producing afterswarms. (The first swarm with the mother queen is called the prime swarm. Beginning about a week later, the colony may produce additional swarms from the daughter queens of the queen cells built to replace the mother queen. These swarms are called the afterswarms.)

Some colonies will afterswarm themselves to destruction by reducing their adult bee population too much. Moreover, I have observed in some cases small hive beetles begin invading the combs when the depleted bee population of the parental colony has been reduced from afterswarming. The bee management imperative is then to find all the queen cells (remove them) and stop the swarming.

The three queen cells at the lower left of Figure 2, the two vacated ones with partly detached caps and the apparently intact one (which was actually empty), do not capture the truly cryptic nature of the queen cells in the scene.

Two more queen cells, for a total of five, not three, are in Figure 2. For the remaining two queen cells, the bees built most of their volumes inside the comb. The eye-catching peanut shape, so striking of the three typical queen cells to the left, is a useless characteristic for finding the remaining two.

Strangely though, the bees had plenty of space between the combs to construct regular peanut-shaped queen cells. I could not determine why the bees built the two queen cells mostly inside the comb. How did I know, or at least strongly suspect in the beginning, the comb “contained” two additional queen cells? The crucial feature was the caps of queen cells. On the right side of the comb in Figure 2, some of the cells are capped, but be careful. Those caps are not all the same, definitely not to the bees.

In general with swarm cells, the bees initially cap the cell in a dome of wax. The sides are braided with pits extending down the sides, where the pattern usually becomes smoother near the cell tip.  As the pupa matures, the bees remove the wax from the cap, fully exposing the cocoon the queen spun as a larva. The wax removal also extends part way up the sides. Sometimes an abrupt transition occurs around the queen cell where the wax pitting stops and the exposed cocoon begins. In Figure 2 the cells with detached caps show the described wax removal and the abrupt transitions. The caps and lower sides are virtually all queen cocoons, not wax. The cell to the far left is a complicated case because it was empty. After the wax removal, the cocoon appears as darker reddish-brown splotches (see Figure 3).

While each queen cell has a small part of one side at or a little above the comb surface, the caps are the most critical indicator telling these are most definitely queen cells. The cap showing the internal cocoon is a key feature of a queen cell holding a mature queen pupa, or in the present case, active queens whose emergence has been delayed. Therefore, to find queen cells, even the ones built into the most well-hidden, hard-to-find places in the combs, search for their caps. During crowded conditions with much burr comb construction webbed in with sealed queen cells, the bees will not build comb on the caps. Even if the comb covers the sides of the cells, the caps remain clear for cells with healthy pupae. The mechanics of how this wax removal works remains unclear. No matter how well hidden the cells –– the queen must be able to emerge from her cell. When building comb around sealed queen cells, the bees do not cover the cap with wax or place even a bit of burr comb on a cap. If the bees build wax on the cap, I immediately suspect the queen cell holds a dead queen pupa.

Most likely, the queen’s cocoon or the queen pupa herself are the source of a pheromone(s) telling the bees not to use the queen cell cap as a wax attachment site, although I have seen the bees build quite close to the caps.

After finding the two hidden queen cells, I gently coaxed most of the bees off the frame by letting its bottom bar rest on the top bars of other frames of the hive body. Using only my hands, I herded the bees down off from the comb with the two queen cells and into the hive. Knowing the colony was afterswarming, I was fully aware moving bees in this manner was a risk. Here is why.

During the afterswarming scenario when the parental colony produces a series of swarms, the bees typically delay the emergence of the daughter queens in their cells. The particular scenarios can be complicated; the bees release the queens in a way that allocates one or more to the successive afterswarms and finally leave one or more in the parental colony (all of which will eventually have only one queen). In the queen cells, the confined queens lose the downy white appearance of a newly-emerged bee and become active, even ready to fly. The bees have various ways to delay a queen’s emergence. On a normal queen cell, where bees cover it, some bees shake their abdomens briefly. The vibration produced is transmitted to the queen inside and thought to slow her emergence behavior, one behavior being cutting a circular hole in the tip of the cell.

From my apiary observations, repeated over the decades, this “stop emerging” message applied by the workers is short-lived. When I cut a queen cell from the comb and isolate it from bees (in a warm place), with a queen eager to emerge, she will   …