It’s the time of year when the bees can swarm their colony to destruction, becoming so weak that small hive beetles and wax moths will consume the combs in the heat of summer.
It’s the time of year when a colony can launch multiple swarms, the bees somehow ensuring each swarm has at least one queen.
It’s the fascinating time of –– afterswarming.
Once the prime swarm has departed, about a week later the colony’s population has typically recovered somewhat, the new bees coming from its capped brood. The older daughter queens in the queen cells (called swarm cells) are finishing their development and need to emerge. The colony needs to allocate daughter queens developing in their swarm cells to the afterswarms and leave a queen for the parental colony.
The colony regulates the emergence of its mutually combative sister queens by delaying and timing their emergence to be ready for launching afterswarms. From among the swarm cells, one daughter queen emerges (probably the oldest one or close to it). Fell (1979) found that usually one daughter queen emerges. With Africanized honey bees, it is also just one emerging daughter queen, and it is the oldest confined queen (Fletcher, 1978; Otis, 1980). Her presence helps delay the emergence of the other queens during afterswarm production. The emerged queen signals her presence by emitting chemical messages (pheromones) and by piping
Briefly, piping is the term for sounds produced by queens, either free-roaming on the comb or confined in their cells. A free-roaming queen on the comb pipes (sometimes called tooting) by emitting a high-pitched sound, produced in a series of pulses. Another “kind” of piping comes from active queens confined in their cells, their emergence delayed. This kind of piping, sometimes called quacking, is heard through the cell as a lower pitch. While piping is an important component of afterswarming, I want to focus on the behavior of the bees on the swarm cells, and how they delay queen emergence.
These bees are in continuous contact with swarm cells. Not only do the bees cover the entire surface of the mature swarm cells, the bees are intent to remain on these cells, which is easily demonstrated. If I gently herd these bees off a swarm cell with just my fingers, they are eager to return. These bees exhibit various behaviors that prevent queens from emerging.
Some workers briefly vibrate their bodies, mostly seen as their abdomens vibrating for 1-2 seconds while standing on a capped queen cell. In the bee literature, this behavior has gone by numerous descriptive names. One term was dorso-ventral abdominal vibration, abbreviated D-VAV or DVAV. Dorso refers to the top or up. Ventral refers to the lower or stomach side or down. Abdominal means the abdomen, what is being vibrated, the last term. The early literature used the abbreviation D-VAV translating it as the “up-and-down vibration of the abdomen.” However, the motion involves more than the bee’s abdomen. The vibration is not like a complicated dance (as with other bee behaviors). Rather it is a simpler motion; the term for that is a “signal.” From many terms came one: “vibration signal” (Schneider and Lewis, 2004).
A worker bee can perform the vibration signal on another worker bee or on queen bees (the mother queen before prime swarm launch or on unmated daughter queens where it conveys various messages (Schneider and Lewis, 2004). For worker bees performing the vibration signal on a capped queen cell, apparently it has an inhibitory effect on queens cutting their emergence slits (Fletcher, 1978; Bruinsma et al., 1981). (The emergence slit is the cut made by an emerging queen, separating the cap from the walls of the queen cell.)
After the queen cuts part of her emergence slit and becomes inhibited (by the bees) from continuing, that leaves a slightly open seam between parts of the cap and queen cell wall. Another way bees delay the queen’s emergence is by filling these emergence slits with wax.
From these brief introductions to some of the main behavioral elements of afterswarming, we are ready to appreciate a rarely-seen episode, our main goal.
When observing bees during afterswarming, Fell (1979) observed a colony delaying the emergence of its daughter queens. One particular incident was quite striking, “a queen attempting to crawl out of her cell was actually pushed back into her cell by a worker.” The bees essentially pushed an emerging queen back into her cell. The behavioral mechanics of that feat are quite astounding.
Years ago, I observed a similar behavior. A colony was in the throes of afterswarming. The bees zealously imprisoned its queens, and pushed one, who almost emerged, back into her cell. Trying to see it again by good luck was doomed to fail from the beginning. (I do not know of any other documented cases of this behavior, but others could be in the bee literature.)
I decided to explore how to “reproduce” the colony conditions for expressing this behavior, or something similar to it.
For multiple attempts, I needed daughter queens during afterswarming with their emergence times being delayed by the bees. The bees had to be intently holding the queens in their cells –– but explicitly where the bees had to back up (reverse) a partly-emerged queen to withdraw back into her cell.
From my frame-hive and top-bar-hive apiaries, I needed a hive design that would provide an easy queen-cell configuration for filming. Figure 1 shows the colony I chose early in the spring. The red rim is the queen excluder, which is over the lowest medium super. (All the rims of my queen excluders are painted red, so I can be sure to retrieve them by fall. With my bee work, queen excluders can be at nontraditional positions in the hives, those not meant for honey production.)
The queen excluder prevented the loss of a large prime swarm. Below the excluder was a super of built comb, providing clustering space for the bees. Early on, I removed one deep and a medium super to lighten the work later on, and help the colony to become crowded for swarming. I wanted the colony to endure the usual time of prime swarm launch, including delaying the emergence of its daughter queens, just like the time extension added to a colony’s swarming time when launching its additional afterswarms.
(The mother queen was in the hive as she would have resided had the weather been rainy, preventing the launch of the prime swarm while the bees delayed the emergence of the daughter queens in their cells. Earlier, I did not search for the mother queen, not wanting to chance any damage to the swarm cells.)
In mid-May while working through a list of jobs at that apiary, I heard a swarm above the thick tree canopy of leaves. The swarm hovered up there for a few minutes, keeping me in suspense. Then the bees began returning to the hive set up to swarm (see Figure 2).
I inspected the hive and found several swarm cells containing active queens, their emergences delayed. I was waiting for this situation. With the hive turned on its end, the swarm cells would be horizontal and protruding from the bottom bars. Positioned like that, I could record the worker behavior on them while letting the bees come onto the cells unrestricted (see Figure 3).
Inside the swarm cells, the queens wanted to emerge but the bees would not let them so I had to give the queens more advantage. One way was to gently cut off the cap end of the cell. Without a cell cap, it is tempting to think the queen would pop out of her cell, almost like a race horse from its starting gate. After all, these are older queens, well past their time of being downy white feeble bees. The bees, however, had been ….