Typically, we consider bees of a swarm to be very sensitive to the presence of their queen, even swarms occurring in the summer. A swarm flying off and abandoning its queen is counterintuitive. With that unsettling notion in mind, consider the three following case studies, along with photographic documentation, never published before.
The first incident occurred on September 1, 2023 at a top-bar apiary with ten colonies in five-foot-long hives. I had been away because of family matters and a couple of colonies, one in particular, had amassed huge small hive beetle populations. The adult beetles were lightly sliming the combs of capped honey in the backs of the hives where the bee coverage was less dense. The bees, repulsed by the thin coating of slime, shifted to the front of the hive to the brood nest. Usually I cannot find any beetle larvae or a small mass of them on the hive floor. (Keep in mind the lower comb edges in a top-bar hive are closer to the hive floor than a comb in a frame.)
With my vacuum system, I was ready to open the affected hives and remove the adult beetles, without shaking all the bees off the combs, avoiding maximum colony disruption. Although the vacuum system is still in development, I can remove several thousand adult beetles, provided the colonies are not fully engulfed in slime as they would be when older larvae have been in the hives with honey.
At the corner support of a hive stand was a small swarm (see Figures 1 and 2). A key component of obtaining the hive resources by the adult beetles is the eviction of the bee population. At my bee house with 30 observation hives, I have had small colonies cluster on the outside of the house. After some gentle finger-tip searching through the bees in a cluster, I have found physogastric queens (heavy with eggs). A physogastric queen on the outside of the hive indicates a dreadful problem in the hive, here eviction from their single comb.
Moreover, a physogastric queen has difficulty flying or just cannot, although she probably tries during the excitement when the swarm launches. Naturally then, we expect these beetle-evicted swarms to land low, if they took flight too soon after the queen stopped laying (which should reduce her weight). In front of a row of frame hives, set low to the ground, a swarm could be clustered flat on the ground. In that position, the swarm appears as a potential usurpation swarm (coming to the apiary), which indeed it may become later on. Except in context (the situation of Figures 1 and 2), the apiary had a severe beetle problem.
To gain control over the swarm, I searched the cluster for the queen (see Figure 3). In a few minutes I found her. She had popped out of the bees at the top of the cluster as I removed handfuls of bees below her. I quickly caged her (see Figures 4 and 5). (Besides removing handfuls of bees on the front of the cluster, I was removing bees from the harder to reach, other side of the cluster too, behind the wooden supports. Without that concurrent front-and-back bee removal, the queen was liable to slip around to the other side of the cluster, and find an exceptionally good hiding place behind the support, becoming difficult to locate.)
Most importantly though, the bees never displayed any balling behavior toward their queen, either before or after caging (like I have observed with swarms whose origins were much less certain, a complication with usurpation swarms taking over an established colony).
Bogged down in an atrocious beetle war at this apiary (my other bee yards were normal), I returned the next morning, ready to remove more adult beetles from the hives. One glance to the corner post of the hive stand shattered my entrenched beetle mindset. The small swarm was gone! I had caged the queen to prevent the bees from leaving.
Had the queen squeezed by the wooden plug in my homemade queen cage? A rare determined (small) queen or two has managed to Houdini herself out this way. Not this queen. A chilled, lethargic queen remained in the cage. About 20 or so worker bees remained on the cage screen (see Figure 6).
Summer swarms will readily join other swarms, but I could see no others nearby. With all the tall old-growth trees around this apiary, most swarms could not be seen. Nevertheless, the workers joining another swarm remains a reasonable explanation. However, when nature reveals something, possibly novel, take notice. Do not ignore it. Therefore, even busy and tired with beetles, I decided to step up my apiary patrolling. I wanted to cage queens from other summer swarms and leave the clusters in place to see if this limited intervention prevented the swarm from leaving like it had done in the past. Of particular importance were swarms showing no balling behavior toward their queens as with this Case 1 swarm. I wondered, too, if this Case 1 episode would be the last of 2023, leaving me to wonder until next summer whether this queen abandonment behavior was some coming trend. I would find the next swarm that same day.
On September 1, 2023, another summer swarm jolted me from apiary work. Upon arriving at my main research apiary in front of the bee house, a swarm had landed at the back corner of a top-bar hive (see Figure 7). The bees could not enter the hive from the rear, so it must be a bivouac site (see Figure 8). These swarms take priority over most all other apiary work. After retrieving a queen cage from the bee truck, I spread the swarm over the top-bar hive, its large flat surface being so convenient. The queen was easy to find. Moreover, the swarm could be easily searched for additional queens. None were found (see Figure 9).
I placed the queen cage on the corner of the hive at the original swarm location and propped the long metal cover so it protected the cluster from rain. Soon the bees clustered around the queen cage and the cage disappeared (see Figure 10).
Other duties kept me away from this apiary the next day. Returning on September 3, I stared at a bare queen cage in disbelief. Another swarm had abandoned its queen and flown off to someplace unknown. The queen was dead (see Figure 11).
September continued steaming hot like a late summer. I kept searching for swarms, patrolling my apiaries hoping to see something before cool temperatures closed the season. After almost ten days of no sightings, that changed dramatically on September 13. In my apiary managed with mostly medium-depth supers, a swarm had landed up under the cover of a hive (see Figure 12). Although the swarm could not enter the hive from that location, the bees were in the gap between the upper edge of the super and the …