It is important to create enough young colonies each year to compensate for losses or to increase the number of colonies. Furthermore, young queens are needed to replace the old ones.
The method described here is a good alternative to making multiple individual splits, which could result in more colonies than you actually want.
The principle of the combined split is that several production colonies each provide (at least) one frame containing brood and bees. Eight to ten such frames will fill a single box. If there isn’t enough food in those frames, a frame with food must be added.
The combined split acts as both a starter and a finisher. The queen cells remain in the hive for the entire period. This leads to very harmonious nucleus colonies, with bees of a suitable age.
Precondition is that the nucleus colonies are created using the same frame size, as the combined split, so that both bees and frames can be used. This is often not possible when visiting a mating station, as large-frame hive systems are generally not permitted there.
Removing a frame with brood and bees slightly hinders the development of productive colonies, but it also delays the onset of swarming. In any case, it causes less disruption and disharmony than brood distancing, discussed elsewhere on this site (see Intermediate Nuclei). The method described here is useful for apiaries with about five colonies or more.
The method:
- Day x (between April 20th and May 10th): Harvesting one or two frames with bees and brood from the production colonies.
Frames with plenty of emerging brood are most suitable. The collection brood chamber should also contain some eggs and/or young larvae so the bees can start developing cells. - Day x+9: Breaking the queen cells and introduce a grafting frame containing young larvae from one or more selected colonies.
The larvae are well cared for by the many emerging young bees. - Day x+14 or x+19: Caging the emerged queens.
If there is a heavy nectar flow, it’s safer to hive on day x+14, as otherwise there is a risk that the bees will fill the cells with comb to store the nectar they have collected. Otherwise, day x+19 is a good option, as the bees can then continue to care for the cells for a while.
After caging the queens, you can place a box containing stores. This can then be used when creating the nucleus colonies. This extra box encourages the bees to spread out more, which is helpful when making the nucleus colonies. - Day x+21: Creating nucleus colonies.
If desired, the nucleus colonies can be sprayed with oxalic acid to combat Varroa mites during their formation.
Be careful that the queen doesn’t fly away when introducing her into the nucleus colony! In many cases, the best way to introduce her is through the nucleus hive’s flight entrance. Another effective method is to place the open queen cage directly on the combs and cover it with a plastic sheet until the young queen has left the cage.
On day x+21, the queens hatch. You can check the contents of still-closed queen cells by carefully making a small incision at the base of the cell. If the queen is still alive—and about to hatch—gently close the cell again. You can then place that cell into a nucleus colony. This isn’t important if you have enough young queens to create enough nucleus colonies.
The limiting factor for the number of nucleus colonies is the number of frames containing bees in the brood chamber. A single-chamber combined split can produce 7 to 9 nucleus colonies. A double-chamber combined split can produce double that number, provided enough young queens have emerged. Incidentally, I prefer two single-chamber combined splits to one double-chamber one, because of the number of high-quality cells a cell builder colony can successfully produce.
Drones joining the nucleus colonies isn’t a problem at all with open mating. When visiting a mating station, it is another matter: there shouldn’t be any drones present, of course. In that case, we have to take a different approach. There are several ways to remove those drones while simultaneously ensuring that almost exclusively young bees are used.
To collect primarily young bees, we take several frames of brood from a colony, without any bees, hang them in an empty box, and place them back on the colony above the queen excluder. It’s primarily young bees that migrate to the brood in the prepared box. Once there are enough bees on the frames, we remove the frames one by one and knock them off into a large bucket, then lightly moisten the bees with a plant sprayer. The frames are returned to the colony in their original location. In this case, however, we lose the advantage of using the young workers from the combined split.
An additional precaution, if we go to a mating station, is to ‘decapitate’ the drone brood from the brood frames we place in the extra box above the queen wexcluder. This prevents one or more drones from emerging in the meantime. When we collect the bees, they are sieved a second time. There are several ways to do this, including using a tube with a screen and a pestle attached to a bucket. We collect worker bees in the tube and gently push them through the screen into the bucket using the pestle. After lightly moistening them with a plant sprayer, they are ready for use.
If you create the collective split later in the season, the nucleus colonies can no longer develop into a viable overwintering unit. It is then a good idea to combine several of them and use the resulting young queens to replace the old queens in production colonies.