Temporary splits

I own a book written by Leonard E. Snelgrove in 1934 called “Swarming – Its Control and Prevention“. This describes a method of swarm control that is still used today. The goal is to separate queen and brood. It is actually a special form of a method known as brood distancing, developed by American George Demaree in 1892 (!). The colony is temporarily split into two parts, with the brood at the top and the queen at the bottom, separated from the brood by a queen excluder. In this system, the two parts are rejoined before the queenless part can raise its own queen. As a result, no rejuvenation of the queen takes place, which is considered a disadvantage.

Snelgrove’s original idea was to control the swarming impulse by providing extra laying space to the queen while maintaining the colony’s strength. This swarm prevention method can be applied both preventively and at a time when there are already queen cells in the colony. The heart of the method is the temporary separation of queen and forager bees from brood and nurse bees in two separate parts of the same hive.

Snelgrove realized, however, that the method could also be used for multiplication. Over time, a number of variants of the method have been developed, depending on its purpose. Snelgrove’s method allows the beekeeper to rear a young queen in the queenless part and then, after removing the old queen, to combine the two parts again, with a very strong colony headed by a young queen as a result.

The method

The Snelgrove board looks like a separator separator board covered with mesh, so that the bees can smell each other, but cannot join each other. The board has a number of wedges, which are located in pairs above and below the mesh and which can serve as an additional hive entrance. With the help of these wedges, the beekeeper can direct the foraging bees to the upper or lower box, so that the bees can be evenly distributed between both boxes. That is why the Snelgrove bottom is superior to a regular separator, which only has one flight opening. The advantage of the method is that less space and material are required and that the swarming impulse is at least temporarily suppressed.

Snelgrove board with 8 wedges.

After the separation of the colony into a queenright and a queenless part, the foragers leave the upper box through the top wedge. The corresponding bottom wedge remains closed. As soon as a number of newly emerged bees have learned to use the upper hive entrance, this wedge is closed and the corrsponding lower wedge is opened, causing the foragers to enter the lower box and in this way strengthen this part of the colony. This process can be repeated once or twice, after about five respectively ten days, using the pair of wedges on one of the sides. The aim is to equalize the strength of the two parts of the population as much as possible.

As a result of the temporary split of the two parts of the colony, any swarm rimpulse immediately disappears. Queen cells are now drawn up in the queenless part. We have the option to breed a new queen in this part or to reunite the two parts after breaking the cells. If we breed a new queen, we have the choice to remove the old queen and then reunite the two colony parts, thus achieving the rejuvenation of the queen. Alternatively, we can separate the two parts definitively, thus increasing the number of colonies.

Where to put the queen?

The part where the old queen is placed – upper or lower box – depends on whether or not there are queen cells in the colony at the time of carrying out the method. If the colony is not in a swarming mood, the queen comes into the lower box, together with the foragers and one comb containing brood. The nurse bees and the rest of the brood then remain in the upper box above the Snelgrove board.

If the colony is in swarming mood, stronger measures are needed. In this case, the queen is placed in the top box, with the brood and house bees. The foragers move to the bottom box and start building queen cells on a frame containing open brood that has been provided.

Does Snelgrove’s method prevent swarming?

Many people doubt if the swarm suppressing effect lasts long, especially if one reuinites the two parts after 9, or even 18, days, because the resulting strong colony can soon return to the swarming mood. There are also fears of a negative effect on foraging behaviour. The intervention certainly has a strong influence on the colony harmony, which may result in more crop loss than if one would carefully tap some brood and bees at intervals. There is also a fundamental objection to brood distancing because of the danger of the brood cooling down and the risk of the nurse bee part suffering from food shortage. In addition, the brood nest can actually be regarded as a kind of honey pump which should be maintained. Consequently, its is imporant tot carefully monitor how the two colony parts are behaving.

The Snelgrove board has recently gained some renewed interest with the popularity of Gerhard Liebig’s ‘Teilen und Behandeln‘ (Separate and Treat) method, in which a colony is split in mid-July à la Snelgrove in order to treat the two colony parts with oxalic acid or lactic acid against Varroa as soon as these parts no longer have brood. The queen is placed in the lower box, together with the foraging bees, but without brood. This box can then be treated with lactic acid or oxalic acid after 3 days, before closed brood appears. In the upper box, in which a new queen is bred, all the brood has emerged after 21 days. This box can now also be treated before the young queen starts laying. Later on, the beekeeper can decide whether the two parts are reunited or kept as individual colonies.