Institute of Northern Ireland Beekeepers

Just over 150 years ago the American beekeeper, Rev L L Langstroth, published a book entitled 'On the Hive and the Honey Bee'. In it he described many of the things that he had observed whilst studying colonies of honey bees of the species Apis mellifera. One of his observations was to have a profound effect on beekeeping and led to the development of the moveable frame hive, which in many variations, is used by beekeepers all over the world.

Langstroth had observed that if a colony of bees were allowed to build their nest in a suitable cavity from scratch, that is without the benefit of any previously built comb, then they would incorporate into the design a number of passageways.

The most obvious of these are those left between adjacent comb faces and the space at the comb edges where it is close to the 'wall' of the confining cavity. Leaving just sufficient space for the bees to be able to go about their daily work means that the colony can maximise the remaining volume of the cavity and build the comb that they need for brood rearing and food storage. It is not really surprising that this 'space' that the bees leave free became known as 'bee-space'.

There is some variation in the actual dimension of 'bee-space' between different races and strains of bee because, in essence, it depends on the physical size of the race/strain. Simply put, bigger bees need bigger passageways. References that give figures seem to quote from 5mm to 9mm (or 3/16" to 3/8"). As bee-space is the essential factor in moveable comb hives it means that, as far as possible, the frames are hung in the boxes that form the modern beehive with bee-space all around them. At the points of support, where it has to be interrupted, the area of contact is minimised. Maintaining bee-space in a hive will not, on its own, ensure that frames can always be easily removed. Two other factors are relevant. Firstly, if a space, as perceived by the bees, is less than a bee space, they might well fill it with propolis. Secondly, if the colony is tight for room to build comb then they might fill some of the passageways with comb. If either or both of these factors are present the combs will be difficult to remove.

Being able to remove frames (and the comb they contain) from a hive has a number of benefits to the beekeeper as all combs can so readily be inspected. Provided the frames can also be returned to a suitable position, the impact of the inspection on the colony should be minimal. It has to be remembered that bee-space has to exist in three directions within a hive; most of which today are of a vertical type with boxes of frames placed above others to provide the capacity needed. In order to provide bee-space in the vertical sense the boxes are made a bee-space higher than the frames that will go in them. If that space is above the frames it is called a 'top bee-space' design, if below, then the design is 'bottom bee-space'. Typically, metal or plastic runners are used to support and position the frames in the vertical direction and these effectively minimise the contact area between frame and box to there should be little propolis. Provided the walls of the boxes are of the same thickness only a small line of propolis will need to be broken in order to separate adjacent boxes.

It is not intended to itemise all the positions in a hive where bee-space may not have been allowed for nor to identify all the areas where contact has not been minimised. Mostly, they are obvious but if not then a ruler or tape measure will usually help. There are many ways to improve the situation but only a few are mentioned below. The key is to identify the problem and then to find how best to apply the solution. This may, or may not, involve some expense!

Hives, of course, do not only consist of frames and boxes. Bees seem to tolerate floors that provide a space of up to 19mm (¾") below the bottom of the lowest frames. However comb building under the bottom bars is much reduced if the wider, 27mm (1 1/16") bottom bars are used.

Queen excluders are used by most beekeepers to constrain the queen to the brood chamber but many of the designs do not fully observe the bee-space or minimise contact. Try to change to those that do a better job! The amount and position of wax and propolis will highlight where the space is incorrect. The slotted type that sits on the top bars invariably becomes propolised (no surprise here) and because it cannot be replaced accurately its new position encourages the bees to add more propolis or wax in the area. This of course makes removal at the next inspection difficult and subsequent replacement even more of a problem. Framed wire excluders do seem to follow the rule better, but some are better at it than others.

Crown boards are a relatively simple component of the hive but it is surprising how many use a height of batten that produces a space either too big or too small above the uppermost frames.

The vertical positioning of frames has already been mentioned but what of the two horizontal directions. The end of the lugs are usually cut square and the gap between the lug end and the rebate provides a very suitable site for propolis. Long lugged frames can be shaped so that the end comes to more of a point thus minimising the scope for propolising.

It is in the other horizontal direction that beekeepers seem to have the most trouble ie. the spacing between adjacent frames. In the UK most brood frames are spaced to either 36.5mm (1 7/16") or 35mm (1 3/8") and this is achieved by a number of different methods. This spacing provides the bees with just the right amount of space to produce cells of the right length on the centrally positioned foundation and allow the bees to move about on the adjacent faces of the comb to service the cells without interfering with each other as they work back-to-back ie two bee-spaces. When cells are being used for food storage they are usually lengthened by the bees and in doing so the space between the adjacent combs is reduced to one bee-space.

The internal width of brood boxes is usually greater than the overall width of the frames that it has been designed to hold. Having the extra space makes it easier to remove the first frame during an inspection however it also usually encourages the bees to widen the outside comb(s) making them harder to remove on subsequent inspections. The use of a correctly sized and spaced dummy board does overcome the problem very effectively.

Finally, a bee-space needs to be maintained between the flank frame and the sidewall of the hive to avoid the presence of brace comb. This is easily achieved by fixing some form of spacer to the hive wall so that the flank frame, and/or its comb, is a bee-space from the wall. Prior to replacing the queen excluder, remember to squeeze the frames together to re-establish the correct spacing right across the brood chamber.

Please do not assume that any equipment purchased, new or second-hand, will observe the 'bee-space / minimum contact' rule. Do your hives obey the rule? If beekeepers play their part and maintain the rule in their hives then their beekeeping will become easier, quicker and more enjoyable. Inspections will be less of an intrusion for the colony and the bees will be less likely to react adversely. What more reasons do you need for paying attention to bee-space? Why not make a start today and check that your spare equipment obeys the rule. It is so much easier to check when it is bee-free. It will soon be time for colony inspections, be observant and identify the occupied hives where the bee-space is wrong, take corrective action and turn a chore into an enjoyable event.


Malcolm Blake, Somerset BKA