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Grafting Honey Bee Larvae

This page is credited in full to Dave Cushman who created it. His voice is expressed in black colour text and any additions or comments in blue belong to myself. Credit: Dave Cushman’s website.

PH.

 

Grafting Honey Bee Larvae
Size and Age of Larvae…

the easiest way that I can describe this, is to say that the larva should be the same size (or a tiny bit more) as an egg, but curled round in a ‘C’ shape. At least by describing it in this way you will never forget that you have a reference source available close at hand.
Wet or Dry…

I do my grafting ‘dry’ in other words I do not prime the cups with royal jelly. I have several reasons, the first of these is that I believe that bees feed a slightly different mix of royal jelly according to the age of the larva being fed. Thus I could be defeating my quality objectives by inadvertently supplying the wrong formula of royal jelly. I save the labour and the not inconsiderable mess of priming the cell cups. In general I get a high proportion of acceptance (usually no more than two failures on any bar, average about one). If anything does go wrong in grafting these figures are reversed with only one or two on a bar being accepted. I then reject these totally and start again.

Those that do use wet grafting usually dilute royal jelly that has been gathered from several cells with distilled water, I have also heard of plain water or water with a very small percentage of honey being used to prime the cups. I think this is completely un-natural and likely to disturb the normal responses of nurse bees, giving rise to less than perfect feeding of our grafted larvae.
Double Grafting…

I do not do this for the same reasons as stated in the previous paragraphs, but I will describe the process so that others may try.

Make your grafts in the normal way, then after a day has elapsed remove the larvae and graft with fresh day old or less larvae again. The idea is that this causes the second batch of larvae to be better fed than the first lot, because of the surfeit of royal jelly. I think it is too much work with no advantage in quality.
Time of day…

I have performed grafting at all times of the day from early in the morning until practically full darkness. I have never noticed any significant difference in performance owing to time of day. The vast majority of my grafting was either conducted at about 4 pm or 8 pm.
Humidity…

Many of the books will tell you to perform grafting in a room with a constantly boiling kettle to keep the atmosphere humid. I do most of my grafting out of doors and the only precautions I take are to do the grafting in the shade. I will also wrap a damp towel around the frames I use, while I move them from the hive to the grafting position and back again. I believe that the Ultra Violet rays of direct sunlight can damage larvae, but as long as no dehydration takes place, the temperature is not particularly important.
Angus’s swarm box method…

A method that I learned from Angus Stokes involves the swarm box lid shown on this page.

The matrix of holes was designed to suit the ‘old style’ of yellow Jenter plug that I use. Using this method, acceptance can be assessed very easily by pulling out a plug and placing your finger over the hole to prevent bees escaping in order to look for acceptance. Should a larva not have been accepted it is a simple matter to remove the first grub using a ‘cotton bud’ and re-graft immediately.

queencell forming stick
Types of Cup…

Dipped wax cups formed around a wetted wooden dowel have a long history. Some systems have had multiple dipping ‘combs’ of forming sticks set at the same spacing as the cups are required so that the cups are first dipped then attached to the bar, with molten wax, before the former is withdrawn, thus a finished cell bar is produced in one operation. This is quite a productive method, but requires several formers to work well. It is economic if many hundreds of prepared bars of cells are required.

The forming stick is best made of beech as this stands up to the constant wetting and retains a degree of polish. Start with a 9 mm (or 3/8″) blank, whittle it round and slightly tapered so that a hemispherical end can be fashioned that is 8 mm (5/16″) in diameter. Then polish smooth with 600 grit ‘wet and dry’ abrasive paper. (place the stick in the chuck of a battery powered drill and wrap the abrasive paper around it with a gloved hand (it will get hot!).

Moulded wax cups have come into use during the last 20 years. The moulds are made from silicone rubber and usually have multiple impressions. The type that I have myself was originally manufactured by Thorne, but they have changed, recently, to a mould that produces ten cups with a smaller, less chunky base. (I suspect that the newer type has a larger diameter hemispherical bottom than the type that I use.)
Silicone Rubber Queencell Cup Mould

The picture at right shows a cross section of the type of wax cup that I use. It has a chunky base that helps with handling and gives rigidity to the base region that will be separated from the cell bar on completion.
Cross Section of the Wax Cups I use

There is a further type that is a combination of the two methods whereby the ‘mould’ is in the form of ten silicone rubber fingers, the tips of which are dipped into molten wax.

(Gilles Fert refers to this as the Kemp type, but I am not sure whether this is the designer’s, producer’s or seller’s name.) The picture at far right is clipped from an old Thomas Catalogue.
Kemp finger type mould ?? ?Kemp finger type mould in use

Plastic Cell Cups from the cell plug box kits can be utilised for direct grafting. There are also plastic cups made for grafting. The Jz-Bz type is the most common in UK and is illustrated at extreme right. There are two versions of the JZ/BZ type of cup and the subtleties of their difference in design is discussed on the page… JZ BZ Comparison.

Coloured Plastic Cell Cup

The yellow type shown immediate right is available in UK and fits into a grooved aluminium rail that is in turn mounted on the underside of the cell bar.

This type benefits from a small flat cut on the end of one of the curved lugs which allows it to ‘snap’ in place and gives a more secure fit. The cups can also be fitted onto tapered wooden dowels (as shown below left).


JZ/BZ Cell Cup
Coloured Plastic Cell Cup on Cellspace Block

Nicot Cell Cup in Wooden Carrier

The cell space blocks shown above can be used to introduce a suitable larva to any frame that has the cell space facility. Even a small mating nuc can be used to raise a queen, but such a queen should be considered a of slightly suspect quality and should not be used for further breeding. I use such queens on occasions to lay up brood in small mating nuc frames to provide extra bees or sealed brood to future mating nucs. I also use the mating nucs to raise second generation queens for rapid assessment.

No amount of care will make up inadequately fertile drones. To make sure that such drones will be available at the time we expect mating. See Grafting Timetable for details.

The choice of old comb, new comb or foundation is influenced by your preferred methods of working… Fresh drawn comb or that built on foundation can be easily cut to reduce the depth, this both enhances visibility and increases the angle that you can get a grafting tool in. Old dark comb provides a contrasting background, but has many cocoons that make the trimming of the cells difficult. There is a device that will achieve a clean cut… The ‘cut throat’ open razor, but these are not a very common item in beekeeper’s toolboxes.

It has been suggested that to gain practice a beginner at grafting should graft a frame of larvae and treat that as just a trial, then to graft another frame (or frames) that will be actually be used. I think this is a good idea although I have not practised it myself. It has also been suggested that the first frame of grafts made in a new season, should also be discarded as ‘getting back into practice’. I have often had failures in my first batch of the season, but I have always put it down to the weather, it may be that performing an initial practice frame may improve the success of first batches.

I agree that practice is important. One year I grafted for 10 days with dismal results, then the weather changed and I achieved my best ever and never so far surpassed, 32 from 36 accepted. At the time I think I was grafting with the best skill I have ever had. Then of course I had had a fair bit of practise. 😉

If using a metal grafting tool there is an advantage in using wax cups as the tool can be pressed into the wax to ease the larvae off. Obviously not important if using a brush, nor possible with plastic cups. I have never seen any odds between plastic or wax in terms of acceptance.

PH

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