Course report – Microscopy

Microscopy Course 19th/20th October 2013

During the year the EBKA has been organising and part funding a number of courses on Beekeeping topics. Each Division was asked to nominate beekeepers with some experience to undertake training in the various disciplines. Those selected are expected to then take back their new knowledge to Divisional meetings to pass on to others.

Dave Eacott and I were nominated to attend the Microscopy course over a weekend in October. We were asked to present ourselves at a village hall near Dunmow along with some flowers, some dead bees and any equipment we might already possess. Harlow Division owns a couple of venerable but useable Microscopes which are available for loan to members. Everything else was provided by Graham Royle NDB a well-known beekeeper and microscopist from Cheshire.

The weekend got off to an exciting start when one of the delegates smashed a honey jar full of live bees on the floor!

During the two days we covered the whole syllabus for the BBKA Microscopy Assessment, with a number of short PowerPoint presentations interspersed with plenty of practical, hands on experience. There was an awful lot to cover, so there was not much time to absorb some of the more complicated aspects of optics/lens theory, but Graham provided copious prepared notes in hand out form on every aspect of the course, along with reading lists and references for those wishing to follow up and learn more. Personally I am content to believe that microscopes work by magic, although I am not sure that will get me through the Assessment should I decide to attempt it.

On day one we covered the differences and uses of the two types of microscope most used by beekeepers, touching on the physics of light refraction and the use of lenses in microscopes.

A lot of the chemicals used for preparing slides are mildly hazardous so inevitably there was a short section on the Health and Safety aspects of microscopy. As usual with H & S its mainly common sense i.e. scalpels are sharp and can cut you, flames are hot can burn you, don’t drink the poisonous chemicals or breathe their fumes etc.

We then learned basic techniques for preparing and mounting bees under the stereo microscope for dissection and undertook the disassembly of several samples from our own colonies. It soon became obvious why 4 or more bees are prepared at a time for dissection. Bees are quite small and even the finest scissors look huge under magnification and despite the instruction “cut carefully from here to here”-it is very easy to produce bee pate!

Having ruined 4 bees each we moved on to “preparation of external anatomy samples for mounting.” In order to look at exoskeleton under high magnification the parts need to be processed to make them flat and transparent. This involves a number of steps and assorted chemicals, which can take up to a week to complete. So after an explanation of what was involved we worked with ready prepared bee parts provided by Graham to produce out own permanent mounted slides.

For the BBKA assessment candidates are required to prepare in advance at least three different prepared slides of bee parts selected from a list provided.

On the second day we covered preparation of pollen slides and looked at the methodology used for identifying the different types of pollen, particularly those likely to be present in pollen loads taken from our own bees. Making and mounting the slides is pretty straightforward although it takes practise to avoid lots of air bubbles in the pink stained glycerine jelly used to collect and mount the pollen grains.

Identifying the type of pollen is another matter. There are thousands of types of plant and they all have slightly different looking pollen grains when viewed under high power magnification. Although books exist on identifying pollen and spread sheets have been developed to help with the process it is not an easy thing to do!

A pound of strained but unfiltered UK produced honey typically has over 1,000,000 grains of pollen in suspension. We were shown how to identify the plants being worked by our bees using a centrifuge to extract pollen from honey samples. It’s possible to do it without a centrifuge, by allowing the pollen to settle out of diluted samples but it takes a few days and some patience.

Graham explained the process of counting the various species of plant pollen on prepared slides and how the results need to be adjusted for over and under representation of each type of pollen in the sample. It seems life is complicated for the forensic honey analyst by the different plant species’ tendency to produce varying quantities of pollen per millilitre of nectar.

The final session was spent using the microscopes for disease testing. We looked at the use of the stereo microscope for looking for acarine in the trachea of our bee samples- we discovered it is easy to wreck the sample without managing to get a good look at the trachea. We also tested our own samples of bees for nosema. From the 14 samples in the room tested, mine were the only bees where any nosema was detected. A little embarrassing! However I felt better about it when told that nosema is endemic and it is pretty much guaranteed to be present in every hive if you look hard enough. It is just the “luck of the draw” if one of the bees used in your sample happens to be carrying the disease! This of course raises the question “why bother to test?” as Fumidil B, the only medicine available for Nosema has been withdrawn from use. Advice from the experienced beekeepers present on the course was “it will probably go away all by itself by the spring, but if symptoms appear (dysentery) try a “Bailey Comb Change” i.e. move them on to new foundation and sterilise/melt down the old.

All in all it was a fascinating weekend. I am certainly now more knowledgeable about bee anatomy and have the tools to find out even more. It will also be interesting to see if I can successfully use the techniques learned for identifying what my bees are foraging on next year.

Dave and I will produce some basic information about microscopy techniques for the HBKA web site and we will be doing a “Microscopy for Beekeepers, a beginner’s guide” at a Division meeting sometime in the New Year.

Martin Cavalier

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