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Choosing the Right Microscope : 13 MICROSCOPY FOR BEEKEEPERS

Choosing the Right Microscope

Alan R Potter, MBE, MPhil, DSc (Managing Director, Brunel Microscopes Ltd) M

icroscopes have always been an intrinsic part

of British Beekeepers’ Association (BBKA) examinations. However, the many difficulties that our bee population has experienced in recent years, has brought renewed attention, not only to the microscopy of bee diseases, but also to the value of microscopes in public education, queen bee insemination and pollen identification. Selecting the correct

microscope for the job can be quite a task for the beginner. The word ‘microscope’ (derived from the Greek micros meaning small and skopein meaning to look) is in fact a generic description of many different types of instrument, much in the same way that the description ‘motor vehicle’ includes, for example, tractors, cars and motorbikes. These three examples have very different functions and none can do the same job as the other. Microscopes can also have very

different functions such as the low power stereomicroscope, high power biological or high power polarising microscope,

August 2013 Vol 95 No 8

to name just three, and again none can fulfil the function of the other.

The place to start is to identify exactly what is needed from a microscope and then choose the correct type at a cost to suit the budget. Beekeeping needs high power microscopes to identify microscopic organisms that cause disease such as bacteria and nosema spores and to identify pollen grains. In addition, low power microscopes are needed for bee dissection, exposing the tracheae, and manipulations such as insemination. Unfortunately, because of the laws of physics that govern the way that light behaves, it is not possible to have one instrument that can do both things. Therefore if both these two areas are to be covered then two microscopes are needed.

The High Power Compound Microscope

These are also sometimes called biological microscopes because they are designed to look at microscopic biological materials. Typically the high power microscope consists of a tube with an eyepiece (sometimes called an ocular) at one end and an objective at the

Figure 1

other (often several mounted on a turret). This tube is mounted on a stand with a platform to hold the slide (called the stage) and a focus mechanism to move the tube with its eyepiece and objective, towards or away from the slide to get the contents in focus. Sometimes it is the stage that moves to achieve focus. The stage has a hole in the centre to allow light to pass through the

slide and into the

Figure 2

objective. The light comes from a mirror (the sun!) or more commonly either a tungsten or LED light source. The high power microscope should have a lens called the condenser, between the stage and the light source to help focus the light onto the slide. Two examples of high power compound microscopes are shown in Figures 1 and 2. All high power microscopes should have these basic features and it is worth noting here that a lot of toy microscopes do not have all of them.

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