The main work to classify the various subspecies or ‘races’ of honey bee around the world was undertaken by Professor Friedrich Ruttner. Starting in the 1960s he collected samples of bees from various parts of the world, and invented and used morphometric techniques to identify the characteristics that defined the different subspecies.
His initial work identified 3 main groupings of bees, which he classified as M (Western/northern Europe), C (Southern/Eastern Europe) and A (Africa). Later on the O (Western Asia) group was added.
Genetics and DNA analysis was still in it’s infancy at this stage, so physical characteristics were key in differentiating between subspecies. However many years later Ruttner’s work was validated by genetic analysis, which found that his groupings and identification of subspecies was broadly correct, with the addition of a new Y (also Western Asia) lineage.
Morphometry and physical analysis
Morphometry can be useful in identifying subspecies, since the differences between pure strains are readily apparent and easy to differentiate on. Most bee breeders have been using wing morphometry for selection for many years, and a wide range of tools and software are available to help with this.
With that in mind, people often wonder why there is a need for genetic subspecies analysis, such as the M/C lineage admixture assay which we offer. Well there are a few problems with morphometry, especially wing venation, which can lead to problems if they are relied on for selection and breeding.
Firstly physical characteristics are easily selected for, especially ones which don’t affect the underlying survival or fitness of the animal. Wing venation is one of these. If you repeatedly measure the wing veins and breed from bees that have wings that match a certain pattern, you can end up with bees which have that wing pattern. Just because the wing pattern changes to be more like a particular subspecies, it doesn’t mean that the rest of the bee will follow!
Secondly we are very often trying to work out the levels of hybridisation between 2 (or more) subspecies. Since a bee can be anywhere on a ‘sliding scale’ between subspecies, so will it’s physical characteristics. This is true for the physical characteristics of many other hybrids. For example, you might consider leg length when distinguishing between a Great Dane and a Chihuahua. However a hybrid between the 2 will have legs that might not match either parent.
Building on the 2 above issues, another issue with morphometry is that it generally only focuses on a single, or small number of characteristics. When in reality it is all features combined that need to be considered. Ruttner’s initial work involved taking over 100 measurements!
So how does genetics help?
While we can only practically consider a few physical characteristics, a honey bee has around 10,000 genes for consideration. Many of these are common across subspecies, or vary within subspecies, while others are unique and can be used as ‘markers’ to identify subspecies.
In very simple terms we can think of these genes a bit like a bag of marbles. One subspecies only has red marbles, the other only blue. When 2 subspecies mate, these marbled are ‘mixed up’ in the resulting offspring. By counting the number of each colour, we can identify that hybridisation has occurred, and how much of each subspecies’ genes are present.
There has been research work done to identify genetic variations (SNPs) which are strongly associated with particular subspecies, and develop a method to ‘pick out’ these key SNPs and work out how much admixture has occurred. We offer this M/C admixture test to beekeepers looking to identify the levels of hybridisation between M and C lineage subspecies in their bees – the 2 commonest subspecies present in the UK and Northern Europe.
The ‘holy grail’ for geneticists is to eventually identify the purpose of every gene, so that we can not only identify what genes a bee has, but also consider what effect they will have, in terms of health, fitness, productivity and more. While this work is still very much in its infancy, we hope to continue to expand and improve the services we can offer as the science progresses.