Honey Bee Genetics

You don’t need to know about bee genetics, but it explains why the colony members work together. They all share the same genes to some extent. The genetic system is that males are haploid (16 chromosomes), and the queen and workers are diploid (16 pairs = 32 chromosomes). This means a drone can only get genes from his mother.

Some workers are 75% related to the queen, and drones are 100% related. So from a genetic viewpoint, it serves everyone in the colony to work together. Which chromosomes come from which bee is an important concept in commercial queen breeding. It is possible to breed from a docile queen only to find that her daughters produce workers from hell.

Sex determination and Diploid drones

The coloured dashes in the picture represent chromosomes/bundles of genetic information. The drone’s mother was produced from half the chromosomes from her father (F) and half from her mother (M). So, the drone has a grandfather, and his chromosomes are a muddle of M and F. But of course, he only has one of a pair, i.e. 16. This is what makes him male. All 16 come from his mother, so he has no father.

In reality, sex determination is more complicated. Sex is determined by a group of DNA segments that code for sex. These groups of DNA are called Alleles. Bees have 20 versions of sex alleles.

If an egg is fertilised by a sperm and their sex alleles are different, the egg becomes a worker. However, if the egg is fertilised by a sperm with the same sex allele, the egg becomes male despite having two sets of chromosomes and is called a diploid drone. Diploid drones cannot function as drones and are cannibalised by nursery bees. This results in empty cells in the brood and is a cause of spotty brood. Severe spotty brood can be a consequence of inbreeding.

Super-sisters

Each worker has a different muddle of chromosomes from her mother, so she is 25% related to her sisters. However, if they have the same father, they both get the identical 16 chromosomes, which makes them 50% related. 50 + 25 = 75. They are 75% related to one another. They are super sisters.

Races of honey bees and temperament

Bees have adapted to suit the conditions where they live. Carniolans originate in the Balkans, and Italians originate in the Mediterranean. Italians produce a stupendous amount of brood, so the pure form is unsuitable for our climate. Carniolans are the commonest race sold to beekeepers. They are placid, whereas the British Black Bee is more defensive. In the UK, these races have been mixed to create mongrels.

There is a famous hybrid bee called a Buckfast. This is derived by mating two bee strains, resulting in a docile bee with hybrid vigour. The disadvantage is that it does not breed true.