- 01-06-2011, 09:32 AM
Honeybees have a haplo / diploid reproductive system. This means males are hatched from unfertilized eggs, so they have no father and only have half the chromosomes of a female.
The queen naturally mates with up to 20 drones, making the colony a collection of many subfamilies (half sisters with the same mother, but different fathers).
Unlike most animals, each one of a drone's 10 million sperm are identical clones. Sister bees with the same father share 75% of their genes. This is far more than the 50% found in other species.
The multiple mating habits of bees has always been an obstacle to progress in breeding bees for specific traits.
To simplify the selection process, queens can be instrumentally inseminated to single drones.
- 01-06-2011, 09:34 AM
All 10 million sperm produced by a single drone are identical clones.
Queens mated to a single drone produce progeny with extreme consistency.
Genetic consistency and genetic diversity are opposite ends of a spectrum. One necessarily gives up diversity in trade for "fixing" any trait in an individual, a colony, or a population.
- 01-06-2011, 09:34 AM
This genetic trade-off can be optimized using single drone inseminations together with mating other queens with large numbers of drones (supermated).
Naturally mated queens normally mate with from ten to twenty drones on their nuptial flights.
Oddly enough, the semen carried in a single drone is more than enough to fill the queen's spermatheca, where sperm are stored for the lifetime of the queen.
- 01-06-2011, 09:35 AM
The queen takes a great risk to gather so much extra genetic diversity for her progeny, to the advantage of her colony.
Recent findings suggest that bees of different patrilines specialize in the various behaviors found in honeybee colonies.
It is thought that the more genetic options, the more behaviors will be optimized.
Using instrumental insemination enables the breeder to go one step beyond nature and inseminate the queen with hundreds of drones.
Drones are chosen from colonies expressing desirable traits such as disease resistance, high honey production and gentleness.
- 01-06-2011, 09:36 AM
Semen is extracted from hundreds of drones from many colonies, mixed together, then used to inseminate many queens. We call these queens "supermated".
Supermated queens have very high brood viability due to the high diversity of sex alleles, which means more bees in their colonies.
By maintaining a high degree of genetic diversity the negative effects of inbreeding are avoided.
Supermated queens contain many times the genetic diversity of naturally mated queens. They are excellent as breeder queens in breeding programs to prevent unintentional inbreeding.