Genetic Diversity in Bees
The Need for Genetic Diversity
In any species that uses sexual reproduction, genetic diversity is essential for the overall success and health of the species. A lack of it leaves the population vulnerable to any new pest, disease or problem that comes along. A lot of it greatly improves the odds of having the necessary traits to survive such things. This need seems at odds with the concept of selective breeding, and to some extent it is. Selective breeding is just that--selective. Meaning you breed out traits you don't like. Of course this narrows the gene pool, hopefully in a positive way, but still it limits the variety as you keep selecting from fewer and fewer ancestors. Whether you believe in a Creator or evolution as the origin of nature, sexual reproduction has as its obvious goal, diversity. The queen mates, not just with one drone, but several, the hives make many drones to keep their genes out there, and even a hive doomed to die from queenlessness will put drones out there to try to preserve those genes in the pool. Every disease narrows the pool to only those that can survive that disease, and every pest narrows the pool to only those that can survive that pest. We beekeepers keep limiting that pool even more by selecting one queen and raising thousands of queens from her, something that never happens in nature, and by buying queens from only a few breeders, who do the same and who share stock with each other, we narrow it even more. The more we narrow the gene pool the less likely it is that the remaining genes will be sufficient to survive the next onslaught of diseases and pests. This is a scary prospect. And all of this is ignoring the built in control over this with the bees' method of gender control being sex alleles that limit the success of inbred bees. An inbred line of bees has many diploid (fertilized) drone eggs (because similar sex alleles line up) that will not be allowed by the bees to develop.
Feral Bees Have Maintained This
The depth of the gene pool for many years, has been maintained by the large pool of feral bees. In recent years, however this pool has shrunk significantly from the influx of diseases and pests not to mention loss of habitat, use of pesticides and fear of AHB.
Here is a study on the current state of genetic diversity in commercial bees in the US:
What can we do?
We cannot propagate bees with a limited gene pool and expect them to survive, let along thrive. So what can we do to promote genetic diversity and still improve the breed of bees we raise? We can change our view from picking only the one best queen we have for the mother and the next best for the drone mother and start thinking in terms, instead of only breeding out the worst. In other words, if a queen has bad traits we don't want, such as bad tempered workers, then we cull those out. But if they have good traits we don't try to replace them with only the genetics of our best queen, but rather try to keep that line going by doing splits, or raising queens, or using the drones from those other lines. Don't use the same mother for every batch of queens. Don't requeen feral colonies that you remove or feral swarms that you catch. If a hive is hot but has other good traits, try raising a daughter and see if you can lose that trait instead of just wiping out that queen's line. Raise your own bees from the local survivors instead of buying queens. Raise your own bees even from the commercial queens you have so they will mate with the feral survivors. Support small local queen breeders so they can keep more genetic lines going. Do more splits and let them raise their own queens rather than buying queens, so that each colony can continue their line.
Copyright 2008 by Michael Bush