Before I switched to Minnesota Hygienic Italians my drones were all real dark colored.  I started with a MH breeder queen and the first year raised enough young queens to replace all of mine.  Those queens open mated with my drones.  The second year I started to see a lot of much lighter colored drones mixed in with the dark ones and by the third year saw few real dark drones.  It sure looks to me like the drones I see are pretty much all my own drones.

This raises the question of how far drones fly and how far queens fly on mating flights.  The results say I am not seeing many drones from neighbors a couple of miles from me that have a lot of bees and have dark drones.  And my queens are not flying far enough to find many foreign drones.  I have seen numerous people say a queen mating flight only takes ten to twenty minutes.  At 15 mph flight speed plus time to find drones and mate does not give the queen time to go too far.  After a couple of years I felt some minor concern about possible inbreeding and so bought five MH open mated queens the last two years to make sure I have some drone diversity.  I have seen zero queens with shot gun patterns of brood, except for EFB cases so probably will not buy any queens this year.  I have raised  a few queens from those open mated queens.  I think my genetic diversity is ok for now.

I am sure how far drones fly and how far queens fly when mating is a function of local terrain and conditions.  In the two directions that I have a lot of neighboring colonies there are a lot of fairly mature woods a mile wide and no direct open corridors other than roads generally with forest on both sides.  This probably does insulate me as I very seldom saw workers at all before I was keeping bees myself.  Without those forest buffers I suspect bees would fly farther.  Even back well before varroa in the 70s and early 80s when I kept bees the first time I seldom saw a worker after I got rid of my own bees.  We had a massive AFB epidemic locally in the early 80s that I think pretty much wiped out local ferals and then varroa came along and finished what was left.   We also burned over half the local domestics due to that AFB epidemic.  Way over half for some guys.  The net result was a lot of little two or three hive out yards went away after the AFB episode.  Now that black bears are back in the area I doubt if many of those little out yards will ever come back as the electric fence needed to keep bears out is too much trouble for two or three hives.

I have also read that virgin queens avoid mating with drones from their own hive.  This makes no sense at all to me.  I have no idea at all how a virgin queen could possibly identify a drone from her own colony in a drone congregation area with a hundred or more drones all chasing her.  I suppose the occasional drone could fly a long way and join a bunch of strangers and I suppose the occasional queen has explorer genes and goes a long way to find a DCA.  But, I am convinced both cases are exceptions at least in my local terrain.

I know this does not answer the question of how long before your existing drones are no longer in the pool.  But, I think it does say locals are not a very big long term issue unless you have close neighboring colonies.  If you are doing high tech breeding where even a few % would be a problem you could sure have a problem.  But, few of us are any place close to that high tech.  You could test a lot better than I have by using cordovan color genetics.  I am not concerned enough to do that even though it would not be all that hard to do.

Dick

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