If you were given the choice of mite resistant bees that are also excellent egg layers, would that not be the better choice? I'm going to interpret a bit by guessing you are using some type of Italian bees. They are the only race that goes through winter with huge colonies. Buckfast winters small, Carniolan winters small, Caucasian is not adapted to your climate, and most of the black bees winter in very ".
I have had all those bees.
I had Caucasians 45 years ago. Origin was Canada. The colonies were huge.
I had Carniolan bees 10 years. Their colonies were as big as Italian colonies. They were bad swarmers and they had swarming fever when they should lay foragers for main yield.
I had Black Bees during years 1963-1990 because they mated with my Caucasian and Italian virgins. No one breed Black Bees, and they were unselected Rubbish. Then mite killed them all in 5 years.
Now I have problem that there are wild Carniolan bee nests in empty farm houses here and there, and their hybrids make my Italian stock swarmy. But the hybrids are the biggest and most profitable in my yards.
I had Elgon bees 10 years. It is mite resistant, but crossings with Italians made them mad. Monticola genes make them such. But they were not mite resistant.
Italian strains are many. I have had at least 10 different Italian stocks. Their ability to resist diseases are different (nosema, chalk brood, ability to forage, calmnes)
One Italian stock here is very calm, but it has been inbreeded so, that it needs only 2 langstroth boxes. It is breeded by a professional beekeeper.
Then various kind of Buckfasts.
All races can have good layers, but you must select them all the time.
In my climate big hives over winter best and they are early foragers. Professionals want to over winter one box hives. They control amount of laying with excluder, but they keep double brood on first half of summer.
Many use Carniolan bees here. It store pollen over winter, and so it has early build up. When I started to feed Italian bees 25 years ago with pollen, I noticed that speed of Italian build up was exactly the same as with Carniolans. Italian bee rears winter bees as long as it has pollen in the hive. That is why it does not have pollen stores over winter.
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