I've been raising/allowing my own queens for the last three years. At one time, I had two hives that were Russian Mutts. That is to say, they were mostly Russian four/five queens ago. I've introduced swarms from unknown sources and lineage. The swarms were fairly consistent "Italian appearing." A light golden color. I suppose at this point, all the hives are a mix, but I'm noticing more and more that the percentage of dark worker bees is increasing in all my hives. It's not a problem, just a curiosity. Are Russian/Dark bee Drones more successful at what they do? Do they generate a larger population of Drones ? Other than appearance, they are just "normal" bees to me.