'''Mid Summer:'''
New queens can be produced either spontaneously in swarming colonies or in a controlled environment in queen rearing operations. New bee colonies get their queen in one of these ways. Because the queen mates freely in the air several kilometres away from its origin, it is possible for the queen to pair with other subspecies besides ''A. m. mellifera''. This kind of [[cross-breeding]] is destructive for conservation activities, which is why queen producers are looking for isolated areas where only ''A. m. mellifera'' colonies, queens, and drones exist in the flight area. This can be arranged either in island environments or on the mainland without any other bees around in a ten-kilometer radius from the mating station.
A colony with a purebred queen will always produce purebred virgin queens. The drones from this queen will also always be purebred. In other words, the drone is a genetic copy of its mother and has no genes from the father at all. The signs of cross-breeding show in the worker bees who have both the maternal genes from the queen and the paternal genes from drones that represent some other subspecies.
Besides resulting in the loss of the potentially unique Nordic Brown bee genotypes, cross-breeding is the main cause for the unfavorable properties of impure ''A. m. mellifera'' bees. The colonies behave aggressively and they have a high swarming tendency. For this reason, the beekeeper has to avoid cross-breeding and ensure the queens’ pure origin and mating.
