>>It is not that you get some sudden change in the character of the bee, but you get survivors from bees that are already there.

Absolutely.  And every year will test the population a little differently - the majority with one trait will disappear (hopefully, leaving behind enough reproductive individuals (or hybrids) to retain the trait's availability for the future) while a part of the population with the favored traits comes to stand out.  Each year colonies with a different set of traits may come to survive predominantly.

Matings with multiple drones increases the pool of diverse traits along patrilines.

Waldemar

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