Bees of a different color
Ever wonder why you sometimes see black bees and yellow bees in the same hive? The answer is simple genetics. Since a queen may mate with many different drones (as many as 20), the progeny of that queen may look strikingly different from one another. Italian drones, for example, have a good chance of fathering yellow bees, and Carniolan drones may father black bees. And while those characteristics are clearly visible, other differences exist which are not so easy to see. Many differing traits within a single hive–including things like wintering ability and disease resistance–are a result of the drone’s chromosomes.
Multiple mating is nature’s way of assuring a mix of genetic information in the hive. If the queen mated just once, then all her offspring would be genetically similar. And genetic similarity is a negative trait when it comes to long-term survival of a species.
Different colored bees in one hive are like different colored cats in one litter. And the reason is exactly the same. A female cat may mate with more than one tom and give birth to a litter of half-siblings–just the same as bees.