Reproduced from: Beowulf Cooper in Village Bees: The native and near-native bees of Britain and Ireland, April 1968
When a native bee crosses with a non-native, the characters of both parents are still present, even if in hidden form, in the offspring. In subsequent generations there will be a random segregation of these characters. If we consider them individually and not as composite units identical with either original parents, all the characters will reappear in subsequent generations. But the assortment is different, and randomly distributed. Some stocks will show more characters of native origin, while others will show more of foreign origin. Beekeepers tend to dismiss all such stocks as ‘mongrels’ and to forget that all the original characters are still there. In this way they falsely accept the superstition of the defunct native bee.
The big factor which they tend to overlook is the strong and real effect of natural selection. This is ever present and always acting, whether the beekeeper knows it or not. The ‘good beekeeper’ (in the management sense) may tend to perpetuate, or try to perpetuate, all the progeny which he raises, but even he will have selective losses in winter, or queens that selectively fail to mate, or selectively mate with drone other than of his own selection. The average beekeeper, the let-alone beekeeper and colonies of bees in the wild, will clearly be subject to a very strong degree of loss, and hence selection, and their drones will often dominate the population. Although part of this selection will be due to chance and be non-directional, a very high proportion will be directional and due to some characters aiding survival; such things as dark body colour, low-temperature working or mating, heavy pollen collection, high load-carrying ability or tolerance of wind, minimum breeding out of season, longevity, supersedure and many other things, including resistance to certain diseases, can assist preferential survival under pressure of natural selection.
As a result, many of the characters that go to make up a native bee become reselected – some characters fast, some slowly; the majority independent of conscious selection by the beekeeper. A beekeeper who selects for yellow body colour, for example, may find that nature has been selecting for long hairs or native wing-shape, acarine resistance or non-prolificacy; he may end up with a yellow-pigmented bee with otherwise native characters. This is why, in assessing a strain, the breeder must evaluate a wide range of characters and not just go by the overall impression of the bee. The impression may be all that the honey-producer sees, but the breeder must look beyond.