Beowulf Cooper wrote many notes that were gathered together after his death and published by BIBBA as "The Honeybees of the British Isles". Many of the words on this page were written by Beo and are given here more or less as they were written, simply because I doubt that I could improve on them.
In the less settled weather conditions of some years, and particularly in smoky and high-rainfall regions, neither major nor minor drone assemblies may form with sufficient regularity. At such times queens of Italian and other non-native parentage may fail to mate, disappearing or becoming drone-layers. Yet under similar conditions and in the same apiaries, bees with native characteristics do mate freely, become fertile and subsequently produce worker brood. They may take longer to mate than normal, and in early spring and late summer we occasionally find that they have been insufficiently inseminated, leading to their being superseded after a short laying life. However, this ability saves the breeding line which would otherwise die out.
Apiary vicinity mating can occur during bursts of sunshine or during dull weather when ground or plant radiation is high, or when the air is moderately warm. The queen emerges from the hive and is immediately followed by a number of drones from that hive, with one or more of which she mates within the confines of the apiary. (It is the occasional witnessing of this event by beekeepers which must have led to the widespread belief that all matings in these Islands were of a local or apiary-vicinity nature; a belief which has surprised our continental colleagues.)
When queens are seen mating near the hive, they nearly always turn out to be of superseding strains. This is to be expected since drone assembly mating maximises outcrossing and supersedure is favoured by inbreeding as it is largely recessive in character.
It is more than a coincidence that most of the superseding characters, which we know of, are recessive. It is only under conditions of a moderate degree of inbreeding that the character shows up. Apiary vicinity mating behaviour, and the continuance of such bees in recognisable form through many generations is a clear sign of repeated mating within the drone family of the parent.
The effect of this local type of mating behaviour is that a queen is likely to mate with one or more drones from her own hive, which in the case of strains with non-migratory drones, are likely to be her own "brothers". Alternatively she may well be fertilised by drones from other hives in the apiary, whose bees are, more likely than not, related to her. Thus we have here a powerful mechanism for securing some degree of inbreeding, with all its consequent advantages and disadvantages
Since this type of mating is practicable in cool as well as in warm weather, it is of particular value to queens trying to mate very early or very late in the season, or at any time when the weather is too cold for prolonged flight.
I can add that my local conditions are often overcast or cloudy to a greater extent than most of the UK, thus this type of mating has been seen on very many occasions
It has been reported (by Robert Brenchley) that an old copy of the ABC & XYZ, has several eyewitness accounts of AVM in American Italian Strains. Maybe its not specifically an Amm characteristic after all.
Even if drone assembly mating is possible in warm periods during the day, this does not preclude AVM type matings in the cooler evening in addition to those that may have occurred earlier. This can be deliberately influenced by the beekeeper keeping both virgins and drones captive until other strains have finished flying for the day.