The production of males usually signals the beginning of the end of the co-operation and organisation of the nest. The males drink the stores of honey, but do not forage to replace it. The queen is usually old, almost bald and may have lost some of her influence over the persistent or larger workers, and gradually the stores dwindle and the workers die. B. pratorum and B. hortorum usually have quite small colonies, and B. pratorum colonies can reach their maximum size earlier in the year than any other species. There are some very important differences between the bumblebee life cycle and the honeybee life cycle.
Bumblebee queens appear to maintain dominance purely by aggressive behaviour.
This is usually sufficient until unfertilised eggs are laid, or a worker's ovaries develop. The nests were located quite close to each other, so the bees would have probably been foraging from the same area. She found considerable differences in the kinds of pollen eaten by the larvae of the different species. She thought that this might increase foraging speed, and also it seemed that they did not like pushing their heads into the flowers. The analysis of pollen indicates some of the plants the bee visits, but it does not necessarily show all the plants visited by bees, as not all bees collect pollen on foraging trips.