There are more than 200 species of solitary bee in Britain. They are so named because, unlike honeybees and bumblebees, they do not live in colonies. The first solitary bees to appear in the garden, as early as March each year, are the miner bees (Andrena). Similar to honeybees in appearance, they lack pollen baskets on their hind tibiae. These hairy bees make nests in the ground, usually in sandy soil and along paths. The female will dig the nest, stock it with nectar and pollen and then seal it, leaving the young to fend for themselves. Also to be seen later on in the season are the leaf-cutter bees such as the Megachile species, which cut neat circles out of rose leaves and petals to build nests in dead plant stems or sometimes in stacks of old flowerpots. These bees resemble honeybees but can be distinguished by the bright orange pollen brushes under their abdomens. All solitary bees are excellent pollinators and should be encouraged into your garden.
Cuckoo bees lay their eggs in the nests of bumblebees. Having killed the bumblebee queen, the female cuckoo bee leaves her offspring to be reared by the bumblebee workers.
Bees are also parasitized by the Bee Fly Bombylius major. This stout and furry fly looks like a bumblebee with long thin legs. It lays eggs close to the entrance to solitary nests and the larvae feed on bee larvae and their stored food.