How to identify solitary bees
Bees have four wings – whereas flies have two – and are generally hairier than wasps.
You might notice bees buzzing around your bee house. On wet days during the flying season (adult bees are most active in spring and summer), check inside the holes and you might see them sheltering from the rain.
Different species do appear at different times: the red mason bee is the first to emerge, so it is important in pollinating fruit trees, whereas leaf-cutter bees can be active as late as September.
Solitary bees vary massively but you can identify which ones are nesting by the materials they use to cap the tubes in the bee house. Whether they are using mud, leaves or fine hairs, the type of capping indicates the type of bee – and it’s possible you might have more than one type at the same time!
The three bees that you are most likely to find in your bee house are:
1. Red mason bee, Osmia bicornis (Osmia rufa)
With red/gingery hair, the females have small horns on their heads. They use mud to cap tubes in their nest. Active March–July.
2. Leaf-cutter bee, Megachile willughbiella
Broad head, large mandibles for cutting leaves and an upturned abdomen. They use leaves to build their nests. Active May–September.
3. Wool carder bee, Anthidium manicatum
Distinctive yellow and black markings on the flattened abdomen. Their building material of choice is fine plant hairs. Active June–August.