Bombus (Psithyrus) barbutellus-St Davids

This species is distributed widely throughout most of the area covered by this Atlas, but is rarely common. It is widespread in Europe; middle and northern latitudes of Asia, and eastwards to Mongolia (Løken 1973).

Status (in Britain only)
This bee is not regarded as being scarce or threatened.

This cuckoo-bee occurs in a wide variety of habitats.

Flight period
Over-wintered females can be found from late April onwards, males and new females in July to September.

Pollen collected
As this bee is parasitic it does not collect pollen, although females eat pollen in order to develop their ovaries. Foraging for pollen for the nest is carried out by the host workers.

Nesting biology
During spring the over-wintered, fertilised female B. barbutellus searches for a small nest of the host bumblebee, B. hortorum. It enters the nest and eventually dominates, or kills the host queen. The parasite female then lays eggs which will develop into either males or females of B. barbutellus. All foraging and nest duties are carried out by the host workers. It is likely that this species will also attack B. ruderatus.

Flowers visited
Visits are made to a wide variety of flowers.