A univoltine species: mid March to late May or early June. However, in the Maidstone Museum there are two males collected in Kent in July. It is thus possible that in favourable seasons a small, partial, second brood may emerge.
In Thessaly (Greece), Standfuss et al. (2011) report flight activity in March and April
There is a form in central Europe which is regularly bivoltine, flying in April and May, and from July to early August (Kocourek, 1966). It flies in Ukraine from April to late July, and is bivoltine there (Tomozei & Radchenko, 2015).
Parasites: Its nest parasites, or kleptoparasites, are Nomada lineola and N. goodeniana (Osytshnjuk 1977).