A bivoltine species: The first brood flying from early April to mid or late June, the second from late June to the beginning of September. The summer brood is not as prolific as the spring one and in southern Britain probably develops in cells of the progeny of first brood Andrena trimmerana, their flight period coinciding with the second brood of this Andrena. Second brood N. marshamella have also been reported from Ireland (Stelfox, 1927), but it is difficult to speculate which host or hosts these developed with and, as summer bees, if they attack the same or another species. A. trimmerana is not known from Ireland so the most likely host is A. scotica but, as far as is known, this is a purely univoltine species there and would have ceased flying by the time the second brood of the Nomada takes to the wing (Else & Edwards, 2018)
Smit (2018) regards the species as univoltine, with a flight period from March to July