A univoltine species; early May to late July (Else & Edwards, 2018). Amiet et al. (2004) give a flight period in Switzerland from the April to late August.
Parasites and predators In Scotland, the chrysidid wasp Chrysura hirsuta is a possible cleptoparasite of this species (apparently confirmed for other parts of western Europe (F.K. Stöckhert, 1933)). Females of Sapyga quinquepunctata were collected by A.E. Bradley (1919-1921) from walls at Criccieth and Nefyn [as Nevin] (both Gwynedd) in which Osmia parietina was nesting (material in NHML).
Scmidt et al (2017) report from Denmark that it is not known if there are any cleptoparasitic bee that attack O. parietina, but other parasites are known, among other things, Sapyga similis (Fabricius, 1793), which occurs in Denmark, and from Germany are listed among other species of Chrysididae(Scheuchl & Willner, 2016).