Polylectic with a preference for Cistus (Cistaceae). The only pollen sample available so far consist of pollen of Cichorioideae (Asteraceae) (A. Müller, unpublished). Ivo Raemakers observed numerous females of this species collecting pollen on Cistus (Cistaceae) flowers near Perpignan in spring 2010, which is in line with recent observations made by A. Müller in the Alpilles, where several females visited the flowers of Cistus. As the few pollen samples analysed so far also contain small amounts of Asteraceae and Lamiaceae pollen, Osmia nasoproducta is probably not a Cistaceae oligolege. It appears, however, to have a strong preference for Cistus flowers, which might explain why this species is so rarely found. (Müller, A., 2012)