Cleptoparasitic: Hosts: This species is cited as a cleptoparasite of Megachile (Chalicodoma) parietina and M. pyrenaica (Banaszak & Romasenko,1998).
Westrich (1989) cites Megachile parietina, and in southern Europe, Megachile sicula and Megachile pyrenaica as hosts. Kasparek (2015) lists Megachile parietina, and Megachile pyrenaica as hosts and also cites Westrich (1989)
Stelis nasuta opens already sealed nests of its hosts and closes them again after egg deposition. Usually several eggs are deposited in a host cell (Amiet et al., 2004). For further observations on reproductive behaviour see Maneval (1937)