Renter: Existing cavities. Females utilise existing cavities in decaying wood or in masonry. They will often occupy various kinds of trap-nests, for example drilled borings in wooden blocks (Krombein, 1967), or in paper drinking straws packed tightly into tin cans suspended above the ground (Free & Williams, 1970; Raw, 1974). Mavromoustakis (1948) reports nesting in dead twigs of Carob (Ceratonia siliqua; Fabaceae).
Nesting material: Cell partitions and the closing plug consist of leaf pulp (including that derived from Malva moschata, Alnus glutinosa, Leonurus cardiaca, Onobrychis, Medicago sativa, Lotus, and Papaver), sometimes chewed petals (e.g. from Malva, Medicago, Onobrychis, Papaver) are used as well. A nest has been described by Grandi (1961) and nesting biology described, and a completed nest illustrated, by Westrich (1989). A large cluster of cells in a wooden box has been figured by Banaszak & Romasenko (1998). This species generally overwinters as diapausing adults in their cocoons (Raw, 1974).(Banaszak and Romasenko, 2001; Benoist, 1931; Bonelli, 1967c, 1968; Brechtel, 1986; Ferton, 1897; Friese, 1923; Gerstaecker, 1869; Grandi, 1961; Hurd, 1979; Koerber and Medler, 1958; Krombein, 1967; Malyshev, 1937; Marikovskaya, 1968; Mavromoustakis, 1948c; Medler, 1967; Müller et al., 1997; Olifir, 1980; Popov, 1967a; Romasenko, 1980; Smith, 1844; Stoeckhert, 1933; Tasei, 1972; Westrich, 1989; Vicens, Bosch and Blas, 1993; G. Else, unpublished manuscript; G. Le Goff, personal observation)