Excavator: Ground. Nests are constructed in bare ground, most usually in small aggregations (no more than 100 nests)
Banaszak, W (2005) reports that In South Europe, the bee colonizes all kinds of loess or clayey escarpments and steep, poorly vegetated slopes. Probably because of its high thermal requirements, in Central Europe it nested mainly in walls of clay buildings. Until recently, such buildings were common in Polish villages and could serve as favouable nesting sites, partly protected fl.om rain and additionally heated by the warmth radiating out of the building interior.
Just after mating, the fertilized female searcheś for a suitable nesting site. The clay substrate is usually very hard at the beginning, so the female moistens it with water brought in their crop from a nearby puddle. The softened clay is scratched with the mandibles during the mining of long galleries, is formed into small balls and then used for construction of a peculiar chimney attached to the entrance of the nest, and reaching about 1 cm in diameter.
The chimneys, oriented downwards, lead to the nest interior. Nasonov(1892) describes the nest as a simple, nearly smooth, down-curved tunnel, which after a distance of 2-3 cm, branches off into 3-4 tunnels: each with 3-4 brood cells placed side by side. The cell is egg-shaped, about s mm long and 5 mm wide. Since the larvae do not make any
cocoons, the female smoothens the internal surface of the cell and covers it with the quickly hardening secretion of Dufour's gland, forming a waxy lining. The lining protects the developing larva against drying but also against excess moisture and infection by microorganisms. Simultaneously, the lining helps to maintain the liquid consistency of the
stored reserves. At the end of construction of the cell, the female fills it with reserves of nectar and pollen to about 2/3 of its volume. Next, it lays an egg on the surface of the liquid and closes the cell with a clay lid. The whole process of construction of the cell, its provisioning, laying of the egg, and closing it with a lid lasts up to 2 days. One female can build
1-4 nests in its lifetime (Banaszak J, 1971b, Mucalica, 1987).