A detailed study of the behaviour and ecology of marked A. sabulosa females has been made at a Breckland heathland site (Field, 1992). Nests usually occur at relatively low densities. Normally, a female digs a short burrow, ending in a horizontal cell, in bare or sparsely vegetated sand. Later, she temporarily closes the nest entrance using sand and tiny stones, then hunts for lepidopteran caterpillars in vegetation. About half of all cells are provisioned with just one large caterpillar, which is carried back on foot as it is sometimes more than ten times as heavy as the wasp. Other cells are provisioned with two to five smaller caterpillars (see Olberg, 1959). An egg is laid on the first caterpillar provisioned and rarely hatches before permanent closure of the nest burrow. After the last caterpillar has been interred the wasp permanently closes the burrow with a much deeper plug of sand, and camouflages the entrance with debris so that it is invisible to the human eye. All nests are unicellular. The whole nesting cycle, from searching for a digging site to closing the nest permanently after provisioning, takes an average of eight to ten hours of activity. Marked females each dug and provisioned up to ten nests during a summer.