NESTING AND BIOLOGY OF EUSTENANCISTROCERUS AMADANENSIS (HYMENOPTERA, VESPIDAE, EUMENINAE)

The nest structure of Eustenancistrocerus amadanensis was studied in the Crimea. Females nested in the ground, on horizontal or gently sloping spots with sparse vegetation. The granulometric composition of the soil, in which the wasps nested, varied broadly from sandy loams to dense clay loams close by their properties to clay. Eleven nests were studied; five of them had been abandoned by the females before oviposition. The remaining six nests contained 1-4 cells. These nests were 5.0-7.5 cm deep; the diameter of the nest burrow was approximately 3 mm. The cells were not different in diameter from the remaining parts of the nest burrow and were 9-13 mm long. Multicellular nests had a linear-branched structure. The nests also contained empty lateral burrows, but their purpose was not properly ascertained. The nests were surmounted by inclined earthen turrets which were 5-10 mm in height; they were solid at the base and showed a laced structure at their distal ends. To construct the entrance turret, the females ejected small earthen pellets from the nest burrow. After the turret had been constructed, the females continued excavating the nest burrow, but then they ejected and threw out large earthen pellets. Females dismantled the turrets while sealing the nests. The wasps used water to moisten and soften the ground; they took it from wet ground along streams and near the sea coast, as well as from puddles, landing directly on their surface and floating by means of surface tension. Females hunted for two species of coleophorid moths. The nesting rate was very low (1 cell per 2-8 days). Adult feeding was recorded on flowers of ten plant species representing eight families. The species is bivoltine, hibernation occurring at the prepupa stage. A cocoon of an unidentified cuckoo wasp was found in the nests. Reproductive success amounted to 81.1%. A male sleeping aggregation was also recorded. The bionomics of the genus Eustenancistrocerus and related genera are discussed.