On the biology of two species of ground-nesting eumenine wasps (Hymenoptera: Vespidae: Eumeninae) from the Charyn National Park, Kazakhstan

SummaryNine nests of Jucancistrocerus (Eremodynerus) atrofasciatus and 24 nests of Odynerus (Odynerus) tristis were observed in the same clay cliff in the Charyn River canyon near the Valley of Castles, Charyn National Park, Almaty Province of Kazakhstan. Both species used water from the Charyn River for nest construction. The wasps excavated nest burrows in a dense clay loam with a considerable amount of gravel and a predominance of loess and silt. The nests had entrance turrets made of mud; the provision was weevil larvae in the subfamily Hyperinae (Coleoptera: Curculionidae). The nests of J. atrofasciatus were burrowed out mainly in the vertical surface of the cliff and had laced and curved turrets opened downward. They contained 1–3 cells in one or two burrows (a linear-branched nest structure), separated within one burrow by simple partitions. The egg was suspended with a short thread to the cell wall at its inner end; the provision was 15–35 small weevil larvae. In two of the six studied cells, there were empty cocoons of a cuckoo wasp (Hymenoptera: Chrysididae). The nests of O. tristis were burrowed out mainly in the horizontal surface of small ledges, which were present on the cliff, and had solid and straight turrets opened upward. These nests contained 1–6 cells arranged mainly in a branched (sometimes linear-branched) manner. The provision was another species of Hyperinae, with 10 larvae stored per cell. A third of the studied nest cells of O. tristis were robbed by Tetramorium armatum (Hymenoptera: Formicidae). The ants penetrated to the sealed nests with the aid of tiny burrows made by themselves in lateral walls of the cells, as well as through narrow slits, sometimes occurring in the ground. Odynerus tristis nested earlier in spring than J. atrofasciatus. Two of the 13 observed prepupae of O. tristis hibernated for more than one year. Nests of O. tristis are typical of the genus Odynerus, while nests of J. atrofasciatus are quite similar to those of Jucancistrocerus (Jucancistrocerus) caspicus. The latter observation is consistent with the current treatment of Eremodynerus, which J. atrofasciatus belongs to, as a subgenus of Jucancistrocerus rather than a separate genus.