The presence of statocysts and statoliths in social wasps (Hymenoptera, Vespinae).
Static sense organs composed of a hollow statocyst surrounded by sensory hairs and containing aggregate bodies (statoliths) have been detected in various species of Vespinae. On the frons in the groove traversing its center (the frontal groove) there is a deep pit and around it a membrane enclosing a cyst-like sac. In Vespa orientalis there are silicon (Si) and calcium (Ca)-containing aggregates inside the pit arranged in morula-like fashion, and in V. crabro, there are similar aggregates arranged in an ear-like shape. In general this sensillar organ resembles the statocyst located on the bases of the antennules in decapod crustaceans.