Geotropic sensitivity of hornets.

Oriental Hornet workers, Vespa orientalis (Hymenoptera: Vespinae) were measured for their responses to changes in the direction of the gravitational field and this under both static and kinetic (centrifugal) conditions. The hornets can build a comb (oriented towards the gravitational force) when their multifaceted eyes are covered. Building activity is undertaken in the dark as well as by hornets that had been blinded or had eclosed in the dark and had never seen any light. If the frons plate of hornets is damaged, there is no or little building, and the comb direction is distorted. Hornets eclosing from and developing in combs subjected to centrifugal spinning build combs whose direction is affected both by rotation and by the resultant of the gravitational and centrifugal forces.