MODELING THE SUBGENUAL ORGAN OF THE HONEYBEE, APIS-MELLIFERA

In a recent study on the honeybee (Apis mellifera), the subgenual orga n was observed moving inside the leg during sinusoidal vibrations of t he leg (Kilpinen and Storm 1997). The subgenual organ of the honeybee is suspended in a haemolymph channel in the tibia of each leg. When th e leg accelerates, the inertia causes the haemolymph and the subgenual organ to lag behind the movement of the rest of the leg. To elucidate the biophysics of the subgenual organ system of the honeybee, two mat hematical models to simulate the experimentally observed mechanical re sponse are considered. The models are a classical mass-spring model an d a newly developed tube model consisting of an open-ended, fluid-fill ed tube occluded by an elastic structure midway. Both models suggest t hat the subgenual organ included in the haemolymph channel resembles t hat of an overdamped system. In resembling the biophysics of the subge nual organ system in the honeybee, we consider the tube model to be th e better of the two because it simulates a mechanical response which c omplies best with the experimental data, and the physical parameters i n the model can be related to the constituent parts of the subgenual o rgan included in the haemolymph channel.