Inertial mass in the balance body of <i>Pomacea Diffusa</i>. Experiment on the biosatellite “Bion-11”

Abstract

The inertial mass in the balance organ-statocyst of Pomacea diffusa was studied from the moment of hatching from eggs until the end of the life cycle, as well as the effects of weightlessness on the inertial mass during a 14-day orbital flight on the biosatellite “Bion-11”. As the snails grew older, the diameter of the statocyst increased from 150 μm to 650 μm, and the inertial mass contained in it increased from 11–13 statoconia to 700 statoconia. The internal structure of the statoconia had a layered structure with a nucleus in its central region. The main mineral element that gives statoconia heaviness is calcium carbonate, presented in the form of aragonite crystals. A 14-day exposure in weightlessness led to noticeable changes in the morphometric pattern of the inertial mass in the statocyst of flight snails in comparison with the control snails of synchronous tracking. In most of the statoconia, the form factor, length, and width indicators increased, which could indicate the stimulating effect of weightlessness on the inertial mass in the balance organ of Pomacea diffusa.