PERIODIC MUSCULAR-ACTIVITY AND ITS POSSIBLE FUNCTIONS IN PUPAE OF TENEBRIO-MOLITOR

During pupal development, Tenebrio molitor L. show regular periods of rhythmic muscular contractions and associated body movements. These periods of activity last 2.5-5.8 min and are more frequent in newly ecdysed pupae (c. 3h-1). They become less frequent (c. 1.5h-1) when the basal metabolism reaches its lowest level. In the pharate adult stage the clear pattern of muscular activity disappears. Muscular activity is temperature-dependent and is commonly absent below 20-degrees-C. Muscular activity did not disturb the cyclic output of CO2, which is characteristic of metamorphosis. The heart shows characteristic periods (1-3 min) of activity during pupal development. The frequency of these heart pulsation periods depends on metabolic rate. Heart pumping was correlated mostly with muscular contractions. Therefore we suggest that the main physiological function of muscular activity is to support circulation.