Possible role of neurohormones in the process of acclimatization and acclimation in Morimus funereus larvae (insecta)-I. changes in the neuroendocrine system and target organs (midgut, haemolymph) during the annual cycle

Abstract

1. 1. During the process of acclimatization, the neuroendocrine system in Morimus funereus larvae (body weight 200–500 mg) shows cyclic changes in the activity. 2. 2. These changes were observed in the midgut (proteolytic activity) and the haemolymph (proline. histidine) as well. 3. 3. During the annual cycle two periods seem to exist: stable and critical. Medial and lateral neurosecretory cells of the protocerebrum have an additive effect on the midgut proteolytic activity in the stable period (spring, summer, winter). 4. 4. In the critical period (autumn) median and lateral neurosecretory cells have the inverse effect. 5. 5. “Disturbance of hormonal balance” results in the fall of midgut proteolytic activity to a negligible value.