Possible role of neurosecretory cells: Type A in response of Morimus funereus larvae to the effect of temperature

Abstract

1. 1:The effect of three constant temperatures (−1,8 and 23°C) on winter larvae of Morinus funereus during 15 days has been studied. 2. 2.This effect has been examined at different levels of biological organization: organism (body weight). cell (neurosecretory cell—type A of the suboesophageal ganglion) and enzyme (midgut protease and amylase). Changes in the activity of neurosecretory cells and in that of digestive enzymes were observed 6h after exposure to the effect of temperatures. A parallelism in the activity of neurosecretory cells and proteolytic activity was demostrated (6h, 15 days). A compensatory reaction in larvae at −1°C at the level of neurosecretory cell (increase in size, numerous tiny neurosecretory granules) and at the level of protease (increase in proteolytic activity) was shown. In larvae maintained at 23°C the accumulation of neurosecretory material in large aglomerations and decrease in proteolytic activity were observed. The adaptive importance of these changes was discussed.