Effects of thermal stress on activity of corpora allata and dorsolateral neurosecretory neurons in Morimus funereus larvae

The effects of different temperatures (23°C and 8°C) on activity of corpora allata (CA) and dorsolateral (L1, L2) protocerebral neurosecretory neurons were investigated in Morimus funereus Mulsant (1863) larvae collected from a natural population during March. Activity of CA was revealed by monitoring of CA volume and cell number. Increase of CA volume after two day exposure to both temperatures was shown to be the result of increase in cell number. Activity of CA was higher at 23°C than 8°C. Activity of L1 and L2 neurosecretory neurons was inhibited at both temperatures. Neurosecretory neurons were more sensitive to temperature of 23°C than 8°C. It can be supposed that dorsolateral neurosecretory neurons synthesize neurohormones that affect CA activity, depending on environmental temperature.