The effect of thermal stress on Ostrini00a nubilalis HBN (Lepidoptera, Pyralidae)—I. The orle of the neurosecretory cells in the survival of diapausing larvae

1. 1.|The effect of short-term exposure (up to 12 h) to upper limiting temperature (45°C) on A-type medial neurosecretory cells (MNSC) of the protocerebrum of Ostrinia nubilalis larvae was studied.

2. 2.|For evaluation of the activity of MNSC, cytological parameters were used: quantity of the neurosecretory material, size of the neurosecretory granules, shape of the nuclei and size of the nucleoli.

3. 3.|After 1 h exposure to 45°C the activity of the MNSC was increased, after 3 h it was decreased, while after 6 h exposure to the same temperature some renewed increase in the activity was observed.

4. 4.|The significance of oscillatory changes in the activity of A-type MNSC in survival of the thermal stress of O. nubilalis diapausing larvae is discussed.

Author Keywords: Upper limiting temperatures; A-type neurosecretory cells; neurohormones; diapause; Ostrinia nubilalis larvae