Abstract: Performance and body water dynamics in the pupal stage of the cotton bollworm, Helicoverpa armigera, were investigated at 25℃ and relative humidities (RH) of 0%，9%，22.5%, 80%, 92%, and 100%. The non-diapause pupae failed to emerge at RH≤9% and about 20% of them succeeded in eclosion at 22.5% RH. The high humidities showed little influence on their survival. The diapausing individuals rarely died at all the humidities tested except 0% RH for 30 days, during which the diapause termination percent obviously increased with decreasing humidity. Significant linear relationships were found between the rate of cumulative water loss in both diapause and non-diapause pupae since one-day-old and their ages in day. The non-diapause pupae that died at each of the low RHs lost more than 32% of their body water on the day before death. The mean water loss in the diapausing specimens at 0% RH for one month averaged 22.4% and those at RH≥90% did not exceed 3.6% in the same period. The cuticular permeabilities of pupae determined with different specimens in 2,4, 8,12 and 24 hours respectively were always greater than that obtained with the identical specimens in the corresponding periods except in 2 hours. The maximum permeability of the nondiapause pupae, 9.0 and 10.7 μg·cm^-2·h^-1·mm Hg^-1 for female and male respectively, occurred in 4 hours while that of the diapausing individuals, 4.7(♀) and 5.4(♂) μg·cm^-2·h^-1·mm Hg^-1, appeared in 2 hours.

Key words: Helicoverpa armigera, pupae, extreme humidity, cuticular permeability, water loss