Survival and chill-coma in the adult lesser mealworm,Alphitobius diaperinus (Coleoptera: Tenebrionidae), exposed to low temperatures

The survival of adult Alphitobius diaperinus (Coleoptera: Tenebrionidae) at low temperatures has been investigated under laboratory conditions: LT₅₀ ranges from 9.5 days at 6°C to 47.6 days at 10°C and LT₉₉ ranges from 20 days at 6°C to 102.2 days at 10°C. Mean survival shows no significant differences between sexes, but at 10°C, all the males are dead after 88 days and all the females after 107 days. Temperature of 6°C is progressively lethal for the beetles: activity ceases, all the insects are in chill-coma after 12 days and died after 22 days. At 10°C, after 1 month, 70% of the insects are still active. Chill-coma is a reversible state but insects which entered chill-coma last did not recover in most cases and also died the last. During winter sanitary disinfections, A. diaperinus is submitted to subzero temperatures: the rate of adult survival is a key factor governing the population dynamics in the poultry houses.