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 r anges from 9.5 days at 6 degrees C to 47.6 days at 10 degrees C and LT99 ra nges from 20 days at 6 degrees C to 102.2 days at 10 degrees C. Mean surviv al shows no significant differences between sexes, but at 10 degrees C, all the males are dead after 88 days and all the females after 107 days. Tempe rature of 6 degrees C is progressively lethal for the beetles: activity cea ses, all the insects are in chill-coma after 12 days and died after 22 days . At 10 degrees C, after 1 month, 70% of the insects are still active. Chil l-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 di sinfections, A. diaperinus is submitted to subzero temperatures: the rate o f adult survival is a key factor governing the population dynamics in the p oultry houses. (C) 1999 Elsevier Science Ltd. All rights reserved.