بررسی اثر سازگاری با دماهای پایین بر تحمل به سرمای حشره Alphitobius diaperinus

Alphitobius diaperinus (Panzer)(Col; Tenebrionidae), is one of the most predominant poultry litters inhabiting insect species all over the world. The damage done by its larvae searching for a pupation site is the reason for their label as a “pest species” in poultry houses. The pest beetle, imported from tropical regions into temperate regions via contaminated foodstuffs. Survival of adult A. diaperinus after cold acclimation has been investigated under acute and chronic cold stresses. Acclimation conditions were: 1, 2, 4 and 8 days at 5, 10, 15, 25 ºC and a fluctuating temperatures of 5-10-15 ºC (8:8:8 h). Acute and chronic cold stresses were induced by keeping beetles at -8 ºC for 8h and 0 ºC for 2, 3, 4, 5 and 6 days respectively. Survival was recorded after 5 days of recovery at 25 ºC. Survival was 0% after acute cold stress for all of the beetles acclimated to 25 ºC and also beetles acclimated to 5 ºC for 1 and 8 days. Survival increased to 100% after acute cold stress in beetles acclimated to fluctuating temperatures for 2 days. The lethal time for 50% of the population (Lt50) was calculated for beetles after chronic cold stress and ranges from 4.89 days in beetles acclimated to fluctuating temperatures for 4 days to 0.018 days in beetles acclimated to 5 ºC for 8 days. It can be concluded that, fluctuating temperatures was the best condition for increasing cold tolerance of the pest species.