Effects of developmental stage, cold acclimation and diet on the cold tolerance of three species of Cryptolestes (Coleoptera: Laemophloeidae)

Flat grain beetles (Coleoptera: Laemophloeidae) are common stored-product insect pests in Canada, infesting cereals bins, equipment and end products flour mills. We studied the cold tolerance of three most flat beetles: Cryptolestes ferrugineus, turcicus pusillus, by measuring survival at −10 °C supercooling point (SCP) for different life stages (egg, young larva, old pupa adult) reared on mixed with brewer’s yeast. Probit analysis was used to estimate lethal time 50 95% mortality. This done non-acclimated individuals (only held 30 °C) or cold-acclimated (held 18, 10 5 °C, 1 week/temperature). In general, adults were cold-hardy stage each species. Acclimated insects anywhere from no increase 14-fold more cold-tolerant than corresponding ferrugineus species (58 d reach mortality acclimated adult), C. next cold-tolerant, (39 d) pusillus least (11 d). The diets measured both insects. diet (whole wheat kernels, cracked kernels germ (90:5:5 mass ratio) white-wheat yeast (95:5 had highest followed 100% flour. Supercooling ranged −20.6 −26.7 °C. slightly lower SCP