تاثیر ذخیره در دمای پایین بر ویژگی های زیستی Hippodamia variegata (Coleoptera: Coccinellidae)

Storing mass-reared biological control agents, when there is low demand is an essential necessity in biological control industry. Storage without significant reduction in the efficacy of these agents is a useful method for increasing shelf-life of stored insects. The ladybird Hippodamia variegata is a widespread and voracious aphidophagous predator, with an important role in decreasing pest population in different parts of the world. We investigated the effect of storage at low temperature, in both constant 1 and 6°C (24 hours a day) and fluctuating thermal regimes 12:0°C – 12 and 0°C alternating every 12 hours (for 15, 25, 35, 45 and 60 days) on survival, pre-oviposition duration, fecundity and predation capacity of H. variegata. The survival of adult beetles significantly declined with increasing storage duration at all storage temperatures. Storage of adult H. variegata for 35 days at 6°C and 45 days at 12:0°C had no significant effects on fecundity of ladybirds, but longer storage durations decreased fecundity, significantly. Storage at 1°C significantly decreased the fecundity of beetles. Prolonged cold storage caused an increase in the pre-oviposition period at all storage temperatures. Storage of the adults H. variegata at 6°C for 25 days resulted in higher consumption of aphids than in control insects. Number of aphids consumed by control beetles were similar to those stored at 12:0°C. Low temperature storage (1°C) caused lower predation rate alongside worse life history parameters. Generally, 6 and 12:0 °C are more proper temperatures for storage of the ladybirds with least negative impacts on life history parameters. The current research can help in the application and utilization of stored H. variegata prepared to suppress aphid populations in a biological control program in the following season.