Effects of Temperature and Substrate on Survival and Lipid Consumption of Hibernating Coleomegilla maculata lengi (Coleoptera: Coccinellidae)

The influence of temperature and substrate quality on the hibernation of the polyphagous predator Coleomegilla maculata lengi Timberlake was examined. Survival rate and lipid content were periodically evaluated at six temperatures (20, 10, 4, −0.5, −4, and −10°C) on two substrates (fallen leaves and wood chips). Rapid total mortality was observed at −10, 10, and 20°C. At −4 and −0.5°C, survival extended until May, but only at −0.5°C was the survival rate higher than that observed at natural hibernation sites. Fallen leaves were a better substrate than wood chips except in situations of sudden warming and subsequent snow melt. The rate of lipid consumption increased with temperature, and no significant variation was found between substrates.