Ecological Characteristics of 28-spotted Larger Lady Beetle, Henosepilachna vigintioctomaculata (Motschulsky) (Coleoptera: Coccinellidae) and Its SeasonalFluctuation in Gangneung, Korea

摘要

The seasonal fluctuation of the large 28-spotted lady beetle, Henosepilachna vigintioctomaculata (Motschulsky), was observed in potato fields of Gangneung region, Gangwondo Province. The effects of their leaf consumption over a 24 hour period and developmental periods by different temperatures were investigated, and then the developmental threshold (DT) and effective cumulative temperature (ET) of each stage were calculated. Various developmental stages of H. vigintioctomaculata were captured in thefields from May to September, with three peaks in late May, late June, and late August. Leaf consumption by larval stages increased with the development of instar. The 4th instar larvae consumed potato leaves much more than other stages. Egg hatchabilityand emergence rate of H. vigintioctomaculata were lower at 10°C and 30°C, but higher at around 20~23°C. The developmental periods of each stage became shorter as temperature increased; 90 days at 10°C, 40 days at 20°C and 25 days at 25°C. Base ondevelopmental velocity to temperature, calculated DT and ET were 7.3°C and 83.