Effect of temperature on the life cycle and predatory capacity of ladybird beetle Micraspis discolor Fabricius (Coleoptera: Coccinellidae)

Abstract

The effects of temperature on the development and the predatory capacity of Micraspis discolor larvae were studied in laboratory. Two temperature levels 23.50°Cand 30.71^oC on average, were used to assess the life cycle and developmental stages of the ladybird beetle M. discolor. The life cycle of M. discolor was 27.38 days at 23.50°Cand reduced to 19.77 days at 30.71°C, the total larval period was 13.42 and 9.9 days, respectively. The pre-oviposition period of the ladybird beetle M. discolor was 4.95 days at 23.50°C and 5.23 days at 30.71°C. The female beetles laid 282 eggs and the hatching percentage of egg was 81.03 at 30.71°C and 179 eggs and the hatching percentage of egg was 88.73 at 23.50°C. At temperature 30.71°C and 23.50°C, the pupal periods were 4.91 and 2.92 days, respectively. The longevity of adult ladybird beetles was slightly prolonged when they were reared at 30.71°C compared with that when they were reared at 23.50°C. Feeding on the second insturs of B. brassicae the predatory capacity of M. discolor larvae consumed an average 206.28 prey per day at 30.71°C and 161.84 prey per day at 23.50°C.