Development of three species of Epilachna (Coleoptera: Coccinellidae) in three temperature and photoperiod combinations

Three species of Epilachna - E. paenulata (Germar, 1824); E. cacica (Guérin, 1844) and E. spreta (Mulsant, 1850) - were reared on pumpkin leaves (Cucurbita pepo L.) in three different conditions of temperature and photoperiod: (warm – 25°C ± 2°C, photoperiod 12/12 hrs: cold – 20°C ± 2°C, photoperiod 12/12 hrs; normal = ambient temperature, ranging from 16.67°C to 27,02°C, natural photoperiod). Development time and growth rates were statistically compared by Mann-Whitney "U" Test and analysed by the Principal Components Analysis. E. cacica showed the highest size and longest developmental period for all the three environmental conditions, while E. paenulata showed the smallest sire and the shortest developmental period. As a rule, greater size and longer developmental time were obtained at the 1ow temperature, whereas smaller size and shorter period of development were observed at the higher temperature, for the three species. The growth values were compared to Bergmann's and Dyar's rules.