Abstract
In southwestern Japan, the Japanese mealybug Planococcus kraunhiae (Kuwana) (Hemiptera: Pseudococcidae) is one of the most serious pests that attack the Japanese persimmon Diospyros kaki Thunb. (Ebenaceae). Diadiplosis hirticornis (Felt) (Diptera: Cecidomiidae) is thought to be an important natural enemy of P. kraunhiae. In order to establish control measures that use D. hirticornis to control the population of the mealybug, we need fundamental information on the ecological and behavioral characteristics of D. hirticornis. As the first step, we investigated its developmental velocity at 17.5, 20, 22.5, 25, 27.5, 30, and 32.5°C and its hourly adult emergence pattern. The lower developmental threshold was found to be 11.1°C for both male and female individuals. For the whole stages from egg to adult, the day-degrees above the developmental threshold was 232.6 for male and 238.1 for female individuals. D. hirticornis was confirmed to be diurnal. A majority of the males emerged between 6 : 00 and 12 : 00, while most females emerged between 8 : 00 and 18 : 00.
