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Paracentrobia andoi (Ishii) was originally described as Japania andoi Ishii. This paper presents the results of the morphological studies of adult as well as immature stages of this species. Paracentr...obia andoi is a solitary egg parasite of the green rice leafhopper, Nephotettix cincticeps Uhler. It is thelyotokous species, parthenogenetic parasite; only the females were found. There are three larval instars. Laboratory studies of its biology were conducted at 25& 1°C. Under laboratory condition its life cycle lasted 17-23 days : egg, 14-20 hours ; 1st and 2nd instars combined, 1 day; 3rd instar, 1-2 days ; prepupa, 1 day; and pupa, 13 - 18 days. The calculated threshold of development was 16.3% for completing the whole development, i. e., from the egg stage to adult; thermal constant was 149.19 degree-days to complete development. Under outdoor condition the accurnulated degree-days above the developmental threshold were 167.33 degree-days from the egg stage to the adult emergence. In August the development was most rapid. Adults provided with concentrated honey had the longest average life span, 15.9 days in average, under 25°C constant temperature; they had the longest life span at 15”C, 10.87 days in average, if only water was provided. Adult emergence occurred mostly during the morning. Light affected the emergence of adults. The average number of eggs deposited per female was 42.4. The preoviposition period was short. Most eggs were deposited on the first day of oviposition. Oviposition period was 3 days at most. The behavior of adult for oviposition and superparasitism were studied. The parasites hibernate in the pupal stage. They enter in hibernation from the end of October or the beginning of November. The adults from overwintering pupae firstly emerged in April but mostly at the beginning of June. From July to October of 1974 it was found that host densities attained peaks in August and September. The percentage parasitism ranged from 26 to 64 % in the insecticide free plot and from 14-58 % in farmer’s paddy fields. The mymarid parasite was also found parasitized eggs of Nephotettix cincticeps but the percentage parasitism was low, ranging from 0.71 to 3.59 %.続きを見る
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