ヨコバイ類の天敵に関する研究(2) : 水田におけるツマグロヨコバイの卵寄生蜂2種の寄生活動

Two kinds of parasites, Paracentrobia andoi(Ishii) and Gonatocerus sp., were investigated on adults at the paddy field and parasitism on the eggs of the green rice leafhopper, Nephotettix cincticeps Uhler in Shimane Prefecture.
The results are summarized as follows :
1. In Matsue, adults of the first generation of Gonatocerus sp. emerged in the early of July, and the flight reached its peak at the end of September in 1975.
2. Population of Gonatocerus sp. was higher in the end of September than in the other monthes at the paddy field in Matsue.
3. At a period of the rice growing season, females of Gonatocerus sp. were more abundant than the males.
4. On the average 34.07% of the eggs of Nephotettix cincticeps were parasitized by Paracentrobia andoi and 21.95% by Gonatocerus sp. at the paddy fiels in Shimane Prefecture.
5. Total parasitism by two species was 63.17% on the average, ranging from 47.91% to 82.55%, at the paddy fiels in Shimane Prefecture.