In this experiment the growth of Gonatocerus cincticipitis and Paracentrobia andoi, parasitic on the green rice leafhopper, proportions compared with another species and the behavior of searching host of two parasitoids were investigated.
The investigation was conducted in two paddy fields in which one was applied no insecticide(the paddy field-A), and another was applied insecticide(the paddy field-B).
The saturation density of three populations, host and two parasitoids, were found in the paddy field-A, but there was no saturation in the paddy field-B.In the paddy field-A, G. cincticipitis was strongly checked by P.andoi. Although these phenomenon reversed in the paddy field-B, P.andoi was not quite checked by G. cincticipitis. Therefore, it was assumed that P. andoi was dominant compared with G. cincticipitis in this local. In each paddy field, the behavior of searching host of G. cincticipitis showed no difference, but that varied remarkable in P. andoi.