Two parasitoids, Gonatocerus cincticipitis and Paracentrobia andoi, parasitized on the green rice leafhopper, Nephotettix cincticeps, have been recognized to coexist fairly stable in the same paddy field. However, it has been known that no two species having the same niches can exist together owing to the competitive exclusion principle. Hence, authors investigated the spatial distribution patterns of host and two parasitoids and interspecies association between two parasitoids.
The distribution patterns, representing by host eggs and egg masses and parasitized eggs and egg masses in the paddy field, were analyzed by the m*-m relationship proposed by Iwao (1968). Interspecies association was analyzed by the interspecies mean crowding and correlation index (γ) proposed by Iwao (1977).
The intraspecies m*-m regression of host and two parasitoids indicated nearly the random distribution. The interspecies m*-m revealed independent distribution of two parasitoids.
Therefore, it was assumed that two parasitoids could be coexisted by this results.