Studies on the structure and distribution of the parasitic wasp populations of Parasaissetia nigra

Through massive screening and point-surveys,the structure and distribution of Parasaissetia nigra Nietner and its parasitic wasp populations were studied.The results showed that there were 10 species of parasitic wasps,of which there were 2 dominant species,4 common species and 4 rare species.Diversinervus elegans and Tetrastichus murakamii were defined as the dominant parasitic wasps,occupying 64.32% and 11.76% of the total species population density,respectively.Spatial distribution of the parasitic wasp populations is different at different orientations of the rubber tree.The parasitic rate on average was higher at the top than at the bottom.The parasitic rate on average is the highest to the south and lowest to the north.The spatial distribution of P.nigra and its parasitic wasps were determined by Taylor power and Iwao's regression equation.The results were the same and showed that the spatial distribution patterns of both P.nigra and the parasitic wasps belong to aggregative distribution.The higher the parasitic wasps' density,the higher the aggregative degree.