Studies On The Structure And Dynamics Of Arthropod Community In The Weed Habitat Of Rice Ecosystem

A systematical investigation was carried out in the weed habitat around a single cropping rice field in Gutian county from May to September, 2001. The structure, diversity and seasonal dynamics of arthropod community in the weed habitat of rice ecosystem were concluded as follows:1. The total of 373 species (or taxa) of arthropods, including 107 species (or taxa) of predators, 98 species (or taxa) of parasitoids, 115 species (or taxa) of neutral insects and 52 species (or taxa) of insect pests were collected in the weed habitat.2. Based on the measurement of the dominant index (Berger-Parker), the dominant species (or taxa) were Pardosa laura Karsch in the group of predator; were Telenomus dignus Gahan, Telenomus gifuensis Ashmead and Telenomus sp. in the group of parasitoid; were Nisia atrovenosa (Lethierry) and Aphildes in the group of insect pests; were Chironomidae and Collembola in the group of neutral insects.3. Indices of diversity, evenness and dominant concertation were examined in different groups. The descending sort of groups was predators, parasitoids, neutral insects, insect pests by the index of diversity; predators, parasitoids, insect pests, neutral insects by the index of evenness; predators, parasitoids, neutral insects and insect pests by the index of dominant concentration.4. The fluctuating behaviors of species richness were almost identical in various groups. The fluctuating behaviors of the population of predators lagged to that of insect pests. The natural enemies had control effect on the population of the insect pests.5. The effect of predator, parasitoid, insect pest and neutral insect groups in the arthropod community in the weed habitat on the corresponding groups in the paddy habitat were varied. The group of predator had an important role in the rebuilding and the development of the corresponding group in paddy habitat. And other groups of arthropod in weed habitat were less important to the development of corresponding groups in paddy habitat.6. The descending sort of groups of arthropod was predators, insect pests, parasitoids and neutral insects by the similarity degree of arthropod groups between weed habitat and paddy habitat. The arthropod community in the weed habitat plays more important role as a "natural enemy pool" than as a "pest pool".