Correlation On Rice Field Dominant Spiders And Objective Pests: Rice Planhopper And Leafhopper

1. The result of the research on community structure makes it clear that There are total 43 species 29 Genus 11 families of spider in the rice field of DongFang-hong Farm Changsha City. The dominant families are Lycosidae, Linyphiidae, Theridiidae and Terahnathidae; the dominant species are Pirata subpiraticus, Vmmeliata insecticeps, Coleosoma simon and Tetragnatha maxillosa. In the early rice field of the different types of fields, the dominant species of spiders haven't been altered, which are mainly Pirata subpiraticus and Vmmeliata insecticeps. In the late rice field, there exists replacement in the dominant species of spiders. The four kinds of dominant spiders, account for over 94 percent of the total spiders in the early rice field, and about 87 percent in the late rice field. Chemical pesticide has a great influence on the individual number of the four dominant families spiders. The discrepancy of the individual number of dominant spiders in the two types of treatment fields was from 40 percent to 60 percent.2. According to the analysis of the space distribution of spiders, we can find that the dominant species of rice field spiders (Pirata subpiraticus, Vmmeliata insecticeps, Coleosoma simon, Tetragnatha maxillosa) are consistent with rice planthoppers and leffhoppers in their space distribution in every growing period of early of late rice. The space distribution of the mixed species of rice field spiders is closely related to the density of rice planthoppers and lefahoppers.3. Results of reasearch on the niche of dominan planthoppers and their objective pests (such as rice planthoppers and leafhopper) indicates that the increases or decreases of the niche breadth value of spiders followed as that of the pests. That confirms in a further way the strong interaction relationship of spiders and objective pests. The index of niche breadth or niche overlap of spiders in the late rice field is bigger than that of the spiders in the early rice field. In different rice growing period, niche breadth of spiders and the niche overlap index among spiders have alteration, and give a further explantation to this kind of alteration in this paper.