Studies On Reestablishment Of Spider Community In Cabbage Field And Predation Of Dominant Spiders For Major Pests

The reestablishment of the spider community in cabbage field was preliminarily analyzed in Taigu, Shanxi, and the predation of the dominant spiders for major pests was also studied. The species of spider in cabbage field, the reestablishment speed of spider community, the interaction between spider community and its species pool, and the predation of dominant species for major pests were all cleared. Moreover the researched results were provided for conserving and utilizing natural enemies and doing sustainable IPM. 1. 459 and 367 spiders were respectively collected in ridge of field sub—species pool and roadside sub—species pool. After primarily classing and authenticating in lab, these spiders respectively belonged to 10 families, 20 genera, 26 species and 10 families, 18 genera, 24 species. The dynamics of spider community in species pool was analyzed by species richness(S), individual number(N), Shannon—Weiner diversity index(H′) and Pielou evenness(E). Then Berger—Parker index of dominant degree (D) showed that dominant species, population density and dynamics of dominant species. 2. The reestablishment process and speed of spider community in cabbage field were studied during the cabbage season. The structure and dynamics of spider community were analyzed by the method of the above. The reestablishment speed of spider community was described as the percentage of accumulative species. The results showed that these spiders which were investigated belonged to 8 families, 18 genera and 23 species. With the development of cabbage, the species and numbers of spiders gradually increased. And the reestablishment finished on the 29st day after transplantation of cabbage seedling. The rate of reestablishment was 0.5625 species per day in cabbage field. From then on, the species and numbers of spider became decreasing which meant the spider community get into its collapse periods. 3. Applying the mark—recapture methods in this article which testified that the species pool of the spider community in cabbage field provided colonies for community reestablishment and accepted emigrants from collapsing community. There was a mutual complementary relationship between community reestablishment and its species pool.