Abstract: Suction traps were used to investigate the community composition and its characteristics of ballooning spiders in Xiuyan Region of Liaoning Province,Northeast China from May to September 2009. A total of 549 specimens of ballooning spiders were captured, belonging to 14 families. The analysis of the community composition, seasonal dynamics, body lengths, growth phases, and sexual ratio of the specimens showed that the species richness of the ballooning spiders in east Liaoning was abundant, and Linyphiidae and Araneidae were the dominant groups, occupying 58.29% and 11.84%, respectively. In all mature individuals, the most abundant families were of Linyphiidae (74.02%) and Tetragnathidae(11.02%). The ballooning behaviors were observed throughout the investigation period. ANOVA analysis indicated that the number of ballooning spiders collected in early August to  early September was significantly higher than that in other periods. The ballooning spiders had a body length less than 8 mm, and 91.44% of them had a length less than 3 mm. The χ2 test revealed that the individuals at immature stage were significantly higher than those at adult stage, and the male individuals were significantly higher than the females.

Key words: East China Sea, Red Tide, COD, Petroleum hydrocarbons, Eutrophication