Study on the Composition and Dynamics of the Insect Community in Rhus chinensis Forest Plantations

To provide insight into the structure and dynamics of the insect community in Rhus chinensis forest plantations in different period through an investigation of insect community in Yanjing County, Yunnan Province. Three methods were used for collecting insects, trapping using a mixture of sugar, vinegar, wine and water, trapping using plastic bottle under ground and sweeping net. The findings indicated that a total of 1 581 insects belonging to 8 orders and 34 families and 60 species were collected from 5 investigations from July to September. The pest sub-community was the largest proportion in insect communities, accounting for 70.0%, and mainly including Xenocatantops brachycerus, Oides maculates and Apolygus lucorum. The natural enemy sub-community was accounted for 18.3%, and mainly including Ctenophorocera pavida, Chelonus pectinophorae, Coccygomimus nipponicu. The proportion of neutral insect sub-community was accounted for 11.7%, and mainly including Camponotus dolendus. The Margalef richness index of different sub-communities rose to maximum in mid-July, followed by a downward trend, and downed to lowest in mid-September. The diversity index of Shannon-Wiener showed a decreasing trend. The diversity index of neutral insect and pest were the highest in early August, while that of natural enemies occurred in mid-August. The Simpson dominance index of natural enemies was low and stable, while that of neutral insects reached its peak in early August, and the highest index of pests occurred in early September. The Pielou evenness index of neutral insects and pests reached its highest in early August, while that of natural enemies reached its highest in mid-August. The dominant species of insects in R. chinensis forest plantations were different in different periods, and the dominant species were pests and neutral insects. Over time, the trend of Shannon-Wiener diversity index and Pielou index of different insect subcommunities were consistent, indicating that the community structure was relatively stable. Besides that, it was indicated that the occurrence dynamics of pests and natural enemies are correlated.