Diversity and dominant species of arthropods in different forests of Aershan,Inner Mongolia

Taking different forests in Aershan of Inner Mongolia as sample plots, diversity and dominant species of arthropods were studied. The results show that two classes, 17 orders, 68 families, 130 species and 3742 individuals were identified and 92.31% of total species appeared in natural forests, and 75.38% of total species appeared in plantations. The orders of Lepidoptera, Coleoptera, Diptera and Hymenoptera covered most of the collected arthropods. In different forest types, diversity indices is natural mixed forests （Betula platyphylla x Larix gmelinii）〉 natural pure B. platyphylla forests〉natural pure L. gmelinii forests〉plantations with pesticide treatment〉plantations without pesticide treatment. In natural forests, more than 70% of the arthropod families, species and individuals were distributed in shrub and herb layer, while in plantations 75% of the arthropod families, 78% of species and 80% of individuals were also distributed in shrub and herb layer. Lepidoptera, including Loxostege sticticalis （Linnaeus）, Chilo suppressalis （Walker） and Lymantria dispar （Linnaeus）, had the highest dominant degree.