Abstract: Endangered plant Tetraena mongolica is a deciduous dwarf shrub endemic to China, belonging to a monotypic genus of Zygophyllaceae. In this paper, an investigation was conducted on the insect community in T. mongolica stands. A total of 11363 insect specimens were collected, belonging to 263 species, 11 orders, and 67 families or super-families, among which, Homoptera had the highest abundance and dominance, Hymenoptera had the greatest species richness and diversity, whereas Diptera had the highest evenness index. The most abundant groups (>10%) were Psyllidae and Cicadellidae, and the common groups (1%-10%) were Curculionoidea, Chalcidoidea, Meenoplidae, Tenebrionidae, Formicidae, Pentatomidae, Piesmidae, Miridae, and Catantopidae. As for the trophic structure, herbivorous insects had the greatest species richness and abundance, among which, sucking groups were most abundant. Most of the insect natural enemies were of parasitic, and their diversity index was the highest. Both the species richness and the abundance of predacious and neutral insects were relatively smaller, but predators had the highest evenness index. Compared  with the herbaceous layer in the stand, shrub layer was higher in insect species richness and abundance, with a higher dominance of dominant species, but lower in diversity and evenness index. The two layers had a low similarity in insect community structure, but both of them had numerous species in Hymenoptera.

Key words: Delphastus catalinae, Serangium japonicum, Interactive system, Interspecies competition