Abstract:

The bark beetle species on Pinus armandi and their niches were studied in the middle areas of Qinling Mountains. The results showed that 19 species of bark beetles infecting and damaging Pinus armandi in pine ecosystem of Qinling Mountains were found, but only 11 species of them could be competitive and coexistent one another. Although each of the 11 species of the bark beetle had its own spatial niche and overlogs niche, they could attain competitive equilibrium and coexistance according to their requirment for different nutrition and space, the interference of population density and the different time interval attacking the host tree. In the construction of the ecosystems of bark beetles on Pinus armandi in Qinling Mountains, the bark beetles first attacked the healthy tree, carrying the blue stain fungi into it, quickly weakened the trees vigor, then the mainly secondary bark beetles Ips acuminatus, Pityogenes japonicus and Ips sexdentatus attacked the weakened trees. Finally, other bark beetles infected to the withered trees, and utilizing the surplus spatial niche and trophic niche of the host trees. Consequently, the relatively steady ecosystem of the bark beetles on Pinus armandi could be constructed.

Key words: Qingling Mountain, Pinus armandi, Bark beetles, Niche, Ecosystem