ENERGY DYNAMICS OF THE GRASSHOPPER(CHORTHIPPUSDUBIUS ZUB) POPULATIONS IN THREE DIFFERENTPLANT COMMUNITIES IN INNER MONGOLIALGRASSLAND ECOSYSTEM
草原生态系统狭翅雏蝗种群的能量动态

Chorthippus dubius (Zub.) is a dominant species of grassshopper in northwestern pasture of China. The present paper deals with the energy flow through the grasshopper populations in three different plant communities representing different degree of degradation in Inner Mongolian grassland. Results indicated that the amount of energy consumed and assimilated from the net production of aboveground vegetation was of the order of 0.21%-1.03% consumed and 0.1%-0.59% assimilated. Additional 0.21%-1.93% of this production were out and dropped by the grasshopper populations. Approximately 0.03%-0.06% of the energy of net aboveground primary production were converted by the grasshopper populations into body and were available to higher trophic levlls.By comparison, the grasshopper population in the most degraded plant community had the strongest grazing pressure on the pasture, but the population in restorative plant community had the hightest net production. Similar efficiencies were found among the Chorthippus dubius populations in these three different communities, i. e., growlh efficiency (P/A), 30%-32%, ecological efficiency (-P/C), 14%-18%, and assimilation efficiency (A/C), 48%-58%.