关键词: 净初级生产力, 净生态系统生产力, 衰退, 谷地云冷杉林, 碳密度

Abstract: The waxy spirals produced by female Aleurodicus dispersus during oviposition could be a chemical barrier against some herbivorous insects such as Stephanitis typica. In this paper, a laboratory leaf disc bioassay was conducted to study the antifeedant activities of aromatic esters, phenol, and hydrocarbon in the female A. dispersesecreted waxes against 5th-instar S. typica nymph. At concentration 10 mg·mL^-1, the dibutyl phthalate in the secreted waxes had strong anntifeedant activity, followed by 3,5-bis (1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid methyl ester, di-n-octyl phthalate, and hexadecane, while 4,4′-methylenebis \[2,6-bis (1,1-dimethylethyl)\] phenol had no antifeedant activity. The antifeedant activity of dibutyl phthalate increased with its increasing concentrations, and the median antifeedant concentration against theS. typica was 0.929  mg·mL^-1. The results implied that the aromatic esters
 from the waxy spirals exhibited significant antifeedant activity. These findings provided a new evidence for the interspecific interactions in phytophagous insects.

Key words: valley spruce-fir forest, carbon density, net primary production, net ecosystem production, decline.