Abstract: This study aimed to explore the damage process of Apopestes spectrum (Esper) to murals in Mogao grottoes, so as to provide the effective scientific basis for the prevention of this dominant insect pest. Combined with microclimatic environment monitoring in Mogao grottoes, the spatial distribution characteristics and preferences of A. spectrum adults to murals of different pigments in a simulated cave inside cave 53 of Mogao grottoes were observed simultaneously. The environmental monitoring results indicated that in the peak active season of A. spectrum adults from August to September 2011, the temperature and relative humidity were very close in the simulated cave and cave 53, which was 17.97℃ and 18.02℃, and 37.04% and 37.13%, respectively, suggesting that the artificial cave can simulate the environmental condition of natural cave preferably. The observation results of spatial distribution showed that the numbers of A. spectrum adults differed greatly on mural surfaces in different orientation of simulated cave, distributed more on the upper southern wall and two sides of the eastern wall than on the ground, the ceiling, and the upper western wall. Tests of preferences of moths towards murals of different pigments indicated that there were distinct differences in the preference of A. spectrum adults towards different mural pigments, with the largest number of adults on briquettes with indigo, iron oxide red, and ink, and the less number of adults on briquettes with the pigments red lead and malachite. The Pearson correlation analysis showed that the number of adults on mural surfaces with different pigments had a significantly negative correlation with lightness of pigments, suggesting that lightness of pigment surface is one of the key factors that influence the tendency of A. spectrum adults towards pigments. This study can provide a significant reference for studying insect damage mechanisms to wall paintings in other cavetemple sites.

Key words: Apopestes spectrum, behavior, Mogao grottoes, simulated caves, mural pigments; , preference, cultural relics&rsquo, conservation, Dunhuang