仿爱夜蛾排泄物对敦煌莫高窟壁画损害过程的模拟研究

Simulation Research on the Damage done by Apopestes Spectrum Moth Excreta to the Murals in the Mogao Caves at Dunhuang

为确定敦煌莫高窟壁画病害昆虫仿爱夜蛾成虫排泄物的成分,研究其对壁画造成危害的机理,我们利用气相色谱-质谱联用仪(GC-MS)对仿爱夜蛾成虫排泄物进行了分析。分析结果显示,仿爱夜蛾成虫排泄物的成分主要为醇类、酮类及有机酸类,仿爱夜蛾雄虫排泄物的成分比雌虫更为复杂。这些排泄物在壁画表面堆积并形成颜色较暗的扩散圈。主要结论为:仿爱夜蛾成虫排泄物在壁画表面附着及入渗扩散,污染壁画画面;成虫排泄物中有机成分也是造成壁画颜料及其胶结材料腐蚀退化的重要因素;成虫排泄物的累积与干燥收缩可诱发并加重壁画起甲病害。

This study aims to determine the composition of the matter excreted by Apopestes spectrum moths in the Dunhuang Mogao Grottoes, and to study the chemical mechanism by which this matter does damage to the murals in the caves. Researchers used GC-MS methodology to analyze the excreta of adult Apopestes spectrum, and then applied the resulting chemical compounds to simulated murals to observe the effect the matter had on the various pigments used to paint the murals. The results show that the chemicals contained in this type of moth’s excreta are primarily alcohols, ketones, and organic acids. Further, it can be observed that the matter excreted by male Apopestes spectrum are more complex in composition than that produced by females of the species, and that when such matter accumulates on the surfaces of murals, dark diffusion circles will be formed. The authors have come to the following conclusions through this research: the excreta of adult Apopestes spectrum easily adheres to the surfaces of cave murals and can quickly permeate and contaminate paintings;the organic elements in the excreted matter are the primary vehicles that cause erosion and degeneration in the mural pigments and cementing in the excreta itself;and that the accumulation and dry shrinkage in the excreta can induce and aggravate flaking on the murals.