马赞峰 韦卫 武发思 汪万福

内容摘要：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。

关键词：仿爱夜蛾;排泄物;壁画;腐蚀机理

中图分类号：K854.3  文献标识码：A  文章编号：1000-4106（2021）04-0125-08

Abstract：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 moths 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.

Keywords：Apopestes spectrum; excreta; mural; erosion mechanism

仿爱夜蛾（Apopestes spectrum）属鳞翅目夜蛾科，国内分布于陕西、甘肃、宁夏、新疆、四川，国外分布于阿富汗、伊朗[1]，其寄主植物为苦豆子。

据1996—2000年对危害敦煌莫高窟的仿爱夜蛾调查结果表明：在莫高窟現存有壁画、彩塑的492个洞窟中，有仿爱夜蛾成虫分布或受其排泄物危害的洞窟为75个，占总洞窟的15.2%[2]。由于仿爱夜蛾成虫有从8月到次年5月在洞窟中越冬的习性，仿爱夜蛾成虫与其他病害昆虫在壁画表面停留时，其排泄物不仅污染壁画画面（图1），影响艺术效果，而且排泄物中的水分、有机物等与壁画颜料、地仗成分产生化学作用，造成壁画颜料层龟裂、起甲甚至脱落等现象（图2），加重了壁画病害的发生，给壁画保护修复工作造成很大困难。……