Scanning Electron Microscopic Investigations of the Breakdown of Wool by Insect Larvae

Abstract

Although wool and other keratinous materials consist of highly crosslinked protein matter and thus are virtually insoluble and resistant to biological attack, some insect larvae are able to digest and use them as food. The digestion of wool by these moth and beetle species involves processes that are not yet fully understood. Scanning electron microscopic investigations of larvae excreta have helped to shed more light on this subject by showing the breakdown of wool and the digestion of the morphological components of wool by moth and beetle larvae, on the basis of the remaining wool fragments. The feces of all larvae species, excreted after feeding on untreated and mothproofed wool, were found to contain wool fragments in different stages of deg radation. In the last stage of degradation, the wool was broken down to its fibrillar structures. Microscopic observations of the excreta indicated a preferential breakdown in the larval gut of some of the low sulfur regions of the wool.