Wool, fur and feathers consist
primarily of keratin which is one of the most indegestible
proteins. There are, however, some insects which are adapted
for feeding on this diet. Special conditions in their gut enable
them to break down the sulphur linkages in the keratin and
thus render it digestible. Suffice to say that the items listed
above are complex chemical structures consisting of three alpha-helical
polypeptide strands coiled into a rope and eleven of these
units to make a micro-fibril.
In the wild insects that can digest keratin probably feed on
the remains of animals left by the carrion eaters, but they
are also found in nests and lairs containing down or hair.
However, keratin alone does not provide a sufficient diet for
the normal development of an insect. It lacks, for instance,
certain vitamins. In the wild an insect wil have plenty of
opportunities for supplementing it's diet, but this is not
possible if it is feeding on a completely clean textile. If
if is to thrive it must be able to eat small ammounts of food
remains or traces of sweat and urine. In addition to the true
specialists there are many animals occurring indoors which
occasionally gnaw textiles. This may be because there are stains
on the material to which they are attracted, but they may also
do so in order to pupate. Rats and mice often cause serious
damage by gnawing textiles, particularly in store and warehouses,
when they are gathering nesting materials.
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