Tineola bisselliella, the webbing clothes moth, feeds on animal-based materials rich in a tough structural protein called keratin. Wool, fur, silk, feathers, felt, and leather are all on the menu. But only the larvae do the eating. Adult clothes moths don’t have functional mouthparts and never consume food at all.
Keratin Is the Key Ingredient
What connects every food source for clothes moth larvae is keratin, the same protein that makes up human hair and fingernails. Wool fibers, animal fur, bird feathers, and silk all contain keratin in varying amounts. Feathers, for example, are roughly 91% keratin by weight. The larvae have evolved a rare ability to break this protein down, something most organisms cannot do because keratin’s molecular structure is reinforced by strong chemical bonds that resist ordinary digestion.
The larvae don’t do it alone. Bacteria living in their gut, particularly Bacillus species, produce a cocktail of protein-cutting enzymes that attack keratin from multiple angles. Researchers identified at least 16 different protein-breaking enzymes in one key gut bacterium, along with a specialized enzyme that snips apart the tough sulfur bonds holding keratin fibers together. This combination of enzymes is what allows a tiny caterpillar to chew through your winter coat.
What They Eat in the Wild
Before clothes moths became household pests, they thrived in nature. Their natural habitat includes bird nests, rodent burrows, and insect nests, anywhere animal-derived material accumulates. Researchers studying wild reservoirs found that Tineola bisselliella can successfully develop from egg to adult on a wide range of natural materials: bird nesting material (including carcasses of dead chicks), empty wasp nests containing insect debris, and even the dried bodies of other insects like beetles, termites, and other moths.
Accumulations of insect remains in old bee, wasp, ant, or termite nests serve as excellent breeding grounds. This is why infestations sometimes seem to appear from nowhere. A bird nest in your attic or a wasp nest under the eaves can be the starting point for larvae that eventually find their way to your closet.
What They Eat in Your Home
Inside a home, larvae target anything made from animal fibers. The most commonly damaged items include wool sweaters and suits, fur coats, silk garments, feather pillows, felt hats, and leather goods. Each female moth lays around 40 to 50 eggs, and it only takes a single larva feeding on an expensive garment to cause visible damage.
Cotton, polyester, rayon, and other plant-based or synthetic fabrics are rarely attacked on their own. Larvae can’t digest these materials. The exception is when synthetic or cotton fabrics are blended with wool, or when they’re heavily soiled with food stains, sweat, or body oils. The organic residue gives the larvae enough nutrition to feed in areas they’d otherwise ignore, which is why stained clothing is at much higher risk than clean garments stored properly.
Why Dirty Clothes Are More Vulnerable
Clothes moth larvae are strongly drawn to fabrics contaminated with perspiration, food spills, and skin oils. These residues provide supplemental nutrients, particularly salts and fats, that pure wool alone may lack in sufficient quantities. A clean wool sweater stored in a sealed container is far less attractive than one tossed into a dark corner of a closet after being worn. This preference for soiled fabric also explains why damage often concentrates around collars, cuffs, and underarm areas where body oils accumulate.
How to Recognize Feeding Damage
Clothes moth larvae don’t eat fabric in clean, round holes the way you might expect. Instead, they thin out the material gradually, leaving irregular, rough-edged holes. You’ll often find silk mats on or near the damaged area, sometimes woven into small tubes or tunnels where the larvae shelter while feeding. Tiny fecal pellets, roughly the color of the fabric being consumed, collect around these silk webs. If you notice patches of fabric that look worn or threadbare in storage rather than from use, larvae are a likely cause.
Catching an infestation early requires checking stored woolens, furs, and feathered items regularly for larvae (small, cream-colored caterpillars), silk webbing, fecal pellets, and thinning fabric. Damage tends to happen in undisturbed, dark areas: the backs of closets, inside storage boxes, under furniture, or in attics where items sit for months without being moved.