Here's how to get rid of 'moths' eating your clothes

By Ying Lou and Andreas ZwickMolecular Systematist for The Conversation

Have you opened your post-lockdown wardrobe, only to discover some of your beautiful summer clothes have holes in them? You’re probably blaming clothes moths but the real culprits are the larvae (caterpillars).

But who are these moths? The fact that they’re feeding on your precious clothes, fabrics and yarn actually reflects an interesting and – for moths – unusual biology.

An old foe

Early references to clothes moths in Greek and Roman literature suggest humans have been battling clothes moths for thousands of years.

Clothes moths are part of an ancient lineage of moths (Tineidae) and as such have preserved some quirky behaviours and adaptions that have led to a few species becoming pests.

The most well-known species of clothes moths in Australia are the webbing clothes moth (Tineola bisselliella) and the case-making clothes moth (Tinea pellionella).

These common names refer to the appearance of silk spun by the caterpillars as shelter.

The adult clothes moth ranges in size from 4mm to 9mm – about the size of a grain of rice. Once the larvae turn into adult moths, they never eat again.

An inconvenient diet

The evolutionary origin of clothes moths diverged from 98 per cent of all other moths a long time ago, so these moths do some things differently from most other moths.

Most tineid species don’t feed on living plants like “normal” caterpillars, but on rotting wood, fungi, lichens, detritus and even bat poo in caves. So it is unsurprising some species even feed on the keratin (a kind of protein) found in natural fibres.

They love to nibble on items derived from animals such as fur, wool and silk. But the synthetics or mixed fibres in your wardrobe aren’t safe either. Clothes moth larvae have been known to feed on synthetic and blended fibres, particularly those stained with sweat or food.

The preferred diet of these caterpillars means some species have become unwelcome pests in our homes.

(The authors are associated with Australian National University and CSIRO)

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