Clothes Moths: Know Thy Enemy

Letitia Steer

In the spotlight today are two  types of moths that are a perennial problem for conservators in the UK. The culprits discussed in this blog attack museum objects (especially taxidermy and animal specimens),  as well as  damaging carpets and clothing in domestic environments. They may go unnoticed now,  but as spring arrives beware, they take no prisoners!

A victim – this poor penguin is currently being kept as an example of moth devastation. Courtesy of UCL, Grant Museum of Zoology, LDUCZ-Y1601

The two types of moth in today’s crimes-against-conservation spotlight include the common or webbing clothes moth (Tineola bisselliella):


Adult webbing clothes moths caught in pest trap, the back has a golden sheen

and the case-bearing or case-making clothes moth (Tinea pellionella).


An adult case bearing moth, with a silvery sheen (image from Wikipedia, ©entomart)


The common or webbing clothes moth

The larvae of this species spin silk tubes or sheets of webbing across the material they are eating, under which they can freely move over the surface, chomping as they go.


FACT: These villains not only hide in the shadows but are capable of laying  batches of up to 100 eggs on fur, feathers, skin, wool or other protein-containing  materials. The adult moth lays the eggs (the larvae), which cause the damage when they hatch from the eggs and spin silk webbing as they feed and grow,  before pupating and hatching out as adults to mate and lay eggs​ to keep the cycle of destruction​ going.


The case-bearing or case-making clothes moth

The larva spins a case or bag around itself, leaving the ends open so that it can use its jaws and legs. It then eats as it crosses the material, carrying its case and leaving a trail of grazed textile or fur with fragments of excreta or frass. The larva molts within the case, and when fully grown it pupates within the cocoon. Eventually the adult moth emerges to mate and lay eggs. Infested material is often littered with empty silk bags or cases, which resemble grains of rice.


The larvae hatching, leaving behind its frass (image from Wikipedia)

Mythbuster: Clothes moth eggs will not remain dormant in textiles and then hatch many months later!


Though this post concludes the first critter watch, this post serves as a warning and highlights the need for vigilance in museum stores,  inside the conservation labs and offices of UCL, and at home!