The clothes moth (Tineola bisselliella) is an unusual moth. Unlike other moth species, which are attracted to light, it is highly photophobic and immediately seeks cover when disturbed. It grows to up to 7 mm in length and, depending on what the larvae feed on, has wings ranging from straw-coloured to golden yellow, without spots or markings. This sets it apart clearly from other moth species. In warmer temperatures, the males can fly up to several hundred metres. Their distinctively erratic, fluttering flight makes them easy to distinguish from their relatives, the food moths; at lower temperatures, however, they are less active. Females, by contrast, are fast runners and generally prefer to remain on the ground, taking flight only after laying their eggs.

Females live for just over two weeks. After mating, they lay up to 250 eggs, depositing them singly or in small groups on a suitable food source. After about two weeks, whitish, translucent larvae hatch. These larvae are the true pests, as adult moths have reduced mouthparts and do not feed.

Immediately after hatching, the larvae begin to build protective silken tubes, using threads produced by their spinning glands along with material from their surroundings and their own excrement. Open at both ends, these tubes protect them from drying out and from being eaten by predators, and the larvae rarely leave them. They feed primarily on keratin, a protein found in wool, silk, feathers, and hair. As a result, they may infest not only textiles and furs, but also carpets and upholstered furniture with horsehair filling. Even accumulations of dust – for example beneath display cases or in ventilation grilles – may be enough to sustain them. Viewed under a microscope, dust can be seen to consist partly of hair, skin flakes, and wool fibres, in other words, the animal protein essential to larval development.