Most species of moth are nocturnal, but there are also species active during the day and at twilight. Moths, and particularly their caterpillars, are a major agricultural pests in many parts of the world. In addition, the larvae of some species eat fabric such as clothes and blankets made from natural fibers like as wool or silk but are less likely to eat mixed materials containing some artificial fibers. Naphthalene (the chemical used in mothballs) is considered more effective, but there are concerns over its effects on human health.

• Moths are related to butterflies, though butterflies are typically more colourful.
• Moth larvae, or caterpillars, make cocoons from which they emerge as fully-grown moths with wings.
• Some moth caterpillars dig holes in the ground, where they live until they are ready to turn into adult moths.