What characteristic distinguishes Lepidoptera from other insects?

The characteristic that most distinctly identifies Lepidoptera, a diverse order that includes butterflies and moths, is their two pairs of wings covered in scales. This feature is not commonly found in other insect orders. The scales can give wings their vibrant colors and patterns, which can play a significant role in camouflage, mate attraction, and warning predators.

While complete metamorphosis is indeed a trait of Lepidoptera, as they transition from egg to larva (caterpillar) to pupa (chrysalis) to adult, it is a characteristic shared with several other insect orders, such as Coleoptera (beetles) and Diptera (flies). Similarly, compound eyes and the presence of a proboscis for feeding are adaptations found in various insect groups. However, the unique structure of their scaly wings serves as a defining characteristic of the Lepidoptera order that sets it apart from others.