noun
common clothes moth
Refers to the species Tineola biselliella, a small moth whose larvae feed on natural fibers such as wool.
コイガの幼虫がセーターに穴をあけた。
The larvae of the common clothes moth made holes in the sweater.
イガ is a broader term for clothes moths (family Tineidae), while コイガ specifically refers to the common clothes moth Tineola biselliella.
The name コイガ is a compound of 小 (ko, 'small') and 衣蛾 (iga, 'clothes moth'). The exact historical derivation is uncertain, but it follows a common pattern for naming small moth species.