The adults moths have reduced mouthparts and live for a few days only. Many species show parthenogenesis. Also the females in many species are wingless; mostly they live in a case, consisting of the old pupal skin which is covered with silk in which are woven parts of plants, sand grains and other debris. The larvae always live in such a case (Davis, 1987a). Nice pictures of the different stages and discussions about the biology can be found in Hermann (1994a).
Their role as leafminers is very limited (Hättenschwiler, 1985a): Apterona species make somewhat irregular fleck mines. Als gall causers they play no role.
Davis (1987a), Hättenschwiler (1985a), Hermann (1994a).