Morphology and Ecology of Immature Stages of Oxyethira acuta KOBAYASHI (Trichoptera, Hydroptilidae)

Abstract

Final instar larva, young larva and pupa of Oxyethira acuta KOBAYASHI are described. Young larvae do not make the case. Final instar larvae bear bottle-shaped cases made entirely of silk. The larvae live on the stems and leaves of higher water plants and feed on the filamentous green algae. They break the cell walls of the algae by their mandibles and suck out the cell contents. O. acuta has a one year life cycle in Lake Utonai, Hokkaidô, northern Japan; young larvae occur in late summer, final instar larvae are found from early autumn to next summer, and pupae occur in summer.