Last modified: Jan. 12, 2022, 6:33 p.m.
A rare early spring species throughout Belgium.
The adults fly in one generation a year; during April and May. They are often found resting during the day on the trunks of oaks and occasionally apple orchards. They are on the wing in the late afternoon and early evening and later comes to light.
The larva lives and feeding internally in galls of hymenopterans on Quercus, mainly on Quercus robur. When fully fed in late summer, it usually leaves the gall and spins up elsewhere, hibernating and pupating in early spring. Pupates in a silken cocoon in the larval habitation, inside an old gall or under bark or moss.