Abstract
The larvae of Gypsonoma bifasciata Kuznetzov and G. hiranoi Kawabe (Olethreutinae, Tortricidae, Lepidoptera) were observed to bore into and feed on cecidomyiid bud galls on the willow Salix eriocarpa. G. bifasciata larvae emerged from the bud galls formed by two cecidomyiid species, Lygocecis yanagi (Shinji) and Rabdophaga rigidae (Osten Sacken) (Cecidomyiidae, Diptera), while G. hiranoi only from a gall by R. rigidae. These moths were thought to hatch before the bud break and utilize the galls as an alternative food resource, since they are usually foliage feeders on young leaves.
