The Artist’s Bracket Ganoderma applanatum is not uncommon on trees in the Wyre Forest, but these fascinating galls on the underside that John Bingham showed us are rarely found. They are caused by the larvae of the Yellow Flat-footed Fly Agathomyia wankowiczii which feed inside the fungus. When each grub is mature, it bores a hole in the top of the gall and drops to the ground where it pupates before emerging as the adult fly. This is the only example of an insect causing a gall in a fungus currently known in the UK!

Galls of the Yellow Flat-footed Fly on the underside of Artist’s Bracket, Hitterhill, 13 April 2019

Photo by Rosemary Winnall