The Portland Ribbon Wave (Idaea degeneraria) is a moth in the Geometridae family.
A medium sized geometrid, this moth is grey-brown, with a darker brown inner area. Like most geometrids, when at rest, this species holds it's wings out flat. There is a small black dot on each wing.
Range & HabitatEdit
This species is a Red Data Book species, and is restricted to the Isle of Portland, in Dorset, which gives the species it's name. It inhabits the grassy coastal cliffs of Portland, and feeds on a range of plants, including Lady's Bedstraw and Dandelion, but it's foodplant in the UK has not been recorded. Odd records do occur elsewhere, due to immigration, probably from mainland Europe. In Europe, this species is widespread and often very common. Why it is so rare in the UK, is not known.