Friend or foe?
April 24, 2010
We have a ‘plague’ of these in our vegetable garden which backs on to woodland. They fly when disturbed but seem to prefer to be resting. Really only need to know if they are friend or foe. Their wings shimmer slightly as if covered in fine gold leaf.
At first we thought that this might be a Caddisfly. According to BugGuide, which only covers North American species, “Adults resemble moths, but wings are hairy instead of scaly.” We decided to search the UK Moths website though, and we believe we identified your insect as a tiny moth, known as Microlepidoptera, and possibly the species Micropteris calthella which is described on UK Moths as “Wingspan 7-10 mm. Another tiny species, with a wingspan of around 8 to 10mm, this moth has metallic bronzy forewings, with purplish tinges in places. Like other Micropterix species, it has a tuft of hairs on the head. It occurs throughout most of Britain, and can be found flying in the daytime in May and June, where it feeds on the pollen of various plants.” An even closer match might be Eriocrania semipurpurella, which UK Moths describes as “Wingspan 10-16 mm. The commonest and most widespread of the Eriocrania species that feed on birch, occurring throughout most of Britain. The adults are difficult to tell apart from E. sangii without reference to the genitalia structure, but the larvae are quite different, semipurpurella being white or yellowish, sangii being quite dark grey. The larva itself mines in a birch (Betula) leaf, forming a large blotch, from March to May. The adults fly in March and April, especially in sunshine.” We don’t believe we have the skill to definitively identify this Microlepidoptera, but you might have better luck trying to sort through the 2012 Moth species on the site UKMoths. Friend or Foe is relative.