Norman Lowe, the moth recorder of the Brecknock Wildlife Trust, identified them:
These are webs of the 'Bird-cherry' Ermine moth, Yponomeuta evonymella, the larvae of which feed almost exclusively on Bird Cherry, although there are related species on other trees and bushes. So the Spindle Ermine has been in evidence producing similar webs on spindle a few weeks ago. Numbers of both species vary from year to year but in good years they can be very numerous and obvious.
Although the damage seems serious, the Bird Cherry bush generally recovers very quickly. The larvae feed for only a few weeks in June and shortly afterwards the plant produces a lot of new growth and doesn’t seem to suffer any long-term damage. The two species (moth and bush/tree) are both native and have evolved alongside each other for thousands of years. Certainly Bird Cherry is very common.Interestingly, on BBC's 'Springwatch' TV program earlier this month, Simon King showed similar pictures of extensive webs made by the 'Spindle' Ermine moth, Yponomeuta cagnagella.
21:00, 25 June 2010