The caterpillar silk webs phenomenon – some of the species that may be found
One of the threatened moths that is found fairly widely in north Dorset is the Small Eggar whose beautiful larvae live in tents on hawthorn or blackthorn. The moth has a lovely subtle pattern and the larvae are beautiful and harmless.
Small Eggar larvae in web Small Eggar larvae Small Eggar moth Photo: Nigel Spring Photo: Nigel Spring Photo: Gill Nash
Another, more common moth with very attractive larvae is the Lackey
Lackey Moth larvae in web Lackey Moth larvae Lackey moth Photo: Tim Norriss Photo: Tim Norriss Photo: Gill Nash
The moth that attracts the most adverse publicity is the Brown-tail which produces highly allergenic hairs when disturbed either as an adult or as a larva and is best avoided.
The pupae are also protected by these hairs and the female moth even puts hairs on the eggs when she lays them. The moth caterpillars live in tents on the various species of shrubs on which they feed. This is the only species of UK moth to hibernate as tiny larvae in a tough gossamer tent. The hairs can irritate the human skin and in some people can cause severe lung irritation. This species has been treated as a pest in certain areas, including the coastal strip of Dorset, and the webs are sprayed or burnt with flamethrowers. Unfortunately, misidentification can lead to the indiscriminate destruction of harmless species too.
Brown-tail moth larvae in web Brown-tail Moth Photo: Tim Norriss Photo: Gill Nash
At this time of year, many hedges, shrubs and trees are shrouded in gossamer silk produced as a protection by the larvae of several species of Small Ermine micromoths. Where Spindle is an abundant hedgerow plant, hundreds of metres of hedge can be covered and the hedge temporarily defoliated by thousands of larvae of the Spindle Ermine. A recent photo of a park in Yorkshire showed all the trees, railings, benches and lawns totally covered in the gossamer produced by the Bird Cherry Ermine.
Spindle Ermine larvae Small Ermine moth. Photo: John East Photo: Gill Nash
The Winter Moth is occasionally a pest of fruit trees and can produce the same kind of silk shrouding as the Small Ermines, as shown in these extraordinary photos from Hampshire.
Winter moth larvae Winter moth larvae Winter moth Photo: Tim Norriss Photo: Tim Norriss Photo: Gill Nash