Oak processionary moth lavae (Thaumetopoea processionea)
The larvae (caterpillars) of some of our native moths construct communal nests of silk webbing often referred to as ‘tents’ and feed gregariously for at least part of their lives.
Species with this habit such as lackey moth (Malacosoma neustria) and brown-tail moth (Euproctis chrysorrhoea) are often encountered on oak during spring and early summer and may initially be mistaken for oak processionary moth.
Small ermine moths (Yponomeuta spp.) also produce large quantities of conspicuous silk webbing on a variety of host trees and shrubs, although they do not occur on oak.
Less frequent are larvae of the small eggar moth (Eriogaster lanestris), which also produce a silk nest. This species was formerly common in hedgerows, but it has become scarce and rather localised.
Although they do not build any form of nest, the hairy larvae of the buff-tip moth (Phalera bucephala) and vapourer moth (Orgyia antiqua) are often seen in groups, sometimes in quite large clusters. Both species have been confused, at times, with oak processionary moth.
Photo of Lackey moth lavae © Steve Bennett ukmoths.org.uk
Photo of Small Eggar moth lavae © Jennifer Wiggins ukmoths.org.uk
Photo of Vapourer moth larvae © Ian Kimber ukmoths.org.uk