Pine processionary maximum recorded of . The species flies from May to July. "T. pityocampa" is a highly social organism. Throughout its life cycle, a pine processionary will make several shelters. The first of these are flimsy and temporary, but in the third instar, they build a permanent nest. Once their permanent nest is built, the caterpillars become foragers staying in the vicinity of the nest. The nest has no openings, so caterpillars force themselves through the layers of the shelter. The waste from the larvae's diet accumulates at the bottom of the nest. The pine processionary caterpillar is responsible for most
Oak processionary UK. The eggs arrived on oak imported to the Richmond and Ealing areas of London in 2006 and the range of the species in the UK has been steadily expanding despite efforts to eradicate it. The wingspan of adult stage moths is between . Their pattern of tan, brown and white make the adults difficult to see against oak bark. Adults fly during July and August. The larvae construct communal nests of white silk from which they crawl at night in single file, head to tail in large processions to feed on foliage in the crowns of trees, returning in