Oak processionary Oak processionary The oak processionary "(Thaumetopoea processionea)" is a moth whose caterpillars can be found in oak forests. They are a human irritant because of their venomous setae (hairs), which can cause skin irritation and asthma. The moths are widely distributed in central and southern Europe, and are occasionally found as far north as Sweden. In the southern countries of Europe the populations are controlled by natural predators, but these predators do not exist in northern Europe. Their range is expanding northward, possibly or partly as a result of global warming. The moth now has an established population in the
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