The Oak Processionary (Thaumetopoea processionea) is a moth whose caterpillars are pests in oak forests and pose a health hazard because of their poisonous setae (hairs), which may cause skin irritation and asthma. The wingspan of adult stage moths is between 25 and 35 mm. 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 the same manner. Oak is its preferred food source, but it also attacks hazel, hornbeam, sweet chestnut, birch and beech
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.[clarification needed] The moth now has an established population in the U.K. The eggs arrived on oak imported to the Richmond area of London in 2006, the range of the species in the U.K has been steadily expanding despite efforts to eradicate it
The moths are posing an increasing threat to humans as their range is being extended by the warming European climate.The backs of older caterpillars (3rd to 6th instars) are covered with up to 63,000 pointed defensive bristles containing an urticating toxin (thaumetopoein or closely related compounds). The setae break off readily, become airborne and can cause epidemic caterpillar dermatitis (lepidopterism), manifested as a papular rash, pruritus, conjunctivitis and, if inhaled, pharyngitis and respiratory distress, including asthma or even anaphylaxis. However, there have been no known deaths related to or caused by such exposures to this toxin. spotted in river homemfélinhos beach http://en.wikipedia.org/wiki/Oak_Process...