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• Processionary caterpillar, larval stage characteristic of the small insect family Thaumetopoeidae (order Lepidoptera), sometimes classified as part of the prominent moth family (Notodontidae). These hairy caterpillars live in communal webs and march in columns to their food source.

Processionaria e razze Showing 1-13 of 13 messages. Processionaria e razze: Mika-hel: 8/24/03 1:21 PM: Non sono solo animali ma anche alieni non sono particolarmente. So you have spotted the nests of the pine processionary caterpillar in the pine trees in, or near your garden,and want to know how to get rid of them, safely. If you live in southern Europe, at certain times of the year, usually starting December/ January, you will notice what seems to be a silky white nest of what could be cotton wool high up in a pine tree. Processionaria - Traduzione del vocabolo e dei suoi composti, e discussioni del forum.

The oak processionary (Thaumetopoea processionea) is a moth whose caterpillars can be found in oakforests, where they feed on oak leaves, causing significant damage. They travel in nose-to-tail processions (hence their name), often arrow-headed, with a leader followed by rows of several caterpillars abreast.^[1] They are a human irritant because of their venomoussetae (hairs), which can cause skin irritation and asthma. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.

Description[edit]

The wingspan of adult stage moths is between 25 and 35 millimetres (0.98 and 1.38 in). 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 the moth also eats the leaves of hazel, hornbeam, sweet chestnut, birch and beech.^[2]

Identification[edit]

The caterpillars live and feed almost exclusively on oak trees. They may march in procession across the ground between oak trees, and cluster together as they feed on oak leaves. In early summer they build silk nests on the trunks and branches, but not in the leaves, of oak trees, and leave silk trails on the trunks and branches. The nests and trails are originally white and visible, but soon become discoloured and hard to see.^[1]

The nests may be hemispherical, teardrop shaped, bag-like, and blanket-like (surrounding part of a trunk or branch), and may be at any height on the tree. The diameter may range from about 25 mm (one inch) to stretching several meters up the trunk. The caterpillars stay in these nests during the day between feeding periods, and later in the summer they remain in the nests to pupate into adult moths.^[1]

The caterpillars are mostly found in oak trees or on the ground under them in late spring and early summer, and do not live on fences, walls, etc. as other caterpillars do. They have very long, white hairs contrasting markedly with shorter hairs.^[1] The caterpillars of several other species may be mistaken for the oak processionary.^[3]

Distribution[edit]

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 are not present 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 UK. The eggs arrived on oak imported to the Richmond and Ealing areas of London in 2006^[4] and the range of the species in the UK has been steadily expanding despite efforts to eradicate it.^[5]

Public health problem[edit]

The moths pose an increasing nuisance to humans as their range is extended.^[6] The backs of older caterpillars (3rd to 6th instars) are covered with up to 63,000 pointed defensive bristles,^{[citation needed]} sized between 0.2 and 0.3 millimeters, which contain an urticating toxin, the protein thaumetopoein.^[7] 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.

It has been found that the skin irritation and itching caused by contact with these hairs can be largely eliminated by the use of cetirizine-based antihistamine tablets.^{[citation needed]}

Transmission of the hairs can be airborne, by ground contact via plants or grass or even by water contact in stillwater e.g. garden ponds. The hairs remains toxic beyond the life cycle of the moth and in some cases can remain a problem for several seasons.^{[citation needed]}Mowing a lawn can bring a person into contact with these hairs. One alternative is to adopt a grass mulching technique to reduce possible contact, and to speed up the biological breakdown of the irritant hairs.^{[citation needed]}

Damage to trees[edit]

Large populations can strip trees bare, leaving them weakened and vulnerable to other threats.^[1]

Control[edit]

Nests can be removed, or the caterpillars sprayed with pesticides soon after they hatch. However, neither approach is 100% effective.^[8] Male moths can be trapped in pheromone traps; this does not significantly reduce the population, but provides an indication of moth distribution.^[1]

United Kingdom[edit]

The caterpillars were accidentally introduced to the UK in 2005, almost certainly as eggs on live oak plants imported from continental Europe. Later distribution of the pest probably arose from several similar introductions, in addition to spread from the original point of introduction.^[1] By 2019 they had spread to all 33 London boroughs, and the Government had spent £37 million trying to control them.^[8]The general public have been asked to look out for these caterpillars and to report them, rather than deal with them themselves. The London Boroughs of Brent, Ealing, Hounslow and Richmond upon Thames set up task forces to deal with outbreaks. Sightings of these caterpillars in other areas should be reported to the Forestry Commission,^[9] whose research agency issued guidance on the way to contain outbreaks and deal with infestations, so as not to increase the risk to the public.^[10]

On 31 March 2008 an emergency amendment added the moth to the list of pests in The Plant Health (Forestry) Order 2005, and has required all oak trees coming into the UK from the rest of Europe to have Plant Passports.^[11]

In 2013 the Forestry Commission announced helicopters would be deployed to 'blanket spray woodland' where the caterpillars posed a health threat.^[5]

In 2015 fifteen OPM nests were found in Hampstead Heath, Highgate Wood and Queen's Park; in 2018 over 2,000 were found at those sites.^[8] In April 2018 an outbreak of the caterpillars was declared in Greater London and surrounding areas.^[12] In Spring 2019 more were reported at Bracknell by the BBC News website [2], and a number were also found in Virginia Water.

On 15 July 2019 strengthened measures on the import of most species of oak into England were introduced to protect native trees from the threat of the pest.^[13]

Belgium[edit]

The moth is reported as being fairly common in Belgium, notably in the Campine but also elsewhere, the population fluctuating from year to year.^[14] In 2007 infestations in the province of Limburg were so acute that soldiers were deployed to burn them.

Netherlands[edit]

In the Netherlands, the caterpillars are dealt with by biological pest control. As in Germany, local authorities use fluids containing Bt toxins, a biological pesticide. These fluids are sprayed onto the infected trees. In cases of serious contamination, the use of relatively mild chemical pest killers has been allowed by local authorities.^{[citation needed]}

An experiment with bird houses for the great tit began in 2016. It has been observed that great tits like to eat the young, not yet hairy caterpillars in April.

Because chemicals may be harmful to other insects, an alternative is to use vacuuming equipment to remove the caterpillars and then incinerating them.

References[edit]

1. ^ ^abcdefg'Oak Processionary Moth - Tree pests and diseases'. Forestry Commission (UK). 11 September 2018. Retrieved 31 January 2019.
2. ^Tree News, Autumn/Winter 2007, page 4 internal Sylva supplement
3. ^'Native species that may be mistaken for oak processionary moth'. Forest Research. 2019. Retrieved 31 January 2019.
4. ^forestry.gov.uk
5. ^ ^abDixon, Helen (7 May 2013). 'Helicopters to spray woodland to halt march of toxic caterpillars'. Daily Telegraph. Retrieved 7 May 2013.
6. ^'Toxic caterpillar infestation plagues Germany'. Deutsche Welle. Retrieved 4 July 2019.
7. ^Lamy, M.; Pastureaud, M. H.; Novak, F.; Ducombs, G.; Vincendeau, P.; Maleville, J.; Texier, L. (1986). 'Thaumetopoein: An urticating protein from the hairs and integument of the pine processionary caterpillar (Thaumetopoea pityocampa Schiff., Lepidoptera, Thaumetopoeidae)'. Toxicon. 24 (4): 347–56. doi:10.1016/0041-0101(86)90194-7. PMID3087028.
8. ^ ^abcSleigh, Sophia (31 January 2019). 'Toxic caterpillar invasion spiralling out of control following 'phenomenal' population explosion'. Evening Standard. Retrieved 31 January 2019.
9. ^The Forestry Commission. Oak processionary mothArchived 4 August 2008 at the Wayback Machine
10. ^Forest Research Survey and intervention in relation to different phases of the oak processionary moth life cycle. Accessed 2008-05-31
11. ^Office of Public Sector Information. Explanatory memorandum to the Plant Health (Forestry) (Amendment) Order 2008 No. 644.[1] Retrieved 31 May 2008.
12. ^'Health warnings after toxic caterpillar outbreak in London'. BBC News. 28 April 2018. Retrieved 28 April 2018.
13. ^'Tighter restrictions on oak tree imports come into force'. GOV.UK. Retrieved 2020-01-28.
14. ^'Thaumetopoea processionea (Linnaeus, 1758)'. Catalogue of the Lepidoptera of Belgium. Archived from the original on 2019-02-01.

• Maier, H.; Spiegel, W.; Kinaciyan, T.; Krehan, H.; Cabaj, A.; Schopf, A.; Honigsmann, H. (24 November 2003). 'The oak processionary caterpillar as the cause of an epidemic airborne disease: survey and analysis'. British Journal of Dermatology. 149 (5): 990–7. doi:10.1111/j.1365-2133.2003.05673.x. PMID14632804. S2CID6559088.
• Rahlenbeck, S.; Utikal, J. (1 August 2015). 'The oak processionary moth: a new health hazard?'. British Journal of General Practice. 65 (637): 435–6. doi:10.3399/bjgp15X686341. PMC4513735. PMID26212843.

External links[edit]

• Kimber, Ian. '71.001 BF2022 Oak Processionary Thaumetopoea processionea (Linnaeus, 1758)'. UKMoths. Retrieved 4 July 2019.
• Lepiforum e. V.(in German)
• De Vlinderstichting(in Dutch)

The pine processionary (Thaumetopoea pityocampa) is a moth of the subfamily Thaumetopoeinae in the family Notodontidae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775. Sometimes placed in the genus Traumatocampa, it is one of the most destructive species to pines and cedars in Central Asia, North Africa and the countries of southern Europe.^[1] The urticating hairs of the caterpillar larvae cause harmful reactions in humans and other mammals. The species is notable for the behaviour of its caterpillars, which overwinter in tent-like nests high in pine trees, and which proceed through the woods in nose-to-tail columns, protected by their severely irritating hairs,^[2] as described by the French entomologist Jean-Henri Fabre.

Life cycle[edit]

Though most pine processionary moths only live one year, some in high altitudes or more northern areas may survive for over two years. The adult moths lay their eggs near the tops of pine trees. After hatching, the larva eat pine needles while progressing through five stages of development. In order to maintain beneficial living conditions, silken nests are built over the winter. Around the beginning of April, the caterpillars leave the nests in the procession for which the species is known. They burrow underground and emerge at the end of summer.^[3] High numbers of adults are produced in years with a warm spring.^[4]

The eggs are laid in cylindrical bodies ranging from 4 to 5 cm (1.6 to 2.0 in) in length. The eggs are covered with scales which come from the female and mimic pine shoots.^[3]

The larva is a major forest pest, living communally in large 'tents', usually in pine trees but occasionally in cedar or larch, marching out at night in single file (hence the common name) to feed on the needles. There are often several such tents in a single tree. When they are ready to pupate, the larvae march in their usual fashion to the ground, where they disperse to pupate singly on or just below the surface.^[5]

Fabre conducted a famous study on the pine processionary caterpillar where a group of them followed head-to-tail in a circle around the rim of a flower pot; they continued marching in the circle for a week. He described the experiment in his 1916 book 'The Life of the Caterpillar'.^[6] The study has been cited innumerable times by inspirational and religious speakers who view it as a metaphor for blindly following a leader or for confusing activity with accomplishment. Fabre considered his caterpillars to be mindless automatons, trapped because they were pre-programmed to blindly follow trails, in this case the endless one that they had laid down around the circular rim of the pot. More recent studies, however, indicate that the caterpillars were actually physically trapped on the narrow rim of the pot, their feet unable to gain the secure purchase that would be needed to descend its steep, vertical walls.^[7][8] In one experiment, groups of processionary caterpillars of the same age as those observed by Fabre were placed on a flat table top and surrounded be a circular glass ring, 8 inches in diameter and 1 inch high. The caterpillars soon moved to the edge of the arena where they began to circle, one behind another. They were allowed to procession in this manner until they had a well established trail along the edge of the ring. The ring was then removed, freeing the caterpillars of any constraint to their activity other than their trail. The circular processions persisted for an average of just two minutes before the caterpillars marched off in a straight line. However, when circular trails were established in a similar manner by younger caterpillars they continued to circle for as long as 12 hours after the physical constraint was removed, a considerable time but far short of the seven days observed by Fabre.

The moth's pupal stage occurs in a white silken cocoon under soil. The pupae measure around 20 mm and are a pale brownish-yellow color that changes into a dark reddish brown.^[3]

As an adult, T. pityocampa has predominantly light brown forewings with brown markings. The moth's hindwings are white. Females have larger wingspans of 36 to 49 mm (1.4 to 1.9 in), compared to a male's 31 to 39 mm (1.2 to 1.5 in).^[3] Adults only live for a single day, when they mate and lay eggs. How far they are able to spread depends on how far the female is able to fly during her short time as an adult. Her average flying distance is 1.7 km (1.1 mi), with a maximum recorded of 10.5 km (6.5 mi). The species flies from May to July.^[9]

Shelter building[edit]

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.^[5]

Impact of foraging[edit]

The pine processionary caterpillar is responsible for most of the defoliation of southern Europe.^[10] Although pines are most susceptible to the caterpillar, other conifer trees such as larches are also vulnerable. The caterpillars can completely defoliate trees if large quantities are present.^[11]

Midwinter foraging and thermoregulation[edit]

The biologist Terrence Fitzgerald has written, 'Colonies are active throughout the winter months. Activity records of colonies foraging in pine forests in mountainous regions near Barcelona, Spain, obtained with infrared activity monitors, show that the caterpillars leave their nests soon after sunset and travel to distant feeding sites on the branches of the host tree. There, they feed overnight then return to the nest at dawn.' The caterpillars have been observed foraging on the coldest nights and can move at sub-zero temperatures. The nests are positioned so that they can be warmed by the sun. The caterpillars rest during the day and the heat in the nest helps them to digest their food. When they emerge from their nests in late March, they are fully grown and leave their nest processing towards pupation sites in the ground.^[12]

Processionaria Farfalla

Trail marking and processionary behaviour[edit]

The caterpillars lay down a pheromone trail from the tip of the abdomen as they advance over the branches of the host tree. Although the caterpillars also secrete silk and mark their pathways with the material, it plays little or no role in trail following. Most likely, silk helps the caterpillars grip on smooth plant surfaces. The caterpillars can distinguish old from new trails. Caterpillars preferentially follow trails marked by larger numbers of caterpillars. Trail marking enables the caterpillars to aggregate at feeding sites and allows them to find their way back to nest after feeding. When they move over the branches, caterpillars may travel head to tail in small groups or alone. In either case, they rely on the trail marker to find their way.^[5]

Lengthy processions are formed when fully grown caterpillars abandon their host tree in search of pupation sites, when as many as three hundred caterpillars may travel long distances from the natal tree looking for soft soil in which to bury themselves and form cocoons. During processions, stimuli from setae on the tip of the abdomen of the caterpillar in front serve to hold processions together, taking priority over the trail pheromone or silk. A caterpillar can readily be induced to follow a model made of a wooden dowel covered with the integument of the abdomen of a killed caterpillar.^[5]

Anti-predator defence[edit]

Towards the end of their larval development, pine processionary caterpillars are highly irritating to the skin. Contact with the hairs of the caterpillar can cause severe rashes (urticaria) and eye irritation. Some individuals may have an allergic reaction to the caterpillar's hairs.^[5][13] Fifth-stage larvae can eject hairs when threatened or stressed; the hairs, which have the form of harpoons, then penetrate and irritate all areas of exposed skin nearby with an urticating protein.^[14]Allergic reactions may follow in susceptible individuals on subsequent exposure to the hairs.^[5]

Natural controls[edit]

Processionaria Bruco

The pine processionary is an economic pest in coniferous forests in southern Europe. It is controlled to some extent by predators, parasites and viruses which attack the moth at many stages of its life cycle:^[14]

• Eggs are eaten by the orthopteran Ephippiger ephippiger.^[14]
• Larvae are eaten by birds such as great tit (Parus major) and great spotted cuckoo (Clamator glandarius).^[14]
• Larvae are parasitised by solitary wasps (Ichneumonidae, Braconidae) and some species of flies (Tachinidae).^[14]
• Pupae are eaten by hoopoes (Upupa epops).^[14]
• Adults are eaten by bats.^[14]
• Larvae may be infected by the processionary moth virus Smithiavirus pityocampae.^[14]

Artificial control[edit]

Processionaria Verme

Efforts to control the pine processionary have included biological control using Bacillus thuringiensis, which is effective on eggs and first- or second-stage caterpillars (in September or October),^[15] or insecticides such as diflubenzuron, an insect growth regulator, which can be sprayed from aircraft.^[16] Monitoring can include the use of pheromone traps.^[15] Older methods used insecticides in oil, inserted directly into nests, or mechanical removal of nests.^[15]

References[edit]

Processionaria Nido

1. ^Kerdelhué, Carole; Zane, Lorenzo; Simonato, Mauro; Salvato, Paola; Rousselet, Jérôme; Roques, Alain; Battisti, Andrea (2009). 'Quaternary history and contemporary patterns in a currently expanding species'. BMC Evolutionary Biology. 9 (1): 220. doi:10.1186/1471-2148-9-220. ISSN1471-2148. PMC2753568. PMID19732434.
2. ^'FMV'(PDF). Archived from the original(PDF) on 28 July 2007. Retrieved 21 June 2013.
3. ^ ^abcd'Pest profile: pine processionary moth'(PDF). Archived from the original(PDF) on 4 March 2016. Retrieved 2 July 2013.
4. ^Mestre, João. Forest Health and Climate Changes. Universidade de Trás-os-Montes is Alto Douro, 2012.
5. ^ ^abcdefFitzgerald, T. D. 'Social Caterpillars' http://web.cortland.edu/fitzgerald/
6. ^Fabre, J-H. The Life of the Caterpillar. (1916) Chapter III: The Procession.
7. ^Fitzgerald, T. D. 2003. 'The role of a trail pheromone in the foraging and processionary behavior of Thaumetopoea pityocampa'. Journal of Chemical Ecology. 12: 513-532
8. ^Fitzgerald, T. D. 2008. 'Lethal Fuzz'. Natural History Magazine. 177: 28-33.
9. ^Pine processionary moth - Tree pests and diseases - Forestry Commission
10. ^Li, S.; Daudin, J.J.; Piou, D.; Robinet, C.; Jactel, H. (9 June 2015). 'Periodicity and synchrony of pine processionary moth outbreaks in France'. Forest Ecology and Management. 354: 309–317. doi:10.1016/j.foreco.2015.05.023.
11. ^GB, Forestry Commission. 'Pine processionary moth - Tree pests and diseases'. www.forestry.gov.uk. Retrieved 1 March 2016.
12. ^Fitzgerald, T. D. 'Social Caterpillars' http://web.cortland.edu
13. ^'Fabre, J-H. (1916) 'The Life of the Caterpillar'. Chapter VI. The Pine Processionary: The Stinging Power'. Efabre.net. Archived from the original on 9 July 2013. Retrieved 8 May 2013.
14. ^ ^abcdefghBonnet, Catherine and Jean-Claude Martin and René Mazet (August–October 2008). 'La Processionnaire du Pin'(PDF). Stantari No. 14. INRA. pp. 29–33. Retrieved 29 December 2011.
15. ^ ^abcControl of the pine processionary
16. ^Treatment with growth regulators

External links[edit]

• Kimber, Ian. '71.002 BF2021 Pine Processionary Thaumetopoea pityocampa ([Denis & Schiffermüller], 1775)'. UKMoths. Retrieved 4 July 2019.
• INRA website: Processionnaire du pin (in French)
• https://orugaprocesionaria.org/ (in Spanish)