Pine processionary

The Greek physician Dioscorides noted in the 1st century AD the urtication caused by the pine-dwelling {{lang|el|pityokampē}} caterpillar, the name meaning "Aleppo pine larva" ({{langx|grc|πιτυοκάμπη}}; from {{lang|grc|πίτυς}} pitys "pine" and {{lang|grc|κάμπη}} kampē "caterpillar"),{{LSJ|pituoka/mph|πιτυοκάμπη}}, {{LSJ|pi/tus|πίτυς}}, {{LSJ|ka/mph2|κάμπη|ref}}. in his 77 AD book De materia medica, Pliny the Elder recorded a treatment for the resulting itching in his Natural History; Theophrastus had earlier recommended the medicinal plant elecampane (horse-heal) in oil and wine to treat contact with "pine larvae" in his Historia Plantarum.{{cite book |last=Roques |first=Alain |title=Processionary moths and climate change : an update |publisher=Springer |publication-place=Dordrecht |year=2015 |isbn=978-94-017-9339-1 |oclc=893559920 |page=1}}

The French entomologist Jean-Henri 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.{{cite book |last=Fabre |first=Jean-Henri |author-link=Jean-Henri Fabre |title=The Life of the Caterpillar |year=1916 |url=http://www.efabre.net/chapter-iii-the-pine-processionary-the-procession |at=Chapter III: The Procession |access-date=29 December 2011 |archive-date=1 June 2020 |archive-url=https://web.archive.org/web/20200601080641/http://www.efabre.net/chapter-iii-the-pine-processionary-the-procession |url-status=live }} 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 pot rim. Fabre's caterpillars may have been physically trapped on the narrow rim of the pot, but circular trails established by young caterpillars do continue to circle for as long as 12 hours even when free on a flat surface.{{cite journal |last=Fitzgerald |first=Terrence D. |title=The role of a trail pheromone in the foraging and processionary behavior of Thaumetopoea pityocampa |journal=Journal of Chemical Ecology |volume=29 |issue=3 |year=2003 |issn=0098-0331 |doi=10.1023/a:1022875102682 |pages=513–532|pmid=12757316 |s2cid=9980410 }}{{cite journal |last=Fitzgerald |first=Terrence D. |title=Lethal Fuzz: Toxic hairs enable some caterpillars to venture forth in conspicuous processions |journal=Natural History Magazine |date=September 2008 |volume=177 |issue=7 |pages=28–33 |url=https://www.naturalhistorymag.com/htmlsite/0908/0908_feature.html |access-date=19 February 2023 |archive-date=19 February 2023 |archive-url=https://web.archive.org/web/20230219155006/https://www.naturalhistorymag.com/htmlsite/0908/0908_feature.html |url-status=live }}

The adult is a stout furry moth which holds its wings like a tent over the body, in the manner of the eggar moths (Lasiocampidae). The adult is larger than the oak processionary, Thaumetopoea processionea, has a crescent marking on the wings (unlike the pale eggar moth; the oak processionary has an indistinct marking), and is found in coniferous rather than broad-leaved forests. The caterpillars are readily recognised by their processionary habit and their presence (with large silken nests and signs of defoliation) in coniferous woods. They are orange-brown and hairy with blue bands.{{cite book |last=Waring |first=Paul |title=Field guide to the moths of Great Britain and Ireland |publisher=British Wildlife Publishing |publication-place=Hook, Hampshire |year=2003 |isbn=978-0-9531399-1-0 |pages=206, 230}}

The species is native to the southern Mediterranean area, North Africa, the Middle East, and southern Europe. It has been spreading northwards since the 1990s, assisted by climate change and by commercial activities including planting of host trees and transportation, and has reached Brittany, forests to the north of Paris, and Strasbourg in northern France.

A paler subspecies, T. pityocampa orana, occurs in North Africa from Morocco to Libya, at altitudes to {{convert|2000|m|ft}} in the Middle Atlas; the adults fly between April and August.{{cite book |last=Freina |first=Josef |title=Die Bombyces und Sphinges der Westpalaearktis (Insecta, Lepidoptera) |publisher=Forschung & Wissenschaft |publication-place=Munich |year=1987 |isbn=3-926285-00-1 |oclc=16807765 |language=de |trans-title=The Bombycid and Sphinx Moths of the Western Palaearctic (Insecta, Lepidoptera) |page=290}}

File:Thaumetopoea pityocampa eggs01.jpg

Though most individuals of the species only live one year, some in high altitudes or more northern areas may survive for over two years. Each female lays an "enormous number" of eggs near the tops of pine trees. After hatching, the larvae eat pine needles while progressing through five stages of development (instars). To survive through the winter, the caterpillars construct a nest of silk threads, making them one of the few species of temperate zone insects where the larvae develop in winter. Around the beginning of April, the caterpillars leave the nests in the procession for which the species is known. They burrow underground, pupate, and emerge between mid May and August.

The eggs are laid in cylindrical bodies ranging from {{convert|4|to|5|cm}} in length. The eggs are covered with scales which come from the female and mimic pine shoots.{{cite web |title=Pest profile: pine processionary moth |publisher=Impact Project |access-date=2 July 2013 |url=http://www.impactproject.eu/uploads/pest_profile__pine_processionary_moth.pdf |archive-url=https://web.archive.org/web/20160304062952/http://www.impactproject.eu/uploads/pest_profile__pine_processionary_moth.pdf |archive-date=4 March 2016 |url-status=dead }}

File:Traumatocampa pityocampa01.jpg

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.

The moth's pupal stage occurs in a white silken cocoon under soil. The pupae measure around {{convert|20|mm|in}} and are a pale brownish-yellow that changes into a dark reddish brown.

As an adult, T. pityocampa has predominantly light brown forewings with brown markings. The moth's hindwings are white. Females have larger wingspans of {{convert|36|to|49|mm}}, compared to a male's {{convert|31|to|39|mm}}. Adults only live for a single day, when they mate and lay eggs. Males are able to fly several tens of kilometres, but the moth's dispersal depends on how far the female is able to fly during her short time as an adult. Her average flying distance is {{convert|1.7|km}}, with a maximum recorded of {{convert|10.5|km}}.{{cite web |title=Pine processionary moth (Thaumetopoea pityocampa) |publisher=Forest Research |url=https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/pine-processionary-moth-thaumetopoea-pityocampa/ |access-date=2 October 2021 |archive-date=26 May 2021 |archive-url=https://web.archive.org/web/20210526153310/https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/pine-processionary-moth-thaumetopoea-pityocampa/ |url-status=live }}{{Cite web |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2699.2010.02289.x |title=The role of topography in structuring the demographic history of the pine processionary moth, Thaumetopoea pityocampa (Lepidoptera: Notodontidae) {{!}} Journal of Biogeography {{!}} Wiley Online Library |access-date=13 August 2023 |archive-date=13 August 2023 |archive-url=https://web.archive.org/web/20230813041605/https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2699.2010.02289.x |url-status=live }}

File:Treviño - Cerro de Treviño - Nido de procesionaria 01 (cropped).jpg collects at the bottom of the tent.]]

T. pityocampa is highly social. Throughout its life cycle, an individual makes several shelters, possibly for protection from predators; the larvae emerge to feed at night. The first of these is flimsy and temporary, but in the third instar, they build a permanent nest. Once the 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 falls as frass and accumulates at the bottom of the nest.

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.

The species is controlled to some extent by predators, parasites and viruses which attack the moth at many stages of its life cycle. For example, eggs are eaten by the orthopteran Ephippiger ephippiger, while larvae are eaten by birds such as great tit (Parus major) and great spotted cuckoo (Clamator glandarius). Larvae are parasitised by solitary wasps (Ichneumonidae, Braconidae) and some species of flies (Tachinidae), and may be infected by the processionary moth virus Smithiavirus pityocampae. Pupae are eaten by hoopoes (Upupa epops), while adults are eaten by bats.

File:Mantis religiosa eating Thaumetopoea pityocampa.webm|Mantis religiosa eating caterpillar, Pyrenees

File:A Calosoma sycophanta eating Thaumetopoea pityocampa.jpg|Calosoma sycophanta beetle eating caterpillar, Turkey

In the third and subsequent instars of their development, pine processionary caterpillars defend themselves from predators with conspicuous hairs containing an irritant chemical, thaumetopoein. Simple contact with the hairs of the caterpillar can cause severe rashes (urticaria) and eye irritation in humans and other mammals,{{cite journal |last1=Oliveira |first1=P. |others=Arnaldo, P. S.; Araújo, M.; Ginja, M.; Sousa, A. P. |title=Cinco casos clínicos de intoxicação por contacto com a larva Thaumetopoea pityocampa em cães |language=pt |trans-title=Report of poison in five dogs after contact with Thaumetopoea pityocampa |journal=Revista Portuguesa de Ciências Clinicas |date=2003 |volume=89 |issue=547 |pages=81–84 |url=http://www.fmv.utl.pt/spcv/PDF/pdf9_2003/547_151_156.pdf |access-date=2 October 2021 |archive-url=https://web.archive.org/web/20070728012451/http://www.fmv.utl.pt/spcv/PDF/pdf9_2003/547_151_156.pdf |archive-date=28 July 2007 |url-status=dead }}{{cite book |last=Fabre |first=Jean-Henri |author-link=Jean-Henri Fabre |title=The Life of the Caterpillar |year=1916 |at=Chapter VI: The Stinging Power |url=http://www.efabre.net/chapter-vi-the-pine-processionary-the-stinging-power |url-status=live |archive-url=https://web.archive.org/web/20130709052754/http://www.efabre.net/chapter-vi-the-pine-processionary-the-stinging-power |archive-date=9 July 2013}} and some individuals may have an allergic reaction.{{cite journal |last1=Vega |first1=J. M. |last2=Moneo |first2=I. |last3=Armentia |first3=A. |last4=Fernández |first4=J. |last5=Vega |first5=J. |last6=De La |first6=Fuente |last7=Sanchez |first7=P. |last8=Sánchís |first8=E. |year=1999 |title=Allergy to the pine processionary caterpillar (Thaumetopoea pityocampa) |journal=Clinical and Experimental Allergy |volume=29 |issue=10 |pages=1418–1423 |doi=10.1046/j.1365-2222.1999.00626.x|pmid=10520065 |s2cid=25310598 }} When stressed or threatened, fifth-stage larvae eject hairs shaped like harpoons, which penetrate all areas of exposed skin nearby and irritate them with an urticating protein.{{cite journal |url=http://www.prodinra.inra.fr/prodinra/pinra/data/2008/07/PROD20086c1fb7e_20080709010355455.pdf |title=La Processionnaire du Pin |language=fr |trans-title=The Pine Processionary |publisher=INRA |journal=Stantari |issue=14 (August–October 2008) |date=2008 |access-date=2 October 2021 |last1=Bonnet |first1=Catherine |last2=Martin |first2=Jean-Claude |last3=Mazet |first3=René |pages=29–33 |archive-url=https://web.archive.org/web/20111004145101/http://www.prodinra.inra.fr/prodinra/pinra/data/2008/07/PROD20086c1fb7e_20080709010355455.pdf |archive-date=4 October 2011 |url-status=dead}}

File:Thaumetopoea pityocampa damage.jpg

The pine processionary is a major economic pest in coniferous forests in southern Europe,{{cite journal |last1=Kerdelhué |first1=Carole |last2=Zane |first2=Lorenzo |last3=Simonato |first3=Mauro |last4=Salvato |first4=Paola |last5=Rousselet |first5=Jérôme |last6=Roques |first6=Alain |last7=Battisti |first7=Andrea |title=Quaternary history and contemporary patterns in a currently expanding species |journal=BMC Evolutionary Biology |volume=9 |issue=1 |year=2009 |pages=220 |issn=1471-2148 |doi=10.1186/1471-2148-9-220 |pmid=19732434 |pmc=2753568 |doi-access=free }} {{open access}} where the caterpillar is responsible for most of the defoliation seen in coniferous trees; outbreaks are somewhat cyclical, with a period of 7 to 9 years.{{cite journal |last1=Li |first1=S. |last2=Daudin |first2=J.J. |last3=Piou |first3=D. |last4=Robinet |first4=C. |last5=Jactel |first5=H. |date=9 June 2015|title=Periodicity and synchrony of pine processionary moth outbreaks in France |journal=Forest Ecology and Management |volume=354 |doi=10.1016/j.foreco.2015.05.023 |pages=309–317}} Although pines are the most susceptible, other conifer trees such as larches are also vulnerable. The caterpillars can completely defoliate trees if large numbers are present.{{cite journal |last1=Ros-Candeira |first1=Andrea |last2=Pérez-Luque |first2=Antonio Jesús |last3=Suárez-Muñoz |first3=María |last4=Bonet-García |first4=Francisco Javier |last5=Hódar |first5=José A. |last6=Giménez de Azcárate |first6=Fernando |last7=Ortega-Díaz |first7=Elena |title=Dataset of occurrence and incidence of pine processionary moth in Andalusia, south Spain |journal=ZooKeys |issue=852 |date=5 June 2019 |issn=1313-2970 | pmid=31210747| doi=10.3897/zookeys.852.28567 |pages=125–136|pmc=6561999 |doi-access=free }}

Global warming is causing the species to affect forests progressively further north. It has for example been a pest of forests in Southern Europe since classical times, but it has already reached the north of France.{{cite journal |last1=Netherer |first1=Sigrid |last2=Schopf |first2=Axel |title=Potential effects of climate change on insect herbivores in European forests—General aspects and the pine processionary moth as specific example |journal=Forest Ecology and Management |volume=259 |issue=4 |year=2010 |issn=0378-1127 |doi=10.1016/j.foreco.2009.07.034 |pages=831–838}}

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), or insecticides such as diflubenzuron, an insect growth regulator, which can be sprayed from aircraft. Monitoring can include the use of pheromone traps. Other methods that have been tried include insecticides in oil inserted directly into nests, and mechanical removal of nests.{{cite web |title=Processionaria do Pinheiro: Diagnostico e Meios de Controlo |language=pt |trans-title=Pine Processionary: Diagnostics and means of control |publisher=ICNF.pt |url=http://www.icnf.pt/portal/florestas/prag-doe/resource/ficheiros/processionaria/processionaria-areas-florestas-2009.pdf |access-date=2 October 2021 |archive-date=24 January 2014 |archive-url=https://web.archive.org/web/20140124224357/http://www.icnf.pt/portal/florestas/prag-doe/resource/ficheiros/processionaria/processionaria-areas-florestas-2009.pdf |url-status=live }}{{cite web |title=Enquadramento Legal do Regime Florestal |language=pt |trans-title=Legal Framework of the Forest Regime |publisher=ICNF.pt |url=http://www.icnf.pt/portal/florestas/gf/regflo/enqleg |access-date=2 October 2021 |archive-date=22 October 2020 |archive-url=https://web.archive.org/web/20201022004328/http://www2.icnf.pt/portal/florestas/gf/regflo/enqleg |url-status=live }}{{cite journal |last1=Sanchis |first1=N. |others=Cobos, P., Cobos, J. M., & Soria, S. |year=1990 |title=Lucha contra la procesionaria del pino Thaumetopoea pityocampa Schiff.(Lepidoptera Thaumetopoidae): ensayos de lucha química con productos inhibidores del desarrollo, bacterianos y piretroides |language=es |trans-title=Struggle against the pine processionary: tests of chemical control with growth inhibitor, bacterial and pyrethroid products |journal=Boletin de Sanidad Vegetal Plagas |volume=16 |issue=1 |pages=229–245 |url=https://www.mapa.gob.es/ministerio/pags/Biblioteca/Revistas/pdf_plagas%2FBSVP-16-01-229-245.pdf |access-date=2 October 2021 |archive-date=2 October 2021 |archive-url=https://web.archive.org/web/20211002125214/https://www.mapa.gob.es/ministerio/pags/Biblioteca/Revistas/pdf_plagas%2FBSVP-16-01-229-245.pdf |url-status=live }}

File:Trap Navarra.JPG|Synthetic pheromone trap, Spain, 2012

File:Écopiège à chenille processionnaire.JPG|"Ecological trap" for processionary caterpillars, France, 2014

File:Cartucho contra la procesionaria (cropped).JPG|Cartridge{{efn|The cartridge is printed {{lang|es|Lucha contra la Procesionaria}}, "Fight against the processionary moth".}} of the Spanish forest pest service, to be fired into pine processionary nests, 2016

File:El Ayuntamiento pone en marcha un plan de choque contra la procesionaria 01 (cropped).jpg|Madrid City Council workers in protective clothing cutting pine processionary nests, 2019

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{{Commons category|Thaumetopoea_pityocampa|Pine processionary}}

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• [http://www.planetepassion.eu/WILDLIFE-IN-FRANCE/Pine-processionary-moth-France.html Wildlife in France: Pine processionary moth]

{{Taxonbar |from=Q261025}}

Category:Thaumetopoeinae

Category:Moths described in 1775

Category:Moths of Europe

Category:Taxa named by Michael Denis

Category:Taxa named by Ignaz Schiffermüller

Category:Articles containing video clips

Category:Insect pests of temperate forests