Bark beetle

{{short description|Subfamily of beetles}} {{use dmy dates |date=January 2025}} {{Automatic taxobox | name = Bark beetles | oldest_fossil = Barremian | image = Dendroctonus ponderosae.jpg | image_caption = Mountain pine beetle, ''Dendroctonus ponderosae'' | taxon = Scolytinae | authority = Latreille, 1804 | subdivision_ranks = Tribes | subdivision = Cortylini Cryphalini Crypturgini Dryocoetini Hylastini Hylesinini Hylurgini Hypoborini Ipini Phloeosinini Phloeotribini Polygraphini Scolytini Scolytoplatypodini Taphrorychini Thamnurgini Tomicini Xyleborini Xyloterini }}

A '''bark beetle''' is the common name for the subfamily of beetles '''Scolytinae'''.<ref name="Kirkendall20152">{{cite book|last1=Kirkendall|first1=Lawrence|title=Bark Beetles: Biology and Ecology of Native and Invasive Species|last2=Biedermann|first2=Peter H.W.|last3=Jordal|first3=Bjarte|date=2015|publisher=Academic Press|chapter=Chapter 3: Bark Beetles: Biology and Ecology of Native and Invasive Species|chapter-url=https://www.researchgate.net/publication/270451584}}</ref> Previously, this was considered a distinct family ('''Scolytidae'''), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants.<ref name="Kirkendall20152" /> Well-known species are members of the type genus ''Scolytus'', namely the European elm bark beetle ''S. multistriatus'' and the large elm bark beetle ''S. scolytus'', which like the American elm bark beetle ''Hylurgopinus rufipes'', transmit Dutch elm disease fungi (''Ophiostoma''). The mountain pine beetle ''Dendroctonus ponderosae'', southern pine beetle ''Dendroctonus frontalis'', and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips ''Ips typographus''. A tiny bark beetle, the coffee berry borer, ''Hypothenemus hampei'' is a major pest on coffee plantations around the world.

== Life cycle and morphology == Bark beetles go through four stages of life: egg, larvae, pupae, and adult, with the time to develop often relying on the species as well as the current temperature. While there is variation among species, generally adults first bore into a tree and lay their eggs in the phloem of the tree. This usually occurs in mid to late summer. Once the eggs hatch, the larvae then live in the tree, feeding on the living tissues below the bark, often leading to death of the tree if enough larvae are present. At the end of the larval stage, chambers are usually constructed for the pupae to overwinter until they are ready to emerge as an adult.<ref>{{Cite web|last=Barkley|first=Yvonne|title=Everything you have always wanted to know about bark beetles, but were afraid to ask.|url=https://www.uidaho.edu/-/media/UIdaho-Responsive/Files/Extension/topic/forestry/ID26-Everything-you-wanted-to-know-about-bark-beetles.pdf |url-status=dead |work=UI Extension Forestry Information Series II |publisher=University of Idaho |archive-url=https://web.archive.org/web/20210629224820/https://www.uidaho.edu/-/media/UIdaho-Responsive/Files/Extension/topic/forestry/ID26-Everything-you-wanted-to-know-about-bark-beetles.pdf |access-date=20 January 2025 |archive-date=29 June 2021 }}</ref>

Bark beetles are distinct in their morphology due to their small size and cylindrical shape. Bark beetles also have small appendages, with antennae that can be folded into the body and large mandibles to aid in the excavation of woody tissue. The legs of most bark beetles are very short and can be retracted or folded into the body. The combination of their shape and appendages greatly helps in the excavation of woody tissue. The eyes are also flattened and hypothesized to help see in low-light conditions.<ref name="Kirkendall20152" />

==Description and ecology== [[Image:Dead pines.jpg|left|thumb|Mountain pine beetles killed these lodgepole pine trees in Prince George, British Columbia.]]Bark beetles feed and breed between the bark and the wood of various tree species. While some species, such as the mountain pine beetle (''Dendroctonus ponderosae''), do attack living trees, many bark beetle species feed on weakened, dying, or dead spruce, fir, and hemlock.<ref name=":02">{{Cite journal|last1=Franceschi|first1=Vincent R.|last2=Krokene|first2=Paal|last3=Christiansen|first3=Erik|last4=Krekling|first4=Trygve|date=2005-05-03|title=Anatomical and chemical defenses of conifer bark against bark beetles and other pests|journal=New Phytologist|volume=167|issue=2|pages=353–376|doi=10.1111/j.1469-8137.2005.01436.x|pmid=15998390|issn=0028-646X|doi-access=free|bibcode=2005NewPh.167..353F }}</ref><ref name="rose2">{{cite report |last1=Rose |first1=A.H. |last2=Lindquist |first2=O.H |orig-year=1977 |year=1994 |edition=Revised |title=Insects of eastern spruces, fir and, hemlock |publisher=Natural Resources Canada |work=Canadian Forest Service |location=Ottawa |isbn=066015112X |id=Fo64-23/1994E |url=https://publications.gc.ca/collections/collection_2014/rncan-nrcan/Fo64-23-1994-eng.pdf }} (cited in Coates et al. 1994, cited orig ed 1977)</ref> Most restrict their breeding area to one part of the tree: twig, branch, stem, or root collar. Some breed in trees of only one species, while others in numerous species of tree. In undisturbed forests, bark beetles serve the purpose of hastening the recycling and decomposition of dead and dying wood and renewing the forest. However, a few species are aggressive and can develop large populations that invade and kill healthy trees and are therefore known as pests.<ref>{{Cite journal|last1=Blomquist|first1=Gary J.|last2=Figueroa-Teran|first2=Rubi|last3=Aw|first3=Mory|last4=Song|first4=Minmin|last5=Gorzalski|first5=Andrew|last6=Abbott|first6=Nicole L.|last7=Chang|first7=Eric|last8=Tittiger|first8=Claus|date=2010-10-01|title=Pheromone production in bark beetles|url=https://www.sciencedirect.com/science/article/pii/S0965174810001682|journal=Insect Biochemistry and Molecular Biology|language=en|volume=40|issue=10|pages=699–712|doi=10.1016/j.ibmb.2010.07.013|pmid=20727970|bibcode=2010IBMB...40..699B |issn=0965-1748|url-access=subscription}}</ref>

Bark beetles often attack trees that are already weakened by disease, overcrowding, conspecific beetles, or physical damage. As a defense mechanism, healthier trees may produce sap, resin or latex, which often contains a number of insecticidal and fungicidal compounds that can kill, injure, or immobilize attacking insects. Sap is one of the first lines of defense of pines against bark beetles. Released sap or resins can plug bored holes of bark beetles and seal wounds. Resins also trap insect pests making some initial entry by bark beetles unsuccessful. Chemical compounds can also be induced by tree species that bind with amino acids in the gut of bark beetles, reducing their ability to process woody materials.<ref name=":02"/> When in large quantities, the sheer number of beetles can overwhelm the tree's defenses with lasting impacts on the lumber industry, water quality, fish and wildlife, and property values.<ref>{{Cite journal|last1=Fettig|first1=Christopher|last2=Klepzig|first2=Kier|last3=Billings|first3=Ronald|last4=Munson|first4=A. Steven|last5=Nebeker|first5=T. Evan|last6=Negrόn|first6=Jose|last7=Nowak|first7=John|date=Jan 2007|title=The effectiveness of vegetation management practices for prevention and control of bark beetle infestations in coniferous forest of the western and southern United States|url=https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=26239&content=PDF|journal=Forest Ecology and Management|volume=238|issue=1|pages=24–53|doi=10.1016/j.foreco.2006.10.011|bibcode=2007ForEM.238...24F |via=Science Direct|url-access=subscription}}{{dead link|date=June 2025|bot=medic}}{{cbignore|bot=medic}}</ref>

The oldest known member of the group is ''Cylindrobrotus'' from the Early Cretaceous (Barremian) aged Lebanese amber.<ref>{{Cite journal|last1=Kirejtshuk|first1=Alexander G.|last2=Azar|first2=Dany|last3=Beaver|first3=Roger A.|last4=Mandelshtam|first4=Mikhail Yu.|last5=Nel|first5=André|date=January 2009|title=The most ancient bark beetle known: a new tribe, genus and species from Lebanese amber (Coleoptera, Curculionidae, Scolytinae)|url=http://doi.wiley.com/10.1111/j.1365-3113.2008.00442.x|journal=Systematic Entomology|language=en|volume=34|issue=1|pages=101–112|doi=10.1111/j.1365-3113.2008.00442.x|bibcode=2009SysEn..34..101K |s2cid=73530299|url-access=subscription}}</ref> A species of the extant mostly Neotropical genus ''Microborus'' is also known from the Cenomanian aged Burmese amber of Myanmar.<ref>{{Cite journal|last1=Cognato|first1=Anthony I.|last2=Grimaldi|first2=David|date=January 2009|title=100 million years of morphological conservation in bark beetles (Coleoptera: Curculionidae: Scolytinae)|url=http://doi.wiley.com/10.1111/j.1365-3113.2008.00441.x|journal=Systematic Entomology|language=en|volume=34|issue=1|pages=93–100|doi=10.1111/j.1365-3113.2008.00441.x|bibcode=2009SysEn..34...93C |s2cid=85272919|url-access=subscription}}</ref>

=== Prey relationships === Bark beetles are preyed upon by birds such as woodpeckers,<ref name=":3">{{Cite web |last=Latif |first=Quresh |title=Beetles and Birds |url=https://www.birdconservancy.org/beetles-and-birds/ |access-date=2022-10-31 |website=Connecting People, Birds and Land for a Healthy World |language=en-US}}</ref> other beetles such as the black-bellied clerid (''Enoclerus lecontei'')<ref name=":4">{{Cite web |title=Bark Beetles Management Guidelines--UC IPM |url=http://ipm.ucanr.edu/PMG/PESTNOTES/pn7421.html |access-date=2022-10-31 |website=ipm.ucanr.edu}}</ref> and certain other members of family Cleridae,<ref name="kaston1939">{{cite report|last=Kaston|first=B.J.|title=The Native Elm Bark Beetle ''Hylurgopinus rufipes'' (Eichhoff) in Connecticut|date=February 1939|id=Bulletin 420|publisher=Connecticut Agricultural Experiment Center|location=New Haven|url=https://portal.ct.gov/-/media/CAES/DOCUMENTS/Publications/Bulletins/B420pdf.pdf|access-date=9 January 2023|via=ct.gov}}</ref>{{rp|8}} flies such as the long-legged flies (Dolichopodidae),<ref name=":0">{{cite book |last1=Wegensteiner |first1=Rudolf |chapter=Chapter 7 - Natural Enemies of Bark Beetles: Predators, Parasitoids, Pathogens, and Nematodes |year=2015 |title=Bark Beetles: Biology and Ecology of Native and Invasive Species |pages=247–304 |editor-last=Vega |editor-first=Fernando E. |place=San Diego |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-417156-5.00007-1 |isbn=978-0-12-417156-5 |last2=Wermelinger |first2=Beat |last3=Herrmann |first3=Matthias |editor2-last=Hofstetter |editor2-first=Richard W.}}</ref> and certain phoretic mites.<ref name=":0" /><ref name=":5">{{Cite journal |last1=Cilbircioğlu |first1=Cihan |last2=Kovač |first2=Marta |last3=Pernek |first3=Milan |date=May 2021 |title=Associations of Phoretic Mites on Bark Beetles of the Genus ''Ips'' in the Black Sea Mountains of Turkey |journal=Forests |language=en |volume=12 |issue=5 |pages=516 |doi=10.3390/f12050516 |issn=1999-4907|doi-access=free |bibcode=2021Fore...12..516C }}</ref> Phoretic mites use the bark beetle to move from one location to the next,<ref name=":0" /><ref name=":5" /> but some of these mite species also prey on the eggs or larvae of the bark beetles or act as parasites.<ref name=":5"/>

=== Parasitoids === The braconid wasp ''Spathius canadensis'' is known to parasitize the native elm bark beetle ''Hylurgopinus rufipes''.<ref name="kaston1939"/>{{rp|33–35}}<ref>{{cite report |last=Kaston|first=J.|chapter=Notes on Hymenopterous Parasites of Elm Insects in Connecticut|pages=351–361|editor-last=Britton|editor-first=W.E.|title=Connecticut State Entomologist Thirty-Sixth Report|year=1936|publisher=Connecticut Agricultural Experiment Station|location=New Haven|chapter-url=https://portal.ct.gov/-/media/caes/documents/publications/bulletins/b396pdf.pdf|access-date=9 January 2023|via=ct.gov|id=Bulletin 396}}</ref>

=== Ambrosia beetles === Some bark beetles form a symbiotic relationship with certain Ophiostomatales fungi, and are named "ambrosia beetles". The ambrosia beetles (such as ''Xyleborus'') feed on fungal "gardens" cultivated on woody tissue within the tree. Ambrosia beetles carry the fungal spores in either their gut or special structures, called mycangia, and infect the trees as they attack them. Once a beetle chooses a tree, they release spores of this fungus along tunnels within the tree. These spores grow and eventually produce fruiting structures to be consumed by the beetles. This can allow for ambrosia beetles to indirectly feed from more tree species due to the reliance on the fungi for food and the fungi's ability to overcome some of the plant's chemical defenses.<ref name=":12">{{Citation|last1=Kirkendall|first1=Lawrence R.|title=Evolution and Diversity of Bark and Ambrosia Beetles|date=2015|url=http://dx.doi.org/10.1016/b978-0-12-417156-5.00003-4|work=Bark Beetles|pages=85–156|publisher=Elsevier|isbn=978-0-12-417156-5|access-date=2021-03-30|last2=Biedermann|first2=Peter H.W.|last3=Jordal|first3=Bjarte H.|doi=10.1016/b978-0-12-417156-5.00003-4|url-access=subscription}}</ref> While the majority of ambrosia beetles infect dead trees, several species will infect trees considered healthy or under stress.<ref name="Kirkendall20152" />

== Biochemistry == {{Expand section|date=January 2023}} The bark beetle's pheromones, including kairomones, can attract other insects.<ref name=":6">{{Citation |last=Klowden |first=Marc J. |title=Chapter 12 - Communication Systems |date=2013-01-01 |url=https://www.sciencedirect.com/science/article/pii/B978012415819100012X |work=Physiological Systems in Insects (Third Edition) |pages=603–647 |editor-last=Klowden |editor-first=Marc J. |place=San Diego |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-415819-1.00012-x |isbn=978-0-12-415819-1 |access-date=2022-10-31|url-access=subscription }}</ref> The pheromones distinguished as kairomones are hormones, pheromones, or allomones of bark beetles, which in turn are used as a locator by insects that are attracted by it, such as flies, which may intend to harm the bark beetle itself.<ref name=":6" /> These chemicals interact with pine trees<ref name=":7">{{Cite journal |last1=Seybold |first1=Steven J. |last2=Huber |first2=Dezene P. W. |last3=Lee |first3=Jana C. |last4=Graves |first4=Andrew D. |last5=Bohlmann |first5=Jörg |date=2006-02-01 |title=Pine monoterpenes and pine bark beetles: a marriage of convenience for defense and chemical communication |url=https://doi.org/10.1007/s11101-006-9002-8 |journal=Phytochemistry Reviews |language=en |volume=5 |issue=1 |pages=143–178 |doi=10.1007/s11101-006-9002-8 |bibcode=2006PChRv...5..143S |s2cid=34160711 |issn=1572-980X|url-access=subscription }}</ref> as the bark beetle's host, based on the behavioral, physiological, and biochemical effects of monoterpenes.<ref name=":7" />

Monoterpenes are a chemical fragrance that plays a significant role in tree-insect interactions, specifically within pine trees. It is an aggregation pheromone that attracts insects to the plant/ tree host, including the bark beetle. Monoterpenes has also been known to prevent fungal growth<ref>{{Cite journal |last1=Fang |first1=Jiaxing |last2=Liu |first2=Man |last3=Zhang |first3=Sufang |last4=Liu |first4=Fu |last5=Zhang |first5=Zhen |last6=Zhang |first6=Qinghe |last7=Kong |first7=Xiangbo |date=2020-10-07 |editor-last=Foyer |editor-first=Christine |title=Chemical signal interactions of the bark beetle with fungal symbionts, and host/non-host trees |url=https://academic.oup.com/jxb/article/71/19/6084/5863268 |journal=Journal of Experimental Botany |language=en |volume=71 |issue=19 |pages=6084–6091 |doi=10.1093/jxb/eraa296 |pmid=32589724 |issn=0022-0957|doi-access=free }}</ref> and are also toxic to bark beetles at high vapor concentrations.<ref name=":7" /> This latter process demonstrates a defense of pines using monoterpenes against the bark beetle.

== Taxonomy == There are around 6,000 described species of bark beetles in 246 genera, placed into 26 distinct tribes.<ref>{{Cite journal |last1=Pistone |first1=Dario |last2=Gohli |first2=Jostein |last3=Jordal |first3=Bjarte H. |date=April 2018 |title=Molecular phylogeny of bark and ambrosia beetles (Curculionidae: Scolytinae) based on 18 molecular markers: Molecular phylogeny of bark and ambrosia beetles |url=https://onlinelibrary.wiley.com/doi/10.1111/syen.12281 |journal=Systematic Entomology |language=en |volume=43 |issue=2 |pages=387–406 |doi=10.1111/syen.12281|hdl=1956/17546 |s2cid=90571090 |hdl-access=free |url-access=subscription }}</ref>

== As invasive species == Bark beetles are most commonly recognized by their impact on the lumber industry. Massive outbreaks of mountain pine beetles in western North America after about 2005 have killed millions of acres of forest from New Mexico to British Columbia.<ref>{{cite news|author=Jim Robins|date=17 Nov 2008|title=Bark Beetles Kill Millions of Acres of Trees in West|work=The New York Times|url=https://www.nytimes.com/2008/11/18/science/18trees.html?_r=1&pagewanted=all}}</ref> Bark beetles enter trees by boring holes in the bark of the tree, sometimes using the lenticels, or the pores plants use for gas exchange, to pass through the bark of the tree.<ref name=":02"/> As the larvae consume the inner tissues of the tree, they often consume enough of the phloem to girdle the tree, cutting off the spread of water and nutrients. Ambrosia beetles are also known to aid in the spread of pathogens, such as diseases that can cause cankers, further damaging the trees they infect.<ref>{{Cite journal|last1=Li|first1=You|last2=Skelton|first2=James|last3=Adams|first3=Sawyer|last4=Hattori|first4=Yukako|last5=Smith|first5=Matthew E.|last6=Hulcr|first6=Jiri|date=2020|title=The Ambrosia Beetle Sueus niisimai (Scolytinae: Hyorrhynchini) is Associated with the Canker Disease Fungus Diatrypella japonica (Xylariales)|journal=Plant Disease|volume=104|issue=12|pages=3143–3150|doi=10.1094/pdis-03-20-0482-re|pmid=33136520|bibcode=2020PlDis.104.3143L | s2cid=225788674 |issn=0191-2917|doi-access=free}}</ref> Like many other insects, Scolytinae emit pheromones to attract conspecifics, which are thus drawn to trees already colonized by bark beetles. This can result in heavy infestations and eventually death of the tree.<ref name=":02"/><ref name=":2">{{Cite web |title=Bark Beetle FAQs |url=https://www.readyforwildfire.org/forest-health/bark-beetle-information/bark-beetle-faqs/ |access-date=2022-10-31 |website=Ready for Wildfire |language=en-US |archive-date=2022-10-31 |archive-url=https://web.archive.org/web/20221031035539/https://www.readyforwildfire.org/forest-health/bark-beetle-information/bark-beetle-faqs/ |url-status=dead }}</ref> Many are also attracted to ethanol produced as a byproduct of microbial growth in the dead woody tissues.<ref>{{Cite journal|last1=Lindelöw|first1=Åke|last2=Risberg|first2=Birger|last3=Sjödin|first3=Kristina|date=1992|title=Attraction during flight of scolytids and other bark- and wood-dwelling beetles to volatiles from fresh and stored spruce wood|url=http://dx.doi.org/10.1139/x92-029|journal=Canadian Journal of Forest Research|volume=22|issue=2|pages=224–228|doi=10.1139/x92-029|bibcode=1992CaJFR..22..224L |issn=0045-5067|url-access=subscription}}</ref> Increases in international trade, as well as the use of wood containers for storage, has aided numerous species of bark beetle in spreading across the world.<ref>{{Cite journal|last1=Brockerhoff|first1=E. G.|last2=Liebhold|first2=A. M.|date=2017-07-20|title=Ecology of forest insect invasions|url=http://dx.doi.org/10.1007/s10530-017-1514-1|journal=Biological Invasions|volume=19|issue=11|pages=3141–3159|doi=10.1007/s10530-017-1514-1|bibcode=2017BiInv..19.3141B |s2cid=34192154|issn=1387-3547|url-access=subscription}}</ref> They are also extremely adaptable and able to quickly spread through new environments, as seen in France with eleven different species.<ref>{{Cite journal|last1=Barnouin|first1=Thomas|last2=Soldati|first2=Fabien|last3=Roques|first3=Alain|last4=Faccoli|first4=Massimo|last5=Kirkendall|first5=Lawrence|last6=Moutter|first6=Raphaëlle|last7=Daubree|first7=Jean-Baptiste|last8=Noblecourt|first8=Thierry|date=2020-11-09|title=Bark beetles and pinhole borers recently or newly introduced to France (Coleoptera: Curculionidae, Scolytinae and Platypodinae)|url=http://dx.doi.org/10.11646/zootaxa.4877.1.2|journal=Zootaxa|volume=4877|issue=1|pages=51–74|doi=10.11646/zootaxa.4877.1.2|pmid=33311325| s2cid=228840630 |issn=1175-5334|url-access=subscription}}</ref> Bark beetle infestations are also predicted to increase with global warming, meaning infestations will most likely increase in frequency as temperatures rise.<ref>{{Cite journal |journal=Journal of Ecology |last1=Andreas Sommerfeld|last2=Werner Rammer|last3=Marco Heurich|last4=Torben Hilmers|last5=Jörg Müller|last6=Rupert Seidl|date=2020-07-20|title=Author response for 'Do bark beetle outbreaks amplify or dampen future bark beetle disturbances in Central Europe?' |doi=10.1111/1365-2745.13502/v3/response1| s2cid=242935910 |doi-access=free}}</ref><ref name=":1">{{Cite web |title=Bark Beetles and Climate Change in the United States |work=Climate Change Resource Center |url=https://research.fs.usda.gov/centers/ccrc |access-date=2022-10-31 |publisher=United States Forest Service |language=en}}</ref> Besides the fact that these rising temperatures provide the optimal conditions for larval growth, the development time that the larvae need to become an adult also drops, from 8–9 weeks to 6–7 weeks. As a third the result of global warming, the breeding season of the bark beetle is extended, meaning that number of generations per year will increase.<ref>{{cite web |last1=Chinellato |first1=F. |last2=Battisti |first2=A. |last3=Finozzi |first3=V. |last4=Faccoli |first4=M. |year=2014 |title=Better today but worse tomorrow: How warm summers affect breeding performance of a Scots pine pest |work=ResearchGate |url=https://www.researchgate.net/publication/269276793 }}</ref> All these factors contribute to an increasing amount of bark beetles and will thus likely result in an increasing frequency of infestations. In the past, fire has been suggested as potential mechanism for controlling bark beetle populations; however, most studies of wildfire after beetle outbreaks have found no effect of beetle-caused tree mortality on wildfire size or severity.<ref>{{Cite journal|last1=Harvey|first1=Brian J.|last2=Donato|first2=Daniel C.|last3=Romme|first3=William H.|last4=Turner|first4=Monica G.|date=2013-11-01|title=Influence of recent bark beetle outbreak on fire severity and postfire tree regeneration in montane Douglas-fir forests|journal=Ecology|language=en|volume=94|issue=11|pages=2475–2486|doi=10.1890/13-0188.1|issn=1939-9170|pmid=24400499|bibcode=2013Ecol...94.2475H |s2cid=7023088}}</ref><ref>{{Cite journal|last1=Meigs|first1=Garrett W.|last2=Campbell|first2=John L.|last3=Zald|first3=Harold S. J.|last4=Bailey|first4=John D.|last5=Shaw|first5=David C.|last6=Kennedy|first6=Robert E.|date=2015-07-01|title=Does wildfire likelihood increase following insect outbreaks in conifer forests?|url=http://ir.library.oregonstate.edu/xmlui/bitstream/1957/57120/1/MeigsGarrettForestryDoesWildfireLikelihood.pdf|journal=Ecosphere|language=en|volume=6|issue=7|pages=art118|doi=10.1890/ES15-00037.1|issn=2150-8925|doi-access=free}}</ref><ref>{{Cite journal|last1=Harvey|first1=Brian J.|last2=Donato|first2=Daniel C.|last3=Turner|first3=Monica G.|date=2014-10-21|title=Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies|journal=Proceedings of the National Academy of Sciences|language=en|volume=111|issue=42|pages=15120–15125|bibcode=2014PNAS..11115120H|doi=10.1073/pnas.1411346111|issn=0027-8424|pmc=4210318|pmid=25267633|doi-access=free}}</ref>

Bark beetles can also be transporters of different plant pathogens such as cankers. The transport of the pathogens also result in the increase of fungi, mites and nematodes within the tree.<ref>{{Cite web |title=Bark Beetles and Associated Issues {{!}} {{!}} Wisconsin DNR |url=https://dnr.wisconsin.gov/topic/foresthealth/barkbeetles |access-date=2022-11-29 |website=dnr.wisconsin.gov}}</ref>

== Hazard in Europe == According to a BBC article in August 2025, the spruce bark beetle has already devastated millions of spruce trees across Europe. The beetle has reached the UK by being blown over the English Channel, posing a threat to its forests. In order to face the threat, UK scientists are using drones, sniffer dogs, and even nuclear waste models, claiming to have eradicated it in vulnerable regions of the south and southeast. But as climate change continues and weakened trees, it’s getting harder to control the beetle. Experts warn that if their numbers grow, these "public enemy number one" insects could cause massive damage.<ref>{{Cite web |date=2025-08-31 |title=Dogs and drones join forest battle against eight-toothed beetle |url=https://www.bbc.com/news/articles/clyr8yml9rro |access-date=2025-08-31 |website=www.bbc.com |language=en-GB}}</ref>

==Gallery== <gallery class="center" perrow="5" heights="200" widths="200"> Image:Bayerischer wald1.jpg|Effects of bark beetle in the Bavarian Forest Image:Bark beetle gallery.jpg|Bark beetle gallery engraving the sapwood Image:Bark beetle galleries.JPG|Bark beetle galleries with bark showing exit holes Image:Schorskevervraat op eik.jpg|Some species produce single winding tracks Image:Elm bark beetle galleries 01.JPG|Bark beetle galleries on a dead American elm Image:Lapač kůrovce.JPG|Bark beetle trap Image:Fichtenstamm entrindet - Detail.jpg|Manually decorticated trunk of a spruce as protection to bark beetles </gallery>

==References== {{Reflist}}

==External links and further reading== {{Commons category|Scolytinae}} {{Wikispecies|Scolytinae}} * [http://www.barkbeetles.info American and Mexican Bark and Ambrosia beetles] * Nordhaus, Hannah. ''Bark Beetle Outbreaks in Western North America: Causes and Consequences''. University of Utah Press: Salt Lake City, 2009. {{ISBN|978-0-87480-965-7}}

Category:Scolytinae Category:Woodboring beetles Category:Insect pests of temperate forests Category:Insect vectors of plant pathogens Category:Taxa named by Pierre André Latreille