View source for Bark beetle

:''The unrelated [[sawyer beetle]]s (''Monochamus'') and some other wood-boring beetle [[taxa]] (especially [[Cucujoidea]]) are sometimes called "bark beetles" too.''
{{Taxobox
| name = Bark beetles
| image = Dendroctonus ponderosae.jpg
| image_width = 220px
| image_caption = [[Mountain pine beetle]],<br />''Dendroctonus ponderosae''
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| classis = [[Insect]]a
| ordo = [[beetle|Coleoptera]]
| familia = [[Curculionidae]]
| subfamilia = '''Scolytinae'''
| subfamilia_authority = [[Pierre André Latreille|Latreille]], 1807
| subdivision_ranks = [[Tribe (biology)|Tribe]]s
| subdivision = 
[[Cortylini]]<br />
[[Cryphalini]]<br />
[[Crypturgini]]<br />
[[Dryocoetini]]<br />
[[Hylastini]]<br />
[[Hylesinini]]<br />
[[Hypoborini]]<br />
[[Ipini]]<br />
[[Phloeosinini]]<br />
[[Phloeotribini]]<br />
[[Polygraphini]]<br />
[[Scolytini]]<br />
[[Scolytoplatypodini]]<br />
[[Taphrorychini]]<br />
[[Thamnurgini]]<br />
[[Tomicini]]<br />
[[Xyleborini]]<br />
[[Xyloterini]]
}}

A '''bark beetle''' is one of approximately 220 [[genera]] with 6,000 [[species]] of [[beetles]] in the [[subfamily]] '''Scolytinae'''. Traditionally this was considered a distinct [[family (biology)|family]] '''Scolytidae''', but nowadays it is understood that bark beetles are in fact very specialized members of the "true [[weevil]]" family ([[Curculionidae]]). Well-known species are members of the [[type genus]] ''[[Scolytus]]'' - namely the [[European elm bark beetle]] ''[[Scolytus multistriatus|S. multistriatus]]'' and the [[large elm bark beetle]] ''[[Scolytus scolytus|S. scolytus]]'', which like the [[American elm bark beetle]] ''[[Hylurgopinus rufipes]]'' transmit [[Dutch elm disease]] [[fungi]] (''Ophiostoma''). Another well-known species of Europe is the ''[[Ips typographus]]''.

==Ecology==
[[Image:Dead pines.jpg|left|thumb|[[Mountain pine beetle]]s killed these [[Lodgepole Pine]] trees in [[Prince George, British Columbia]].]]
Bark beetles are so-named because the best known species reproduce in the inner bark (living and dead phloem tissues) of [[tree]]s. Some species, such as the [[Mountain Pine Beetle|mountain pine beetle]] (''Dendroctonus ponderosae''), attack and kill live trees. Most, however, live in dead, weakened, or dying hosts. Bark beetles are ecologically and economically significant. Even outbreak species can help to renew the forest by killing old trees. Other species aid in the decomposition of dead wood. However, several outbreak-prone species are known as notorious [[pest (organism)|pest]]s.

Bark beetles often attack trees that are already weakened by [[disease]], [[drought]], [[smog]], conspecific beetles or physical damage. Healthy trees may put up defenses by producing [[resin]] or [[latex]], which may contain a number of insecticidal and fungicidal compounds that can kill or injure attacking insects, or simply immobilize and suffocate them with the sticky fluid. Under outbreak conditions, the sheer number of beetles can however overwhelm the tree's defences, and the results can be disastrous for the [[lumber industry]]. 

[[Image:Sumava-kalamita.jpg|thumb|left|Forests of [[Šumava]] damaged by ''Ips typographus'' and clearings after consecutive logging]]
In some places, like [[Šumava]] National Park in the [[Czech Republic]]'s [[Bohemian forest]], problems with bark beetles have become a heated issue with a political dimension. On one side, some experts (usually with a background in [[environmental science]]s) demanded that nature be left alone and that natural processes be allowed to take their course, even if it meant that the bark beetle would destroy most of the forest. On the other side, other experts (usually with a background in [[forest management]]) demanded intervention. During the 1990s and 1980s, the Šumava park management mostly favoured intervention. Many outside groups became involved in the dispute, such as the lumber industry (which supported intervention because of possible profit to be made), or some local politicians, afraid that tourists would turn back from a forest decayed after a beetle invasion. The anti-intervention side got support from entomologists from the [[Academy of Sciences of the Czech Republic|Czech Academy of Sciences]] and from several [[environmental organization]]s, such as [[Friends of the Earth]]. At the height of the dispute, there were cases where activists literally defended the trees with their bodies, tying themselves to the trunks, and the dispute was widely covered in the main Czech daily newspapers and on TV news.<ref>{{cite news |author=Daniela Lazarová |year=2003 |publisher=[[Radio Prague|Radio Praha]] |url=http://www.radio.cz/en/article/44362 |title=Czech National Park infested with bark beetle |date=2003-08-21 |accessdate=2008-07-08}}</ref>

Some bark beetles form a symbiotic relationship with certain [[Ophiostomatales]] [[fungi]], and are named "[[ambrosia beetle]]s" after these "ambrosia fungi". The ambrosia beetles (such as ''[[Trypodendron]]'') feed on fungal "gardens" and are one of only three insect groups known to farm fungi. The other two groups are ants and [[termite]]s, neither of which is particularly closely related to beetles. Courtesy of the fungus, ambrosia bark beetles are able to indirectly feed from many more species of trees than their evolutionary relatives that do not feed on fungi, by having the fungi do the work of overcoming the plant's chemical defenses. The beetles carry the fungal spores in special structures called [[mycangium|mycangia]], and inoculate the trees as they attack them.

Like many other insects, Scolytinae will emit [[pheromones]] to attract [[conspecific]]s which are thus drawn to trees already beset with bark beetles. This can result in heavy infestation and eventually death of the tree. Many are also attracted to ethanol, one of the by-products of decaying trees.

===Gallery===
<gallery>
Image:Bark beetle gallery.jpg|<center>Bark beetle gallery engraving the sapwood
Image:Bark beetle galleries.JPG|<center>Bark beetle galleries with bark showing exit holes
image:Schorskevervraat op eik.jpg|<center>Some species produce single winding tracks
Image:Elm bark beetle galleries 01.JPG|<center>Bark beetle galleries on a dead [[American Elm]]
</gallery>

==References==
{{Reflist}}

==External links==
{{Commonscat|Scolytinae}}
{{wikispecies|Scolytinae}}

*[http://www.barkbeetles.info American and Mexican Bark and Ambrosia beetles]
*[http://www.forestencyclopedia.net/p/p6 Southern Pine Beetle on the Forest Encyclopedia Network]
*[http://www.padil.gov.au/viewPest.aspx?id=453 PaDIL Sheet on ''Scolytus scolytus'']

on the [[University of Florida|UF]] / [[Institute of Food and Agricultural Sciences|IFAS]] Featured Creatures Web site
*[http://entomology.ifas.ufl.edu/creatures/trees/southern_pine_beetle.htm  ''Dendroctonus frontalis'', southern pine beetle] 
*[http://entomology.ifas.ufl.edu/creatures/trees/beetles/black_turpentine_beetle.htm ''Dendroctonus terebrans'', black turpentine beetle] 
*[http://entomology.ifas.ufl.edu/creatures/trees/beetles/ips_beetles.htm ''Ips'',  engraver beetles]

[[Category:Woodboring beetles]]
[[Category:Curculionidae]]
[[Category:Pest insects]]

[[ca:Escolití]]
[[cs:Kůrovci]]
[[da:Barkbille]]
[[de:Borkenkäfer]]
[[fr:Scolytinae]]
[[lt:Kinivarpos]]
[[nl:Schorskevers]]
[[ja:キクイムシ]]
[[no:Barkbiller]]
[[pl:Kornikowate]]
[[sl:Zalubniki]]
[[fi:Kaarnakuoriaiset]]
[[sv:Barkborrar]]
[[th:ด้วงเจาะเปลือกไม้สน]]
[[uk:Короїди]]