View source for Chionea

{{Short description|Genus of flies}}
{{Automatic taxobox
| image                  = Chionea lutescens, male, Pyhäranta, Finland (cropped).jpg
| image_caption          = ''[[Chionea lutescens]]''
| taxon                  = Chionea
| authority              = [[Johan Wilhelm Dalman|Dalman]], 1816
| display_parents        = 2
| diversity_link         =
| diversity              = ca. 40 species
| type_species           = ''[[Chionea araneoides]]''
| type_species_authority = [[Johan Wilhelm Dalman|Dalman]], 1816
| subdivision_ranks      = Species
| subdivision            = See text
}}
'''''Chionea''''' is a genus of wingless [[Limoniidae|limoniid]] [[crane fly|crane flies]]. It consists of two subgenera, the [[holarctic]] ''Chionea'' and [[palaearctic]] ''Sphaeconophilus''. About 37 species are currently recognized in the northern hemisphere,<ref>{{Cite journal|last1=De Jong|first1=Herman|last2=Ciliberti|first2=Pasquale|date=2014|title=How cold-adapted flightless flies dispersed over the northern hemisphere: phylogeny and biogeography of the snow fly genus Chionea Dalman (Diptera: Limoniidae)|url=https://resjournals.onlinelibrary.wiley.com/doi/10.1111/syen.12075|journal=Syst. Entomol.|volume=39|issue=1 |pages=563–589|doi=10.1111/syen.12075 |bibcode=2014SysEn..39..563D |s2cid=86307492 }}</ref> but there are probably several undescribed species. They are commonly called '''snow flies'''.
==Description==
[[File:Running-gif-8bit.gif|left|thumb|314x314px|Snow fly running in the Cascade mountains]]
Adults are found during the winter season in forested environments, where they can be observed walking across the surface of the snow. Many species live at high elevations, with some examples of ''C. nigra'' found in the [[Rocky Mountains]] above 3400 m.<ref name=":0" />
Adults seem to actively seek out the coldest place they can find and drink water by pressing their [[proboscis]] against the snow (Marchand, 1917). Adults are not known to feed. Adults have a significantly longer lifespan than other crane flies, living as long as two months.<ref name=":0" />
''Chionea'' are highly active in cold environments that are lethal to most insect species. Adults are often found in motion as they move across the surface of the snow, walking at speeds near their peak velocity.<ref name=":2" /> They have been observed walking at speeds at up to {{Convert|0.8|m|ft}} per minute in sub-zero conditions,<ref>{{Cite journal |last=Hågvar |first=Sigmund |date=20 Jul 2010 |title=A review of Fennoscandian arthropods living on and in snow |url=https://www.eje.cz/pdfs/eje/2010/03/01.pdf |url-status=live |journal=[[Eur. J. Entomol.]] |volume=107 |issue=3 |at=287 |doi=10.14411/EJE.2010.037 |issn=1210-5759 |eissn=1802-8829 |s2cid=17539655 |archive-url=https://web.archive.org/web/20220618002549/https://www.eje.cz/pdfs/eje/2010/03/01.pdf |archive-date=18 Jun 2022 |access-date=23 Mar 2023}}</ref><ref>{{Cite journal |last1=Hagvar |first1=S. |last2=Vanin |first2=Stefano |last3=Ostbye |first3=E. |date=Jun 2010 |title=Contribution to the Fennoscandian distribution of Chionea Dalman, 1816 (Diptera, Limoniidae), with notes on the ecology |url=https://eprints.hud.ac.uk/id/eprint/11628/1/VaninH |journal=Norwegian Journal of Entomology |language=en |volume=57 |issue=2 |pages=166–176 |issn=1501-8415 |quote=Walking speeds from 26-80 cm per minute wererecorded (Fig. 6), with approximately half a meter as a mean value.}}</ref> and males have been observed to leap when alarmed.<ref name=":0" />
The winglessness of the genus is probably attributable to the fact that at sub-freezing temperatures, it is challenging to generate energy required for maintaining flight. ''Chionea'' lack flight musculature, allowing for the storage of additional eggs within the thoracic cavity. However, the [[haltere]]s have not been reduced and remain innervated. Thus, halteres likely serve as sensory organs for ''Chionea''.<ref name=":0" />
Up to 200 eggs have been found in female snow flies, which are laid singly.<ref name=":0" /> The larvae develop in wooded regions, small caves, and [[rodent]] burrows. The diet of larvae likely consists of decomposing organic debris, such as decaying leaves, grass stems, and rodent feces found in burrows.<ref name=":0" />
==Cold tolerance==
As ''Chionea'' are adapted to living on snow and in subnivean habitats,<ref name=":0" /><ref name=":2">{{Cite journal|last=Hågvar|first=Sigmund|date=1971|title=Field observations on the ecology of a snow insect, ''Chionea araneoides'' Dalm.(Dipt., Tipulidae) |journal=Norsk Entomologisk Tidsskrift |trans-journal=Norwegian Journal of Entomology |volume=18 |issue=1 |pages=33–37 |url=http://www.entomologi.no/journals/nje/old/V18/NET_18_01_1971.pdf#page=35}}</ref> they are considered cold tolerant insects. In the wild ''Chionea'' are frequently observed at temperatures as cold as 0 and -6°C.<ref name=":2" /> In experiments conducted in laboratory environments, ''Chionea'' are active and alive until the temperature drops to a mean low of -7°C, their [[supercooling]] point.<ref>{{Cite journal|last1=Somme|first1=Lauritz|last2=Ostbye|first2=Eivind|date=1969|title=Cold-Hardiness in Some Winter Active Insects|url=http://www.entomologi.no/journals/nje/old/nye/NET_16_01_1969.pdf#page=46|journal=Norsk Ent. Tidsskr|volume=16|pages=45–48}}</ref><ref name=":4">{{Cite journal |last1=Golding |first1=Dominic |last2=Rupp |first2=Katie L. |last3=Sustar |first3=Anne |last4=Pratt |first4=Brandon |last5=Tuthill |first5=John C. |date=November 2023 |title=Snow flies self-amputate freezing limbs to sustain behavior at sub-zero temperatures |journal=Current Biology |language=en |volume=33 |issue=21 |pages=4549–4556.e3 |doi=10.1016/j.cub.2023.09.002 |pmc=10842534 |pmid=37757830|bibcode=2023CBio...33E4549G }}</ref> Some individuals, however, have been observed to be active at temperatures as low as -17°C.<ref name=":3">{{Cite journal|last1=Vanin|first1=S|last2=Bubacco|first2=L|last3=Beltramini|first3=M|date=2008|title=Seasonal variation of trehalose and glycerol concentrations in winter snow-active insects|journal=Cryoletters|volume=29|issue=6|pages=485–491|pmid=19280052}}</ref><ref name=":4" />
The antifreeze agent found in ''Chionea'' [[hemolymph]] has been determined to be sugar trehalose.<ref name=":3" /> They may also produce [[glycerol]] in their [[hemolymph]], preventing them from freezing.<ref>{{Cite book |last=Perry |first=Lorne |url=https://books.google.com/books?id=aHmfnFzFG0kC&dq=%22Chionea%22+%22glycerol%22&pg=PA90 |title=Drawing from the Mountain: An Illustrated Journey |date=2006 |publisher=Rocky Mountain Books Ltd |isbn=978-1-894765-81-7 |language=en}}</ref> Additionally, if a snow fly senses frostbite in its leg, it will instantly [[Autotomy|self-amputate]] or detach its leg to prolong survival, much like a lizard detaches a tail if it is attacked.<ref name=":4" />
==Reproduction==
Mating is indiscriminate (probably because it is very hard to find a specimen of the other sex for them) and takes 30 to 70 minutes. Winged crane flies and wingless snow crane flies mate tail to tail and this has been verified with video evidence by Vanessa Logsdon et al.
==Predators==
One of the reasons why adults emerge in winter seems to be the absence of [[predator]]s. However, "ice crawlers" ([[Grylloblattidae]]) have been shown to feed on them. Because the [[cysticercoid]] form of a [[tapeworm]] species has been found in two out of three ''C. stoneana'' specimens in eastern Kansas, they also have to be eaten by mice, which are the tapeworm's host. The snow fly larvae likely take up these tapeworms via mouse feces.<ref name=":1" />
[[File:Chionea Parasitic Collar.png|thumb|A high magnification dorsal view of a snow fly specimen with a nematode dauer placed around the snow fly's cervix ("neck").]]
==Parasites==
Tapeworm [[cysticercoid]]s, possibly of the genus [[Hymenolepis (flatworm)|''Hymenolepis'']], have been found in the abdomens of ''Chionea stoneana''.<ref name=":0">{{cite journal |last1=Byers |first1=G. |title=Crane fly genus ''Chionea'' in North America |journal=The University of Kansas Science Bulletin |date=1983 |volume=52 |issue=6 |pages=59–195}}</ref>
While most likely not a parasite of snow flies, a species of [[nematode]], similar to ''[[Rhabditis]]'', can sometimes be found in a ringed capsule, which is called a [[dauer larva|dauer]], around the neck of adult snow flies.<ref name=":0" /> Immature nematodes develop inside the dauer before ultimately dispersing from it.<ref name=":0" /><ref name=":1">{{Cite journal|last=Schrock|first=J. R.|date=1992|title=Snow flies|journal=Emporia State University}}</ref> It has been speculated that the female nematode lays this ring around the fly's neck when it emerges from the [[pupa]] and cannot yet move properly. These nematodes are presumed to be phoretic, meaning that they use the snow fly as a mechanism for dispersal, and not snow fly parasites.<ref name=":0" />
==Species==
: ''This list was adapted from the {{cite web |title=Catalogue of the Craneflies of the World (Diptera, Tipuloidea: Pediciidae, Limoniidae, Cylindrotomidae, Tipulidae) |url=https://ccw.naturalis.nl/ |publisher=Naturalis Biodiversity Center}} (January 2007).''
'''Subgenus ''Chionea''''' ([[Holarctic]])
* ''[[Chionea albertensis]]'' <small>Alexander, 1941</small> (Canada, United States south to [[Oregon]], [[Idaho]])
* ''[[Chionea alexandriana]]'' <small>Garrett, 1922</small> (Canada, USA to [[California]], [[Utah]])
* ''[[Chionea araneoides]]'' <small>Dalman, 1816</small> (Europe: Sweden to Italy, Romania and Russia)
* ''[[Chionea carolus]]'' <small>Byers, 1979</small> (USA: California, [[Nevada]])
* ''[[Chionea crassipes]]'' <small>Boheman, 1846</small>
** ''Chionea crassipes crassipes'' ([[Scandinavia]], Russia to Japan)
** ''Chionea crassipes magadanensis'' <small>Narchuk, 1998</small> (Russia: [[Magadan Oblast]])
* ''[[Chionea durbini]]'' <small>Byers, 1983</small> (USA: California)
* ''[[Chionea excavata]]'' <small>Byers, 1983</small> (USA: California, Nevada)
* ''[[Chionea hybrida]]'' <small>Byers, 1983</small> (USA: Idaho, Utah)
* ''[[Chionea jellisoni]]'' <small>Byers, 1983</small> (USA: [[Montana]], Idaho, Utah)
* ''[[Chionea jenniferae]]'' <small>(Byers, 1995)</small> (USA: California)
* ''[[Chionea kanenoi]]'' <small>Sasakawa, 1986</small> (Japan: [[Honshū]])
* ''[[Chionea lyrata]]'' <small>Byers, 1983</small> (USA: California)
* ''[[Chionea macnabeana]]'' <small>Alexander, 1947</small> (Canada, USA to [[Washington (U.S. state)|Washington]], Oregon)
* ''[[Chionea mirabilis]]'' <small>Vanin, 2008</small> ([[Korea]])<!-- Zoosystema30:413. -->
* ''[[Chionea nigra]]'' <small>Byers, 1983</small> (USA: Utah, [[Colorado]])
* ''[[Chionea nipponica]]'' <small>Alexander, 1932</small> (Russia:[[Primorsky Krai]], Japan)
* ''[[Chionea nivicola]]'' <small>Doane, 1900</small> (USA: Washington, Oregon, Idaho, Montana)
* ''[[Chionea obtusa]]'' <small>Byers, 1983</small> (Canada, USA to Oregon, Idaho)
* ''[[Chionea pusilla]]'' <small>Savchenko, 1983</small> (Russia: Primorsky Krai)
* ''[[Chionea racovitzai]]'' <small>Burghele-Balacesco, 1969</small> (Romania)
* ''[[Chionea reclusa]]'' <small>Byers, 1995</small> (USA: [[Illinois]])
* ''[[Chionea scita]]'' <small>Walker, 1848</small> (Canada, USA to [[Kentucky]], [[Tennessee]] and [[Georgia (U.S. state)|Georgia]])
* ''[[Chionea stoneana]]'' <small>Alexander, 1940</small> (USA: Minnesota to Indiana, south to [[Kansas]], [[Oklahoma]] and [[Missouri]])
* ''[[Chionea valga]]'' <small>Harris, 1841</small> (Canada, USA south to Minnesota, [[Wisconsin]], Tennessee, [[North Carolina]] and [[Virginia]])
* ''[[Chionea wilsoni]]'' <small>Byers, 1983</small> (USA: Alabama, Tennessee, North Carolina)
'''Subgenus ''Sphaeconophilus''''' ([[Palaearctic]])
* ''[[Chionea alpina]]'' <small>Bezzi, 1908</small> (Europe: France to Spain, Germany to [[Montenegro]])
* ''[[Chionea ancae]]'' <small>(Menier and Matile, 1976)</small> (France)
* ''[[Chionea arverna]]'' <small>(Brunhes, 1986)</small> (France: [[Massif Central]])
* ''[[Chionea austriaca]]'' <small>(Christian, 1980)</small> (Austria)
* ''[[Chionea belgica]]'' <small>(Becker, 1912)</small> (Europe: Belgium, Denmark, Germany, Hungary, [[Netherlands]], Switzerland)
* ''[[Chionea besucheti]]'' <small>(Bourne, 1979)</small> (Switzerland)
* ''[[Chionea botosaneanui]]'' <small>(Burghele-Balacesco, 1969)</small> ([[Czech Republic]], [[Poland]], [[Romania]], [[Slovakia]])
* ''[[Chionea catalonica]]'' <small>(Bourne, 1979)</small> (Spain: central [[Pyrenees]])
* ''[[Chionea jurassica]]'' <small>(Bourne, 1979)</small> (France)
* ''[[Chionea lutescens]]''
** ''[[Chionea lutescens lutescens]]'' <small>Lundstrom, 1907</small> (Europe: Sweden to [[Portugal]], [[Ukraine]], Russia)
** ''[[Chionea lutescens stelviana]]'' <small>Suss, 1982</small> (Italy: [[Lombardia]])
* ''[[Chionea pyrenaea]]'' <small>(Bourne, 1981)</small> (France: Pyrenees)
==See also==
* [[Snow scorpionflies]]
==References==
{{Reflist}}
* Marchand, W. (1917). Notes on the habits of the snow-fly (''Chionea''). ''Psyche'' 24:142-152. [https://web.archive.org/web/20070927020233/http://psyche2.entclub.org/articles/24/24-142.pdf PDF] ([[Creative Commons License|Creative Commons Attribution 2.5 license]])
==External links==
* [http://www.cedarcreek.umn.edu/insects/newslides/029002042xxxapl.jpg Picture of a ''Chionea'' species]
{{Taxonbar|from=Q4357396}}
[[Category:Limoniidae]]
[[Category:Nematocera genera]]
[[Category:Taxa named by Johan Wilhelm Dalman]]