''Chionea'' is a genus of wingless limoniid

crane flies A crane fly is any member of the dipteran superfamily Tipuloidea, which contains the living families Cylindrotomidae, Limoniidae, Pediciidae and Tipulidae, as well as several extinct families. "Winter crane flies", members of the family T ...

. It consists of two subgenera, the

holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

''Chionea'' and

palaearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

''Sphaeconophilus''. About 37 species are currently recognized in the northern hemisphere, but there are probably several undescribed species. They are commonly called snow flies.

Description

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 The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

above 3400 m. Adults seem to actively seek out the coldest place they can find and drink water by pressing their

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...

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. ''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. They have been observed walking at speeds at up to per minute in sub-zero conditions, and males have been observed to leap when alarmed. 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 ''Halteres'' (; singular ''halter'' or ''haltere'') (from , hand-held weights to give an impetus in leaping) are a pair of small club-shaped organs on the body of two orders of flying insects that provide information about body rotations du ...

s have not been reduced and remain innervated. Thus, halteres likely serve as sensory organs for ''Chionea''. Up to 200 eggs have been found in female snow flies, which are laid singly. The larvae develop in wooded regions, small caves, and

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

burrows. The diet of larvae likely consists of decomposing organic debris, such as decaying leaves, grass stems, and rodent feces found in burrows.

Cold tolerance

As ''Chionea'' are adapted to living on snow and in subnivean habitats, they are considered cold tolerant insects. In the wild ''Chionea'' are frequently observed at temperatures as cold as 0 and -6°C. In experiments conducted in laboratory environments, ''Chionea'' are active and alive until the temperature drops to a mean low of -7°C, their

supercooling Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid below its freezing point without it becoming a solid. Per the established international definition, supercooling means ''‘cooling a substance be ...

point. Some individuals, however, have been observed to be active at temperatures as low as -17°C. The antifreeze agent found in ''Chionea''

hemolymph Hemolymph, or haemolymph, is a fluid, similar to the blood in invertebrates, that circulates in the inside of the arthropod's body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph c ...

has been determined to be sugar trehalose. They may also produce

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

in their

, preventing them from freezing. Additionally, if a snow fly senses frostbite in its leg, it will instantly self-amputate or detach its leg to prolong survival, much like a lizard detaches a tail if it is attacked.

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 Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s. However, "ice crawlers" (

Grylloblattidae Grylloblattidae, commonly known as the icebugs or ice crawlers, is a family of extremophile (psychrophile) and wingless insects that live in the cold on top of mountains and the edges of glaciers. It is the only member of Grylloblattodea, which ...

) have been shown to feed on them. Because the

cysticercoid A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infections, cysticercoids can be seen in free form as well as enclosed by ...

form of a

tapeworm Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass being Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Ce ...

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. Chionea Parasitic Collar

Parasites

Tapeworm

s, possibly of the genus ''Hymenolepis'', have been found in the abdomens of ''Chionea stoneana''. While most likely not a parasite of snow flies, a species of

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

, similar to ''

Rhabditis ''Rhabditis'' is a genus of nematodes in the family Rhabditidae. ; Names brought to synonymy: ''Rhabditis (Caenorhabditis)'' Osche, 1952 is a synonym for ''Caenorhabditis ''Caenorhabditis'' is a genus of nematodes which live in bacteria-rich ...

'', can sometimes be found in a ringed capsule, which is called a dauer, around the neck of adult snow flies. Immature nematodes develop inside the dauer before ultimately dispersing from it. It has been speculated that the female nematode lays this ring around the fly's neck when it emerges from the

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

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.

Species

: ''This list was adapted from the (January 2007).'' Subgenus ''Chionea'' (

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

) * ''

Chionea albertensis ''Chionea albertensis'' is a species of limoniid crane fly in the family Limoniidae Limoniidae is the largest of four crane fly families, with more than 10,700 species in more than 150 genera. Some studies have suggested it to be a paraphyleti ...

'' Alexander, 1941 (Canada, United States south to

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

) * ''

Chionea alexandriana ''Chionea alexandriana'' is a species of snow fly (''chionea'') in the family Limoniidae Limoniidae is the largest of four crane fly families, with more than 10,700 species in more than 150 genera. Some studies have suggested it to be a parap ...

'' Garrett, 1922 (Canada, USA to

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

) * ''

Chionea araneoides ''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, but ...

'' Dalman, 1816 (Europe: Sweden to Italy, Romania and Russia) * '' Chionea carolus'' Byers, 1979 (USA: California,

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

) * '' Chionea crassipes'' Boheman, 1846 ** ''Chionea crassipes crassipes'' (

Scandinavia Scandinavia is a subregion#Europe, subregion of northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. ''Scandinavia'' most commonly refers to Denmark, Norway, and Sweden. It can sometimes also ...

, Russia to Japan) ** ''Chionea crassipes magadanensis'' Narchuk, 1998 (Russia:

Magadan Oblast Magadan Oblast is a federal subjects of Russia, federal subject (an oblast) of Russia. It is geographically located in the Russian Far East, Far East region of the country, and is administratively part of the Far Eastern Federal District. Magadan ...

) * '' Chionea durbini'' Byers, 1983 (USA: California) * '' Chionea excavata'' Byers, 1983 (USA: California, Nevada) * '' Chionea hybrida'' Byers, 1983 (USA: Idaho, Utah) * '' Chionea jellisoni'' Byers, 1983 (USA:

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, Idaho, Utah) * '' Chionea jenniferae'' (Byers, 1995) (USA: California) * '' Chionea kanenoi'' Sasakawa, 1986 (Japan:

Honshū , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian ...

) * '' Chionea lyrata'' Byers, 1983 (USA: California) * '' Chionea macnabeana'' Alexander, 1947 (Canada, USA to

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

, Oregon) * '' Chionea mirabilis'' Vanin, 2008 (

Korea Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...

) * '' Chionea nigra'' Byers, 1983 (USA: Utah,

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

) * '' Chionea nipponica'' Alexander, 1932 (Russia:

Primorsky Krai Primorsky Krai, informally known as Primorye, is a federal subjects of Russia, federal subject (a krais of Russia, krai) of Russia, part of the Far Eastern Federal District in the Russian Far East. The types of inhabited localities in Russia, ...

, Japan) * '' Chionea nivicola'' Doane, 1900 (USA: Washington, Oregon, Idaho, Montana) * '' Chionea obtusa'' Byers, 1983 (Canada, USA to Oregon, Idaho) * '' Chionea pusilla'' Savchenko, 1983 (Russia: Primorsky Krai) * '' Chionea racovitzai'' Burghele-Balacesco, 1969 (Romania) * '' Chionea reclusa'' Byers, 1995 (USA:

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

) * ''

Chionea scita ''Chionea scita'' is a species of crane fly in the family Limoniidae. ''C. scita'' is known as a type of snow crane fly because it is commonly seen walking on piles of snow during the winter months. These flies are also often observed in caves an ...

'' Walker, 1848 (Canada, USA to

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

and

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

) * '' Chionea stoneana'' Alexander, 1940 (USA: Minnesota to Indiana, south to

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

and

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

) * '' Chionea valga'' Harris, 1841 (Canada, USA south to Minnesota,

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

, Tennessee,

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

and

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

) * '' Chionea wilsoni'' Byers, 1983 (USA: Alabama, Tennessee, North Carolina) Subgenus ''Sphaeconophilus'' (

Palaearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

) * '' Chionea alpina'' Bezzi, 1908 (Europe: France to Spain, Germany to

Montenegro , image_flag = Flag of Montenegro.svg , image_coat = Coat of arms of Montenegro.svg , coa_size = 80 , national_motto = , national_anthem = () , image_map = Europe-Mont ...

) * '' Chionea ancae'' (Menier and Matile, 1976) (France) * '' Chionea arverna'' (Brunhes, 1986) (France: Massif Central) * '' Chionea austriaca'' (Christian, 1980) (Austria) * '' Chionea belgica'' (Becker, 1912) (Europe: Belgium, Denmark, Germany, Hungary,

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

, Switzerland) * '' Chionea besucheti'' (Bourne, 1979) (Switzerland) * '' Chionea botosaneanui'' (Burghele-Balacesco, 1969) (

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

) * '' Chionea catalonica'' (Bourne, 1979) (Spain: central

Pyrenees The Pyrenees are a mountain range straddling the border of France and Spain. They extend nearly from their union with the Cantabrian Mountains to Cap de Creus on the Mediterranean coast, reaching a maximum elevation of at the peak of Aneto. ...

) * '' Chionea jurassica'' (Bourne, 1979) (France) * ''

Chionea lutescens ''Chionea'' is a genus of wingless limoniid crane flies. It consists of two subgenera, the holarctic ''Chionea'' and palaearctic ''Sphaeconophilus''. About 37 species are currently recognized in the northern hemisphere, but there are probably se ...

'' ** '' Chionea lutescens lutescens'' Lundstrom, 1907 (Europe: Sweden to

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...

, Russia) ** ''

Chionea lutescens stelviana ''Chionea'' is a genus of wingless limoniid crane flies. It consists of two subgenera, the holarctic ''Chionea'' and palaearctic ''Sphaeconophilus''. About 37 species are currently recognized in the northern hemisphere, but there are probably se ...

'' Suss, 1982 (Italy:

Lombardia The Lombardy Region (; ) is an administrative regions of Italy, region of Italy that covers ; it is located in northern Italy and has a population of about 10 million people, constituting more than one-sixth of Italy's population. Lombardy is ...

) * '' Chionea pyrenaea'' (Bourne, 1981) (France: Pyrenees)

References

* Marchand, W. (1917). Notes on the habits of the snow-fly (''Chionea''). ''Psyche'' 24:142-152
PDF
( Creative Commons Attribution 2.5 license)

External links

Picture of a ''Chionea'' species
{{Taxonbar, from=Q4357396 Limoniidae Nematocera genera Taxa named by Johan Wilhelm Dalman

Description

Cold tolerance

Reproduction

Predators

Parasites

Species

See also

References

External links