Chionea
Chionea lutescens
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Limoniidae
Subfamily: Chioneinae
Tribe: Cladurini
Genus: Chionea
Dalman, 1816
Type species
Chionea araneoides
Dalman, 1816
Species

See text

Diversity
ca. 40 species

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,[1] 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 above 3400 m.[2]

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.[2]

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.[3] They have been observed walking at speeds at up to 0.8 metres (2.6 ft) per minute in sub-zero conditions,[4][5] and males have been observed to leap when alarmed.[2]

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 halteres have not been reduced and remain innervated. Thus, halteres likely serve as sensory organs for Chionea.[2]

Up to 200 eggs have been found in female snow flies, which are laid singly.[2] 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.[2]

Cold tolerance

As species of Chionea are adapted to living on snow and in subnivean habitats,[2][3] they are considered cold tolerant insects. It has been frequently reported that Chionea are observed at temperatures between 0 and -6 °C.[3] In an experiment conducted in a laboratory environment, Chionea araneoides specimens died at a mean temperature of -7.5 °C, their supercooling point;[6] another experiment on an undetermined species of European Chionea demonstrated a supercooling point of -11.2 °C.[7] The antifreeze agent found in Chionea hemolymph has been determined to be sugar trehalose.[7] They may also produce glycerol in their hemolymph, preventing them from freezing.[8]

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 predators. 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.[9]

A high magnification dorsal view of a snow fly specimen with a nematode dauer placed around the snow fly's cervix ("neck").

Parasites

Tapeworm cysticercoids, possibly of the genus Hymenolepis, have been found in the abdomens of Chionea stoneana.[2]

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, around the neck of adult snow flies.[2] Immature nematodes develop inside the dauer before ultimately dispersing from it.[2][9] 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.[2]

Species

This list was adapted from the "Catalogue of the Craneflies of the World (Diptera, Tipuloidea: Pediciidae, Limoniidae, Cylindrotomidae, Tipulidae)". Naturalis Biodiversity Center. (January 2007).

Subgenus Chionea (Holarctic)

  • Chionea albertensis Alexander, 1941 (Canada, United States south to Oregon, Idaho)
  • Chionea alexandriana Garrett, 1922 (Canada, USA to California, Utah)
  • Chionea araneoides Dalman, 1816 (Europe: Sweden to Italy, Romania and Russia)
  • Chionea carolus Byers, 1979 (USA: California, Nevada)
  • Chionea crassipes Boheman, 1846
    • Chionea crassipes crassipes (Scandinavia, Russia to Japan)
    • Chionea crassipes magadanensis Narchuk, 1998 (Russia: Magadan Oblast)
  • 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, Idaho, Utah)
  • Chionea jenniferae (Byers, 1995) (USA: California)
  • Chionea kanenoi Sasakawa, 1986 (Japan: Honshū)
  • Chionea lyrata Byers, 1983 (USA: California)
  • Chionea macnabeana Alexander, 1947 (Canada, USA to Washington, Oregon)
  • Chionea mirabilis Vanin, 2008 (Korea)
  • Chionea nigra Byers, 1983 (USA: Utah, Colorado)
  • Chionea nipponica Alexander, 1932 (Russia:Primorsky Krai, 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)
  • Chionea scita Walker, 1848 (Canada, USA to Kentucky, Tennessee and Georgia)
  • Chionea stoneana Alexander, 1940 (USA: Minnesota to Indiana, south to Kansas, Oklahoma and Missouri)
  • Chionea valga Harris, 1841 (Canada, USA south to Minnesota, Wisconsin, Tennessee, North Carolina and Virginia)
  • Chionea wilsoni Byers, 1983 (USA: Alabama, Tennessee, North Carolina)

Subgenus Sphaeconophilus (Palaearctic)

  • Chionea alpina Bezzi, 1908 (Europe: France to Spain, Germany to Montenegro)
  • 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, Switzerland)
  • Chionea besucheti (Bourne, 1979) (Switzerland)
  • Chionea botosaneanui (Burghele-Balacesco, 1969) (Czech Republic, Poland, Romania, Slovakia)
  • Chionea catalonica (Bourne, 1979) (Spain: central Pyrenees)
  • Chionea jurassica (Bourne, 1979) (France)
  • Chionea lutescens
    • Chionea lutescens lutescens Lundstrom, 1907 (Europe: Sweden to Portugal, Ukraine, Russia)
    • Chionea lutescens stelviana Suss, 1982 (Italy: Lombardia)
  • Chionea pyrenaea (Bourne, 1981) (France: Pyrenees)

See also

References

  1. ↑ De Jong, Herman; Ciliberti, Pasquale (2014). "How cold-adapted flightless flies dispersed over the northern hemisphere: phylogeny and biogeography of the snow fly genus Chionea Dalman (Diptera: Limoniidae)". Syst. Entomol. 39 (1): 563–589. doi:10.1111/syen.12075. S2CID 86307492.
  2. 1 2 3 4 5 6 7 8 9 10 11 Byers, G. (1983). "Crane fly genus Chionea in North America". The University of Kansas Science Bulletin. 52 (6): 59–195.
  3. 1 2 3 Hågvar, Sigmund (1971). "Field observations on the ecology of a snow insect, Chionea araneoides Dalm.(Dipt., Tipulidae)" (PDF). Norsk Entomologisk Tidsskrift [Norwegian Journal of Entomology]. 18 (1): 33–37.
  4. ↑ Hågvar, Sigmund (20 Jul 2010). "A review of Fennoscandian arthropods living on and in snow" (PDF). Eur. J. Entomol. 107 (3). 287. doi:10.14411/EJE.2010.037. eISSN 1802-8829. ISSN 1210-5759. S2CID 17539655. Archived (PDF) from the original on 18 Jun 2022. Retrieved 23 Mar 2023.
  5. ↑ Hagvar, S.; Vanin, Stefano; Ostbye, E. (Jun 2010). "Contribution to the Fennoscandian distribution of Chionea Dalman, 1816 (Diptera, Limoniidae), with notes on the ecology". Norwegian Journal of Entomology. 57 (2): 166–176. ISSN 1501-8415. Walking speeds from 26-80 cm per minute wererecorded (Fig. 6), with approximately half a meter as a mean value.
  6. ↑ Somme, Lauritz; Ostbye, Eivind (1969). "Cold-Hardiness in Some Winter Active Insects" (PDF). Norsk Ent. Tidsskr. 16: 45–48.
  7. 1 2 Vanin, S; Bubacco, L; Beltramini, M (2008). "Seasonal variation of trehalose and glycerol concentrations in winter snow-active insects". Cryoletters. 29 (6): 485–491. PMID 19280052.
  8. ↑ Perry, Lorne (2006). Drawing from the Mountain: An Illustrated Journey. Rocky Mountain Books Ltd. ISBN 978-1-894765-81-7.
  9. 1 2 Schrock, J. R. (1992). "Snow flies". Emporia State University.


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