Colias is a genus of butterflies in the family Pieridae. They are often called clouded yellows in the Palearctic and sulphurs (a name also used for other coliadine genera) in North America. The closest living relative is the genus Zerene, which is sometimes included in Colias.
This genus occurs throughout the Holarctic, including the arctic regions. They are also found in South America, Africa, China and India. Their caterpillars feed on certain Fabaceae, for example vetches (Vicia). The adults forage for nectar. most are thus beneficial by keeping weeds at bay, some occasionally become nuisance pests on crops like alfalfa. In some species, the wings of males have brilliant ultraviolet reflection, while those of females do not. Adults of both sexes have various colour forms. Males are particularly conservative based on their genitalia structures. These structures are difficult to identify making it difficult to classify the Colias.
Most if not all species of this genus, as usual for Coliadinae, do not sequester toxins or other noxious compounds from their food plants. They are therefore a well-loved prey item of insectivores as compared to Pieris of the related Pierinae. They make up this disadvantage by being more nimble and better able to evade attacks by would-be predators.
Notable lepidopterologists who did many studies on this genus included Julius Röber, J. Malcolm Fawcett, George B. Johnson and Henry Rowland-Brown.
Systematics Hybridization runs rampant in these polytypic and clinalPaul C. Hammond, 1990 Patterns of geographic variation and evolution in polytypic butterflies Journal of Research on the Lepidoptera 29(1-2):54-76. butterflies, confounding molecular phylogenetics studies. In general, cladistic analyses of only one type of data (particularly mtDNA sequences) cannot be considered reliable. Regardless, the evolutionary distance within some "species" is so large that cryptic speciation rather than (or in addition to) interbreeding seems to be the cause. For example, the Beringian populations traditionally assigned to the northern clouded yellow (C. hecla) could warrant recognition as a species; hybridization between North American and Asian populations seems to have played a role in their evolution, but as a whole they appear to be a rather old and distinct lineage.
Thermoregulation Colias are behavioral thermoregulators. They will move their habitats in order to regulate their body temperature. This leads to them having specific and narrow temperature ranges that they could live in. This leaves the Colias to be extremely vulnerable to climate change. The degree of melanism on their wings and fur thickness are major parts of their thermoregulation. The wing absorption/melanization is determined by the proportions of their coloration. They are in a class of pollinators that require minimum fuel due to their small size. When they need pollen they are attracted to flower patterns in the ultraviolet, similar to themselves.
Flight Colias spend most of their time in active flight and are very strong flyers. Flying is essential for them mate as well as pollinate. But they are very susceptible to temperature and have flight restrictions based on their body temperature. Flight activity is restricted between 27-40 degrees Celsius. Their flight performance is best once at 33-38 degrees Celsius. In order to maintain these temperatures the Colias will use a lateral basking posture. When they reach a temperature outside of the flight activity zone, Colias will find a shaded area under plants in order to cool down.
Species The genus Colias has approximately 90 different species. It is often difficult to find differences between the species, since they are mostly identified through their wing structure and pattern.Listed alphabetically: Colias adelaidae Verhulst, 1991 Colias aegidii Verhulst, 1990 Colias alfacariensis Ribbe, 1905 – Berger's clouded yellow Colias alexandra W. H. Edwards, 1863 – Queen Alexandra's sulphur, Alexandra sulfur, or ultraviolet sulfur Colias alpherakii Staudinger, 1882 Colias aquilonaris Grum-Grshimailo, 1899 Colias arida Alphéraky, 1889 Colias audre (Hemming, 1933) Colias aurorina Herrich-Schäffer, 1850 – Greek clouded butterfly or dawn clouded yellow Colias baeckeri Kotzsch, 1930 Colias behrii W. H. Edwards, 1866 – Behr's sulphur or Sierra green sulfur Colias berylla Fawcett, 1904 – Everest clouded yellow Colias canadensis Ferris, 1982 – Canada sulphur Colias caucasica Staudinger, 1871 – Balkan clouded yellow Colias chippewa W. H. Edwards, 1872 – heath sulphur Colias chlorocoma Christoph, 1888 Colias christina W. H. Edwards, 1863 – Christina sulphur Colias christophi Grum-Grshimailo, 1885 Colias chrysotheme (Esper, 1781) – lesser clouded yellow Colias cocandica Erschoff, 1874 Colias croceus (Geoffroy, 1785) – dark clouded yellow or common clouded yellow Colias dimera Doubleday, 1847 – dimera sulphur Colias diva Grum-Grshimailo, 1891 Colias dubia Fawcett, 1906 – dwarf clouded yellow Colias electo (Linnaeus, 1763) – African clouded yellow Colias elegans Schultz, 1904 Colias elis Strecker, 1885 (often included in C. meadii; paraphyletic?) Colias eogene C. & R. Felder, 1865 – fiery clouded yellow Colias erate (Esper, 1805) – eastern pale clouded yellow Colias erschoffi Alphéraky, 1881 Colias eurytheme Boisduval, 1852 – orange sulphur, alfalfa butterfly Colias euxanthe C. & R. Felder, 1865 – Puno clouded yellow Colias felderi Grum-Grshimailo, 1891 Colias fieldii Ménétriés, 1855
Colias flaveola Blanchard, 1852 – flaveola clouded yellow Colias gigantea Strecker, 1900 – great (northern) sulphur Colias grumi Alpheraky, 1897 Colias harfordii W. H. Edwards, 1877 – Harford's sulphur Colias hecla Lefèbvre, 1836 – northern clouded yellow, Greenland sulphur, or hecla sulphur (paraphyletic?) Colias heos (Herbst, 1792) Colias hofmannorum Eckweiler, 2000 Colias hyale (Linnaeus, 1758) – pale clouded yellow Colias hyperborea Grum-Grshimailo, 1899 Colias interior Scudder, 1862 – pink-edged sulphur Colias johanseni Troubridge & Philip, 1990 – Johansen's sulphur Colias krauthii Klots, 1935 Colias lada Grum-Grshimailo, 1891 Colias ladakensis Felder & Felder, 1865 – Ladakh clouded yellow Colias leechi Grum-Grshimailio, 1893 Colias lesbia (Fabricius, 1775) – Lesbia clouded yellow Colias libanotica Lederer, 1858 (sometimes included in C. aurorina) Colias marcopolo Grum-Grshimailo, 1888 Colias marnoana Rogenhofer, 1884 Colias meadii W. H. Edwards, 1871 – Mead's sulphur Colias montium Oberthür, 1886 Colias mukana Berger, 1981 Colias myrmidone (Esper, 1781) – Danube clouded yellow Colias nastes Boisduval, 1834 – Labrador sulphur Colias nebulosa Oberthür, 1894 Colias nilagiriensis Felder, C & R Felder, 1859 Colias nina Fawcett, 1904 – Fawcett's clouded yellow Colias occidentalis Scudder, 1862 – western sulphur or golden sulfur Colias palaeno (Linnaeus, 1761) – moorland clouded yellow, Arctic sulphur, palaeno sulphur or pale Arctic clouded yellow Colias pelidne Boisduval & Le Conte, 1829 – blueberry sulphur or pelidne sulphur Colias phicomone (Esper, 1780) – mountain clouded yellow Colias philodice Godart, 1819 – common sulphur, clouded sulphur Colias ponteni Wallengren, 1860 Colias pseudochristina Ferris, 1989 Colias regia Grum-Grshimailo, 1887 Colias romanovi Grum-Grshimailo, 1885 Colias sagartia Lederer, 1869 Colias scudderii Reakirt, 1865 – willow sulphur Colias shahfuladi Clench & Shoumatoff, 1956 Colias sieversi Grum-Grshimailo, 1887 Colias sifanica Grum-Grshimailo, 1891 Colias staudingeri Alphéraky, 1881 Colias stoliczkana Moore, 1882 – orange clouded yellow Colias tamerlana Staudinger, 1897 Colias thisoa Ménétriés, 1832 Colias thrasibulus Fruhstorfer, 1908 – lemon clouded yellow Colias thula Hovanitz, 1955 – Thula sulphur Colias tibetana Riley, 1922 Colias tyche (Böber, 1812) – pale Arctic clouded yellow, Arctic green sulphur, or Booth's sulphur Colias viluiensis (Ménétriés, 1859) Colias wanda Grum-Grshimaïlo, 1907 Colias wiskotti Staudinger, 1882
Distinguishing characteristics Colias are usually some shade of yellow, orange or white. Their uppersides feature black borders (usually solid in males, often with pale spots in females). They always perch with wings closed, but upperside pattern may be seen faintly through the wing, or glimpsed in flight.Brock, J.P. & Kaufman, K. Kaufman Field Guide to Butterflies of North America. Houghton Mifflin, 2003, p. 60.
Gallery
References
Further reading Vladimir Lukhtanov & Alexander G. Lukhtanov, 1994 Die Tagfalter Nordwestasiens: (Lepidoptera, Diurna) V. Eitschberger Joseph T. Verhulst (English translation R. Leestmans, editing E. Benton and R. Leestmans), 2000 Les Colias du Globe translation Monograph of the genus Colias Keltern, Germany: Goecke & Evers Glassberg, Jeffrey Butterflies through Binoculars, The West (2001) Guppy, Crispin S. and Shepard, Jon H. Butterflies of British Columbia (2001) James, David G. and Nunnallee, David Life Histories of Cascadia Butterflies (2011) Pelham, Jonathan Catalogue of the Butterflies of the United States and Canada (2008) Pyle, Robert Michael The Butterflies of Cascadia (2002) "Le genre Colias" provides distribution information in French.
External links
Colias images at Consortium for the Barcode of Life Images representing Colias at Encyclopedia of Life Euroleps via search, includes images Rusinsects Photos and text relating to Palaearctic species Die Gattung Colias von J. Fuchs Oleg Kosterin Images from Siberia Butterflies and Moths of North America Butterflies of America