Colias is a genus of butterflies in the familyPieridae. 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,[4] which is sometimes included in 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.[7]
Hybridization runs rampant in these polytypic and clinal[8] butterflies, confounding molecular phylogenetics studies. In general, cladistic analyses of only one type of data (particularly mtDNAsequences) 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.[9]
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.[11]
^Bjorn Petersen, 1963. The male genitalia of some Colias species.Journal of Research on the Lepidoptera 1: 135-156.[1]Archived 2017-06-03 at the Wayback Machine
^Lucien A Berger, 1986 Systématique du genre Colias F: Lepidoptera-Pieridae Bruxelles: Imprimerie des Sciences, 1986.
^Paul C. Hammond, 1990 Patterns of geographic variation and evolution in polytypic butterflies Journal of Research on the Lepidoptera 29(1-2):54-76.
[2]Archived 2013-12-03 at the Wayback Machine
^Brock, J.P. & Kaufman, K. Kaufman Field Guide to Butterflies of North America. Houghton Mifflin, 2003, p. 60.
Further reading
Vladimir Lukhtanov & Alexander G. Lukhtanov, 1994 Die Tagfalter Nordwestasiens: (Lepidoptera, Diurna) V. Eitschberger ISBN9783923807024
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 ISBN9783931374150
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)
Colias [fr] "Le genre Colias" provides distribution information in French.