Swamp metalmark (Calephelis mutica)

GenusCalephelis (1)
SizeWingspan: 2.2 - 2.8 cm (2)

The swamp metalmark has not yet been classified by the IUCN.

The swamp metalmark (Calephelis mutica) is an orange-brown butterfly of North America that is brighter and sharper in colour than its relatives (3). While some swamp metalmark individuals have a bold, black thorax, most are coloured with distinct orange-brown and black stripes. The underside of the wings is often yellow-orange. The swamp metalmark also often has small, irregular spots, which have a metallic iridescence, along the edges of the wings (2) (3) (4). 

The swamp metalmark can be found within fragmented areas of Wisconsin, the Ozark Mountains and the Ohio Valley in the United States (2). 

In Wisconsin, the swamp metalmark has been spotted in Fond du Lac, Marinette, Marquette, Ozaukee and Washington Counties (5).  Historically this species also occupied central Kentucky, eastern Iowa, Indiana, Michigan, Arkansas, Missouri, Oklahoma and Pennsylvania (4) (5).

Suitable habitat for the swamp metalmark includes grasslands, wetlands, alkaline fens and moist to wet meadows in peatland (2) (3) (5). It lives in close association with native thistles, which are the primary food source for the larval swamp metalmark (5).

Adult swamp metalmarks appear in late summer in the northernmost parts of its range, where it produces a single brood each year. In the southern parts of its range, this species produces multiple broods, with adults appearing in late spring and again in late summer (5) (6). The female swamp metalmark lays the eggs on thistles, upon which the larvae feed. The larvae, which are covered in dense white hairs as camouflage against their thistle host, metamorphose in spring (5).   

The adult swamp metalmark feeds on the nectar of yellow flowers, such as black-eyed susans (Rudbeckia hirta) (7).

The swamp metalmark typically only moves over an area of just a few hundred yards over the course of its lifetime, meaning that habitat fragmentation is a severe threat to the future survival of this species. Fire suppression and human use of wetlands are the two primary threats to the swamp metalmark’s habitat (5). 

Although the swamp metalmark has not been the target of any known conservation measures, it is listed by a number of U.S. states as ‘Critically Imperilled’, ‘Imperilled’ or ‘Vulnerable’. A potential conservation measure for this species would be to introduceit into prairie preserves to increase its range (5).

Find out more about the swamp metalmark:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (August, 2011)
  2. Bess, J. (2005) Conservation Assessment for the Swamp Metalmark (Calephelis mutica McAlpine). USDA Forest Service, Eastern Region. 
  3. Glassberg, J. (1999) Butterflies Through Binoculars: The East. Oxford University Press, New York. 
  4. Opler, P. (1998) Peterson Field Guides: Eastern Butterfiles. Houghton Mifflin, New York. 
  5. Wisconsin Department of Natural Resources - Swamp metalmark,Calephelis muticum (August, 2011)
  6. Brock, J. and Kaufman, K. (2003) Field Guide to Butterflies of North America.  Houghton Mifflin, New York. 
  7. Butterflies and Moths of North America (August, 2011)