Byssus Skipper — wisconsinbutterflies.org Page 1 of 7
Wisconsin Butterflies
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Search species Byssus Skipper Problema byssus
This is a confusing species to identify. I have spent more time studying this species than any other species of insect. Part of the problem is that it is not as common, especially in Wisconsin and it has a subspecies in the southeastern part of the United States which is more common, has more written about it, is easier to identify, and is often pictured in books. The subspecies that we have here is more variable, especially the males, which are sometimes nearly unmarked from below. In the Field Guide to The Skipper Butterflies of Illinois (Bouseman, Sternburg, and Wiker, 2006), this species is said to be using more disturbed habitats including roadsides and restored prairie and is apparently more common than it used to be.
Weekly sightings for Byssus Skipper
Identifying characteristics
Below, the male of this species is variable, but ranges from a very bright yellowish orange to a somewhat darker orange with a darker margin, occasionally an obvious lighter area in the middle of the hindwing, and a white fringe. The female from below is much darker, and often is nearly brown with a very obvious spot band in the hindwing with all the spots of nearly the same size and in a crescent. Above, the male is yellowish orange with black margins. The male has no stigma, but does have a black mark at the end of the cell. There usually is little darkening of the veins, and there are a few dark marks toward the body on the forewing. The female is nearly brown with a very distinct row of orange spots on the forewing.
Similar species
The female Delaware Skipper is very similar to the male Byssus Skipper. In fact, the first photo I took of
http://wisconsinbutterflies.org/butterfly/species/147-byssus-skipper 6/5/2009 Byssus Skipper — wisconsinbutterflies.org Page 2 of 7
a male Byssus Skipper, I originally assumed was a Delaware Skipper female. It wasn’t until I had done some additional research about the Byssus Skipper, which I was attempting to photograph, that I noticed that it might not be a Delaware Skipper. After much research into the differences between the two, I did determine that my photos were of a Byssus male. Later I was questioned about this determination and I revisited my photos and research and asked the opinions of others more familiar with the Byssus than myself and have determined that the photo was indeed a Byssus Skipper male. The differences between the two from above are minimal. Looking at the photo on the bottom that compares the two from both above and from below, notice that the female Delaware has very darkened veins, a large dark mark near the body, and orange fringe, while the Byssus does not have darkened veins, it has few dark markings near the body, and has white fringe. These characteristics are somewhat variable, and not all specimens would have all three characteristics the same, thus it is important to try to see or photograph this skipper from below so that you can also use these characteristics to help in identification. In 2007 I was able to take photos of many Delaware females and the two males on this page. The amount of black near the body on the forewing above does appear to be diagnostic. All female Delaware Skippers have much more black compared to the Byssus Skipper and each one that I saw perching was easy to identify based upon that characteristic. The Delaware Skipper from below is very uniform in color with no markings and fringe that is orange and nearly the same color as the wings. The Byssus Skipper from below is much brighter, has obvious darkened margins, and has white fringe, which contrasts greatly with the wing color. The Byssus Skipper has been found only in the far southwestern part of Wisconsin so it is not likely to be an identification problem throughout most of Wisconsin, but it looks so much like the Delaware it may be that it has simply been overlooked. The female Byssus is also very similar to the female Black Dash. The markings and coloration from above are nearly the same on these species but the spot band below on the Black Dash has the two middle spots more elongated than the others, while the Byssus Skipper female has spots that are nearly the same size. The seventh and eighth photos on this page are of a fairly worn individual, but without a good photo showing clearly that the spots are all similar; it cannot be identified with certainty. This individual was clearly larger than a Black Dash and was found on the dry hillside, a more likely habitat for the Byssus Skipper that has since been found there.
Habitat
High quality prairie habitat, but may be found in restored prairie habitat or along roadsides where the larval host plant, big bluestem is found.
Flight
This species is single brooded and flies from late June through July.
Abundance
Uncommon in the southwestern part of the state.
Early Byssus Skipper Sightings
Date County Reported by Jun 23, 2007 Lafayette Todd Sima and Mike Reese Jun 24, 2007 Grant Mike Reese Jul 2, 2006 Lafayette Todd Sima, Mike Reese Jul 6, 2008 Lafayette Ann & Scott Swengel
http://wisconsinbutterflies.org/butterfly/species/147-byssus-skipper 6/5/2009 Byssus Skipper — wisconsinbutterflies.org Page 3 of 7
Jul 6, 2008 Grant Ann & Scott Swengel
Locations
Skippers | Grass-Skippers
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Male, Hardscrabble SNA, Lafayette Co., WI. July 2, 2006.
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Male, Hardscrabble SNA, Lafayette Co., WI. July 2, 2006. Same individual as above.
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Male, Hardscrabble SNA, Lafayette Co., WI. June 23, 2007. Same individual as the photo above.
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Male. Dewey Heights Prairie SNA, Grant Co., WI. June 24, 2007.
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Male, Hardscrabble SNA, Lafayette Co., WI. June 23, 2007.
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Male. Dewey Heights Prairie SNA, Grant Co., WI. June 24, 2007. Same individual as above.
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Female, Hardscrabble Prairie SNA, Lafayette Co., WI, July 28, 2005.
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Female, Hardscrabble Prairie SNA, Lafayette Co., WI, July 28, 2005.
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This photo compares the Byssus Skipper male, left photos, with Delaware Skippers, a female top right and an unknown gender Delaware Skipper bottom right. The photos from below and the photo on the top right were all taken on July 2, 2006 on the same hillside at Hardscrabble State Natural Area in Lafayette County.
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