…during much of July and so will be posting a little less frequently. But summer has arrived and brings with it a new group of moths that love the hot and humid weather. Here are five of the seventeen new moths plus one returning visitor that showed up at my porch light over the weekend. I’ll be writing about these species later in August. There are already a few in the works on the moths Habrosyne scripta (almost done!), Oreta rosea, Phlogophora iris, Campaea perlata, and Monopis spilotella seen this year and last year.
This small butterfly with dark brown wings and yellow spots is the Arctic Skipper (Carterocephalus palaemon). I saw it a few days ago on a warm, sunny, and humid afternoon on June 12. It was resting on a blade of grass in a sunny opening in an encroaching forest. Although the Arctic Skipper is widely distributed and ranked a G5 or “globally secure” there is only one record that I could find of it from Carlton County and it is historical but there was no information about when or where it was seen or who saw it.
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Papilionoidea (Butterflies and Skippers)
Family Hesperiidae (Skippers)
Subfamily Heteropterinae (Intermediate Skippers)
Genus/species Carterocephalus palaemon
The upper wing surface is dark brown to almost black with roughly rectangular yellow spots. Below they are like the color of a deer fawn and marked with black-rimmed yellow spots. Wingspread is 2.5 to 3.2 cm.
A circumboreal species found in North America from Alaska to Canada’s Atlantic coast and south to California and Pennsylvania. Not truly an Arctic species.
Larval Host Plants
Larvae of Carterocephalus palaemon eat grasses. In California purple reedgrass (Calamagrostis purpurascens) is reported as a larval host. In some European countries, brome (Bromus spp.) are preferred larval hosts. Purple moor-grass (Molinia caerulea) has been reported as a larval host in Scotland. Purple reedgrass is rare in Minnesota and purple moor-grass does not grow here. There are bromes both native and introduced in the state as well as the native Canada bluejoint grass (Calamagrostis canadensis). It is likely that Carterocephalus palaemon larvae feed on other grass species besides the few mentioned in the literature.
Arctic Skipper Carterocephalus palaemon (Pallas, 1771) at BAMONA.
Carterocephalus palaemon (Pallas, 1771) at the Bourgogne-Nature website.
Chequered Skipper (Carterocephalus palaemon) at the Sottish Natural Heritage website.
Species Carterocephalus palaemon – Arctic Skipper – Hodges#3982 at the Bug Guide website.
One thing that often happens when doing an inventory of plants and animals in a particular region such as in the county where I live is the discovery of species not previously known from there. This has been my experience with plants in Carlton County beginning in 1992. Back then there was only Ownbey’s and Morley’s Vascular Plants of Minnesota: A Checklist and Atlas for plant species occurrences by county for Minnesota. The internet has greatly expanded the available information on species distributions and this holds for plants, lichens, and many kinds of animals such as moths. Many museums and universities have searchable databases listing taxa by region or even county level often on maps showing where these species have been found. Some even provide historical data such as when a particular species was seen and/or collected.
Unfortunately, finding a volume like Ownbey and Morley for moths even for a state seems pretty much out of the question. There are other sources of data on moth species occurrences although their reports may not be complete. The first two sources I rely on are the maps at the Moth Photographers Group (MPG) and Butterflies and Moths of North America (BAMONA). Maps at MPG are based on archived specimens and are accurate to the county level. BAMONA is based on citizen-scientist contributions and these are accurate to township level. The weakness in both of these sources is the human factor. For both MPG and BAMONA there seem to be more records near larger population centers where colleges and universities, and hence entomologists and/or interested amateurs, are located compared to areas of the country with smaller populations and distant from colleges.
The third source I look to for Minnesota moths is a Minnesota DNR report (A Survey of Lepidoptera in Three Priority Areas of the Minnesota State Parks System) published in 2009. This report lists all the moth (768) and butterfly (72) species found in thirteen Minnesota state parks between southeastern and northeastern Minnesota over a two-year period. Jay Cooke State Park, which is in Carlton County in northeastern Minnesota, was not included in the survey. The purpose of the survey was to determine what other lepidopteran species might be affected if a Bt spraying program were initiated to control the introduced Gypsy Moth (Lymantria dispar dispar), a potential pest insect in the state. Thankfully, Bt was not used and a mating disrupting pheromone was instead.
I have not done a complete list of new species records for Carlton County because it does not matter as almost every moth I find is a new record for the county. However, as I add more species to the checklist I have noticed that some appear to be new records for the state. Four of these are shown in the photo gallery above. These are not the only ones just some of the most recent. Looking at the maps at MPG and BAMONA it quickly becomes clear that there is a deficit in the record of the lepidopteran fauna of Carlton County (not too unlike the record of the county’s flora). One could get the impression that there is little moth biodiversity here but that would be a mistake. As of June 15, I have photographed and identified almost 270 species of moths. Of these, 100 were photographed and identified this year over a two month period. Even more importantly all were taken on my property. What other species might be found in the oak-maple-basswood forests? Or the bogs? Or the cedar swamps?
Ownbey, G. B., and T. Morley. (1991). Vascular plants of Minnesota: a checklist and atlas. University of Minnesota Press, Minneapolis, Minnesota. 320 pages.
Quinn, Edward M., and Danielson, Ron. (2009). A Survey of Lepidoptera in Three Priority Areas of the Minnesota State Parks System Final Report. 49 pages.
Species accounts at Butterflies and Moths of North America
Species accounts at Moth Photographers Group