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