The curious case of Anisota stigma (or is it manitobensis?)

One of the more rewarding aspects of photographing/collecting Lepidoptera is the occasional discovery of a species new to an area (and/or well outside it’s known range). Such is the case with Spiny Oakworm Moth (Anisota stigma). Or is it the Manitoba Oakworm Moth (A. manitobensis)? Both of them belong to the Lepidopteran Family Saturnidae (discussed in the previous blog post) which we are adding to our website later this spring.

Back in 2005 (July 15 to be exact) Barbara and Loren Padelford discovered and photographed an interesting moth at Smith Falls State Park which was determined to be a Manitoba Oakworm Moth which had not yet been found in Nebraska. This was quite a discovery as according to the Moth Photographers Group website the nearest record of this moth to Nebraska was in southern Manitoba, some 600 miles distant.

Anisota stigma, Smith Falls State Park, Cherry County, BP

In researching the genus Anisota we discovered a record of a sibling species (A. stigma) from Brown County (probably the Niobrara Valley Preserve) by Roy Beckemeyer on July 22, 1998. This was also quite a find as the other nearest records were from eastern Iowa or Oklahoma, both also roughly 600 miles distant. At this point I thought maybe I should look at the moths I had collected over the years from the Niobrara Valley Preserve to identify at a later date. Lo and behold there was another Anisota (which looked like A. stigma), also from Brown County in 1998 (July 2).

Anisota stigma? Niobrara Valley Preserve, Brown County, NE. July 2 1998

At this point we sent pics of my Niobrara Valley Preserve and the Padelford’s Smith Falls specimens to Dr. James Tuttle (North American Saturnid Moth expert). He was quite surprised to find either species in Nebraska but was of the opinion that the NVP specimen was A. stigma. He was also on the fence as to whether these are two species or one and suggested DNA analysis might be needed to make a clear determination (if that was indeed possible). To that end I donated my specimen to the UNL collection where it is available for future research. There have been no records of these moths for nearly 20 years, although this might be the result of not looking for them.

Finding these moths in north-central Nebraska was surprising in that there are no records nearby. On the other hand, it is somewhat surprising (to me anyway) that there are no other records for the state even though the larval stage of both “species” feed on oaks which are widespread across eastern Nebraska. So, look back through your old moth pictures and collections. Maybe there are more “treasures” there waiting to be discovered. Let us know what you find at

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