The European mantid (Mantis religiosa) has been observed at several sites spanning a distance of approximately 50 km in northern Door County, Wisconsin. A reliable sighting of an unidentified praying mantid on Chambers Island in Green Bay suggests the possibility that the species occurs there as well. Lake-induced moderation of the Door County climate may have resulted in conditions especially conducive for the establishment of European mantids.
Kisselburg, Mark A. and Cochran, Philip A.
"Mantis Religiosa (Mantodea: Mantidae) in Door County, Wisconsin,"
The Great Lakes Entomologist, vol 34
Available at: https://scholar.valpo.edu/tgle/vol34/iss1/4