This species was accidentally introduced to the United States in the 1890s. During the early 20th century it was present from eastern Connecticut northward into New Brunswick, Canada, but a subsequent severe population collapse reduced the territory to parts of coastal Maine and Cape Cod, Massachusetts, by the late 20th century. One theory for the decline appeared to be parasitism by a fly introduced to combat gypsy moths. Starting in 2015 there has been a population spike and territory expansion in coastal Maine. In Europe, there are multiple parasitic and predator species, yet there is still a history of population outbreaks.