On October 14, 2021, the U.S. Fish and Wildlife Service (Service) issued a proposed rule to list the bog buck moth (Hemileuca maia menyanthevora) (= H.iroquois) as endangered under the Endangered Species Act (ESA). The Federal Register notice also states that the Service will make a final determination on the proposed listing within one year, and that it is seeking comments on the proposed designation.

The bog buck moth occurs in groundwater-fed wetlands in Oswego County, New York, and Ontario, Canada, with large amounts of bog buckbean (a plant that is a key food source, or “host plant” for bog buck moth larvae, much as milkweed is a host plant for monarch butterfly larvae). An additional population was previously documented in Jefferson County, New York, but it was extirpated in the 1970s by flood control activities that flooded the wetlands where the moth was located; the former habitat area in Jefferson County is no longer suitable habitat for the bog buck moth. The State of New York listed the bog buck moth as a state endangered species in 1999; in 2010 the species was listed as endangered under the Ontario Endangered Species Act and in 2012 on Schedule 1 of Canada’s Species at Risk Act.

The Federal Register notice indicates that the bog buck moth is primarily threatened by habitat loss due to changes in vegetation (invasive species) and climate change, which has caused increased precipitation, reduced snowpack, and higher water levels in Lake Ontario, all of which are related to degraded habitat for the moth. In New York, the habitat for all known populations of the moth is in conservation ownership and so is protected from the effects of human-induced habitat destruction or alteration of the wetland habitat. Similarly, habitat in Ontario is generally protected from authorized damage or destruction.

The Service did not propose to designate critical habitat for the moth, finding that such a designation would not be prudent at this time. The bog buck moth co-occurs along with another federally-listed species that is highly collected and was listed in part due to collection pressure on the population, and so identifying and mapping the critical habitat for the bog buck moth would increase the risk of collection for the other species, which is not identified by name in the proposed listing.