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For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
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Jay Watson
Conservation Biologist

Lake Huron Locust (Trimerotropis huroniana)



Lake Huron Locust (Trimerotropis huroniana), a State Endangered species, is silvery gray to pale brown, yellow ochre or brick red with mottling, males more heavily than females. The long forewings usually have faint cross-bands, the hind wings are pale yellow with a smoky band. Males measure 19-21mm and females 26-28mm. This species inhabits exposed, high-quality open dunes as well as upper beach areas with very sparse grasses, forbs, and beach shrubs on the northern shores of the Great Lakes.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Lake Huron Locust (Trimerotropis huroniana). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Trimerotropis huroniana in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG2G3
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: This species may be confused with the related grasshopper Trimerotropis maritima (the seaside grasshopper). T. huroniana is silvery gray to pale brown, yellow ochre or brick red with mottling, males more heavily than females. The long forewings usually have faint cross-bands; the hind wings are pale yellow with a smoky band. The low pronotum is cut twice across the middle, the pronotal length behind the furrows nearly twice that anterior to the furrows. Males measure 19-21mm and females 26-28mm. The inner face of the hind femur is solid black on the proximal half in contrast to that of the cogeneric, T. maritima, with a narrow black band. Both species have a black band near the tip of the inner femur. The hind tibia is dull yellow.

Habitat: Inhabits exposed, high quality open dunes as well as upper beach areas with very sparse grasses, forbs, and beach shrubs on the northern shores of the Great Lakes. T. maritima is found farther south along the Great Lakes shorelines. Individuals, particularly males, may be found on sunny days in the least vegetated "blowout" areas of the dunes. The less mottled females have been observed more than the males on the sand/gravel beach just above the high water mark.

State Distribution: Recorded only from Door County in Wisconsin.

Phenology: The species is univoltine and overwinters as an egg in the sandy soil. Adults may be found from mid July until frost. The species is ground-dwelling and has not been observed climbing on vegetation. In stormy weather they will be found in the denser grass cover at the crest of the dunes. The flight sound is a peculiar crepitation interrupted about three times per second so that it seems to be composed of separate notes. The species is very alert but does not fly far when disturbed in contrast to T. maritima. In courtship, males stridulate in a series of trills when approaching females.

Management Guidelines: The Lake Huron locust has narrow habitat preferences and is threatened shoreline recreational development along the Great Lakes. Dune habitat conservation with minimized human use will benefit this species. Where disturbance jeopardizes the quality of the open dune habitat or at sites where vegetation becomes abundant, populations are lost and the species is replaced by more cosmopolitan grasshoppers. At sites where the habitat is narrow, high water years may lead to local extirpations.



Lake Huron Locust

Photo © Brian Scholtens.

Lake Huron Locust

The Lake Huron locust is a globally rare insect endemic to dune habitats of the Great Lakes.

Photo © Brian Scholtens.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Lake Huron Locust. Only natural communities for which Lake Huron Locust is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Natural community Score
Great Lakes Beach 3
Great Lakes Dune 3
Lake Michigan 2

Ecological landscape associations

The table below lists the ecological landscape association scores for Lake Huron Locust. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Lake Huron Locust occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, October 08, 2020