A Sand-dwelling Mayfly -
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State Rank Reason (see State Rank above)
This sand-dwelling mayfly is currently listed as "S1" Species of Concern in MT due to extremely limited and/or rapidly declining population numbers, range and/or habitat, making it highly vulnerable to extirpation in the state. This large river species has probably lost miles of habitat due to dams on the Milk, Tongue, Bighorn, and Missouri Rivers. This species is limited by intact large, prairie river habitat and potentially may be threatened by coal bed natural gas (CBNG) development in the Powder River basin of Wyoming (Stagliano 2012).
This predaceous, little 2-tailed mayfly species (most mayflies have 3 tails) prefers large, warm water sandy rivers in the prairie regions of Saskatchewan and the Western Prairie States. It is an indicator species of a largely intact Large Prairie River Ecological System that is being lost in North America. It is fairly unique in the Ephemeroptera order by being predaceous; most mayfly species are herbivorous feeders on algae, diatoms and other plant materials. It "runs" along underwater sandbars searching for prey in a similar fashion to tiger beetles on terrestrial sandbars. It is a rare and uncommonly collected mayfly because of it's fast swimming ability and the use of the river current to escape.
Acanthomola pubescens is a synonym of Anepeorus rusticus (Wang and McCafferty 2004).
A. rusticus is known to occur in Saskatchewan and the Intermountain West (Montana, Alberta), but extirpated from Utah (NatureServe 2015). In Montana, A. rusticus has been reported from 2 (5 samples) sites on the Powder River and could potentially be found in the lower Yellowstone River.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
This species is associated with larger, perennially flowing prairie rivers with sand-dominated bottoms (shifting sandbars) and cobble riffles.
It is fairly unique in the Ephemeroptera order by being predaceous; most mayfly species are herbivorous feeders on algae, diatoms and other plant materials. It "runs" along underwater sandbars searching for prey in a similar fashion to tiger beetles on terrestrial sandbars.
Anepeorus rusticus is seriously declining in the state probably due to siltation and habitat changes brought on by the building of dams on the large prairie rivers and long-standing drought in Montana.
Threats or Limiting Factors
Threats to this species include the loss of large river shifting sandbar habitat due to flow reductions and modification caused by dams, drought and water diversions. This species is limited by intact large, prairie river habitat and potentially may be threatened by coal bed natural gas (CBNG) development in the Powder River basin of Wyoming (Stagliano 2012).
Literature Cited Above
Legend: View Online Publication Wang, T.-Q. and W.P. McCafferty. 2004. Heptageniidae (Ephemeroptera) of the world. Part I: phylogenetic higher classification. Transactions of the American Entomological Society, 130(1): 11-45. Additional References
Legend: View Online Publication Do you know of a citation we're missing? Stagliano, D.M. 2016. Mayflies (Insecta: Ephemeroptera) of conservation Concern in Montana: Status Updates and Management Needs. Western North American Naturalist 76(4):441-451. Additional Sources of Information Related to "Insects"