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Article by William T. Mason, Calvin R. Fremling, and Alan V. Nebeker regarding aquatic insects (including mayflies) as biological indicators of a body of water's health and quality. Authors credited respectively: National Biological Service, Winona State University, and U.S. Environmental Protection Agency. Introduction: "Aquatic insects are among the most prolific animals on earth, but are highly specialized and represent less than 1% of the total animal diversity (Pennak 1978). Most people know the 12 orders and about 11,000 species of North American aquatic insects (Merritt and Cummins 1984) only by the large adults that fly around or near wetlands. Aquatic insects are excellent overall indicators of both recent and long-term environmental conditions (Patrick and Palavage 1994). The immature stages of aquatic insects have short life cycles, often several generations a year, and remain in the general area of propagation. Thus, when environmental changes occur, the species must endure the disturbance, adapt quickly, or die and be replaced by more tolerant species. These changes often result in an overabundance of a few tolerant species, and the communities become destabilized or "unbalanced." Article copied from the Invertebrates chapter of the monograph Our Living Resources, 1995. 3 pages. Part of the Cal R. Fremling Collection.

Publication Date


Item Type





Winona, Minnesota


Biologists; Upper Mississippi River; Ecology; Mayflies; Laboratory; Pollution


Special Collections-Library



Rights Management

Requests to reproduce this image must be granted by the Winona County Historical Society.

Contributing Institution

Winona County History Center

Master File Format


Fiscal Sponsor

This project has been financed in part with funds provided by the State of Minnesota from the Arts and Cultural Heritage Fund through the Minnesota Historical Society.

Scanning Responsibility

Northern Micrographics

Date Digital

2019-06-24 00:00

Metadata Creation Responsibility

Anna Gaffey

Unique Identifier


Aquatic insects as indicators of environmental quality



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