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Insects as Bioindicators of Water Quality

Bioindicators are biological systems that can show (indicate) a measurable effect. Aquatic insects can be used as bioindicators of water quality. The Indiana 4-H bioindicator cards show larval stages of aquatic insects that may be found in Indiana streams. A tolerance score (0-10) is used to estimate water quality. The score represents the insect’s sensitivity to pollution. Insects with a score of 0 are intolerant to pollution (cannot tolerate any water pollution) while insect families with a score of 10 are very tolerant of polluted water.

Publications (PDF):

Materials Needed: data sheet, dip net, plastic bowl or dishpan (white), egg cartons or ice cube trays (2-3, white) and a stream to sample. The white color makes it easier to see the insects.


Note: The cards are grouped by insect order and identified to the family level. Note: Insects with a tolerance score of “undetermined” are not included on the data sheet.

Assessing the water quality for your site:

Data Sheets:

Word document data sheet; Excel File data sheet

Biotic Index table:

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These Instructions in a Word document