Guide to Aquatic Invertebrates

​​ Cast of Characters

This resource is designed to provide a better understanding of the wide variety of aquatic invertebrates found in our rivers, streams and wetlands. In addition to images, general information is included about the distinguishing features of the aquatic stage that aid in identification, and a scale for the organisms' feeding group, tolerance, size range and habitat. Larval and adult images are also provided for many families.

Aquatic invertebrates are excellent indicators of watershed health because they: live in the water for all or most of their life, stay in areas suitable for their survival, are easy to collect, differ in their tolerance to amount and types of pollution, are easy to identify in a laboratory and in the field, often live for more than one year, and are important components of a stream's nutrient and energy system.

Plants and animals are classified according to the hierarchial system that arranges the organisms into groups based upon their similarities. These groups are arranged from general to very specific. The science of classification is known as taxonomy.

Insect groups

Non-insect groups

Additional Information

  • Functional Feeding Groups - Functional feeding groups are a classification approach that is based on behavioral mechanisms of food acquisition rather than taxonomic group.
  • Glossary of Select Terms - The glossary includes select terminology used here and it also includes other terms often associated with the description of aquatic invertebrates.
  • Biological Integrity - After the counting, sorting and identification is complete the benthic macroinvertebrates collections are assessed using six metrics.