Summary #
Beyond simple identification, understanding the functional roles of stream organisms — how they feed, what they eat, and where they live — provides deeper insight into stream health. This page introduces functional feeding groups and their significance for water quality assessment.
One way that macro invertebrates can be classified is by using their functional ecology, or food gathering techniques. The basic groups include: scrapers, shredders, collectors and predators. Scrapers usually have very flat, sleek bodies that allow them the easily cling to rocks and scrape off algae for food. Some species of mayflies and stoneflies are scrapers. Shredders are organisms that devour the large particulate matter in the streams, such as dead leaves in the fall. Collectors are usually either filtering collectors or gathering collectors. Filtering collectors usually cling to the rocks, either through suction-cup like appendages or protective structures (cases) that they build and attach to the rock with ‘glue’. Nets or fine hairs are then released into the water to collect whatever food particles are passing by. Gathering collectors usually burrow into the sandy or muddy bottoms of the stream to find food. Collectors always search for fine particulate organic matter. Filtering collectors include caddis flies and black flies while an example of a gathering collector is a midge. The last group, predators, is self-explanatory in their feeding ecology. These insects prey on other macro invertebrates. Dragonfly nymphs are often found in area streams as dominating predators. Expect the number of predators to be the lowest portion of the population, if the predator population was too large, the entire macro invertebrate community would collapse.
For additional information on macroinvertebrates please go to Macroinvertebrate Guide.http://amrclearinghouse.org/Sub/WATERmonitoring/MacroGuide.htm
Sources/Links (as provided in the source text):
- http://amrclearinghouse.org/Sub/WATERmonitoring/MacroGuide.htm
Related Pages #
- Developing a Monitoring Plan
- Water Quality — What biological monitoring tells us
- Collection Methods — How to collect biological samples
- Macroinvertebrate Guide — Identifying stream organisms
Source and Last Reviewed #
Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.
[Admin note: Some external links in this article may be outdated. Verify before relying on them. Flag dead links for removal or replacement.]
Tags: monitoring, education
