Aquatic Invertebrates Arranged
by Functional Feeding Group
The functional feeding group approach was developed by aquatic ecologists, particularly those investigating riverine systems, as an alternative to the trophic level approach (herbivore, detritivore, carnivore) to understanding food web relationships. In temperate regions especially, much of the organic material processed in streams and rivers originates in the terrestrial portions of the drainage system. The functional feeding group approach is an attempt to classify organisms, especially insects, according to their role in the processing of this organic matter. In assigning an organism to a functional feeding group, a number of factors are considered: the origin and size of the food items ingested (plant or animal, coarse or fine), the general location from which the food is taken (from substrates, or from the water column), the mechanisms of food aquisition (behavioural or morphological adaptations), as well as the trophic role. Tables 6C and 6D, in the 3rd edition of An Introduction to the Aquatic Insects of North America, present a more detailed explanation of the classification system. Quite often, an organism can be placed in more than one functional feeding category -- in this guide, when this occurs, the most important role is listed first.
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Filtering Collectors |
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Gathering Collectors |
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Scrapers and Grazers |
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Shredders |
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Predators (Engulfers) |
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Predators (Piercers) |
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Piercer Herbivores |
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Scavengers and Omnivores |