—By Scott C. Yaich, Ph.D.
You don't have to journey to a faraway galaxy to see an amazing world inhabited by "brain-jacking" parasites and monsters with extendable lower lips that can reach out and snatch unsuspecting prey. You only have to visit your nearest pond or wetland and take a close look at some "duck soup." Stir up the shallow water along the shoreline to create your own duck soup. Next scoop up some water and floating debris, and pour the mixture into a flat pan. Now take a close look. Anyone who still has at least a hint of a child's sense of wonder, regardless of their chronological age, will be delighted by the diversity of tiny aquatic life squirming and swimming in the pan. Study some close-up photos (Google "macroinvertebrate images") and basic life history information, and you will be positively astounded.
An aquatic macroinvertebrate is defined simply as an invertebrate (any animal without a backbone) that lives in the water and is large enough to be seen without a microscope. Although many macroinvertebrates are insects (and not just "bugs," which constitute only one category of insects), many more are from other classes of life such as crustaceans (freshwater shrimp and water fleas), nematodes (worms), and mollusks (snails and tiny fingernail clams).