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Aquatic Insects

Aquatic insects are the largest group of Ohio stream wildlife. They can be identified by three distinct body parts - a head, a thorax and three pairs of legs, and an abdomen. Most grow up under water as larvae, but fly away as adults. Some skate on the surface, some crawl on the bottom, and some even live upside down! Some eat plants, some are predators, and many are eaten by other species of wildlife.

Life Cycles

Aquatic insects have two primary life cycles. One involves four stages - egg, larva, pupa, and adult - as in caddisflies and aquatic beetles. The other involves three stages - egg, nymph, and adult - as in mayflies and stoneflies.

Mayflies

Mayflies live for only a day after becoming an adult. The immatures - or nymphs - live in a variety of stream habitats from which they emerge as adults in very large numbers. Mayflies are excellent indicators of good water quality.

Dragonflies

Underwater or in the air, dragonflies are ferocious predators. Larvae typically go through 10-15 instars over a period of 1-5 years before crawling out of the water. They attach to a stick or plant, squeeze through a slit, and dry their wings before flying away as an adult.

Beetles

Beetles function not only as predators, but also as herbivores depending on the species and life stage. Most life on the bottom, but some live in the water column and are good swimmers. Larvae and adults are an important food source for fish. Adult beetles have wings and can fly.

Caddisflies

As larvae, many caddisflies construct intricate nets, portable cases, and other retreats. The larvae can be predators, filter-feeders, shredders, collector-gathers, or scrappers. Caddisflies are good indicators of water quality and an important food source for fish.

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Learn about mollusks

Learn about stream fish

Learn about reptiles and amphibians

Scioto River Valley Federation   P. O. Box 1501   Delaware OH 43015
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