Dragonflies

Benthic Macroinvertebrates

Sensitive Benthos

Moderately Tolerant Benthos

Pollution Tolerant Benthos

Dragonfly nymph

Metamorphosis:

incomplete (see our life cycle page for more information)

Nymphs:

vary in shape, but most have robust, elongated, or "spider-like" bodies, often with algae growing on their backs; six legs at side of body or near front on elongated species; two large eyes at sides of heads; a pair of small wings begins to develop on back; color varies from brown, black, but often green; length up to 2 inches

Reproduction:

eggs are deposited on surface of water and drift to bottom.

Adults:

similar to adult damselflies, but the two pairs of wings are flat or horizontal at rest; some species can attain lengths of over 4 inches.

Food:

predaceous, nymphs feed upon other aquatic macroinvertebrates, small fish, and tadpoles.

Scientific Name:

Class: Insecta
Order Odonata
Suborder Anisoptera

Indicator Role:

Dragonflies are found in slower moving streams and in ponds, often reflecting waters with lower dissolved oxygen levels.

Adult dragonfly

Information Source:

McDonald, B., W. Borden, J. Lathrop.1990. Citizen Stream Monitoring: A Manual for Illinois. Illinois Department of Energy and Natural Resources, ILENR/RE-WR-90/18. Springfield, Illinois.

For more pictures, see our photo library on Odonates

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