Nemouridae

Nemouridae is a family of stoneflies (order Plecoptera) known as nemourid stoneflies. The group comprises numerous genera and hundreds of species distributed largely in the temperate regions of the Northern Hemisphere. They inhabit cool, fast-flowing streams and rivers, often in forested landscapes with clean, well-oxygenated water.

Nymphs, or naiads, are aquatic and live in riffles and leaf litter along stream margins. They are typically slender, with two long cerci, and feed on detritus, algae, and periphyton. Adults usually have two pairs of wings and long antennae, although some species are brachypterous or wingless. Adults are generally short-lived and focus on dispersal to find mates.

Life cycle and development follow incomplete metamorphosis. Eggs are laid in water, from which naiads hatch and undergo several molts, developing over one to several years before reaching their final molt to winged adults. Emergence typically occurs in spring and early summer, depending on species and local conditions.

Ecology and significance: Nemouridae plays an important role in stream ecosystems as detritivores and as prey for aquatic and terrestrial predators. Because they require clean, well-oxygenated water, nemourids are commonly used as bioindicators of freshwater quality. Their presence and diversity can reflect habitat integrity and water health.

Genera: The family includes a variety of genera, with Amphinemura and Nemoura among the better-known examples. Overall, Nemouridae represents a historically important and ecologically informative group within Plecoptera.