Upon emergence, adults disperse widely and are frequently captured in light-traps. When larvae complete their development, they leave the water and pupate in cells in protected areas on the adjacent shore. Both stages include scrapers of periphyton, collector–gatherers of fine detritus, and wood gougers. Adults and larvae of some species may also occur on these same substrates in spring ponds or along wave-swept shores of lakes. Both adults and larvae are found mostly in streams, where they inhabit a variety of substrates, including gravel riffles, algae laden rocks, aquatic macrophytes, and decaying wood. The sclerotized larvae are elongate, rounded in cross-section, and have a ventral caudal operculum that closes a chamber containing hooks and numerous filamentous gills ( Plate 16.22, Fig. Adults are less than 4.5 mm long, smaller than Dryopidae adults, and have filiform or slightly clubbed antennae ( Plate 16.22, Fig. Both larvae and adults are usually aquatic and often occur together in a few species, adults are riparian inhabitants. Riffle beetles are widespread and often abundant. Hilsenhoff, in Ecology and Classification of North American Freshwater Invertebrates (Third Edition), 2010 b. Stoneflies were absent at the lower site. Insect proportions below the agricultural reach were 44% dipterans, 34% mayflies, and 20% caddisflies in riffles ( Earl and Blinn 2003). Total insect densities were comparable at the same downstream site used for algae however, insect diversity was reduced. Riffles averaged 524 animals/m 2 compared to 1954 animals/m 2 in pool habitats. Insect densities were typically higher in May and June compared to late summer and fall. Cheumatopsyche and Hydropsyche were common caddisfly taxa, and chironomid midges and black flies made up most of the dipteran assemblage. The most abundant mayflies in riffle habitats were Choroterpes, Epeorus, Leptohyphes, and Serratella. Riffle habitats in the same headwater sites described for algae were typically composed of the following insect categories: 32% mayflies, 26% caddisflies, 23% true flies (Diptera), 13% stoneflies, and 5% beetles ( Earl and Blinn 2003). LEROY POFF, in Rivers of North America, 2005 Invertebrates
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