Macroinvertebrates of the Pacific Northwest

A FIELD GUIDE

Companion to the CD-ROM Stream Bugs as Biomonitors: Guide to Pacific Northwest Macroinvertebrate Monitoring

Jeff Adams and Mace Vaughan THE XERCES SOCIETY Ephemeroptera: Baetidae Ephemeroptera: Ameletidae Ephemeroptera: Ephemerellidae Ephemeroptera: Leptophlebiidae (small minnow mayflies) (ameletid minnow mayflies) (spiny crawler mayflies) (prong-gill mayflies) Habitat: flowing and still waters Habitat: rocks; flowing waters Habitat: rocks; flowing waters Habitat: flowing and still waters Behavior: swimmers Behavior: swimmers/clingers Behavior: clingers Behavior: swimmers/clingers Feeding: collector-gatherers Feeding: collector-gatherers Feeding: collector-gatherers Feeding: collector-gatherers Tolerance: tolerant Tolerance: moderate Tolerance: sensitive Tolerance: moderate The most common mayflies; Sometimes common in small, Diverse in number of species Very common; found in a variety have 2 or 3 tails and round, flat mountain streams; 3-tailed and appearance; when resting, of freshwater habitats; have 3 tails gills; the antennae are much mayflies with a striking color the gills may move rapidly; and usually have long, forked longer than the head is wide; in a pattern, a large head, and short gills are never present on the gills; may have tusks at lower sample tray, usually dart or swim antennae; have round, flat gills first and second abdominal elevations; undulate through the quickly, stop, float down with with a dark line on the outside; segments; usually crawl around water of a sample tray and often legs spread, then swim again. fast-swimming. the bottom of a sample tray. wave gills when resting.

Ephemeroptera: Heptageniidae Ephemeroptera: Leptohyphidae Ephemeroptera: Ephemeridae Plecoptera: Peltoperlidae (flat-headed mayflies) (little stout crawler mayflies) (common burrower mayflies) (roach-like stoneflies) Habitat: rocks; flowing waters Habitat: warmer valley streams Habitat: pools and edges of Habitat: rocks, mosses, leaf Behavior: clingers and rivers valley streams and rivers packs; flowing water Feeding: scrapers Behavior: clingers Behavior: burrowers Behavior: clingers Tolerance: moderate Feeding: scrapers Feeding: collector-gatherers Feeding: shredders Mayflies with very flattened bod Tolerance: tolerant Tolerance: tolerant Tolerance: sensitive ies and 2 or 3 tails; legs spread Stout-bodied mayflies; usually Large, soft-bodied, and usually Small stoneflies; shaped like to the sides; the head appears tan or beige with 3 tails; the pair yellowish to gray; the front of tear drops with very short tails; rounded with large eyes; some- of gills on the second abdominal the head has tusks; gills on the legs relatively short; the gills times swim in a sample tray by segment are large triangular abdomen are large and feather- are hidden under wingpads; undulating awkwardly, but usu- plates that cover the remaining like; burrow in mud and soft look like tiny roaches; slow and ally cling closely to the bottom. gills. sediments; rare in rocky riffles. camouflaged in a sample tray.

Plecoptera: Pteronarcyidae Plecoptera: Perlidae Plecoptera: Perlodidae Plecoptera: Chloroperlidae (giant stoneflies) (golden stoneflies) (little yellow stoneflies) (little green stoneflies) Habitat: rocks, leaf packs; Habitat: rocks; flowing waters Habitat: rocks; flowing waters Habitat: rocks, leaf packs; flowing waters Behavior: clingers Behavior: clingers flowing water Behavior: clingers Feeding: predators Feeding: predators Behavior: clingers Feeding: shredders Tolerance: sensitive Tolerance: moderate Feeding: predators Tolerance: moderate Large, active stoneflies with Medium-sized, active, diverse Tolerance: moderate The largest stoneflies, with dark clusters of finger-like gills stoneflies; look similar to golden Common, small, tan stoneflies; bodies and short tails; slow and between their legs and some- stoneflies, but without clusters the abdomen is long, widest in the lumbering; clusters of white gills times between their tails; color of gills; may have one or two middle; tails are shorter than the cover the underside of the thorax; ranges from tan to black with finger-like gills between their length of the abdomen; they crawl the top of the first thoracic seg- light color patterns; gills are legs; may have light stripes near the bottom or sometimes wig ment may have pointed corners. less obvious in earlier instars. running down the abdomen. gle in the water of a sample tray.

Plecoptera: Nemouridae Plecoptera: Leuctridae Plecoptera: Capniidae Trichoptera: Hydropsychidae (little brown stoneflies) (rolled-winged stoneflies) (slender winter stoneflies) (net-spinner caddisflies) Habitat: rocks, organic debris; Habitat: rocks, leaf packs; Habitat: rocks, leaf packs; Habitat: rocks; flowing waters flowing water flowing water flowing water Behavior: clingers Behavior: clingers Behavior: sprawlers/clingers Behavior: sprawlers/clingers Feeding: collector-filterers Feeding: shredders Feeding: shredders Feeding: shredders Tolerance: tolerant Tolerance: moderate Tolerance: moderate Tolerance: sensitive Have solid plates on top of all Very common; small, hairy, red- Long, thin stoneflies; bodies Bodies are gray to tan; the ab 3 thoracic segments and a tuft dish-brown stoneflies; the legs uniformly gray to reddish- domen is usually widest in the of hair on each of the 2 legs at are relatively long; most have brown; the entire abdomen is middle; the tails are long; very the end of the abdomen; build small gills beneath the neck or the same width; the tails are small in late summer or fall stationary shelters; in a sample head; crawl slowly and blend long, but break easily; may samples; may get caught in the tray, wiggle side-to-side or crawl into the debris in a sample tray. look very similar to a fir needle. surface tension of a sample tray. with body hunched up.

Trichoptera: Rhyacophilidae Trichoptera: Philopotamidae Trichoptera: Psychomyiidae Trichoptera: Polycentropodidae (free-living caddisflies) (finger-net caddisflies) (net-tube caddisflies) (tube-maker caddisflies) Habitat: rocks; flowing waters Habitat: under rocks; flowing Habitat: rocks; flowing waters Habitat: solid substrates; flowing Behavior: clingers waters Behavior: clingers or still water Feeding: predators Behavior: clingers Feeding: collector-gatherers Behavior: clingers Tolerance: moderate Feeding: collector-filterers Tolerance: moderate Feeding: predators The only caddisflies that do not Tolerance: moderate Similar to free-living and tube- Tolerance: moderate build shelters or cases; most are The bodies are usually yellowish maker caddisflies, but have no The heads usually have many bright green to greenish-brown; with tan heads; unlike others plate on the last abdominal dark spots; the long bodies are may or may not have gills; un on this page, have a white fleshy segment and lack spots on the usually pinkish; have no plate like others on this page, have extension at the front of the head; have a hatchet-shaped ap- on top of the last abdominal a hard plate on top of the last head; build stationary shelters; pendage at the base of the front segment; build stationary abdominal segment. wiggle actively in a sample tray. legs; build stationary shelters. shelters.

Trichoptera: Glossosomatidae Trichoptera: Hydroptilidae Trichoptera: Helicopsychidae Trichoptera: Leptoceridae (saddle-case-maker caddisflies) (purse-case-maker caddisflies) (snail-case-maker caddisflies) (longhorned case-maker Habitat: rocks; flowing waters Habitat: mostly slower waters Habitat: gravels; flowing waters caddisflies) Behavior: clingers Behavior: clingers/climbers Behavior: clingers/climbers Habitat: most fresh waters Feeding: scrapers Feeding: scrapers Feeding: scrapers Behavior: clingers/sprawlers Tolerance: moderate Tolerance: tolerant Tolerance: tolerant Feeding: predators/collector-gath- The body is distinctive with dark Mature larvae of these algae Unmistakable, coiled sand erers hard parts on the head, the legs, eaters build purse-like cases of cases are shaped like a snail; Tolerance: moderate and the top of the first thoracic silk with sand or algae; the body the body is also dramatically The cases are made of sand or segment; the body is slightly is usually distinctly flattened curved; found from cold springs organic debris; the hind leg is long curved, as is the unique tortoise- side-to-side, with hard plates on to warm rivers and from fast and curved behind the head; the shell-like case that these caddis- the top of each thoracic segment; streams to lake shores, but most only caddisflies with antennae flies build of sand and pebbles. small and difficult to see. common in large warm rivers. long enough to be noticeable.

Trichoptera: Brachycentridae Trichoptera: Lepidostomatidae Trichoptera: Uenoidae Trichoptera: Limnephilidae (humpless case-maker (case-maker caddisflies) (case-maker caddisflies) (northern case-maker caddisflies) Habitat: slower current of Habitat: rocks; flowing waters caddisflies) Habitat: flowing waters smaller streams Behavior: clingers Habitat: most fresh waters Behavior: clingers/climbers Behavior: climbers/sprawlers Feeding: scrapers Behavior: climbers/sprawlers Feeding: shredders/collectors Feeding: shredders Tolerance: moderate Feeding: shredders Tolerance: moderate Tolerance: sensitive Relatively common case-maker Tolerance: moderate Diverse in appearance and The case can be spiraling pieces caddisflies; the case is either Diverse group of large caddisflies. feeding; the case is either round of plant matter, a sand cone, or thick and pebbly (moderately [Less common case-maker cad- or square in cross section; legs 4 wood-paneled sides; the head tolerant) or long, thin, and disflies are not included in this may be long for filtering food; is usually dark with light spots; smooth (highly sensitive species guide; please see the CD-ROM the head and legs are tan to the antennae are at the front found in mountain streams). for more detail.] reddish-brown. edge of the eye, but hard to see.

Megaloptera: Sialidae Megaloptera: Corydalidae Odonata: Anisoptera Odonata: Zygoptera (alderflies) (hellgrammites) (dragonflies) (damselflies) Habitat: slow and still waters Habitat: cold rocky streams Habitat: mostly still waters Habitat: mostly still waters Behavior: burrowers/climbers Behavior: clingers Behavior: sprawlers/climbers Behavior: climbers Feeding: predators Feeding: predators Feeding: predators Feeding: predators Tolerance: tolerant Tolerance: sensitive Tolerance: tolerant Tolerance: tolerant Active predators found in slower Large, active predators found in The body is wide; the underside The body is long and thin; areas of streams and in wetlands cold, rocky, mountain streams; of the head has an extendible the underside of the head has and other still water; the abdom the abdominal segments have mouthpart used for grabbing an extendible mouthpart used inal segments have a long fila- a long filament sticking out to prey, but usually held tight to for grabbing prey, but usually ment sticking out to each side; each side; the abdomen has the head; the abdomen has no held tight to the head; the end the abdomen has a single, long a pair of prolegs at the end, gills or tails, but may have 3 of the abdomen has 3 flat, tail- filament at the end. each with a pair of hooks. short, sharp points at the end. like gills.

Lepidoptera: Pyralidae Coleoptera: Elmidae Coleoptera: Psephenidae Arachnida: Hydracarina (aquatic caterpillars) (riffle beetles) (water pennies) (water mites) Habitat: open rivers and streams Habitat: flowing waters Habitat: strongly flowing waters Habitat: most fresh waters Behavior: clingers Behavior: clingers/climbers Behavior: clingers Behavior: swimmers/clingers Feeding: scrapers Feeding: collector-gatherers Feeding: scrapers Feeding: predators/scavengers Tolerance: tolerant Tolerance: moderate Tolerance: tolerant Tolerance: tolerant Usually found in larger, warmer Larvae and adults are both Flat, round beetle larvae; tan Common in most freshwater rivers; build silken shelters on regularly collected in riffle to brown, often with a mottled habitats, and often collected rocks in flowing water; the thorax samples; adults are very small pattern; plates extending from in riffle samples; look like tiny and abdomen have clusters of and slow moving; larvae have the body segments cover the red, gray, or green dots with gills; the eyes are a small group of long, hardened bodies; generally head and legs. [Other beetle 8 legs; move rapidly around spots; the middle of the abdomen well-camouflaged and difficult families are less common in the bottom of a sample tray. has four pairs of tiny prolegs. to see in a sample tray. riffles; please see the CD-ROM.]

10 Crustacea: Decapoda Crustacea: Amphipoda Crustacea: Isopoda Crustacea: Ostracoda (crayfish) (scuds) (aquatic sow bugs) (seed shrimp) Habitat: most fresh waters Habitat: most fresh waters Habitat: most fresh waters Habitat: most fresh waters Behavior: sprawlers Behavior: climbers/swimmers Behavior: sprawlers Behavior: climbing/swimming Feeding: collector-gatherers Feeding: collector-gatherers Feeding: collector-gatherers Feeding: collector-gatherers Tolerance: moderate Tolerance: tolerant Tolerance: tolerant Tolerance: tolerant One of the largest and most easily Bodies are flattened side-to-side, Bodies are flattened top-to- Generally white to grayish-green; observed macroinvertebrates in curved from head to tail, and bottom and grayish to brown; tiny, clam-like, jelly-bean-shaped Northwest streams; has 8 legs and gray to green; may carry eggs found in most aquatic habitats, crustaceans; the exoskeleton is 2 large claws; the exoskeleton under the abdomen; usually but can be common in shallow expanded to cover the body with is usually quite hard. Only the swim or crawl on their side in a flowing waters; crawl flat along a bivalve “shell”; 1 dark eye and 3 genus Pacifastacus is native to the sample tray. the bottom of a sample tray. pairs of highly modified legs are Northwest. sometimes visible.

11 Diptera: Simuliidae Diptera: Chironomidae Diptera: Ceratopogonidae Diptera: Dixidae (black flies) (midges) (biting midges) (dixid midges) Habitat: most flowing waters Habitat: most fresh waters Habitat: most fresh waters Habitat: slow flowing waters Behavior: clingers Behavior: burrowers Behavior: sprawlers/burrowers Behavior: swimmers/climbers Feeding: collector-filterers Feeding: collectors/predators Feeding: predators Feeding: collector-gatherers Tolerance: tolerant Tolerance: tolerant Tolerance: tolerant Tolerance: moderate Bowling-pin shaped; usually Extremely common, very diverse, Either long, thin, and tubular Often dark; the head is usually brown to black, with 2 fans and usually quite small; some- with a brown head, striped tilted back; swim in a wiggling on the head; move in a sample times red, yellow, gray, or purple; body, and pointed hind end; U-shape; feed with the curve of tray by placing the head down, the body is thin with a hard head or short, thick, and spiny with the U out of the water and head spinning a pad of silk, then and a pair of prolegs at each end; front and rear prolegs; may submerged; have plates on the rear inching the hind end forward often wiggle actively in a sample wiggle actively in a sample tray. end and 1 or 2 pairs of short pro- to hook into the silk. tray. legs at the front of the abdomen.

12 Diptera: Tipulidae Diptera: Blephariceridae Diptera: Deuterophlebiidae Diptera: Athericidae (crane flies) (net-winged midges) (mountain midges) (water snipe flies) Habitat: most fresh waters Habitat: fast, cold waters Habitat: small, fast, cold streams Habitat: swift rocky streams Behavior: burrowers/sprawlers Behavior: clingers Behavior: clinger Behavior: clingers Feeding: predators/shredders Feeding: scrapers Feeding: scrapers Feeding: predators Tolerance: tolerant Tolerance: sensitive Tolerance: sensitive Tolerance: tolerant Very diverse group: some have Unique group with 7 deeply sep The head is dark and distinct Usually brown in color; the fleshy prolegs on the abdomen, arated body sections (the largest with long forked antennae; 3 abdomen has 7 pairs of prolegs some have swollen areas, others includes the head); brown to thoracic segments are clearly and a single proleg at the end; have neither; body gold to brown, black from above; a fleshy sucker visible; the abdomen has 7 the body has fleshy lobes often translucent; the head is is present on the underside of pairs of fleshy legs; found sticking out to the sides and concealed under the skin; hind the first 6 body sections; move on large rocks in fast, well- off of the hind end; crawl along end has 1 to 8 short to long lobes. slowly; found on larger rocks. oxygenated streams. the bottom of a sample tray.

13 Platyhelminthes: Turbellaria Annelida: Oligochaeta Annelida: Hirudinea Nematoda (flatworms or planarians) (aquatic earthworms) (leeches) (roundworms or nematodes) Habitat: most fresh waters Habitat: most fresh waters Habitat: slow or still waters Habitat: all fresh waters Behavior: clingers Behavior: burrowers Behavior: clingers/swimmers Behavior: burrowers Feeding: predators/collectors Feeding: collector-gatherers Feeding: predators Feeding: mostly predators and Tolerance: moderate Tolerance: tolerant Tolerance: tolerant parasites Extremely flattened; gray to Long, tubular, many-segmented The body is usually tough and Tolerance: tolerant brown; very soft body, easily worms with blunt ends and few composed of dozens of segments; Short, unsegmented worms; damaged or torn; no distinguish- distinguishing features; have have front and rear suckers; the clear, gray, or white in color; ing features, but may be shaped tiny bristles on each segment; front sucker may be small; front usually pointed on one end, like a wide arrow and have eye- color ranges from white to red- segments usually have numerous and variously blunt on the other; spots; glide smoothly across the dish brown. eyespots; move by inching along tiny and rarely seen in the field. bottom of a sample tray. with the suckers or swimming.

14 Mollusca: Bivalvia Mollusca: Bivalvia Mollusca: Gastropoda Mollusca: Gastropoda (clams) (mussels) (snails) (limpets) Habitat: most fresh waters Habitat: soft to sandy bottoms Habitat: most fresh waters Habitat: rocks; flowing waters Behavior: burrowers Behavior: burrowers Behavior: clingers Behavior: clingers Feeding: collector-filterers Feeding: collector-filterers Feeding: scrapers Feeding: scrapers Tolerance: tolerant Tolerance: sensitive Tolerance: tolerant Tolerance: tolerant Small- to medium-sized mollusks Large mollusks with 2 hard, Diverse in shape and size, but These snails have a dark, low with 2 round shells attached by a usually oval shells connected by all have a single, coiled shell; cone for a shell instead of the hinge; color may be clear or white a hinge; the outside of the shell the shell is most often cone-like typical coiled shell of most snails; to tan or brown. If it is much is typically brown to black; more or flattened; a hard plate may a large foot and soft body are larger than a pea and has a shell common in still or slow water, cover the opening in the shell protected by the shell; a rasping with ridges, it is probably the but those pictured on the left when the soft body is retracted. mouthpart may also be visible introduced Asian clam. above may be found in streams. when upside down.

15 This guide was developed as a field companion to the Xerces Society’s CD-ROM,Stream Bugs as Biomonitors: Guide to Pacific Northwest Macroinvertebrate Monitoring. The images in this guide are representative of common and readily visible groups of species encountered in wadeable streams of the Pacific Northwest. General information is included on the identification and natural history of each group. Most images are of entire organisms; in some cases close-ups highlight particular features mentioned in the text.

Each entry begins with the scientific name of the group, fol- Shredders shred large pieces of plant matter; lowed by its common name in parentheses. The black and Scrapers eat algae coating underwater surfaces; grey lines to the left of each image indicate the range of body Collector-filterers filter fine particles of decomposing lengths of the mature aquatic forms in each group (immature organic matter suspended in the water; individuals are smaller). An arrowhead indicates that some of Collector-gatherers gather fine particles of decomposing the species in the group may be larger than can be shown. organic matter from the substrate or surface film; Predators Habitat describes characteristics of the aquatic habitat in eat living animals, usually other macroinverte which each group of species is found. brates, but fish and amphibians as well; Parasites live and feed on living animal hosts. Behavior indicates the behaviors typical of each group: Burrowers live among silt, sand, and organic material; Tolerance indicates the ability of a group of species to with- Clingers attach to substrates in current; stand stresses caused by such human disturbances as water Climbers move vertically on plants or debris; pollution, sedimentation, and changes in temperature: Sprawlers live on top of plant debris or soft substrates; Sensitive means that the species in the group are severely Swimmers cling to submerged objects, then swim through affected by human disturbance; the water column in short bursts. Moderate means that species in the group are somewhat sensitive to human disturbance; Feeding indicates the Functional Feeding Group to which the Tolerant means that species in the group can withstand species belong, and thus the feeding methods they employ: a high degree of human disturbance.

Copyright © 2003 by the Xerces Society. All rights reserved. This guide was made possible by generous contributions from the Oregon Watershed Enhancement Board, the Flintridge Foundation, the Bullitt Foundation, and the Norcross Wildlife Founda- tion. Text and most images by Jeff Adams, with contributions from Patrick Edwards. Layout by Mace Vaughan and John Laursen. The Xerces Society 628 NE Broadway, Suite 200 Portland, OR 97232 1-855-232-6639 www.xerces.org