Coelenterata (Hydras) Turbellaria (Flatworms) A tube with tentacles Reproduces asexually by budding Movement: sessile, attached or fixed, not free moving Colour: clear to whitish Flattened shape Distinct head with eye spots Movement: creeps slowly along tray bottom Colour: usually dark, mottled greyish-brown to black Size: 2 to 25 mm Size: 5 to 30 mm Nematoda (Roundworms) Oligochaeta (Aquatic Earthworms) Tapered head Pointed tail Segmented, round, soft bodies, similar to earthworms Tiny bundles of hairs on each segment behind the first Non-segmented Movement: rapid, whip-like Colour: often clear Size: 5 to 15 mm Movement: crawls along the tray bottom, or curls up Colour: often pinkish or brown Size: 1 to 30 mm citizensenvironmentwatch.org 21
Hirudinea (Leeches) INDICATOR BENTHIC MACROINVERTEBRATE Body with 34 annulated segments, suckers on both ends Head often with several pairs of eyes Isopoda (Sow Bugs) 7 pairs of legs Dorso-ventrally compressed 1st antennae longer than 2nd Movement: uses suckers to inch along tray bottom, or swims Movement: crawls along tray bottom, often patterned Colour: greyish Size: 5 to 300 mm Size: 5 to 20 mm Pelecypoda (Clams) Amphipoda (Scuds) Hard oval shell hinged in two halves Six pairs of legs Laterally compressed Do not count empty shells Two pairs equal length antennae Movement: none Movement: swims on its side Colour: often light grey or brown Size: 2 to 250 mm Size: 5 to 20 mm 22 WATER QUALITY Monitoring with Benthic Macroinvertebrates
Decapoda (Crayfish) INDICATOR BENTHIC MACROINVERTEBRATE Trombidiformes-Hydracarina (Mites) Eight legs, like small spiders Large claws; eyes on stalks Round body Looks like small lobster Movement: swims backwards Movement: uncoordinated scrambling, swimming Colour: green, brown, or blue Colour: brightly coloured eg. red, green Size: 10 to 150 mm Size: 0.5 to 7 mm Ephemeroptera (Mayflies) Anisoptera (Dragonflies) Single tarsal claw Big head and eyes Gills under abdomen No external gills Usually three tail filaments Movement: swims up and down in an S pattern Modified labium for catching prey Movement: slow Colour: brown Colour: drab, brownish, green Size: 3 to 28 mm (not incl. tail) Size: 15 to 45 mm citizensenvironmentwatch.org 23
Zygoptera (Damselflies) Plecoptera (Stoneflies) Compound eyes Tubular, thin body Three gills at terminus of abdomen Tarsi with two claws No gills on abdomen Two tail filaments Movement: slow Movement: swims, walks slow Colour: drab Colour: drab, varies Size: 10 to 25 mm Size: 5 to 50 mm Tolerance Value: 7 Tolerance Value: 1 Hemiptera (True Bugs) Megaloptera (Fishflies, Alderflies) Three pairs of soft, folded wings Well developed mandibles Soft body Lateral abdominal gill filaments Movement: swims, skims water surface Colour: black to brownish Size: 15 to 40 mm Three pairs of legs Movement: crawls Colour: drab, brown Size: 25 to 90 mm Tolerance Value: 4 24 WATER QUALITY Monitoring with Benthic Macroinvertebrates
Trichoptera (Caddisflies) INDICATOR BENTHIC MACROINVERTEBRATE Often found in cases (do not count empty cases) Dorsal thorasic plates sclerotized Lepidoptera (Aquatic Moths) Head with ring of ocelli Three pairs of short, segmented, thoracic legs Anal prolegs with hooks Ventral, abdominal prolegs Movement: slowly crawls Movement: crawls like a caterpillar Colour: cream coloured abdomen Size: 2 to 50 mm Size: 10 to 25 mm Tolerance Value: 4 Coleoptera (Beetles) Gastropoda (Snails, Limpets) Three pairs of segmented legs Hardened forewings Larvae with sclerotized head with mandibles Hard spiral or cap-shaped shell Do not count empty shells Movement: crawls, swims Movement: none Colour: black, brown Size: 2 to 40 mm Size: 2 to 70 mm Tolerance Value: 4 & citizensenvironmentwatch.org 25
Chironomidae (Midges) Tabanidae (Horse and Deer Flies) Sometimes in tube of silt, segmented body Characteristic J shape Anterior and posterior parapods Pointed at both ends, segmented Leathery texture Several pairs of creeping welts with hooks on each segment Movement: whip-like motion Movement: none - red, white, yellow Colour: white, cream Size: 2 to 30 mm Size: 15 to 40 mm Tolerance Value: 7 Culicidae (Mosquitos) Ceratopogonidae (No-see-ums) Fused thoracic segments Very slender, pointed at both ends Posterior respiratory siphon Segmented with sclerotized head Movement: twitches when touched Movement: whips, stiffens when touched Colour: brown Size: 3 to 15 mm Size: 3 to 13 mm 26 WATER QUALITY Monitoring with Benthic Macroinvertebrates
Tipulidae (Crane Flies) Simuliidae (Black Flies) Reduced head is retracted into thorax Often with pair of labral fans Posterior respiratory disc with lobes Fattened posterior with attachment organ Movement: worm-like Movement: like an inch-worm Colour: white, yellow, brown Colour: greyish, brown Size: 10 to 50 mm Size: 3 to 15 mm Tolerance Value: 3 Misc. Diptera (Misc. True Flies) Adults with single pair of wings No jointed thoracic legs May have parapods, pseudopodia, creeping welts, appendages Movement: varies CREDITS Images and characteristics adapted from Gartner Lee Limited, 1997; Ontario Benthos Biomonitoring Network, 2005. Tolerance values indicate tolerance to nutrient enrichment (Southern Ontario). Values are between 0 (intolerant) and 10 (very tolerant). Tolerance values adapted from Watershed Report Card, 2000. Size: varies citizensenvironmentwatch.org 27