Freshwater Macroinvertebrate s ANNELIDA Phylum OLIGOCHAETA HIRUDINIA LEECHES

Freshwater Macroinvertebrate s

ANNELIDA -- Phylum OLIGOCHAETA HIRUDINIA (LEECHES)

Anatomy and Appearance ©Elongated form ©Freshwater types small ©Typically a few mm ©Oligochaetes ©Segmented ©Tubificid & Naidid ©Cylindical ©Leeches ©Flattened and large

Vermiform Annelida Nematoda Arthropoda Insecta Chironomidae

Importance ©Oligochaeta ©Detritivores ©Mid food web position ©Euhirudinea ©Parasitic

B A C D E MALACOSTRACANS

Malacostracans ©Mostly marine ©Four orders of freshwater species ©Isopoda (A) ©Amphipoda (B) ©Mystidacea (C) ©Decapoda (D, E) ©Crayfish Shirimp © 600 -800 species

Characteristics ©Larger (1 -30 cm) ©More or less shrimp like ©Sexual ©Many juvenile stages ©Mostly benthic

Importance ©Food web ©Detritus, Carrion, Vegetation, aufwuchs ©“Cleaners” scavenging environment ©Can compete with fish ©Food for vertebrates

INSECTS (also Arthropods) Most kinds are terrestrial. About 14 Orders Several thousand species

Aquatic Insects: Why do we care? Major component of the aquatic food chain - they eat and are eaten Indicators of aquatic health - pollution tolerant vs. non-tolerant species (EPT) Affect human health - vectors for disease (malaria, encephalitis, yellow fever) - they bite you: mosquitoes, gnats, blackflies, and biting midges (Diptera) Many fishing lures modeled after them Lentic – standing water (no flow) Lotic – flowing water DO – fluctuates during the day

How do aquatic insects deal with different O 2 and flowing environments? (2 types of breathing methods) Aeropneustic – get their oxygen from the atmosphere -must keep in contact with the air -or take it with them, making repeated trips -have ‘hydrofuge hairs’ that trap air bubbles -tiny hairs provide surface area for bubbles to attach to, forming a thin film of air called the plastron – allows insects to breath from the air bubble -Coleoptera, Hemiptera -the advantage of periodic contact breathing is that it allows the insect to dive and swim around

Hydropnuestic – use oxygen dissolved in the water -cutaneous respiration (Diptera, Plecoptera) -occurs when the cuticle is thin enough for air to diffuse directly in and out for the insect -allows an insect to remain underwater indefinitely -Tracheal gills -lamellate – flat (Ephemeroptera, Odonata) -filamentous (Megaloptera, Plecoptera) Odanata have gills within their abdomens and pump oxygenated water to their gills through the anus. Can also propel themselves by quickly jetting the water back out. They move fast!!!

What about dealing with flowing water? Lotic insects have morphological features to stay put - suckers (Diptera), hooks (Trichoptera, Megaloptera) - small, flat bodies - sticky secretions - build cases (Trichoptera)

Habitat and Food ©Anywhere anytime ©Anywhere there is water ©Shred, Scrape, collect, capture, filter, pierce ©Creep, Walk, swim…fly ©Several developmental stages ©Like adult or different

Aquatic Insects Immature forms a) Beetle b) Chaoborus (Phantom midge) c) Mayfly d) Dragonfly e) Damselfly f) Caddisfly g) Stonefly

Adult Forms a) Beetle b) Midge c) Mayfly d) Water bug e) Damselfly f) Dragonfly g) Stonefly h) Caddisfly

Beetles Chaoborus (midge) Mayfly Dragonfly Damselfly Stonefly Caddisfly Midge

Beetle Midge (Chaoborus) Mayfly Backswimmer Damselfly Dragonfly Stonefly Caddisfly Midge

Importance ©Huge numbers and diversity ©Middle links in food chain ©Take over from microcrustaceans in shallow water ©Food for vertebrates ©Biting species ©Vector

Aquatic Insects larval or adult form may be aquatic, sometimes both importance in food webs, many roles incl. food for fish some taxa are exceptionally sensitive to pollution a few may be notably resistant often used as indicators of water quality

Some Important Orders of Aquatic Insects Coleoptera (beetles) Hemiptera (true bugs) Diptera (flies) Odonata (dragonflies & damselflies) Megaloptera (dobsonflies & alderflies) Ephemeroptera (mayflies) Plecoptera (stoneflies) Trichoptera (caddisflies)

Order Hemiptera mouthparts modified for piercing predators

Hemiptera (true bugs) • Egg – nymph larva –adult • Predacious “beak” • Wing pads • If wings develop they fold over each other

Order Megaloptera aquatic larvae pointed filaments along length of abdomen hooked prolegs 8 lateral filaments alderflies Sialidae Corydalidae dobsonflies long terminal filament 7 lateral filaments

Megaloptera (alder flies, dobsonflies) • Mouth has large, chewing pinchers (predacious) • Abdomen has strand-like appendages extending from each side • Three pairs of segmented legs on middle section of body with tiny pinchers at the end of each • Each segment contains filaments for respiration • Abdomen ends with two elongated appendages or prolegs

Order Odonata suborder Anisoptera - dragonflies suborder Zygoptera - damselflies - larvae are aquatic (nymphs) - wingpads - raptorial mouthparts - toothed mandibles dragonfly nymph damselfly nymph

Order Odonata

Order Coleoptera larvae and/or adults aquatic forewings modified as elytra water penny crawling water beetle

Coleoptera (beetles) • Egg – larva –pupa – adult • Larva very different from adult • Adults – have hard case on body that does not overlap • Adults have chewing mouthparts • Larva –undeveloped eyes, sometimes have tusks

Order Diptera - aquatic stage: larvae & pupae, not adults - larvae (maggots) lack wing pads; head may be indistinct - no segmented legs on thorax (may have prolegs) Examples: Simuliidae (blackflies) Tipulidae (crane flies) Culicidae (mosquitos) Chironomidae (non-biting midges)

Diptera (midges, mosquitoes, gnats, flies) • Elongate body • Segmented body • Most species rich order (includes Chironomidae) • Adults have one pair of wings • Very diverse morphology

Focus on EPT Taxa Ephemeroptera, Plecoptera, Trichoptera generally pollution-sensitive indicators of stream quality

Order Plecoptera - 2 elongate cerci always present - wingpads present - long slender antennae as much as 4 -6 x width of head - 2 claws on each leg

Plecoptera (stoneflies) • Same life cycle as mayflies • Have 2 filaments • No lamellate gills along abdomen • Some have filamentous gills • Adult wings are flat • Mostly shredders and grazers

Stonefly Family Example Perlidae head w/variable color pattern - gills finely branched - gills only on side of thoracic segments never extend onto abdomen

Order Ephemeroptera mayflies - aquatic nymphs - wingpads present - 2 or 3 caudal cerci - abdominal gills - 1 tarsal claw

Orders you may encounter Ephemeroptera (mayflies) Eggs – larva – subimage - adult Larva – elongate, 3 filaments (tail), can have 2 Lamellate gills along abdomen Well developed legs Perpendicular wings on adults

Some Ephemeropteran Families Baetidae small minnow mayflies collector-gatherers & scrapers - antennae 2 -3 x width of head

Some Ephemeropteran Families Heptageniidae flat-headed mayflies scrapers, some collector-gatherers -head, body & legs dorsoventrally flattened - gills thin, flat discs; round-oval w/o forks or long pointed filaments

Order Trichoptera (caddisflies) -aquatic larvae - very small antennae - wing pads absent - most have hard plates (= nota) on dorsum of thoracic segments 1, 2, and/or 3) - humps often present on dorsal or lateral aspect of abdominal segment 1 - may live in constructed case

Trichoptera (caddisflies) • Have anal prolegs with hook • Less visible antennae • Only order that makes cases • Adult wings down- very hairy

Some Trichopteran Families Hydropsychidae (common netspinner caddisflies) - collector-filterers highly branched gills on abdomen

Some Trichopteran Families Polycentripodidae (trumpet net & tube-making caddisflies) engulfer-predators & collector-filterers trochantin located where base of 1 st leg joins body pointed fore trochantin

Trichopteran Families Helicopsychidae (snailcase maker caddisflies) - scrapers -case coiled like a snail shell - body coiled

References Pennak A Guide to Common Freshwater Invertebrates of North America J. Reese Voshell, Jr. , 442 pp. Ecology and Classification of North Maerican Freshwater Invertebrates, 2 nd Ed. James H. Thorp and Alan P. Covich, Eds. An Introduction to the Aquatic Insects of North America, 3 rd Ed. R. W. Merritt and K. W. Cummins, Eds. Pond and Stream Safari: A Guide to the Ecology of Aquatic Invertebrates. Karen Edelstein. A Guide to Freshwater Ecology Texas Natural Resources Conservation Commission. 1993. Aquatic Macroinvertebrates New York State Department of Envisonmental Conservation http: //www. dec. ny. gov/animals/7105. html

Procedure - samples in well plates - ID to lowest practical taxon using UW key - for insects, key to order w/ gen aquatic insect key & M&C key - for EPT taxa, try to key to family w/M&C - Record specimen #s & ID - can leave specimen in plate or transfer to larger dish in water - keep wet - return to correct spot in plate

Easily Confused Orders Made Easy