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Freshwater Macroinvertebrate Diversity

Freshwater Macroinvertebrate Diversity. ENVIRON 311 / EEB 320 Winter 2007. Phylum Platyhelminthes Class Turbellaria. Flatworms Habitat: widespread in marine and freshwater Notes: Class Turbellaria free-living (Some others are parasites) Dorsoventrally flattened; no body cavity

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Freshwater Macroinvertebrate Diversity

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  1. Freshwater Macroinvertebrate Diversity ENVIRON 311 / EEB 320 Winter 2007

  2. Phylum PlatyhelminthesClass Turbellaria • Flatworms • Habitat: widespread in marine and freshwater • Notes: • Class Turbellaria free-living (Some others are parasites) • Dorsoventrally flattened; no body cavity • Not segmented • Some marine species are brilliantly colored • One of first animals to display bilateral symmetry

  3. Phylum PlatyhelminthesClass Turbellaria • Anatomy/Physiology: • Displays primitive cephalization (development of a head) • Feeding is through ventral mouth • No digestive outlet: wastes diffuse across body membranes • Can reproduce asexually through fragmentation

  4. Phylum AnnelidaClass Oligochaeta • Bristle worms • Habitat: Widespread in marine and fresh waters • In fresh water, commonly prefers fine sediments with plentiful organic carbon • Notes: • Cylindrical, multisegmented body • Setae present • Anterior mouth for eating and anus for excretion • Abundance of certain species may be indicator of pollution

  5. Phylum AnnelidaClass Hirudinea • Leeches • Habitat: Vegetated spots in lakes and sluggish parts of rivers • Notes: • Dorsoventrally flattened • Multisegmented • Parasite of vertebrates and predator of small invertebrates • Three “teeth” in mouth allow it to cut into host • Anticoagulants keep blood flowing • After decent meal, may not need to feed for 100 days

  6. Class Hirudinea • Leech locomotion • Use anterior and posterior suckers in sequence to anchor body while muscles selectively contract • Needs hard substrate for locomotion: cannot live in disturbed, silty habitats Credit: Josee Soucie, Biodidac

  7. Phylum Mollusca • Molluscs (Mollusks) • Class Gastropoda • Snails • Univalve shell covers soft, unsegmented body with foot and tentacles • Highly mobile • Subclass Prosobranchia has gills and operculum • Subclass Pulmonata has lungs and no operculum • Prefer hard waters (used to maintain calcareous shell)

  8. Phylum MolluscaClass Gastropoda, Family Ancylidae Courtesy of: UM Museum Animal Diversity Web • Limpets • Habitat: Well-aerated hardwater streams; other waters with emergent rocks or vegetation • Notes: • Univalve shell does not spiral • Feeds mainly on algae

  9. Phylum MolluscaClass Gastropoda, Family Lymnaeidae • Pond snails • Habitat: varies; common in lakes and ponds • Notes: • Pointy, spiraled shell opens to the right (dextral) • Feeds on periphyton

  10. Ecophenotypes in Snails • Snails at top left and right are different species of lymnaeids • When placed together in the aquarium, the offspring (at bottom of photo) appeared to be intermediate • They turned out to be the species on the top left but their development had been altered by a changed environment Courtesy of: UM Museum Animal Diversity Web

  11. Phylum MolluscaClass Gastropoda, Family Physidae • Pouch snails • Habitat: varies; common in lakes and ponds • Notes: • Pointed, spiraled shell opens to left (sinistral) • Feeds on periphyton

  12. Phylum MolluscaClass Gastropoda, Family Planorbidae Courtesy of: UM Museum Animal Diversity Web • Orb snails • Habitat: common in lakes and ponds • Notes: • Shell spiraled but not pointed; roughly in one plane • Like most other freshwater gastropods, feeds largely on periphyton

  13. Phylum Mollusca • Class Bivalvia • Clams and Mussels • Found in marine and fresh waters • Bivalve shell encloses soft body with foot that can project for movement • Mainly filter feeders • Prefer hard waters to preserve calcareous shell • Almost 1/3 of all freshwater mussels found in the US (most in SE)

  14. Phylum MolluscaClass Bivalvia, Family DreissenidaeDreissena polymorpha • Zebra mussel • Introduced to Great Lakes in 1988; now occurs throughout most of Ohio/Mississippi River system • Occurs on hard substrates • Invasive species that competes with rare native mussels and may exclude other invertebrates • May also increase bioaccumulation of harmful pollutants in smallmouth bass • Via another introduced species: the round goby

  15. Phylum MolluscaClass Bivalvia, Families Corbiculidae and Sphaeriidae • Asian and Fingernail Clams • Habitat: Found in wide variety of lentic and lotic sediments • Corbiculids introduced from Asia • Show fewer and more pronounced ridging on exterior of valves • Sphaeriids native • Show shallow ridging • Gradually disappearing from many areas

  16. Phylum MolluscaClass Bivalvia, Family Unionidae • Freshwater mussels • Habitat: clean streams, lakes • Notes: • One of the most threatened animal groups in North America due to pollution, habitat loss, overharvesting and zebra mussel (which may seal valves shut) • Many lotic species seriously affected by dams Courtesy of: UM Museum Animal Diversity Web

  17. Phylum Arthropoda Courtesy of: UM Museum Animal Diversity Web • Extremely diverse group • Includes the crustaceans, myriapods, arachnids and insects • Wide variety of adaptations • Have colonized freshwater, marine, and terrestrial habitats around the world • Found everywhere from tar pits to the Antarctic ice sheets to ocean trenches

  18. Dominance of the Arthropods • Arthropods make up an enormous proportion of all species of life • The insects themselves make up more than half of all species diversity on the planet • Major advantages of being an insect: • Flight • Size (relative strength, general ease of diffusive respiration) • Rapid reproductive rate

  19. Characteristics of Arthropods • Possess hard exoskeleton • In order to grow, must molt • Segmented body, legs, mouthparts and antennae • Reflects specialization and reduction of segments from earlier forms (e.g. segmented worms) • Head, thorax and abdomen present (though sometimes fused) • Eyes (usually)

  20. Phylum ArthropodaSuperclass Crustacea • Characteristics of crustaceans • Two pairs of antennae • Head and thorax usually fused into cephalothorax • Three pairs of mouthparts • Usually > three pairs of legs • Habitat: • Primarily aquatic and mostly marine

  21. Phylum ArthropodaSuperclass Crustacea, Order Ostracoda • Seed shrimp • Habitat: shallow wetlands to sea floor depths • Notes: • Feed on detritus, plankton • Body protected by bivalve carapace

  22. Phylum ArthropodaSuperclass Crustacea, Order Amphipoda • Scuds, sideswimmers • Habitat: Widespread in marine and fresh waters • Notes: • Laterally compressed body • Seven pairs of “walking” appendages • Feed mainly on detritus • Abundant and important food source for many fishes; where amphipods are in decline, some fish species will follow • Prolific; will often be found mating

  23. Phylum ArthropodaSuperclass Crustacea, Order Isopoda • Sowbugs • Habitat: mostly marine but a few freshwater • Notes • Dorsoventrally compressed • Seven pairs of legs • Tend to prefer vegetated lentic or sluggish lotic habitats • Consume detritus • Related to terrestrial pillbugs

  24. Phylum ArthropodaSuperclass Crustacea, Order Anostraca • Fairy shrimp • Habitat: Ephemeral and permanent wetlands/ponds • Notes: • Lacks carapace • Stalked eyes • Uses many appendages to swim on its back • Many populations only around for short periods of time each year…and may vary greatly in number from year to year • Filter feeders

  25. Phylum ArthropodaSuperclass Crustacea, Order Decapoda • Crayfishes and shrimps • Habitat: Ubiquitous in fresh and marine waters; some are quasi-terrestrial • Notes: • Cylindrical body • Three anterior leg pairs equipped with chelae (moveable fingers) • When startled, raises claws or swims backward using telson • Omnivorous: eats everything from macrophytes to small fish

  26. Phylum ArthropodaSuperclass Hexapoda, Class Parainsecta, Order Collembola • Springtails • Habitat: surface film of fresh water • Notes: • Possess six legs, like the insects, but do not develop wings • Head, thorax and abdomen distinct • Posterior jumping organ (furcula) present • Mainly a terrestrial order • Usually very small (<2 mm)

  27. Phylum ArthropodaSuperclass Hexapoda, Class Insecta • Aquatic insects are ubiquitous in aquatic ecosystems, mostly in the larval stage • Because the adults are able to fly, they have easily colonized almost all terrestrial and freshwater ecosystems • Less successful in the oceans, where flight is not as advantageous

  28. Basic Insect Anatomy • Tarsus/tarsal claw • Cercus • Pronotum • Mesonotum • Metanotum

  29. Class InsectaExopterygotes • Include those insects that possess wingpads in larval (nymphal) stage • Larvae resemble adults (though sometimes loosely), have compound eyes and chitinous (hard) bodies • Pass from egg to nymph to adult stage (no pupal stage) • Aquatic members: • Ephemeroptera, Odonata, Plecoptera and Hemiptera

  30. Class InsectaOrder Ephemeroptera • Mayflies • Habitat: mostly cool lotic waters; some also live in lentic waters • Notes: • Very important source of food for many fish • Usually fairly intolerant of pollution; good indicator taxon • Adults do not feed; only mate and die • Some nymphs are predators, most are grazers or filterers Courtesy of: UM Museum Animal Diversity Web

  31. Class InsectaOrder Ephemeroptera • Many species can move their gills to ventilate when dissolved oxygen levels are low • ID: • usually three terminal filaments • One tarsal claw • Gills may be present on sides of abdomen

  32. Class InsectaOrder Odonata, Suborder Anisoptera • Dragonflies • Habitat: lentic and lotic • Notes: • Obligate predator as both nymph and adult • Nymphs characterized by large extensible labium (lower lip), wide body and tiny cerci on last abdominal segment • Adults hold wings to sides, may be brightly colored

  33. Class InsectaOrder Odonata, Suborder Zygoptera • Damselflies • Habitat: lentic and lotic • Notes: • Obligate predator in all life stages • Nymph characterized by head wider than body and three terminal lamellae (gills) • Also has extensible labium • Adult holds wings up over body; may be highly colored

  34. Dragonfly Feeding

  35. Class InsectaOrder Plecoptera • Stoneflies • Habitat: cool, fast streams • Notes: • Generally sensitive to environmental perturbations; good indicator taxon • Nymphs may be shredders, grazers or predators • Nymphs have two filamentous cerci and two tarsal claws • Adult able to fold wings onto body, generally short-lived and dull-colored

  36. Class InsectaOrder Hemiptera • True Bugs • Habitat: mainly lentic and sluggish lotic • Notes: • Nymph and adult hard to tell apart • Mostly predators; use piercing mouthpart and raptorial forelegs to attack prey • Some forms skate on water surface; others swim below surface

  37. Class InsectaOrder Hemiptera • Unique features: • Males in Family Belostomatidae carry eggs on back until they hatch • Members of Family Notonectidae swim on their backs—hence their common name: backswimmers

  38. Class InsectaEndopterygotes • Include those insects that do not possess wingpads in larval stage • Larvae have simple eyes, bear little resemblance to adults, and have generally softer bodies • Pass from egg to larval to pupal to adult stage • Aquatic members: • Megaloptera, Neuroptera (lacewings), Trichoptera, Lepidoptera (butterflies/moths), Coleoptera, Diptera, Hymenoptera (wasps)

  39. Class InsectaOrder Megaloptera • Dobsonflies, Hellgrammites, Fishflies • Habitat: Mainly swift lotic • Notes: • May grow quite large • Larvae are predatory, characterized by large mandibles, lateral filaments • Adult males grow large tusks, used in mating; usually short-lived • Relatively small group

  40. Class InsectaOrder Megaloptera • Video of a vicious larval dobsonfly • Note display of large mandibles • Also, lateral filaments not used in locomotion

  41. Class InsectaOrder Trichoptera • Caddisflies • Habitat: wide variety of lentic/lotic ecosystems • Notes: • Some larval caddisflies build cases, others are free-living • Note soft abdomen • Wide range of feeding types, from predatory to filter feeding • Characterized by two anal prolegs, in addition to thoracic legs • Adults are dull, resemble moths

  42. Class InsectaOrder Trichoptera • Wide variety of cases among species that build them • May consist of mineral or organic materials • Utilized mainly to allow ventilation; sometimes for protection • Many taxa can be identified by unique cases

  43. Class InsectaOrder Trichoptera • Case building caddisflies spend a lot of time in their cases

  44. EPT • Ephemeroptera, Plecoptera, Trichoptera • Index for streams: the count of EPT taxa (often at the genus level) • AKA: EPT Richness E, P, T = 3 orders of aquatic insects that tend to be most abundant in relatively unpolluted waters, so more is better Usually do % EPT per total

  45. Class InsectaOrder Coleoptera • Beetles • Habitat: wide variety of lentic and lotic • Notes: • Larvae entirely aquatic • Larvae are variable in form but usually elongate and often with unsegmented terminal filaments • Adults often predacious or scavengers • Adults characterized by very hard body and covered first pair of wings

  46. Class InsectaOrder Diptera • True Flies • Habitat: extremely variable; sometimes found in marine ecosystems • Notes: • Very diverse family • Larvae have no segmented legs and often reduced head; may have one or more pairs of prolegs • Larvae have variety of feeding habits • Adults have only one pair of wings • Adults may be parasitic or nectar feeding

  47. Dipteran Photos

  48. The End

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