Unit 3.2 Macroinvertebrates

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Unit 3.2 Macroinvertebrates
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Freshwater Ecology
Light
Sediment
Current
Temperature
Physical
pH
Photosynthesis
Microorganisms
DO
Chemical
Biological
Turbidity
Macrophytes
Nutrients
Fish
Macroinvertebrates
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Photo M.B. Elder
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Photo M.B. Elder
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Macroinvertebrates as Bioindicators
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Macroinvertebrates as Bioindicators

• Includes
• Insects
• Crustaceans
• Mollusks

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Macroinvertebrates as Bioindicators

• Sensitive to Changes
• Cannot easily escape changes
• Collected very easily

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Macroinvertebrates as Bioindicators

• What do macroinvertebrates do?
• Job Example
• Predators dragonfly, damselfly, beetles
• Filter feeders mussels, fly larvae, midge larvae
• Scrapers snails, mayfly larvae
• Collectors worms, planarians
• Shredders amphipods, caddisfly larvae

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Macroinvertebrates as Bioindicators
Group 1 Very sensitive to
Environmental Stresses Stoneflies Mayflies Caddisf
lies Dobsonflies Water penny Group 2
Somewhat sensitive to Environmental
Stresses Dragonflies Craneflies Damselflies Crayfi
sh Scuds Group 3 Tolerant to
Environmental Stresses Midges
Leeches Snails Pouch Snails Blackfly larva
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Macroinvertebrates as Bioindicators

• Conclusion
• Freshwater organisms-the Biotic part of the
  Freshwater environment- have Limits or Optimal
  ranges in water quality where they prefer to
  live.
• The quality of water can be determined by what
  and how many organisms are living in that
  environment.
• Macroinvertebrates are used to evaluate the
  quality and history of the water environment.

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Macroinvertebrates
Macro Invertebrate
Large enough to be seen with the naked eye
Lacking an internal skeleton of cartilage and
bones

• Invertebrates account for 70 of all known
  species of living organisms (microbes, plants,
  and animals
• If we consider just animals, invertebrates
  account for 96 of known species

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The Importance of Macroinvertebrates

• Macroinvertebrates are an essential component
  of freshwater ecosystems
• They serve as food for other organisms (fish,
  amphibians and waterfowl)
• Are essential to the breakdown and cycling of
  organic matter and nutrients
• Macroinvertebrate diversity is vital to a
  properly functioning ecosystem

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Why Study Macroinvertebrates?

• Macroinvertebrates are used to assess the health
  of freshwater environments
• Some macroinvertebrates are sensitive to stress
  produced by pollution, habitat modification, or
  severe natural events
• Sampling and identifying macroinvertebrates can
  reveal whether a body of water is healthy or
  unhealthy and may reveal the cause of the problem
  
• Known as BIOMONITORING

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Macroinvertebrate Biology
Habitat Movement Feeding Breathing
Life History Stress Tolerance
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Habitat
The place where an organism lives
Running waters lotic seeps, springs, brooks,
branches, creeks, streams, rivers
Standing waters lentic bogs, marshes, swamps,
ponds, lakes
erosional (riffles, wave action) or depositional
areas (point bars, pools)
Mineral bedrock, boulders, cobbles, pebble,
gravel, sand, silt, clay
Organic live plants, detritus
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Movement
Locomotion, habits, or mode of existence

• Skaters adapted to remain on the surface of
  water
• Planktonic float in open water
• Divers surface for oxygen, dive and swim when
  alarmed
• Swimmers adapted for moving through water
• Clingers cling to firm substrates in current
• Sprawlers live on the bottom consisting of fine
  sediments
• Climbers dwell on live aquatic plants or plant
  debris
• Burrowers dig down and reside in the soft, fine
  sediment

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Feeding
Macroinvertebrates are described by how they eat,
rather than what they eat
Functional Feeding Groups categories of
macroinvertebrates based on body structures and
behavioral mechanisms that they use to acquire
their food
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Shredders
Chew on intact or large pieces of plant material

• have basic mouthparts, without any special
  modifications
• basic mouthparts include two jaw like structures
  (mandibles) for cutting and grinding and often an
  upper lip (labrum) and a lower lip (labium) to
  help keep food in their mouths

Shredder-herbivores feed on living aquatic plants
that grow submerged in the water (northern
casemaker caddisflies)
Shredder-detritivores feed on detritus, or dead
plant material in a state of decay (giant
stoneflies)
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Collector-gatherers
Eat fine detritus that has fallen out of
suspension that is lying on the bottom or mixed
with bottom sediments

• position themselves on the bottom and eat the
  detritus from the top of the sediment (non-biting
  midges)
• burrow through the bottom and unselectively
  swallow the sediment and fine detritus as they go
  (aquatic earthworms)
• finger-like projections from some of the
  mouthparts (palps) help them gather the fine
  particles of food

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Collector-filterers
Use special straining mechanisms to feed on fine
detritus that is suspended in the water

• spin nets from silk (netspinner caddisflies)
• have hairs on their heads (black flies)
• appendages create water current for their
  feeding (mussels)

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Scrapers

• Adapted to remove and consume the thin layer of
  algae and bacteria that grows tightly attached to
  solid substrates in shallow waters
• Jaws of scrapers have sharp, angular edges
  (function like using a putty knife or paint
  scraper)
• After algae has been removed, the material is
  swept into the mouth by finger like projections
  from other mouthparts
• (flathead mayflies, water pennies, snails)

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Piercers
mouthparts, or sometimes their entire head,
protrude as modifications to puncture plants and
bring out the fluids contained inside

• penetrate the tissues of vascular or aquatic
  plants or individual cells of filamentous algae
  and suck the liquid contents
• (crawling water beetles, microcaddisflies)

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Predators
mouthparts are modified into one or two hard,
sharp, hollow tubes that they use to stab into
their prey (water scorpions)

• subdue and kill other animals by removing their
  body fluids
• Engulf whole animals

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Breathing
Closed Breathing System depend upon oxygen
dissolved in the water for their
breathing Oxygen enters the organisms by simple
diffusion either through their general body
surface or through gills that are specialized for
this purpose, or both Some have behavioral
mechanisms, such as wriggling the body, to
increase the rate of oxygen diffusion
Open Breathing System obtain oxygen directly
from the atmosphere All some attach a quantity
of air to their body, called an air store, and
take it underwater to breathe from (either in a
bubble or in a thin layer) Others breathe by
pushing either spiracles or some type of
extension on the end of their body to the surface
to reach the atmosphere (breathing tubes or
siphons)
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Life History
Reproduction, growth and development of an
organism

• Hermaphroditic organisms contain both male and
  female reproductive organs (flatworms, aquatic
  earthworms, leeches, snails and mussels)
• Oviparous females lay their eggs outside of
  their body
• Ovoviviparous females retain their eggs and
  allow them to hatch within their body and release
  free-living offspring

• Growth is relatively simple in flatworms, aquatic
  earthworms and leeches because they are not
  restricted by any type of external protective
  structures
• Exoskeletons of arthropods does not grow once it
  has been produced, so growth of the organism is
  restricted. As a result, arthropods must shed
  their skin (molt) in order to increase in size
  (3-45 times).
• Mollusks are enclosed in non-living protective
  covers produced by the organism, called shells
  shells are made of protein and calcium carbonate
  made larger by adding material, like a tree
  growth ring

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Stress Tolerance
Anthropogenic pollution, removal of water by
irrigation, dams, deforestation, removal of
riparian vegetation
Natural volcanoes, forest fires, floods,
landslides
Freshwater invertebrates vary in their ability to
cope with environmental stress Biomonitoring
takes advantage of this situation by identifying
whether an aquatic environment is inhabited
predominantly by stress tolerant or stress
intolerant organisms
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Classification
Kingdom Animalia Phylum Arthropoda
(Arthropods) Annelida (Segmented
Worms) Mollusca (Mollusks)
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Group 1 Taxa
Pollution Sensitive Organisms Found In Good
Quality Water
Stoneflies Mayflies Water Pennies Dobsonflies
Riffle Beetles Mussels
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Plecoptera Stoneflies
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Plecoptera Families Perlida
e Perlodidae Leuctridae
plekein to braid (wings of adult are folded
to fit under front wings) ptera tail

• 3 pairs of segmented legs on thorax
• 2 tarsal claws
• 2 stick-like tails
• gills on thorax (often where leg joins thorax)
• long antennae
• double set of wings
• wing pads are often visible
• most are crawlers
• shredder-detritivores or engulfer-predators

Adults long, thin antennae that project from the
head Both pairs of wings are membranous and have
many veins Wings fold, when not is use, so that
they lie flat over the abdomen
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Ephemeroptera Mayflies
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Ephemeroptera Families
Baetidae Heptageniidae Ep
hemeridae
ephemeros lasts a day Ptera - wings

• Usually has 3 tails, although some with 2
• single tarsal claw
• 3 pair of segmented legs on thorax
• gills occur on abdomen (flat plates or
  filaments)
• short antennae
• have a single set of wingpads
• scraper/grazer or collector-gatherers

Adults have triangular shaped wings that are held
straight up when body is at rest
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Coleoptera BeetlesWater Penny
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Coleoptera Family
Psephenidae
koleon sheath ptera wing
hardened front wings provide protective cover for
hind wings and abdomen

• thin, flat, flexible plates to help mold body to
  rock shape
• single hooks at the end of legs
• jaws have thin sharp edge to scrape algae
• dense fringe of fine hairs to increase grip on
  rocks
• gills occur on underside of abdomen
• lotic-erosional
• clingers
• scrapers

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Megaloptera Dobsonfliesand Fishflies
(Hellgramites)
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Megaloptera Family
Corydalidae
megal large or of giant size ptera tail
Adults cylindrical bodies soft abdomen Wings
are large, elongate, membranous with many
veins wings held slanted and roof like over the
abdomen

• 6 legs
• large mandibles, projecting toothed jaws
• large elongate bodies
• head and thorax have thick, hardened skin,
  abdomen
• thin and soft
• 8 pairs of lateral filaments from abdomen
  segments
• gill tufts
• no wing pads occur on thorax
• engulfer-predators
• primarily lotic-erosional
• primarily crawlers, some burrowers, sprawlers

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Coleoptera BeetlesRiffle Beetle
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Coleoptera Family Elmidae
koleon sheath ptera wing
hardened front wings provide protective cover for
hind wings and abdomen

• segmented, hardened, worm-like body
• gills protrude from end of abdomen
• primarily lotic-erosional, lentic-littoral
• scrapers, collector-gatherers
• primarily clingers, also climbers

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Mollusca Mussels
Kingdom Animalia Phylum Mollusca Class
Bivalvia
mollu hard or brittle external coat
bi two valva hinged and movable
pieces volvere to roll or wrap

• mussels and clams are mollusks that have two
  shells
• often the largest invertebrates present in
  freshwater environments
• live throughout lotic and lentic habitats
• collector-filterers, have tubular siphons that
  create a one way current, cilia and mucous
  coating on gill filaments filter suspended
  particles of food
• burrowers
• have parasitic larval stage

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Group 2 Taxa

• Can Exist Under a Wide Range of Water Quality
  Conditions
• Generally of Moderate Quality Water

Caddisflies Damselflies Dragonflies Blackfli
es Craneflies Water Boatman Backswi
mmers Crayfish Amphipods
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Trichoptera Caddisflies
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Trichoptera Family
Hydropsychidae Family Limnephilidae Fami
ly Helicopsychidae
trich hair ptera tail

• 6 segmented legs
• worm-like bodies
• no easily visible antennae
• thick, hardened skin on head
• either live in a fixed retreat or makes a
  portable case
• shredder-detritivores, shredder-herbivores,
  collector-gatherers, collector-filterers, and
  scrapers

Adults have long wings folded back
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Odonata Dragonflies and Damselflies
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Odonata Families
Aeshnidae Gomphidae
Libellulidae Families Calopterygidae
Coenagrionidae Lestidae
odon tooth, refers to mouthparts of the adults

• Wing pads are present on the thorax
• Three pairs of segmented legs extend from the
  thorax
• Two claws occur on the end of segmented legs
• No gills are found on the sides of the abdomen,
  but
• some have three, elongate gills

• Bodies are either long and stout or oval and
  somewhat flattened
• Head is narrower than the thorax and abdomen
• No gills are found on the end of the abdomen
• Three short, stiff, pointed structures occur on
  the end of the abdomen, forming a pyramid-shaped
  valve for the opening on the end of the abdomen

• body is elongate and slender
• head is wider than the thorax and abdomen
• three flat, elongate gills project from the rear
  of the abdomen

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Hemiptera True BugsWater Striders
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Hemiptera Family Gerridae
heteros different ptera - wing
Half wing near body is leathery, half is
membranous

• 3 pairs of segmented legs on thorax
• legs are skinny and long to help distribute body
  weight
• 2 claws on segmented legs
• only middle and hind legs touch water front
  legs are held up
• piercer-predators
• skaters
• lentic-limnetic or lotic-depositional

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Hemiptera True BugsWater Boatman
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Hemiptera Family Corixidae
heteros different ptera - wing
Half wing near body is leathery, half is
membranous

• well developed, prominent eyes
• modified beak (blunt, triangle shaped
  non-segmented mouth)
• swims upright (backswimmers swim on back)
• have short front legs, much shorter than other
  pairs of legs
• two long claws on mid pair of legs
• swimming hairs
• 2 pair of long hind legs with swimming
• dark colored back, light colored stomach
• hind legs are oarlike with swimming hairs
• front legs with stiff setae (hairs) to be used
  like a rake
• surface for air thin film of air on underside
  (plastron)
• collector-gatherers
• lentic-littoral and lotic-depositional habitats

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Hemiptera True BugsBackswimmers
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Hemiptera Family
Notonectidae
heteros different ptera - wing
Half wing near body is leathery, half is
membranous

• oval shaped body, dark colored stomach
• swims on back
• has short front legs
• hind pair of legs are oarlike with swimming
  hairs
• has narrow, segmented beak (mouth)
• uses hind legs as oars
• usually red eyes, well-developed and prominent
• dark colored stomach, light colored back
• lentic-littoral and lotic-depositional habitats
• swimmers
• piercer-predators
• hold stored air in two troughs with fringes of
  hair on the bottom of abdomen

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Diptera True Flies Blackfly
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Diptera Family Simulidae
di two ptera - wing
True flies have two wings, other insects have four

• worm-like with one swollen end (bowling pin)
• usually dark in color
• usually live in colonies
• have well developed, hardened head
• fan-like mouth with brushes used for eating
• proleg under head
• have disc at rear end with many small hooks to
  attach to rocks
• lotic-erosional
• clingers-use silk to stick to substrate
• collector-filterers

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Diptera True FliesCrane Flies
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Diptera Family Tipulidae
di two ptera - wing
True flies have two wings, other insects have four

• fleshy, plump, segmented, worm-like body
• no legs, no wings
• usually brown, white or green in color
• head is retractable
• two spiracles on posterior used for breathing
• burrowers, sprawlers
• shredder-detritivores, collector-gatherers
• lentic-littoral lotic-erosional,
  lotic-depositional

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Crustacea CrustaceansDecapoda (Crayfish)
Kingdom Animalia Phylum Arthropoda Subphylum
Crustacea Class Malacostraca Order
Decapoda Family Astacidae
crusta hard or brittle external coat
deka ten poda foot
Crayfish have five pairs of walking legs

• one pair of antennae much longer than others
• 5 pairs of walking legs
• 2-3 pair of walking legs have hinged claw
• other legs have pointed tip
• 2 large, compound eyes
• live in a variety of habitats
• are mostly nocturnal
• omnivores

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Crustacea CrustaceansAmphipods
(Scuds/Sideswimmer)
Kingdom Animalia Phylum Arthropoda Subphylum
Crustacea Class Malacostraca Order
Amphipoda
crusta hard or brittle external coat
amphi of both kinds poda foot
Two kinds of appendages on bottom of body

• 7 pair of legs
• 2 pair of antennae
• head fused to thorax
• laterally flattened
• white or clear body with many segments
• swims sideways and rests in a curved position
• occur in many habitats
• omnivores, many functional feeding groups

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Group 3 Taxa
Can Exist Under a Wide Range of Water Quality
Conditions, Generally are Highly Tolerant of Poor
Quality Water
Midgeflies/Chironomids Worms Leeches Pouch Snails
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Diptera True FliesMidge/Chironomid
Kingdom Animalia Phylum Arthropoda Class
Insecta Order Diptera Family
Chironomidae
di two ptera - wing
True flies have two wings, other insects have four

• small, slender, slightly curved body
• hardened head capsule (often yellow)
• sometimes has a brush like structure at rear
• occur in all types of habitats
• primarily burrowers
• primarily collector-gatherers

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Worms and Leeches
Kingdom Animalia Phylum Annelida Class
Oligochaeta
Kingdom Animalia Phylum Annelida Class
Hirudinia Order Rhynenobdella
olig long chaite - hair

• flat, segmented body
• head section usually skinnier than rear
• body shape can change with movement
• ventral side is usually paler in color
• ventral suckers on both ends
• sometimes attach to and feed off other organisms

• body is soft, moderately muscular, elongate and
  cylindrical
• body consists of round, ring-like segments
  arranged in a row
• each segment after the first has bundles of tiny
  hairs (chaetae)
• no suckers or eyespots are present
• lentic-littoral, lotic-depositional
• burrowers, collector-gatherers

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Mollusca Clams, Mussels, Snails
Kingdom Animalia Phylum Mollusca Class
Gastropoda
mollu hard or brittle external coat
gaster - stomach pod - foot
digestive system begins in muscular foot
projecting from shell

• snails are freshwater mollusks with one shell
• divided into two major groups, based on
  breathing
• some breathe oxygen dissolved in water (gilled
  snails)
• others obtain oxygen from air by structure that
  works like a lung (lunged snails)
• lentic-littoral, lotic-depositional,
  lotic-erosional
• scrapers

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Pollution Indices
EPT - of EPT taxa found in stream
(Ephemeroptera, Plecoptera, Trichoptera)
mayflies, stoneflies, caddisflies of Aquatic
Worms ( of Midges) numbers of individuals found
that are midges Pollution Sensitivity Index
Assigns Scores to Each Type of Macroinvertebrate
- sum ten indices to get a composite score
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The Importance of Macroinvertebrates

• Macroinvertebrates are an essential component of
  freshwater ecosystems
• They serve as food for other organisms (fish,
  amphibians and waterfowl)
• Are essential to the breakdown and cycling of
  organic matter and nutrients
• Macroinvertebrate diversity is vital to a
  properly functioning ecosystem