1. Freshwater Macroinvertebrates
Freshwater Ecology
Macroinvertebrate Biology
Functional Feeding Groups
River Continuum Concept
Life History
Group 1, 2 and 3 Taxa
Adapted from Wyoming Stream Team’s Freshwater Invertebrates PowerPoint with permission.

2. Freshwater Ecology Physical Biological Chemical light substrate
temperature
current
Physical pH
bacteria
Biological
Chemical DO
macrophytes
Turbidity
macroinvertebrates
Nutrients
Conductivity
fish

3. “Macro” “Invertebrate” Macroinvertebrates
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

4. The Importance of Macroinvertebrates
Essential component of freshwater ecosystems:
Serve as food for other organisms (fish, amphibians and waterfowl)
Aid in the breakdown and cycling of organic matter and nutrients

5. Why Study Macroinvertebrates?
Used to assess the health of freshwater environments
Tolerance of stress produced by pollution, habitat modification, or severe natural events varies
Sampling and identifying can indicate whether a body of water is healthy or unhealthy and may reveal the cause of the problem
Known as BIOMONITORING

6. Macroinvertebrate Biology
Habitat
Movement
Feeding
Breathing
Life History
Stress Tolerance

7. bedrock, boulders, cobbles, pebble, gravel, sand, silt, clay
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

8. BMI Diversity
Greatest diversity found in lotic (running water) erosional habitats where the mineral substrate is predominantly loose cobbles and pebbles, with a few boulders.
Size + irregular composition = infinite array of hiding places, attachment sites, current velocities, surfaces for algae to grow, edges to catch coarse detritus and woody debris, and openings where fine detritus settles

9. Movement Locomotion, habits, or mode of existence
Clingers – maintain a relatively fixed position on firm substrates in current
Climbers – dwell on live aquatic plants or plant debris
Crawlers – have elongate bodies with thin legs, slowly move using legs
Sprawlers – live on the bottom consisting of fine sediments
Burrowers – dig down and reside in the soft, fine sediment
Swimmers – adapted for moving through water
Skaters – adapted to remain on the surface of water

10. 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

11. Chew on intact or large pieces of plant material
Shredders
Chew on intact or large pieces of plant material
Basic mouthparts without any special modifications
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
Material is usually >1 mm, referred to as Coarse Particulate Organic Matter (CPOM)
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)

12. Collectors
Acquire and ingest very small particles (<1 mm) of detritus, often referred to as fine particulate organic matter (FPOM)
Collector-gatherers
Eat fine detritus lying on the bottom or mixed with bottom sediments that has fallen out of suspension
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 fine particles of food
Collector-filterers
Use special straining mechanisms to feed on fine detritus suspended in the water column
Spin nets from silk (netspinner caddisflies)
Have hairs on their heads (black flies)
Appendages create water current for their feeding (mussels)

13. Piercers
Mouthparts, or sometimes their entire head, protrude as modifications to puncture food and bring out the fluids contained inside; modified into one or two hard, sharp, hollow tubes used to stab into their prey (water scorpions).
Piercer-herbivores – penetrate the tissues of vascular or aquatic plants or individual cells of filamentous algae and suck the liquid contents (crawling water beetles, microcaddisflies)
Piercer-predators – subdue and kill other animals by removing their body fluids

14. Scrapers/Grazers
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 putty knife or paint scraper)
After algae has been removed, the material is swept into the mouth by finger-like projections from other mouthparts
Examples: flathead mayflies, water pennies, snails

15. Engulfer-Predators
Feed upon living animals, either by swallowing the entire body of small prey or by tearing large prey into pieces that are small enough to consume
Typically have large jaws with pointed ends and sharp, tooth- like projections for attacking and devouring their prey
Examples: common stoneflies and hellgrammites

16. Autochthonous vs. Allochthonous Inputs
Autochthonous – the relative amount of biomass produced within the system (in-stream); examples: algae, periphyton, macrophytes
Allochthonous – the relative amount of biomass produced outside the system (riparian and upland); examples: tree and shrub leaves and needles
Light is a primary determinant of whether the food base for a given community is live green plants growing within the aquatic environment or decaying plant material that originated in the terrestrial environment

17. River Continuum Concept
Based on what macroinvertebrates eat, the river continuum concept is a way to think about where you might find certain functional feeding groups, based on the food source.

18. 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.
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).

19. 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.
Exoskeleton 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 – 45x).
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

20. Complete Metamorphosis

21. Incomplete Metamorphosis

22. volcanoes, forest fires, floods, landslides
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.

23. Classification Kingdom: Animalia Phylum: Arthropoda (Arthropods)
Annelida (Segmented Worms)
Mollusca (Mollusks)

24. Pollution sensitive organisms found in good quality water.
Group 1 Taxa
Pollution sensitive organisms found in good quality water.
Stoneflies
Mayflies
Water Pennies
Dobsonflies
Riffle Beetles
Mussels

25. Plecoptera: Stoneflies
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Plecoptera
Families:
Perlidae
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
Incomplete Metamorphosis
Adult Characteristics
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

26. Ephemeroptera: Mayflies
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Ephemeroptera
Families: Baetidae
Heptageniidae
Ephemeridae
Ephemeroptera: Mayflies
Ephemeros: lasts a day
Ptera: wings
Incomplete Metamorphosis
Adult Characteristics
Triangular shaped wings that are held straight up when body is at rest
Usually has 3 tails, although some with 2
Single tarsal claw
3 pairs of segmented legs on thorax
Gills occur on abdomen (flat plates or filaments)
Short antennae
Single set of wingpads
Scraper/grazer or collector-gatherer

27. Coleoptera: Beetles Water Penny
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Ephemeroptera
Families: Baetidae
Heptageniidae
Ephemeridae
koleon : sheath
ptera: wing
Complete Metamorphosis
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

28. Megaloptera: Dobsonflies and Hellgramites
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Megaloptera
Family: Corydalidae
Megaloptera: Dobsonflies and Hellgramites
megal: large or of giant size
ptera: tail
Complete Metamorphosis
Adult Characteristics
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

29. Coleoptera: Beetles Riffle Beetle
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Elmidae
Coleoptera: Beetles Riffle Beetle
Complete Metamorphosis
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

30. Mollusca: Mussels Mussels and clams are mollusks that have two shells
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

31. Group 2 Taxa
Can exist under a wide range of water quality conditions, but water quality is generally moderate.
Caddisflies
Damselflies
Dragonflies
Blackflies
Craneflies
Water Boatman
Backswimmers
Crayfish
Amphipods

32. Trichoptera: Caddisflies
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Trichoptera
Family: Hydropsychidae Family: Limnephilidae
Family: Helicopsychidae
Trichoptera: Caddisflies
trich: hair
ptera: tail
Complete Metamorphosis
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
Adult Characteristics
Adults have long wings folded back

33. Odonata: Dragonflies & Damselflies
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Families: Aeshnidae
Gomphidae
Libellulidae
Families:
Calopterygidae
Coenagrionidae Lestidae
Body elongate and slender
Head wider than thorax and abdomen
Three flat elongate gills project from the rear of the
abdomen
Wing pads are present on the thorax
Three pairs of segmented legs extend from the thorax
Two claws at 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
Incomplete Metamorphosis
odon: tooth, refers to mouthparts of the adults

34. Hemiptera: True Bugs Water Striders
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Gerridae
Hemiptera: True Bugs Water Striders
Incomplete Metamorphosis
heteros: different
ptera: wing
Adult Characteristics
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-predator
Skaters
Lentic-limnetic or lotic-depositional

35. Hemiptera: True Bugs Water Boatman
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Corixidae
Hemiptera: True Bugs Water Boatman
Incomplete Metamorphosis
Well-developed, prominent eyes
Modified beak (blunt, triangle-shaped non-segmented mouth)
Swims upright (backswimmers, on back)
Short front legs, much shorter than other pairs of legs
Two long claws on mid pair of legs
Swimming hairs
2 pairs of long hind legs with swimming
Dark colored back, light colored stomach
Hind legs are oar-like 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-gatherer
Lentic-littoral and lotic-depositional habitats
Adult Characteristics
Half wing near body is leathery, half is membranous
heteros: different
ptera: wing

36. Hemiptera: True Bugs Backswimmers
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Notonectidae
Incomplete Metamorphosis
heteros: different
ptera: wing
Adult Characteristics
Half wing near body is leathery, half is membranous
Oval shaped body, dark colored stomach
Swims on back
Short front legs
Hind pair of legs are oar-like with swimming hairs
Narrow, segmented beak (mouth)
Usually red eyes, well-developed and prominent
Dark colored stomach, light colored back
Lentic-littoral and lotic-depositional habitats
Swimmers
Piercer-predator
Hold stored air in two troughs with fringes of hair on the bottom of abdomen

37. Diptera: True Flies Blackfly
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Simulidae
Diptera: True Flies Blackfly
di: two
Ptera: wing
Complete Metamorphosis
Adult Characteristics
Two wings, other insects have four
Worm-like with one swollen end (bowling pin)
Usually dark in color
Typically live in colonies
Well-developed, hardened head
Fan-like mouth with brushes used for eating
Proleg under head
Disc at rear end with many small hooks to attach to rocks
Lotic-erosional
Clinger – use silk to stick to substrate
Collector-filterer

38. Diptera: True Flies Crane Flies
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Tipulidae
Diptera: True Flies Crane Flies
Complete Metamorphosis
di: two
Ptera: wing
Adult Characteristics
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

39. Crustacea: Crustaceans Decapoda (Crayfish)
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca Order: Decapoda
Family: Astacidae
Complete Metamorphosis
Adult Characteristics
Crayfish have five pairs of walking legs
crusta: hard or brittle external coat
deka: ten
poda: foot
Incomplete Metamorphosis
One pair of antennae much longer than others
5 pairs of walking legs, 2 – 3 pairs have hinged claw; other pairs have pointed tip
2 large compound eyes
Live in a variety of habitats
Mostly nocturnal
Omnivores

40. Crustacea: Crustaceans Amphipods (Scuds/Sideswimmer)
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca Order: Amphipoda
Incomplete Metamorphosis
Adult Characteristics
crusta: hard or brittle external coat
amphi: of both kinds
poda: foot
Two kinds of appendages on bottom of body
7 pairs of legs
2 pairs of antennae
Head fused to thorax
Laterally flattened
White or clear body with many segments
Swims sideways and rests in a curved position
Occurs in many habitats
Omnivores, many functional feeding groups

41. Midgeflies/Chironomids
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

42. Diptera: True Flies Midge/Chironomid
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Chironomidae
Diptera: True Flies Midge/Chironomid
Complete Metamorphosis
“di” – two
“ptera” - wing
Adult Characteristics
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

43. Worms and Leeches Flat, segmented body
Kingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
Worms and Leeches
Kingdom: Animalia
Phylum: Annelida
Class: Hirudinia
Order: Rhynenobdella
Incomplete Metamorphosis
olig: long
chaite: hair
Incomplete Metamorphosis
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

44. Mollusca: Clams, Mussels, Snails
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Mollusca: Clams, Mussels, Snails
Mollu: hard or brittle external coat
gaster: stomach
pod: foot
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)
Digestive system begins in muscular foot projecting from shell
Lentic-littoral, lotic-depositional, lotic-erosional
Scrapers