freshwater invertebrates

8/8/2019 Freshwater Invertebrates

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Stream Ecology



F reshwater Ecology

Physical

Biological Chemical

light

currenttemperature

substrate

pH

DO

Turbidity

Conductivity

photosynthesis

macroinvertebrates

macrophytes

fish



M acroinvertebrates

³Macro´

³I

nvertebrate´

Large enough to be

seen with the naked

eye

Lacking an internal

skeleton of cartilageand 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



he Importance of M acroinvertebrates

Macroinvertebrates are anessential component of

freshwater ecosystems

They serve as food for other

organisms (fish, amphibiansand waterfowl)

Are essential to the breakdown

and cycling of organic matter

and nutrients

Macroinvertebrate diversity is

vital to a properly

functioning ecosystem



W hy Study M acroinvertebrates? 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 revealwhether a body of water is

healthy or unhealthy and may

reveal the cause of the problem

K nown as BIOMONITOR I NG



M acroinvertebrate Biology

Habitat

Movement

Feeding

Breathing

Life History

S

tress Tolerance



H abitat The place where an organism lives

Running waters ± lotic ± seeps,

springs, brooks, branches, creeks,

streams, rivers

Mineral

bedrock,

boulders, cobbles, pebble, gravel,

sand, silt, clay

Standing waters ± lentic ± bogs,

marshes, swamps, ponds, lakes

erosional (riffles, wave action) or

depositional areas (point bars, pools)

Organic

live plants, detritus



M ovement

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 legsS prawlers ± 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

Locomotion, habits, or mode of existence



F eeding

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



Shredders

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

Material is usually >1 mm, referred to as Coarse Particulate Organic Matter

(CPOM)

Chew on intact or large pieces of plant material

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)



C ollectors

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)

Acquire and ingest very small particles (<1 mm) of detritus,

often referred to as fine particulate organic matter (FPOM)

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



P iercers

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

mouthparts, or sometimes their entire head, protrude as modifications to puncture

food and bring out the fluids contained inside

mouthparts are modified into one or two hard, sharp, hollow tubes that they use to

stab into their prey (water scorpions)



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 using a putty

knife or paint scraper)

After algae has been removed, the

material is swept into the mouth byfinger like projections from other

mouthparts

(flathead mayflies, water pennies, snails)



Engulfer- P redators

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 attackingand devouring their prey

e.g. (common stoneflies and hellgrammites)



Autochthonous vs. Allochthonous Inputs

Autochthonous ± the relative amount of biomass

produced within the system (in stream) algae, periphyton,

macrophytes

Allochthonous ± the relative amount of biomass

produced outside the system (riparian and upland) 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



River C ontinuum C oncept



River

C ontinuumC oncept



Breathing

Closed Breathing System

depend upon oxygen dissolved in the

water for their breathing

Oxygen enters the organisms bysimple 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 totheir 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 onthe end of their body to the surface to

reach the atmosphere (breathing tubes

or siphons)



Life H istoryReproduction, 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



C omplete M etamorphosis



Incomplete M etamorphosis



Stress Tolerance

Anthropogenic pollution, removal of water

by irrigation, dams,

deforestation, removal of

riparian vegetation

Freshwater invertebrates vary in their ability to cope with

environmental stress

Biomonitoring takes advantage of this situation by identifyingwhether an aquatic environment is inhabited predominantly by stress

tolerant or stress intolerant organisms

Natural

volcanoes, forest

fires, floods,

landslides



C lassification

K ingdom: Animalia

Phylum: Arthropoda (Arthropods)

Annelida (Segmented Worms)

Mollusca (Mollusks)



Group 1 Taxa

Pollution Sensitive Organisms Found In

Good Quality Water

StonefliesMayflies

Water Pennies

Dobsonflies

Riffle BeetlesMussels



P lecoptera: StonefliesK ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Plecoptera

Families: Perlidae

Perlodidae

Leuctridae

³ plekein´ ± to braid (wings of adult are folded to fit under front wings)

³ ptera´ ± tail

3 pairs of segmented legs on thorax

2 tarsal claws

2stick-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 flatover the abdomen

Incomplete Metamorphosis



Ephemeroptera: M ayfliesK ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Ephemeroptera

Families: Baetidae

Heptageniidae

Ephemeridae

³ephemeros´ ± lasts a day

³Ptera´ - 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 havetriangular shaped

wings that are held

straight up when

body is at rest




C oleoptera: Beetles

W

ater P

enny

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera

Family: Psephenidae

³koleon´ ± sheath

³ 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

CompleteMetamorphosis



M egaloptera: Dobsonflies

and F ishflies ( H ellgramites)

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Megaloptera

Family: Corydalidae

³megal´ ± large or of giant size³ ptera´ ± tail

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

Adults:

cylindrical bodies

soft abdomen

Wings are large,elongate,

membranous with

many veins

wings held

slanted and roof

like over theabdomen




C oleoptera: Beetles

Riffle Beetle

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera

Family: Elmidae

³koleon´ ± sheath

³ 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




M ollusca: M usselsK ingdom: Animalia

Phylum: Mollusca

Class: Bivalvia

³ bi´ ± two

³valva´ ± hinged and movable pieces

³volvere´ ± to roll or wrap

³mollu´ ± hard or brittle external coat

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



CaddisfliesDamselflies

Dragonflies

Blackflies

CranefliesWater Boatman

Backswimmers

Crayfish

Amphipods

Group 2 Taxa

Can Exist Under a Wide Range of Water QualityConditions

Generally of Moderate Quality Water



Trichoptera: C addisfliesK ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Trichoptera

Family: Hydropsychidae

Family: Limnephilidae

Family: Helicopsychidae

³trich´ ± hair

³ 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




Odonata: Dragonflies and

Damselflies

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Odonata

Families: Aeshnidae

Gomphidae

Libellulidae

Families: Calopterygidae

Coenagrionidae

Lestidae

³odon´ ± tooth, refers to mouthparts of the adults

body is elongate and slender

head is wider than the thorax and abdomen

three flat, elongate gills project from the rear of the abdomen

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 theabdomen, forming a pyramid-shaped valve for the opening

on the end of the abdomen

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 Incomplete Metamorphosis



H emiptera: True Bugs

W ater Striders

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hemiptera

Family: Gerridae

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

³heteros´ ± different

³ ptera´ - wing Half wing near body is leathery, half is membranous





W ater Boatman

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hemiptera

Family: Corixidae

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







Backswimmers

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hemiptera

Family: Notonectidae

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






Diptera: True F lies

Blackfly

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Simulidae

³di ± two

³ ptera´ - wingTrue 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




Diptera: True F lies

C rane

F lies

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Tipulidae

³di ± two


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




C rustacea: C rustaceans

Decapoda ( C rayfish)

K ingdom: Animalia

Phylum: Arthropoda

Subphylum: Crustacea

Class: Malacostraca

Order: Decapoda

Family: Astacidae

³deka´ ± ten

³ poda´ ± foot

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

Crayfish have five pairs of walking legs

³crusta´ ± hard or brittle external coat




C rustacea: C rustaceans

Amphipods

(Scuds/Sideswimmer)

K ingdom: Animalia

Phylum: Arthropoda

Subphylum: Crustacea

Class: Malacostraca

Order: Amphipoda

³amphi´ ± of both kinds

³ poda´ ± foot

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

Two kinds of appendages on bottom of body

³crusta´ ± hard or brittle external coatIncomplete Metamorphosis



Midgeflies/Chironomids

Worms

Leeches

Pouch Snails

Group 3 Taxa

Can Exist Under a Wide Range of Water QualityConditions, Generally are Highly Tolerant of Poor

Quality Water



Diptera: True F lies M idge/ C hironomid

K ingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Chironomidae

³di´ ± two


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




W orms and Leeches

K ingdom: Animalia

Phylum: Annelida

Class: Oligochaeta

K ingdom: Animalia

Phylum: Annelida

Class: Hirudinia

Order: Rhynenobdella

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-likesegments 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

³olig´ ± long

³chaite´ - hair

Incomplete MetamorphosisIncomplete Metamorphosis

i d A i li



M ollusca: C lams, M ussels,

Snails

K ingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

³mollu´ ± hard or brittle external coat

³gaster´ - stomach

³ 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)

lentic-littoral, lotic-depositional, lotic-erosional scrapers

digestive system begins in muscular foot

projecting from shell



P ollution 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

freshwater invertebrates

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