1. Little Creatures that tell us the health of our natural waterways
Macroinvertebrates
Little Creatures that tell us
the health of our natural waterways

2. What are Benthic Macroinvertebrates?
Benthic = bottom dwelling
Macro = large enough to be seen without aid of a microscope
Invertebrate = without a backbone
Commonly called: “macros”
Found in Fresh Water Streams
Eat leaves & algae in stream
Source of Energy for larger animals

3. Kinds of Macroinvertebrates
Mayfly, caddisfly, stone fly larva
Worms
Water beetles
Clams
Snails
Crayfish

4. Why Study Macros?
Macros are COOL! (collectible, observable, omnipresent, & learnable)
Macroinvertebrates are an essential component of freshwater ecosystems
They serve as food for other organisms
Are essential to the breakdown and cycling of organic matter and nutrients
Macros can be used as bio-indicators of water quality
they have different tolerances to pollution
some are sensitive; others are tolerant

5. Indicator Species
They indicate to scientists when there is a problem in nature- specifically the stream environment
What might be a problem in the stream that is indicated by Macros?
Red doesn’t show up on BRMES projectors.

6. One Way to categorize Macros is by how they EAT
Shredders: Chew on intact or large pieces of plant material
Collectors: Acquire and ingest very small particles (<1 mm) of detritus
Piercers: Mouthpartsprotrude as modifications to puncture food and bring out the fluids contained inside
Srapers/Grazers: Remove and consume the thin layer of algae and bacteria that grows tightly attached to solid substrates in shallow waters
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
Purple doesn’t show up on BRMES projectors either.

7. How we will group Macros
Pollution Sensitive- need clean water
Moderately Sensitive- tolerant to some pollution
Pollution Tolerant- can survive with poor water quality

8. What do Macroinvertebrates tell Scientists about a Stream?
Abundant and diverse macroinvertebrates tell scientists a stream is healthy
More group 2 macros tell scientists the water quality may be decreasing
Group 3 macroinvertebrates that only survive in poor water, tells scientists that the water quality is poor and needs help

9. Group One Macros
Different kinds of stoneflies, mayflies, and Megaloptera tell a scientist the stream is healthy.

10. Stoneflies (Order Plecoptera)
2 tails
abdomen
thorax
head
3 plates
sometimes gills
visible on thorax
2 claws
Thorax divided into 3 parts
Pair of legs for each part
2 claws at end of each leg
Only 2 tails
Gills may be visible on thorax (“hairy armpits”) or under neck
Shredders and predators
Mostly sensitive to pollution
adult

11. Mayflies (Order Ephemeroptera)
head
thorax
abdomen
2 plates
gills
tails or
cerci
Six legs attached to thorax
Thorax does not appear divided
Gills along the abdomen
2 or 3 tails
1 pair wing pads, if present
Generally collector gatherers and shredders
Sensitive or moderately tolerant of pollution
adult

12. WATER PENNY Measures 1/4 inch in length Flat disk-like body
Head and legs concealed from above
6 legs and branched gills on underside
Prefers cold running water
Water pennies prefer cold, fast-moving streams. Their smooth, flattened bodies enable them to resist the pull of the current.
Water pennies are usually found on smooth rocks where they graze on attached algae
Sensitive to pollution

13. Caddisflies (Order Trichoptera)
6 legs attached to thorax
Fleshy abdomen; some with hair-like gills
Prolegs with hooks at end of abdomen; some with hair-like tufts
Some build cases from rocks and/or plant material (case-makers)
Some spin nets as a retreat and to collect detritus (netspinners)
Some crawl around in search of prey (free-living)
Sensitive or moderately sensitive to pollution
netspinner
larva
head
thorax
abdominal gills
(Netspinner)
abdomen
prolegs with hooks
adult
pupa
casemaker

14. Dobsonflies & Alderflies (Order Megaloptera)
Large gill filaments along abdomen
Abdomen ends with single, long, pointed tail filament
More tolerant of pollution than dobsonflies
Dobsonflies
Stout, flexible filaments, extend from abdomen
Long, somewhat flattened body
2 prolegs at the end, with two claws on each proleg
Sensitive to pollution
alderfly
dobsonfly

15. Group 2 Macros Group 2 Macros are found in moderatel healthy streams
The number of different macroinvertebrates becomes less as pollution rises
Soft-bodied worms and fly larva also increase

16. Dragonflies & Damselflies (Order Odonata)
Large abdomen tapers to point(s), but no tail
Internal gills are not visible
Damselflies
Narrow abdomen ends with 3 paddle-like gills
Dragonflies & Damselflies
Predators
Extendable, hinged jaw captures prey
Somewhat tolerant
dragonflies
gills
damselfly

17. Craneflies (Order Diptera)
Long, fleshy abdomen
Head often withdrawn & concealed by thorax
Some have pairs of prolegs beneath abdomen
Somewhat tolerant (other Diptera are more tolerant)
Some are shedders, others predators
pupa
head
prolegs

18. Water Boatman & Backswimmer (Order Hemiptera)
Water Strider
“Skates” around on top of water
Front legs grab & beak pierces prey
Water Boatman
Oval body with wavy lines across a dark colored back
Oar-like legs
Backswimmer
Similar to boatman; swims upside down
Dark underside & light-colored back
CAUTION -- can bite!
water strider
water boatman
backswimmer

19. Group 3 Macros
Group 3 Macros are found in streams with poor water quality
Stoneflies are not present at all
A few mayflies and caddisflies- maybe there
Most found are soft-bodied animals: fly larvae, leeches and planaria (round worm, tape worm).

20. Midges (Order Diptera)
Worm-like, but with definite head and prolegs (usually)
“Twitchy” swimmers
Pollution tolerant
head
prolegs
pupa

21. Blackflies (Order Diptera)
Shaped like bowling pin
Two fans on top of head for filtering
Attaches to substrate with ring of hooks at end of abdomen
Single proleg beneath head
Tolerant of pollution
fan
pupa

22. Worms and Leeches flat, segmented body
Incomplete Metamorphosis
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

23. Planaria- Flatworm

24. LEECH Measures 1.0 mm to 5.0 cm in length.
34 Segments
Suckers on both ends
Measures 1.0 mm to 5.0 cm in length.
Typically dorsoventrally flattened.
Leeches are common in warm protected waters of lakes, ponds, streams, and marshes.
Leeches usually avoid light by hiding under rocks or among aquatic vegetation or detritus.
Silty substrates are unsuitable for leeches because they cannot attach properly.

25. Macroinvertebrate means…
Small creature that you need a microscope to see
Small creature that you can see without a microscope
Small creature that lives on land

26. Benthic means… Living at the bottom of a stream
Living on land, near a stream
Living by floating in a stream

27. Macroinvertebrates tell if a stream is healthy or not.
True
False
Unsure

28. A sample of a Macroinvertebrate is…
Small bird
Mayfly larva
Butterfly larva
Turtle

29. Macroinvertebrates that tell if water is clean need only a little bit of oxygen
True
False

30. Macroinvertebrates that survive in low oxygen water tell scientists
The water is polluted
The water is clean
That it is water

31. Large amounts of caddisfly larva, mayfly larva, and stone fly larva are found in…
Polluted water
Moderately clean water
Healthy, good quality water

32. Smaller amounts of caddisfly, mayfly and stone fly larva, along with some worms are in this type of water
Polluted water
Moderately clean water
Healthy, good quality water

33. Stoneflies are not present at all, more leeches, and fly larvae are found in this stream
Polluted water
Moderately clean water
Healthy, good quality water