1. MACROINVERTEBRATE IDENTIFICATION
Developed by
Mike Clapp, CAM Junior High School Science Teacher
and
Judy Bufford, Science Education Consultant
Water Resources Education Center

2. Classification Kingdom - Animalia Phylum - Arthropoda Class - Insecta
Order - Ephemeroptera
Family - Baetidae
Genus - Baetis
Species – Baetis tricaudata

3. Insects
Incomplete metamorphosis
Complete metamorphosis

4. Body Parts of an Insect Head - mouth parts, eyes, and antennae.
Thorax - muscles and attachments for the legs and wings.
Abdomen - digestive and respiratory functions.
Head
Thorax
Abdomen

5. Mayflies (Order Ephemeroptera)
2 - 3 tails = mayfly
Sometimes the center tail is very short
Gills along abdomen
Generally collector gatherers and shredders
Sensitive to pollution
2 plates
head
thorax
abdomen
gills
tails or
cerci
adult

6. Stoneflies (Order Plecoptera)
Always 2 tails
Gills on thorax
Shredders and predators
Sensitive to pollution
3 plates
head
Gills on thorax
thorax
abdomen
2 tails

7. Caddisflies (Order Trichoptera)
Case builders, net spinners, free living (green rock worms)
Sensitive to pollution
net spinners have fluffy gills on abdomen, free-living have filaments
shredders
adult
predators
Filterers/predators

8. Midges (Order Diptera)
Worm like
Twitchy, jerky swimmers
Pollution tolerant
head

9. Craneflies (Order Diptera)
Cannot see head
Large, long abdomen
Last segment fleshy lobes
Somewhat Tolerant
Other Diptera are more tolerant
end

10. Blackflies (Order Diptera)
Tolerant of Pollution
Attach at end with a ring of hooks
Two fans on top of the head
Filter Feeders

11. Riffle Beetles & Water Pennies (Order Coleoptera)
Whitish color
This Order is Very Diverse
Sensitive to Pollution
Riffle Beetle
Diving beetle
Other beetles- Somewhat tolerant

12. Dobsonflies (Order Megaloptera)
Hair like filaments along abdomen
Long somewhat flattened abdomen
2 prolegs at the end with two claws on each proleg
Sensitive to Pollution
Note: Alderfly same Order but long pointy tail and more tolerant of pollution

13. Dragonflies, Damselflies (Order Odonata)
Dragonflies have internal gills
Dragonflies have no tails and a large abdomen
Damselflies have paddle like gills (3)
Predators-engulfers
Somewhat tolerant
Dragonflies
Damselflies

14. Water Boatmen & Backswimmer (Order Hemiptera)
Carry a bubble of air
Long back legs used for swimming
Babies look like adults
Pollution Tolerant
Piercing mouthpart
Water Boatmen
Backswimmer

15. Crayfish (Order Decapoda)
Crustaceans
5 pairs of walking legs
Somewhat Tolerant of Pollution

16. Aquatic Sowbug (Order Isopoda)
Crustaceans
7 pairs of long walking legs
Body is flattened from top to bottom
Somewhat Tolerant of Pollution

17. Scuds/ Sideswimmers (Order Amphipoda)
Crustaceans
7 pairs of walking legs
Body is strongly flattened side to side
Somewhat tolerant of pollution

18. Snails (Class Gastropoda)
Hard spiral shell
Lunged snails are pollution tolerant
Left Handed / Right handed

19. Clams & Mussels (Class Bivalvia)
Clams are smaller and rounder than mussels
2 shells hinged together
Somewhat tolerant of Pollution
Important for stream health because they filter feed and purify the water

20. Aquatic Earthworm (Class Oligochaeta)
Segmented worm
Tolerant of Pollution

21. Leeches (Class Hirudinea)
Segmented worm
Suckers on both ends, rear sucker is larger
Tolerant of Pollution

22. Other macros Water Mites Somewhat Tolerant Arachnids – 8 legs
Flatworms
No segments
Eyespots

23. Macroinvertebrate Sampling Procedure

24. Macroinvertebrate sorting

25. Data Analysis Pollution Tolerance Index (PTI) Taxa Richness EPT
Presence / Absence Scoring
Taxa Richness
Number of different kinds
EPT
Mayflies, Stoneflies, Caddis flies
Percent Diptera (True Flies)
How much of the sample are fly larvae?
Dominance
Which kinds are the most abundant?

26. Questions?