1. Water Canaries Assessing Benthic Macroinvertebrates
Created by Libby Campbell, BTW Educator, 2003
Bridging the Watershed An Outreach Program of the Alice Ferguson Foundation in Partnership with the National Park Service and Area Schools

2. Macroinvertebrate Identification Worksheet
Specimen # _____
Characteristics
Body shape_________________
Legs ______________________
Tail _______________________
Other features _______________
Sketch

3. Consider the following when trying to identify an organism

4. Macroinvertebrate Body Characteristics
Segments
Wormlike– Is
the abdomen
fleshy or have
armored plates?
Does it look easily
squishable?
Segmented critters
Not wormlike
Tiny—in nature, tiny generally means less than a centimeter—test to tell: do you have a hard time seeing anything more than a squiggly line?
Large and plump

5. Legs Six true legs plus lateral filaments Six segmented legs Prolegs
More than six legs

6. Tails Tail-like projection Featherlike tails No tail or tiny tail
Two tails

7. Details to notice: gills
Abdominal filamentous gills
Abdominal gills
Internal
gills

8. Practice ID Visible Gills? Legs? Number? Length? Placement?
Details? Antennae? Eyes? Wings? Tail?

9. Directions
You will be shown pictures/drawings of 15 different types of organisms.
Each slide will be visible for 2 minutes.
Use your worksheet to draw each specimen.
Begin with basic body shape and most important details.
If there is more than one image on a slide, choose one to draw.
Each organism or set of organisms represents one category that
corresponds to the data sheet you will use in your field study.

10. Specimen 1
Crayfish: decapoda, or ten-legged

11. Specimen 2
Mayfly larva: note three tails (some species have two tails), abdominal gills visible, and short antennae

12. Specimen 3
Stonefly larva: note long antenna, two tails, no abdominal gills

13. Specimen 4
Leech: note the segmentation and absence of head or tail

14. Specimen 5
Case-making caddisflies

15. Specimen 6
Clam, probably exotic Asian clam

16. Specimen 7
Damselfly nymph: note three tails that are featherlike, broader than a mayfly tail.

17. Specimen 8
Scud: note more than 6 legs, curled, shrimp-like, flattened side to side

18. Specimen 9
Net-spinning caddisflies. Note the six legs, three dorsal plates, and filamentous gills on the underside.

19. Specimen 10
Crane fly, a True Fly larva. Usually quite large, with tail-like projections.

20. Specimen 11
Dragonfly larva: note the tiny three tails and variable body shapes.

21. Specimen 12
Beetles. This category is highly variable.

22. Specimen 13
Lunged snails, with opening on the left. Flat coiled snails are also lunged snails.

23. Specimen 14
Black fly larva. Very small, with bulge at one end where it has a suction cup, with which it attaches itself to rocks, and then waves the projections at the other end to catch food.

24. Specimen 15
Fish fly larva. Note the lateral filaments, or “fake” legs. Sometimes very large (up to 4 inches) with sharp biting jaws.

25. End of Drawing Activity
Use your drawings and reference material
to identify your organisms.
After students have had the opportunity to try to identify their organisms, go back through the specimens to be sure they have identified them correctly.

26. This key corresponds to the categories used on the Tally sheet students will use in the field study.

27. Benthic macroinvertebrates can be classified according to their sensitivity to pollutants.

28. Sensitive Mayfly larvae Stone Fly larvae Most caddisfly larvae
Beetles (adults and larvae)

29. Somewhat Sensitive Dragonfly and damselfly larvae
Netspinner caddisfly larvae
Crayfish
Gilled snails
Aquatic sowbugs
Scuds
Clams and mussels
True fly larvae
Hellgrammites, Fishfly and Alderfly larvae

30. Tolerant Lunged snails Black fly larvae Midge larvae Aquatic worms
Flatworms
Leeches

31. THE END