1. Ecology of Macroinvertebrates

2. What Problems Must Macroinvertebrates Solve Because They Live In Streams?
Aqueous medium (tough to get O2)
Medium that is generally moving upstream-downstream
Daily variation in physio-chemical characteristics
Seasonal variation in hydrology
Connected to upstream conditions
Linked to land-water interface
black flies

4. Some Guiding Principles for Classification
Everyone can classify objects
Ways macroinvertebrates may be classified:
Functional feeding groups
Morphology
Locomotion
Microhabitat (i.e. niche)
Type of metamorphosis
Means of obtaining oxygen
Need for oxygen / Ability of stream to provide that oxygen
net spinning caddisfly

5. Feeding Groups

6. Biotic Indices
A way to classify based on macroinvertebrates’ tolerance to pollution
Generally this means organic pollution
Or that which affects oxygen levels in the stream

8. Biotic Indices Some organisms require water with a lot of oxygen in it
Others have adaptations to obtaining the oxygen they need

9. Ability of water to hold oxygen

10. Adaptations for Obtaining Oxygen
Morphological
Tubes
Soft tissue between segments & gills
Hair-like/Plate-like wings
Behavioral
Body pumping
Swimming to surface
Construct burrows or tubes

11. Presence of Gills

12. Air bubbles

13. Air tube

14. Hemoglobulin

15. Plastron trapped air space next to insect’s body creates a bubble
Oxygen in air space used up by insect but replaced by oxygen diffusing in from surrounding water
Thus, insect never has to surface to replenish air bubble

16. Representative Mayflies
armored mayfly
flathead mayfly
Adult is Leptophlebia nebulosa from
Hexagenia by Sczcytko at this website:
Hexagenia
prong gill mayfly adult

17. Body shape (Mayfly)
Mayfly example of typical insect body: head, thorax, abdomen
Student Watershed Research Project (SWRP) Macroinvertebrates

18. Mayfly adult

19. Representative Dragonflies & Damselflies
broadwing damselfly larva
darner dragonfly larva
Calopteryx from
Aeshnidae? From
Aeshnidae larva from:
Calopterigidae larva from:
darner dragonfly adult
broadwing damselfly adult

20. Representative Stoneflies
perlodid stonefly
common stonefly
Isoperla from Sczcytko’s collection
Common stonefly adult from:
Perlodidae from:
Perlodidae adult from:

21. Stonefly adult (Little Yellow Stone)
Little Yellow Stone (Family Perlodidae, Genus Isoperla). Nymph is a predator which is sensitive to temperature and sediment pollution.
Student Watershed Research Project (SWRP) Macroinvertebrates

22. Representative True Bugs
giant water bug
water strider
water scorpion
back swimmer

23. Representative Hellgrammites or Alderflies (Top) & Spongillaflies (Bottom)
Alderfly larva
spongillafly
adult alderfly

24. Caddisflies (Tricoptera) Sensitive
Larvae:
Soft “worm-like”bodies
Head contains a hard covering
Larvae are known for their construction of hollow cases that they either carry with them or attach to rocks
built from twigs or bark, small stones, or rolled leaves
used for protection and pupation
Anal hooks usually present
Large - Length up to 2 inches
The name Trichoptera, derived from the Greek words "trichos" meaning hair and "ptera" meaning wings, refers to the long, silky hairs that cover most of the body and wings.
Student Watershed Research Project (SWRP) Macroinvertebrates

25. Legs and prolegs (Caddisfly)
Jointed legs are used primarily for movement.
Prolegs are non-jointed appendages – aren’t easily identified as legs
Prolegs on midge
Caddis removed from case
Student Watershed Research Project (SWRP) Macroinvertebrates

26. Case (Caddis fly)
Case 1: Fall caddis (Family Limnephilidae, Genus Dicosmoecus)
Case 2: American Grannom (Family Brachycentridae, Genus Brachycentrus)
Case 3: Periwinkle, Cinnamon Sedge (Family Limnephilidae, 35+ genus in Oregon)
Student Watershed Research Project (SWRP) Macroinvertebrates

27. Caddisfly larvae w/ case October caddis
Fall caddis (Family Limnephilidae, Genus Dicosmoecus)
Student Watershed Research Project (SWRP) Macroinvertebrates

28. Representative Caddisflies
humpless casemaker caddisfly
saddlecase maker caddisfly
Glossosomatidae from
net spinning caddisfly

29. Aquatic moths obtain oxygen through diffusion across soft tissue
Family
Tolerance
Feeding Guild
Pyralidae
Moderate
Shredder

30. Representative Beetles
Riffle beetle adult

31. Water Pennies (Coleoptera) Sensitive
Circular-shaped
Attach firmly to rocks
Sensitive – need high oxygen and fast flowing water
The name Coleoptera, derived from the Greek words "koleos" meaning sheath and "ptera" meaning wings, refers to the modified front wings which serve as protective covers for the membranous hind wings.
Student Watershed Research Project (SWRP) Macroinvertebrates

32. Representative Flies midge larva cranefly larva midge adult
Cranefly from
Chrinomidae adult from
cranefly larva
midge adult

33. Cranefly (Diptera) Wide Range
Worm-like
Head capsule, usually retracted into “accordion-like” body
Shredders
The name Diptera, derived from the Greek words "di" meaning two and "ptera" meaning wings, refers to the fact that true flies have only a single pair of wings.
Student Watershed Research Project (SWRP) Macroinvertebrates

34. Midge Larvae (Diptera) Tolerant
Pear-shaped body, with swollen base where they attach
Filter feeders
                                                                                              

35. Crayfish (Decapoda) Wide Range
4 pairs of walking legs
Large pair of pinchers
Up to 6 inches
Deca = ten, poda = legs
Student Watershed Research Project (SWRP) Macroinvertebrates

36. Scuds (Amphipoda) Wide Range
“Shrimp-like”
Prefer muddy substrate with rooted vegetation
amphi = both (as in both sides, all around), poda = feet
Student Watershed Research Project (SWRP) Macroinvertebrates

37. Snails (Gastropoda) Tolerant
Cylindrical shell
May be right or left handed
Gastro = stomach, poda = foot
Student Watershed Research Project (SWRP) Macroinvertebrates