1. Aquatic Organisms by LeAnne Yenny

2. Benthic Macroinvertebrates
Used as bioindicator organisms
The presence or absence of these organisms in a stream can be used to reveal the overall ecological quality of the water.
Generally, unpolluted waters support a greater variety of freshwater macros than polluted water.

3. Life Cycles Incomplete metamorphosis (3 stages)
Eggs to Nymph to Adult
Include mayflies, stoneflies, dragonflies, damsalflies, true bugs
Complete metamorphosis (4 stages)
Eggs to Larva to Pupa to Adult
Include flies, beetles, caddisflies, dobsonflies

4. Functional Feeding Groups
Based on their feeding methods and adaptations
They are an important part of the food web
They are a primary link between the base of the food chain and the larger animals such as fish

5. Shredders
The first group of macroinvertebrates to break down the detritus (leaves that have started to decompose).
Includes craneflies, some caddisflies, stoneflies, sowbugs, and scuds.
They break the detritus down into fine particles.

6. Collectors
Drifting downstream the fine particles become food for the collectors.
They use various methods of either filtering or gathering of fine particles. Filterers use fan-like filaments near the mouth to capture food particles.
Includes some mayflies, midges, and net-spinning caddisflies.

7. Grazers (also called Scrapers)
Feed on the algae that grow on the surface of rocks.
Includes some caddisflies, the water penny (a beetle), and certain midges and mayflies.

8. Predators
The shredders, collectors, and grazers are a food source for the predators.
Includes dobsonfly, dragonfly.
Predators have large powerful mouth parts for grasping prey.

9. 1. Bacteria + Leaves. = Detritus (slimy. leaves) 2. Shredders break
1. Bacteria + Leaves = Detritus (slimy leaves) 2. Shredders break down leaves 3. Collectors filter and gather leaf parts 4. Grazers eat algae 5. Predators feed on all macros

10. Water Quality Indicators
Each macroinvertebrate belongs in a Taxa - a group indicating the level of pollution tolerance

11. Taxa 1 Includes: Caddisfly (Trichoptera) Stonefly (Plecoptera)
Water Penny
Riffle Beetle
Mayfly (Ephemeroptera)
Gilled Snail
Dobsonfly

12. STONEFLY LARVA
STONEFLY ADULT
Order: Plecoptera

13. ADULT MAYFLY
MAYFLY LARVA
Order: Ephemeroptera

14. CADDISFLY LARVA
ADULT CADDISFLY
Order: Tricoptera

15. Can you tell the difference?
Mayfly emerger
Caddis comparison
Stonefly nymph

16. Taxa 2 Includes: Crayfish Sowbug Scud Alderfly Larva Fishfly Larva
Damselfly
Watersnipe Fly
Crane Fly
Beetle Larva
Dragonfly
Clam

17. Taxa 3 Includes: Aquatic Worm Midge Fly Larva Blackfly Larva Leech
Pouch Snail
Pond Snail
Other Snails

18. Questions?