1. Benthic Macroinvertebrates
Identification

2. Backswimmer

3. Caddisfly Larva

4. Crane Fly

5. Crayfish

6. Damselfly

7. Damselfly

8. Dragonfly

9. Hellgrammite

10. Mayfly

11. Mayfly

12. Stonefly

13. Water Boatman

14. Water Penny

15. Water Strider

16. benthic macroinvertebrates- animals without a backbone, visible to the unaided eye, living in or on the stream bottom
one of the best indicators of stream health
present throughout the year
population reflects environmental changes

17. Examples:
insects, snails, clams, mussels, crustaceans, worms, and leeches
Large proportion in a stream are insects.

18. Insects go through metamorphosis (life changes) from egg to adult.
Due to these life cycles, the size and abundance of insects present in a stream will vary with the season.
Insects have a rigid exoskeleton that must be replaced in order for them to grow.

19. complete metamorphosis- 4 stages
(88% of all insects)
egg- female insect lays eggs
larva- hatch from egg, usually worm-like shape, do not look like adult
pupa- inside a cocoon, larva develops adult shape (4 days to months)
adult- emerges from cocoon

20. egg
larva
pupa
adult

22. incomplete metamorphosis - 3 stages
(12% of all insects)
egg- female lays eggs
nymph- looks like small adult, usually without wings, molt exoskeleton 4-8 times
adult- insect stops molting when adult size is reached and now have grown wings

23. egg
nymph
adult

25. Complete metamorphosis orders(species)
Tricoptera (caddis flies)
Megaloptera (dobsonflies, fish flies, alderflies)
Coleoptera (beetles)
Diptera (true flies)

26. Incomplete metamorphosis orders(species)
Ephemeroptera (mayflies)
Plecoptera (stone flies)
Odonata (dragonflies, damselflies)
Hemiptera (true bugs)

27. -nymphs and larva feed and grow Late Spring/Early Winter
Seasonal Cycle
Summer
-eggs hatch
Fall/Winter
-nymphs and larva feed and grow
Late Spring/Early Winter
-adults emerge 7

28. Stream Communities and Feeding Groups
Shredders
-macroinvertebrates with chewing mouth parts
-feed on decaying organic matter processes into finer particles
-aquatic sowbugs, a few caddisfly larvae, some cranefly larvae, scuds, and most stonefly nymphs

29. Grazers / scrapers
-feed on algae
-most caddisfly larvae and water pennies
-changes in habitat result in an increase of grazers with a decrease of shredders

30. Collectors
-feed on fine organic particles
-blackfly larvae, most caddisfly larvae, mayfly nymphs, midge larvae, riffle beetles, and riffle beetle larvae
-collectors are found in all stream regions, but are dominant in the lower regions of a stream system

31. Predators
-feed on prey
-alderfly larvae, backswimmers, most beetles and beetle larvae, damselfly nymphs, dobsonfly larvae (hellgrammites), dragonfly nymphs, fishfly larvae, some stonefly nymphs, and some cranefly larvae
-predators are found in all stream regions (wherever prey is found)