1. Phylum Arthropoda Class Insecta Order Trichoptera

2. Trichoptera Characteristics
Tricho = hair; ptera = wing; silky hairs cover much of the body and wing
320 sp in PA (Masteller), >7000 in world.
Adults are nocturnal, weak fliers; most are short-lived; vestigial mouthparts; wings held tentlike over abdomen.
Holometabolous
Most have little economic, but great ecological importance.

4. Adults

5. Larvae and Cases

6. Immatures Eruciform (caterpillar-like) body
Abdomen often enclosed in case of natural materials such as sticks, plant fragments, sand grains, etc.
Well-developed head capsule
Thread-like abdominal gills usually present in case-makers
Often one pair of hooked prolegs present on terminal caudal appendage

7. Ecological Roles
Grazers/scrapers-feed on biofilm of diatoms and algae comprising the periphyton. Includes some mayflies (e.g., Stenonema) and some caddisflies.
Shredders-feed directly on CPOM, converting it to FPOM. Includes some stoneflies, caddisflies, and cranefly larvae.
Collectors
Filtering collectors-may build a net which they either pick clean or consume, contents and all. Includes many caddisflies (e.g. Brachycentrus and Hydropsyche.)
Gathering collectors-collect FPOM from around and under rocks as well as from interstitial spaces. Includes, among others, mayflies such as Baetis and Ephemerella.
Predators-examples include most beetle larvae and most stonefly larvae.

8. References
Masteller, E. Trichoptera of Pennsylvania
Wright, M. Key to Trichoptera (Caddisflies) of Pennsylvania