Phylum Arthropoda
Class Insecta
Order Trichoptera
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 shortlived; vestigial mouthparts; wings held tentlike over
• Holometabolous
• Most have little economic, but great ecological
Larvae and Cases
• 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 casemakers
• Often one pair of hooked prolegs present on terminal
caudal appendage
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.
Masteller, E. Trichoptera of Pennsylvania
Wright, M. Key to Trichoptera (Caddisflies) of Pennsylvania