Exam 2
• Next Thursday
• Topics:
– Development, Trophic relationships
– Hoeinghaus et al. large-river food webs
– Illinois macroinvertebrate paper
Trichoptera
• Large group ~ 1350 spp. North America
• Closely related to Lepidoptera
• Holometabolous
Trichoptera in most freshwater
habitats
• Spring and seepage streams, rivers
• Lakes
• Marshes, temporary ponds
Trichoptera diet
• Larvae eat algae, decaying vascular plants,
and microorganisms on plants
• Few larvae are predators
• Best known for nets, retreats, cases = silk
from labrum
• Several forms
Net Spinners
Net Spinners
Net Spinners
Purse Case Builders
Saddle Case Builders
Tube Case Builders
(portable)
Other cases
Free Living
Adults
• Eggs in gelatinous
case attached to
submerged vegetation
or log
Morphology
• Anal prolegs have anal claw
• Mandibles curved, often crossing each
other
ID of Trichoptera: 12 families
• Anal claw comb-shaped, case is snailshaped
• Helicopsychidae
Hook-shaped anal claw
• Dorsum of all three thoracic segments
covered in sclerotized plates
• Abdomen with ventral rows of branched gills
• Hydropsychidae
• Common netspinners
• Dorsum of all three thoracic segments
covered in sclerotized plates
• No gills on abdomen, portable cases
• Hydroptilidae = micro caddisflies (2-6 mm)
Thoracic segment 3
membranous
• Thoracic segment 2 membranous or
small plates
• Abdominal segment 9 membranous
• Labrum T-shaped
• Philopotamidae
Thoracic
segment 3
membranous
• Thoracic segment 2 membranous or
small plates
• Abdominal segment 9 membranous
• Labrum rounded, sclerotized
• Trochantin pointed
• Polycentropodidae
– No cases
Thoracic segment 3
membranous
• Thoracic segment 2 membranous or
small plates
• Abdominal segment 9 sclerotized
• Abdominal segment 1 with hump,
prosternal horn
• Phryganeidae
– Cases of plant fragments
Thoracic segment 3
membranous
• Thoracic segment 2 membranous or
small plates
• Abdominal segment 9 sclerotized
• Abdominal segment 1 w/o hump, no
prosternal horn
• No case
• Rhyacophilidae
• Thoracic segment 2 membranous or
small plates
• Abdominal segment 9 sclerotized
• Abdominal segment 1 w/o hump, no
prosternal horn
• Tortoise-like case
• Glossosomatidae
Thoracic
segment 3
membranous
• Thoracic segment 2 sclerotized
• Antennae long, hook-shaped anal claws
• Leptoceridae = long-horned caddisflies
Thoracic
segment 3
membranous
• Thoracic segment 2 sclerotized
• Antennae short
• Tarsal claw on hind leg smaller than
others
• Molannidae = hood-cased caddisflies
Thoracic
segment 3
membranous
•
•
•
•
Thoracic segment 2 sclerotized
Antennae short
Tarsal claws similar on all legs
Abdominal segment 1 no hump,
pronotum divided by crease
• Brachycentridae
Thoracic
segment 3
membranous
•
•
•
•
•
Thoracic segment 2 sclerotized
Antennae short
Tarsal claws similar on all legs
Abdominal segment 1 hump
Anterior margin of mesonotum notched on
sides of midline, head elongate
• Uenoidae
Thoracic
segment 3
membranous
•
•
•
•
•
Thoracic segment 2 sclerotized
Antennae short
Tarsal claws similar on all legs
Abdominal segment 1 with hump
Anterior margin of mesonotum not notched
on sides of midline, head round
• Limnephilidae