Trichoptera

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Trichoptera
-- closely realted to lepidoptera -- large,
holometabolous order (gt1300 spp) -- most are
univoltine and larvae and pupae are nearly always
aquatic -- about 2/3 of described spp cannot be
identified in pupa stage. -- inhabit a diverse
array of habitats 18 families (100 in cool,
lotic habitats) 17 families (95 in warm, lotic
habitats) 7 families (38 in lentic habitats) 3
families (17 in temporary pools) -- case-making
behavior closely linked to ecological
specialization.
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General life Cycle
eclosion
Winged Adult (lt 3 mos)
Pupae (2-3 weeks)
Egg (few weeks or diapause)
Larvae (5 instars 1-12 mos)
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Diapause larval stage
Emergence (fall reproduction)
Larval development complete. Diapause in last
instar
Pupation. Fasten Case and stop feeding
pupae
spring
summer
fall
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Diapause adult stage
Fall reproduction
Emergence (winged adult)
Pupae
Oviposit in fall
spring
summer
fall
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• Diapause in Trichoptera
• Suspends development until conditions
• are favorable
• 2) Synchronize adult emergence after periods
• of dissimilar larval development

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Caddisflies can generally be divided into 5
groups

• Free-living forms
• -- larvae move around actively and do not
  construct a retreat until pupation.
• -- mostly predators and most primitive
  trichopterans
• -- occur mostly in streams of W. North America
• Includes Rhyacophilidae

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Rhyacophilidae
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• Saddle-case makers
• -- construct portable, tortise-like retreats
• -- mostly grazers found in streams
• -- during pupation, larvae attach dome firmly to
  substrate.
• includes Glossosomatidae

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Glossosomatidae
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3) Purse-case makers -- larvae are very small
(lt3mm) and are free living until final instar
stage. -- first 4 instar stages (3 wks) differ
considerably from the fifth instar the only
example of heteromorphosis known in
Trichoptera. includes Hydroptilidae
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Hydroptilidae
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4) Net spinners or retreat makers -- most are
sedentary and construct fixed retreats with
capture nets to strain food particles. -- one
family (Hydropsychidae) produce sound by rubbing
femur on underside of head. includes Philopot
amidae Psychomyiidae Polycentropodidae Hy
dropsychidae
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Philopotamidae
Membranous, T-shaped labrum
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Psychomyiidae
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Polycentropodidae
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Hydropsychidae
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5) Tube-case makers -- larvae of these families
construct portable, tublar cases that enable them
to move from place to place. -- respiration is
enhanced in these families because undulating
movements of larvae create water currents inside
case (e.g. can survive at lower DO
levels). includes Limnephilidae Helicopsychi
dae Brachycentridae Calamoceratidae Seric
ostomatidae Odontoceridae Molannidae Lept
oceridae Phryganeidae Lepidostomatidae
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Limnephilidae
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Helicopsychidae
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Odontoceridae
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Molannidae
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Leptoceridae
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Brachycentridae
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Phryganeidae
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Sericostomatidae
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Megaloptera
Fishflies and alderflies
-- Small, holometabolous order that contains 2
families Corydalidae Sialidae General
life-cycle
Spring/summer
Egg larvae pupae
winged adult
10-12 instars 30-65 mm
aquatic
terrestrial
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Corydalidae (Dobsonfly or Fishfly) -- Late
instars have very large, distinctive mandibles
but smaller larvae can resemble those of
Gyrinidae. -- Can be distinguished from
coleopterans by terminal prolegs that contain a
pair of hooks --Larvae inhabit streams/springs
with high DO -- All larvae are predaceous. 2-5 yr
life cycles
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Sialidae (Alderflies) --Larvae are
predaceous -- Found mostly in depositional
sediments of streams, ponds and lakes. -- 1-2
year cycles, similar to corydalids. -- Long,
single tail filament helps distiguish larvae from
other aquatic insects. --Eggs are laid on
overhanging leaves, twigs or bridge abuttments
similar to corydalids. --Apparently, adults do
not feed.
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Aquatic Neuroptera
Sisyridae (spongillaflies)
-- Larvae found associated with freshwater
sponges -- Occur on surface or cavity of sponge
where they use specialized stylets to pierce
sponge cells -- Most spp are multivoltine with
larvae having only 3 instar stages -- Eggs laid
on vegetation or substrate above water where they
hatch and larvae fall into stream -- Larvae have
no special adaptation to aquatic environments.
They respire through the cuticle. -- Usually
only collected by locating and collecting
freshwater sponges.
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General life-cycle of Neuroptera
1 wk
Few days
Few weeks
Eggs larvae pupa
winged adult
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