1. Lentic – standing water (no flow) Lotic – flowing water
Aquatic Insects: Why do we care?
Major component of the aquatic food chain
- they eat and are eaten
Indicators of aquatic health
pollution tolerant vs. non-tolerant species (EPT)
Affect human health
vectors for disease (malaria, encephalitis, yellow fever)
they bite you: mosquitoes, gnats, blackflies, and biting midges (Diptera)
Many fishing lures modeled after them
Lentic – standing water (no flow)
Lotic – flowing water
DO – fluctuates during the day

2. How do aquatic insects deal with different O2 and flowing environments
How do aquatic insects deal with different O2 and flowing environments? (2 types of breathing methods)
Aeropneustic – get their oxygen from the atmosphere
must keep in contact with the air
or take it with them, making repeated trips
have ‘hydrofuge hairs’ that trap air bubbles
tiny hairs provide surface area for bubbles to attach to, forming a thin film of air called the plastron – allows insects to breath from the air bubble
Coleoptera, Hemiptera
the advantage of periodic contact breathing is that it allows the insect to dive and swim around

3. Hydropnuestic – use oxygen dissolved in the water
cutaneous respiration (Diptera, Plecoptera)
occurs when the cuticle is thin enough for air to diffuse directly in and out for the insect
allows an insect to remain underwater indefinitely
Tracheal gills
lamellate – flat (Ephemeroptera, Odonata)
filamentous (Megaloptera, Plecoptera)
Odanata have gills within their abdomens and pump oxygenated water to their gills through the anus. Can also propel themselves by quickly jetting the water back out.
They move fast!!!

4. What about dealing with flowing water?
Lotic insects have morphological features to stay put
- suckers (Diptera), hooks (Trichoptera, Megaloptera)
small, flat bodies
sticky secretions
build cases (Trichoptera)

5. Orders you may encounter Ephemeroptera (mayflies)
Eggs – larva – subimage - adult
Larva – elongate, 3 filaments (tail), can have 2
Lamellate gills along abdomen
Well developed legs
Perpendicular wings on adults

6. Plecoptera (stoneflies)
Same life cycle as mayflies
Have 2 filaments
No lamellate gills along abdomen
Some have filamentous gills
Adult wings are flat
Mostly shredders and grazers

7. Trichoptera (caddisflies)
Have anal prolegs with hook
Less visible antennae
Only order that makes cases
Adult wings down- very hairy
Trichoptera (caddisflies)

8. Odonata (dragonflies, damselflies)
Eggs –larva –teneral adult - adult
Predacious
No external gills
Longer body on damselflies (wings up)
Dragonflies (wings down)

9. Diptera (midges, mosquitoes, gnats, flies)
Elongate body
Segmented body
Most species rich order (includes Chironomidae)
Adults have one pair of wings
Very diverse morphology

10. Hemiptera (true bugs) Egg – nymph larva –adult Predacious “beak”
Wing pads
If wings develop they fold over each other

11. Coleoptera (beetles) Egg – larva –pupa – adult
Larva very different from adult
Adults – have hard case on body that does not overlap
Adults have chewing mouthparts
Larva –undeveloped eyes, sometimes have tusks

12. Megaloptera (alder flies, dobsonflies)
Mouth has large, chewing pinchers (predacious)
Abdomen has strand-like appendages extending from each side
Three pairs of segmented legs on middle section of body
with tiny pinchers at the end of each
Each segment contains filaments for respiration
Abdomen ends with two elongated appendages or prolegs