Aquatic Insects:
3% of insects are aquatic 1-2% of earth’s
surface is covered by
freshwater and nearly all aquatic systems except the ocean
Ponds and lakes have lots of plants but have
low oxygen content
Streams and rivers having moving waters with
higher oxygen content
Adaptation: Breathing
organ allows dissolved oxygen to pass by diffusion under water
gills
Adaptation: breathing
outgrowths of the tracheal system covered by a thin layer of cuticle permeable to
gases
Dragonfly Larvae Gill
Abdomen of larvae dragonfly have
internal gills
Dragonfly Larvae Gill
Caudal end of alimentary tract
rectal gill
Dragonfly Larvae Gill
Water pumped into rectum provides oxygen to
closed tracheae
Dragonfly Larvae Gill
contraction of abdomen expels water and thrusts insect forward
Doubles as jet propulsion system
Structures visible as thin, silvery films of air covering parts of body surface and involve scales or microscopic ridges projecting from cuticle
Plastron
Plastron Capabilites:
Allows aquatic insects to remain what?
constantly submerged as they most likely lack the ability to reach surface
Diving insects carry trapped air bubbles and deplete
oxygen more quickly
need replenishment
source of air stores (trapped bubbles)
Plants can also trap air which acts as a resource for insects
Insects can remain submerged for long
periods with high
concentrations of
Hemoglobin in hemolymph
respiratory pigment that facilitates binding of oxygen
Hemoglobin
larvae of midges,bloodworms live in muddy ponds/streams where
dissolved oxygen is low
Air from surface through breathing tubes
siphons
(work like a diver’s snorkel)
Aquatic plants maintain buoyancy by storing oxygen
(waste product)
in vacuoles
doesn't need to swim to surface with air stores
Mosquito larvae siphon tube is
spiracle extension
Mosquito larvae has many characterisitcs
-Live on surface on the water
- dives when body surface is bothered into a ball deep into the water
- Hairs have waterproof coating at the end of siphon(keeps water out)
Adaptation Swimming:
This helps dragonflies become adapted for swimming and use their abdomen with the use of?
Natatory legs
Water striders:
Have hydrofuge hair piles, elongated legs & body to have the ability to
walk on water due to high surface tension of water and their hydrophobic legs
Mosquitoes Adaptations
Can occupy temporary water for multiple reasons like
Fast development
larval dormancy
immediate egg-laying to the newly filled site
Adaptation: Avoiding Predators
Does Trichoptera have this adaptation to help avoid predators?
protective shell and create nets to filter food
Insects as Bioindicators
give idea of the overall biodiversity of plants and animals
Insect abundance
water quality has become a regular practice for determining pollution
insects as biomarkers
Biomonitoring
water quality through EPT richness index formula
Ephemeroptera, Plecoptera, Trichoptera sensitive to pollunants
total ept taxa/ total taxa found X 100% = %Abundance
Ephemeroptera: Mayflies
Immatures having these different charactersitics
- are aquatic # naiads
- Well-oxygenated water
- short-lived adults, live for years in water
- Detritivores & herbivores
- subimago stage:winged non reproductive form
- an excellent food source for birds
- Adult non feeding only mate
Plecoptera: Stoneflies
Characteristics
- naiads live in the benthic zone
- obtain oxygen by exoskeleton diffusion
- intolerant of pollution
- an indicator of excellent water quality
- emerge seasonally; spring or summer but winter stoneflies during fall and winter
Trichoptera: Caddisflies
Characterisitcs
- wings held over the abdomen
- threadlike antennae
- diverse order of aquatic insects
- larvae build protective cases
- case held together by silk secretions produced from salivary glands
- Prolegs on abdominal segments hold the case in place