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Definition (PA Code, Chapter 93): ◦ Spend a “living portion of their life cycle” in an
aquatic environment◦ Can be seen without the aid of a microscope◦ Animals without a backbone
Examples: crayfish, snails, insect larvae
What are aquatic macroinvertebrates?
http://www.dec.ny.gov/animals/35772.html
Like plants, macroinvertebrates can serve as indicators of water quality.
Sensitive to a variety of chemical and physical stressors:◦ Nutrient loading◦ Unstable hydrology◦ Habitat destruction
Why study macroinvertebrates in wetlands?
Minnesota Pollution Control Agency staff evaluating invertebrate samples
http://www.pca.state.mn.us/
Macroinvertebrate community data can be used to:◦ Monitor the condition of a
wetland◦ Determine the
effectiveness of wetland mitigation
◦ Make decisions regarding permit issuance
How is macroinvertebrate data used by wetland managers?
Aquatic macroinvertebrates fall mainly into 3 different phyla:
◦ Phylum Mollusca
◦ Phylum Annelida
◦ Phylum Arthropoda
Aquatic Macroinvertebrate Phyla
Scientific Classification:
KingdomPhylumClassOrder
Family Genus Species
Clams and snails
Phylum Mollusca
Helisoma sp.
http://spinner.cofc.edu
Physa sp.
Stagnicola elodes
LR
Aquatic earthworms and leeches◦ Aquatic earthworms are very similar to terrestrial
earthworms – eat mud and small bits of organic bottom as they move through substrate.
Phylum Annelida
Class Malacostraca: Crayfish and Amphipods
Characteristics:◦ Large diversity in this class◦ 20-segmented body◦ Two pairs of antennae◦ Two pairs of maxillae
Phylum Arthropoda
http://www.dec.ny.gov/animals/35772.html; http://iz.carnegiemnh.org/crayfish/
Class: Insecta 3 distinct body regions
◦ Head◦ Thorax◦ Abdomen
2 pairs of wings
3 pairs of jointed legs
Phylum Arthropoda
http://www.snh.org.uk/
1 pair of antennae
Compound eyes
Mouthparts consisting of:
◦ 1 pair of mandibles◦ 1 pair of maxillae◦ 1 labrum◦ 1 labium
How can we identify insects?
http://bugs.bio.usyd.edu.au/
10 most common aquatic insect orders
Aquatic Insect OrdersOrder ExampleCollembola SpringtailsEphemeroptera MayfliesOdonata Dragonflies and DamselfliesPlecoptera StonefliesHemiptera True bugsMegaloptera AlderfliesTrichoptera CaddisfliesLepidoptera Butterflies and MothsColeoptera BeetlesDiptera Mosquitoes, Blackflies, Chironomids
Common name: Mayflies Nymph characteristics:
◦ Possess 2-3 tails at end of abdomen◦ Gills arise from side of abdomen
Order Ephemeroptera
http://www.dec.ny.gov/animals/7470.html
Adult characteristics:◦ VERY short-lived
Do not feed – just reproduce, then die
◦ Occur in large swarms
Swarms are so large that they can be detected on radar!
Order Ephemeroptera
Common name: Stoneflies Larval characteristics:
◦ Each leg ends in 2 claws◦ Possess 2 cerci at the end of abdomen◦ Antennae typically 4-6 times the width of the
head
Order Plecoptera
http://www.dec.ny.gov/animals/7450.html
Common name: Caddisflies Larval characteristics:
◦ Often possess 2 prolegs with hooks at tip of abdomen
◦ Can free-living or build complex casings◦ Often have thread-like gills on abdomen
Order Trichoptera
http://www.dec.ny.gov/animals/35772.html
Common name: Dragonflies, Damselflies Larval characteristics:
◦ Damselflies: Delicate looking 3 caudal leaf or paddle-shaped gills at tip of
abdomen◦ Dragon flies:
Stout body, gills located inside abdomen tip
Order Odonata
http://www.dec.ny.gov/animals/35772.html
Larvae have a HUGE, hinged lower jaw that can be extended to capture prey as large as fish!
Order Odonata
Adult characteristics:◦ Dragonflies:
Wings are held out to the side when at rest Rear wings have a broader base than front pair
◦ Damselflies: Wings are held above the body when at rest Wing pairs of similar shape and size
Order Odonata
http://www.ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html
Common name: True bugs Characteristics:
◦ Mouthparts are modified into a beak called a rostrum
◦ May be found with air bubble in the water◦ 1st pair of wings are modified into leathery
coverings for hindwings (hemelytra)
Order Hemiptera
http://www.dec.ny.gov/animals/35772.html
Interesting facts:
Watch out in the water! Also known as toe-biters, these bugs will take a stab at unsuspecting humans swimming in ponds or lakes.
Rostrum operates by piercing the prey, ejecting digestive enzymes into the prey, and then sucking out the digested remains.◦ Allows the bugs to feed on large prey, including snakes
and small turtles.
Order Hemiptera
Common names: Mosquitoes, Blackflies, Craneflies, Chironomids
Larval characteristics:◦ HUGE diversity, difficult to id any farther than
family◦ Lack jointed legs on the thorax◦ Often have tubercules – small, fleshy appendages
Order Diptera
http://www.dec.ny.gov/animals/35772.html
Many different “metrics” are used to describe macroinvertebrate communities.
Most common metric:◦ Taxa richness: # of taxa in a community◦ Prediction: As water quality ↓, taxa richness ↓
Related metric: ◦ EPT richness: # of Ephemeroptera, Plecoptera,
and Trichoptera taxa in a community◦ Thought to be more pollution sensitive
How to classify macroinvertebrates
Functional feeding groups◦ Measures functioning rather than structure of the
community
◦ Types of groups: Scrapers - remove attached algae Shredders – utilize large pieces of organic matter Collectors – utilize small particles of organic matter,
either by filtering or gathering them. Predators – capture prey
Other metrics
MetricPredicted response to
increasing perturbation
% scrapers Decrease% collectors Variable% predators Variable% shredders Decrease% omnivores/scavengers Increase
Functional feeding groups
http://www.epa.gov