Aquatic Macroinvertebrates. What are Aquatic Macroinvertebrates? Macroinvertebrates are small...
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Transcript of Aquatic Macroinvertebrates. What are Aquatic Macroinvertebrates? Macroinvertebrates are small...
What are Aquatic Macroinvertebrates?
Macroinvertebrates are small organisms that do not have a backbone.
A great diversity of types. Insects Spiders Leeches Snails and clams Worms
What are Aquatic Macroinvertebrates?
Aquatic macroinvertebrates are those that live in water.
The majority of aquatic macroinvertebrates are insects Insects can have three different life
stages: larvae, pupae, and adult Which stage is aquatic depends on the
type of insect
Insect Lifecycles - Incomplete Metamorphosis
Some insects do not have a pupae
They molt from a larval form to the adult
What are Aquatic Macroinvertebrates?
For most insects it is the larval form that is aquatic
Common insect orders that have aquatic larvae but terrestrial adults include Odonata – dragon flies and damselflies Ephemeroptera – Mayflies Plecoptera – Stoneflies Trichoptera – Caddisflies Diptera – Flies and Mosquitos
What are Aquatic Macroinvertebrates?
Beetles, Order Coleoptera, have both aquatic larvae and adults Interestingly, the pupae are often
terrestrial Many of the true bugs, Order Hemiptera,
spend their entire life cycle in the water
What are Aquatic Macroinvertebrates?
While insects are the most common aquatic macroinvertebrates, there is a wide variety of non insect forms Includes members of the Mollusc,
Annelid, and Arthropod Phyla to name a few
I. Molluscs
A. The Phylum Mollusca is the second largest animal phylum in terms of number of species
While most species are marine (saltwater), two groups are common in North Dakota Clams or mussels (bivalves) – not
usually found in wetlands Snails (gastropods)
I. Molluscs
B. Gastropods – the snails
Several different kinds
Common snails in wetlands include the genus Physa
II. Annelida
A. Class Hirudinea – The Leeches Several different types Usually considered indicators of poorer
water quality Probably some exceptions to this
Characterized by suckers on both the anterior and posterior end
Also called blood suckers
II. Annelida
Many are ectoparasites that feed on a blood meal They attach to their host, inject an
anticoagulant and an anesthetic This allows them to feed on a blood
meal usually undetected There are some species that are
vegetarians and some that are scavengers
II. Annelida
B. Class Oligochaeta Aquatic worms - small segmented worms
that live in the bottom sediments of rivers, streams, lakes, and marshes Actually quite a few different kinds Often overlooked because of their small
size Tubifex worms are often used for fish
food
III. The Arthropods
Include the insects, crsutaceans, and others
Largest group of aquatic macroinvertebrates
Aquatic insects
There is a great diversity of insect species that are aquatic
Many have an aquatic larval stage, but the adult has wings and lives in the habitat near water
A few groups have an entire life cycle in the water
Aquatic insects
A. Order Ephemeroptera - Mayflies Larvae are aquatic Spend the majority of their life as larvae Adults are short lived – 24 – 48 hours
Where the term Ephemeroptera comes from - ephemeral
Aquatic insects
Many different roles and adaptations Some cling to rocks, others burrow, and
some swim Usually considered indicators of good
water quality
Aquatic insects
B. Order Trichoptera - Caddisflies Larval and pupal forms are aquatic Considered to be indicators of good to
moderate water quality In many of the species the larvae form
elaborate cases that they live in
Aquatic insects
Larvae can often be identified by the following features Usually live in a case Have two “legs” on the back of their
abdomenThese have hooks that the animal
uses to anchor itself
Aquatic insects
C. Diptera – Flies and Mosquitoes Larval and pupal stages are aquatic Wide variety – some indicators of good
water quality, others indicate poor water quality
Larvae do not have legs – most are wormlike with very strange features
Aquatic insects
D. Order Hemiptera – True bugs Spend their entire life cycle in the water –
although many can fly and migrate Mouthparts consist of a tube used for
sucking Many are predators
Aquatic insects
E. Order Odonata – Dragonflies and Damselflies
Larval forms (called nymphs or naiads) are aquatic
Both larvae and adults are predators
III. Aquatic insects
Both damselfly and dragonfly larvae have a prehensile jaw that they can use to spear prey
Damselfly larvae are usually thinner, have three caudal gills
Dragonfly larvae have a stouter body, caudal appendages are much reduced
Aquatic insects
F. Order Coleoptera – Aquatic Beetles Beetles are the most diverse group of
animals on earth Many forms are aquatic
One of the few groups where both larvae and adults are aquatic
While some are considered to have little value in water quality determination, others are useful
Chrysomelidae
Most members of this group are terrestrial
Do not have many obvious adaptations for aquatic life
Found mainly on aquatic vegetation
Haliplidae – Crawling water beetles
Small aquatic beetles
Crawl around on submerged vegetation and debris
Top picture – adult Bottom picture -
larvae
Gyrinidae – Whirlygig beetles
Often found buzzing around on waters surface
Unique in that they have two sets of eyes
Dytiscidae – Predaceous diving beetles
Many different types found in wetlands Both adults and larvae are aquatic Both adults and larvae are predators
IV. Other Arthropods
A. Order Amphipoda – Scuds (see picture on previous slide)
Can be very common in some areas One type, the genus Gammarus, is found
primarily in lakes and marshes Larger of the two types found in ND An important forage food for fish in
Devils Lake
IV. Other Arthropods
B. Order Decapoda – the Crayfish Common inhabitants of rivers, streams,
and lakes Only a couple of species in North Dakota Crayfish usually feed at night and are
primarily scavengers Fairly short lived with a life span usually of
2 years or less
IV. Other Arthropods
C. Class Branchiopoda – the water fleas, clam shrimp, fairly shrimp, and others
Water fleas are commonly known as Daphnia
Usually found in lentic waters Their body is covered by a carapace They can be an important part of the food
chain in aquatic ecosystems