Microscopes

MICROSCOPES
Lesson 5 - Page 4

Pond Life - Meroplankton

You are looking under microscope and you find this critter. It is segmented with 6 legs so it gives you a clue that it is an arthropod. However you need to find the key characteristic that you can identify it. It was in the plankton so you suspect that it is meroplankton. So this specimen may be a stage to becoming a full flying arthropod (insect). Look on the Meroplankton key and see if you can identify.

	Describe
Head
Antenna
Abdomen
Appendages
Tail

Arthropods - segmented, exoskeletons

Water mites
.5-5mm

1. 8 legs
2. round body
3. larvae (parasitic)
4. nymph looks like adult

Class Arachnida
Order Acarina

Alderfly nymph
5-25mm

1. one tail
2. long filaments along the abdomen
3. meroplankton

Class Insecta
Order Megaloptera
Family Sialidae

Caddisfly larva
3-40mm

1. cylindrical case for protection
2. distinct case but different materials

Class Insecta
Order Trichoptera

Stonefly nymph
<15 mm

1. two jointed tails (cerci)
2. carnivorous
3. indicates clean water

Class Insecta
Order Plecoptera

Mayfly nymph
<15mm

1. three jointed tails
2. leaf-like gills on sides

Class Insecta
Order Ephemeroptera

Damselfly
Nymph
<15mm

1. three leaf like tail appendages (gills)
2. extendable jaws

Class Insecta
Order Odonata
Zygoptera

Dragonfly nymph
<15mm

1. robust
2. no tail appendages
3. extendable jaws

Class Insecta
Order Odonata
Anisoptera

Water boatman nymph.and adult
10-15mm

1. no jaws
2. tube-like beak
3. nymphs don’t have wings

Class Insecta
Order Hemiptera
Family Corixidae

Water beetle
<45mm

adult

nymph

1. strong jaws
2. tough shield
3. fierce predator

Class Insecta
Order Coleoptera
Family Elmidae

1. strong jaws
2. long segmented body
3. short legs

Mosquito larva
1-20 mm

1. long slender body
2. moves in undulating s curves

Class Insecta
Order Diptera

Drawings redrawn from http://www.microscopy-uk.org.uk/pond/index.html

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