Stream Study: Biota

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Stream Study Biota
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Caddisfly Larva

• Caddisflies are the larval form of an insect that
  flies in the air when it is an adult.
• They usually live in caddises, or homes, built
  out of pebbles or debris that they have woven
  together out of silk.
• They hold themselves together in the cases with 2
  anal hooks, and poke their heads out only to feed
  on algae, crustaceans and black fly larva.
• They have gills on their abdomen and are
  indicators of clean water.

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Leech

• Leeches are related to earthworms.
• They are excellent swimmers, but swim mainly at
  night and stay under rocks during the day.
• They feed off of vegetation, dead material, or
  blood.
• They can tolerate oxygen poor water.
• In the 1500s, leeches were put on patients to
  bleed them. Actually, they remove only a few
  drops of blood, and do so very painlessly. They
  inject you with freezing agent and an
  anticoagulant. Few people could even tell if
  they were on them.
• The red ones have hemoglobin (iron) and the dark
  ones have cuprocyanin (copper) to carry oxygen.

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Mayfly Nymph

• Mayfly nymphs are the aquatic stage of an insect
  that eventually flies in the air.
• They are characterized by having 3 tails.
• Mayfly nymphs have gills on their abdomen and are
  indicators of clean water.
• Mayflies are herbivores. They may be aquatic for
  up to 3 years. When they become adults, usually
  in May, they have no mouthparts. They must mate
  within a few days, and then they die from lack of
  food energy.

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StoneflyNymph

• Aquatic stoneflies are the nymph stage of an
  insect that eventually becomes an insect that
  flies in the air.
• Stonefly nymphs have 2 tails.
• They obtain their oxygen from gills on their
  legs.
• They are predators, feeding largely on mayfly
  nymphs.
• They are the indicators of the best, clean water
  found in streams.

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Sowbugs

• Sowbugs are aquatic scavengers that feed off of
  dead plant and animal matter in a stream or pond.
  
• They generally are found under rocks and scurry
  away from light.
• They do not require large amounts of oxygen, and
  large numbers of them may indicate the presence
  of a lot of dead matter.
• They are very similar to their terrestrial
  cousins, sowbugs that live under rocks in gardens
  and in forests.

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Snails

• Snails are herbivores, eating algae off rocks and
  plants. They may also be scavengers, eating dead
  material in the stream.

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Hellgramites

• This is the larva of a Dobsonfly.
• Both larva and adults have large mouthparts
  adapted for piercing bodies and sucking out the
  fluids which forms their food!

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Brook Lamprey

• Brook lamprey live in the mud in stream banks.
• They live several years.

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Mosquito Larvae

• These larvae are known as wigglers
• Normally they like still water
• They are bum breathers. That is, their
  spiracles (air openings) are located on the end
  of their abdomen.
• They must breathe air, so they float up and push
  their air tubes out of the water to get air.

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Algae

• Algae are individual cells, or organisms, that
  often group together for mutual benefit.
• They have chlorophyll, so the can do
  photosynthesis. As producers, they are an
  important part of the food chain. Marine algae
  produce 60 of the worlds oxygen!
• While algae are normally useful, they can be a
  problem. If they bloom (grow quickly) they can
  use up their food reserves and die suddenly.
  When they are decomposed, bacteria use up a lot
  of oxygen in the water, which can kill fish.

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Water Pennies

• Water pennies, or riffle beetles, are aquatic
  larva of adult terrestrial beetles.
• They cling tightly to rocks in riffles, or
  rapids. However, if you pry them off, you can
  see their legs underneath their large back cover.

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Bryozoa

• Bryozoa means fern animal. They are colonial
  animals that wave microscopic arms, or fronds,
  out into the water to catch algae.
• They sometimes form large gelatinous spheres as
  large as a basketball in size. In these
  colonies, or towns, there may be hundreds of
  thousands of individuals, all living for
  themselves, but together.

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Bloodworm/Midge Larva

• Bloodworms are not worms at all, but are the
  larval form of a midge insect that does not even
  bite!
• They have hemoglobin, like us, so that they can
  carry oxygen efficiently in oxygen poor
  environments.
• They live in the bottom of streams and ponds
  where there is little oxygen.
• They feed off dead plant and animal matter.
• Bloodworms are indicators of oxygen poor water.

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Water Strider

• The water strider is a well-known bug that skates
  and jumps on the water surface.
• Its legs have waxy hairs on their tips making it
  possible for the insect to walk on water
• Water striders eat aquatic insects.

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Water Boatman and Backswimmer

• The water boatman and backswimmer look alike at
  first glance but can be told apart because the
  backswimmer swims on its back (go figure!)
• Backswimmers carry air with them when they dive.
  The air is in two troughs on the lower side of
  the abdomen. They fly easily and feed on aquatic
  insects
• Water boatmen are the most common aquatic bugs.
  They spend most of their time on the submerged
  vegetation and on the bottom. Most water boatmen
  are strong fliers.

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Whirligig Beetle

• Whirligig beetles are the only beetles that can
  swim on the surface film of water.
• Whirligig beetles are oval, black beetles that
  are found gliding or skating across the pond.
• Their compound eyes are divided in 2 parts- one
  part is used for looking above the surface of the
  water and the other part is used for looking
  below the water surface.
• They can dive below the water surface by trapping
  an air bubble under their abdomen.
• They feed on insects as well as dead plant/animal
  matter.

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Other Pond Organisms