Hints to Indentifying Stream Invertebrates
Mayfly
- If a bug has three tails, it is a Mayfly, if it has two, look for further clues.
- Gills are on abdomen, lower body
- They dance (swim) in the water, often fold their tail like a scorpion
- If there are lots, they are Mayflies (stoneflies die off more quickly)
- 750 different kinds in total
- This one is covered with an algae-like material (camouflage)
- Ones with flat heads scrape algae off rocks for food
- During fly stage, no longer has a mouth, just an egg laying machine.
- Lives approx one year in water, 4 days as a fly
- Adult has sail wings
Stonefly
- Segmented body. Like an ant
- Two tails
- Smooth body
- Gills under armpits
- They walk, don’t swim
- Have antennae
- Very susceptible to pollution
- Crawls out of head when becoming a fly.
- Wings lie flat to body, one overlapping the other
Caddisfly
- Makes its home from stones, twigs or organics
- Ones with green body and red head bite. Free swimming (no home) predators, eat meat
- Have two hooks on their tail to hold onto their casing (home)
- Curl up when washed out of their home
- Wings are like a pup tent
Beetle
- Image to the right is riffle beetle in larva stage
- Image to the left is riffle beetle as an adult
- Stays aquatic
Aquatic Worms
- Come in a variety of colour
- Look through a magnify glass to see if it has a head and legs, it may be a midge fly larva
Cranefly
- The ones like the one in the photo, are predators. They suck water into their skin and then push it out to move. Like a squid.
- Non predator looks the same except for the bulbous end
Water Snipe
- Looks similar to the Cranefly larva, but has legs like a caterpillar
Water mites
- Small
- Tennis ball with legs
- Comes in a variety of colours
- Each colour is a different kind
Scud
Links added March 4, 2006, courtesy of Niall Williams