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Worm-like animals O H P S 1 Freshwater Invertebrate C O R E Identification Guide This guide can be used for the OPAL Water Survey
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Midge larvae Flatworms Cased caddisfly larvae P Dragonfly larvae S 10 S 10 • Red, green, brown or transparent • Often black or grey C O R E C O R E • Wriggling movement • Move by gliding
Leeches • Suckers at either end • Moves by stretching Rat-tailed maggot (hoverfly larvae) out body • Long thin breathing tube Worms • Lives in mud • Like a small earthworm • Body within a case; insect hides when D HEA
N L T H disturbed Snails O • Fat body P 1 Other animals S • Case can be made of small stones, sand • Angular head C O R E Note: you may find these other animals in your survey. While they are very interesting creatures, grains or plant material (a) • No tails but 5 short spines they do not give information about pond health, • Look for sticks that crawl! so they have no score. at the end of the body
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P Caseless caddisfly larvae P Damselfly larvae S 10 S 10 C O R E C O R E leaf-shaped tails Water mite
Water flea Daphnia( ) • Tiny animal • Often in very large numbers • A bit like a thin caterpillar Water spider • 3 pairs of legs at the front
• Silvery bubble • Hooks at the end of body • Angular head • Hard shell covering body over the body • Crawls rather than swims • 3 leaf-shaped tails (one or more may be lost) • Shell may be (a) pointed or (b) a flat coil • Lives under the water • Can vary greatly in size Silhouettes show maximum life size. Animals may be smaller than this. If no silhouette is shown, the photograph is at life size. Larvae are the young of aquatic insects.
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Higher scoring invertebrates T T
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Water beetles P P Water bugs Pond skaters P need cleaner water to live in 5 S S 5 S 5 C O R E C O R E C O R E D HEA
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O H Alderfly larvae P S 10 gills C O R E
size range
Backswimmers • Swim on their backs, just under • One tail • Skate on the water surface the water surface • Tapering body • 4 long skating legs and 2 short legs at • Use long hair-fringed legs as oars the front • Pincer-like jaws • Pair of antennae • Fine gills along the body
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O H 5 Mayfly and P S 5 C E S Lesser water boatmen O R stonefly larvae C O R E • Swim the right way up Mayfly larvae • Hard shiny wing cases covering the body • Wing cases look black/brown but close up are speckled or striped • 3 thin tails • Oval-shaped, 6 legs tails • Swim in short • May have bubble attached to the back • Curved, flattened bodies darting movements • Scavenging water • Long antennae beetles have a less • May appear slightly transparent streamlined shape • Swim quickly on their sides tail Stonefly larvae Beetle larvae • 2 thin tails Water scorpion D HEA N L T
• Generally moves • Dark-coloured crawling insect Water slaters O H P 1 by crawling • Front legs pincer-like S C O R E • Long thin breathing tube at back of body (in adult) Photographs: Cyril Bennett, Steve Cham, Niels Sloth (Biopix), Simon Pawley (FBA), Jeremy Biggs, Roberto Scherini (www.linea.it), Robert Zoralski (www.insects.pl), Alexander • Larvae are very varied; some have distinct body length up to 5 cm Grau and David Kohler (heteropterologie.de), Malcolm Storey heads, pincer-like jaws, tapering bodies (www.bioimages.org.uk), and obvious legs Simon Turner, Morten DD Hansen, Neil Rose, Roger • Many have two tails (check these are not Key, Brian Jones, Tim Apps, • Looks like a woodlouse mayflies that have lost a tail) Water stick insect Michael R Clapp (nwnature. • Flattened body net), Frank Köhler (www. • Others are more caterpillar-like with very • Long thin body koleopterologie.de). Designed • Moves by crawling by FSC Publications. © OPAL short legs and fat bodies • Thin breathing tube at back 2015. All rights reserved.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 cm
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