3. Coleoptera

Question 1

Coleoptera

Dytiscidae - Adults

Answer 1

Structure
•	Oval shaped bodies
•	Rounded backs
•	Elongated hind legs with last segment flattened 
        and fringed

Behaviour
• Fast swimming/diving using hind legs together like
oars
• Resting just below water surface, head down and
tip of abdomen pushing through surface film

Habitat
• Amongst plants on the edges of ponds/pools
• Backwater areas of streams

Question 2

Coleoptera

Dytiscidae - Larva

Answer 2

Structure
•	Streamlined spindle-shaped bodies
•	Large heads
•	Well-developed mouthparts
•	Fringed swimming legs

Behaviour
• Swims slowly with alternate rowing of the legs

Habitat
• Amongst plants on the edges of ponds/pools
• Backwater areas of streams

Question 3

Coleoptera

Elmidae - adults

Answer 3

Structure
•	Very small
•	Slender antennae, last segment widened in some 
        species
•	Sharp claws on the feet

Behaviour
• Very slow moving
• Walking/crawling whilst clinging to substrate with long claws

Habitat
• Stones or any solid substrate
• Fast streams

Question 4

Coleoptera

Elmidae - larvae

Answer 4

Structure
• Different body shapes according to species
• All body segments hardened
• Three tufts of anal gills

Behaviour
• Moves as slow as the adults
• Tufts of anal gills visible at intervals

Habitat
• Stones or any solid substrate
• Fast streams

Question 5

Coleoptera

Gyrinidae - adults

Answer 5

Structure
• Oval bodies, streamlined and shiny
• Hind legs fringed, flattened like paddles
• Eyes are divided , one half can look skywards, the
other half into the water

Behaviour
• Floats on the water surface in circular patterns
• Scatter or dive when disturbed
• Able to fly - they need to climb onto an emerging
object in order to take off

Habitat
• On the surface of the water
• Quiet ponds or flowing water

Question 6

Coleoptera

Gyrinidae - larvae

Answer 6

Structure
•	Long slender body
•	Feathery gills on the sides
•	Four hooks on last segment of abdomen Well 
        developed mouthparts

Behaviour
• Crawling on submerged vegetation or substrate
• Active swimming in a wavy, sinuous manner

Habitat
• Under stones or other solid substrate
• On vegetation
• Slow to moderately fast streams

Question 7

Coleoptera

Helodidae - larvae

Answer 7

Structure
• Small broad body, clearly segmented
• Long hair on the last segment

Behaviour
•	Cling to vegetation
•	Move around in an awkward wriggling fashion with 
        antenna arched side-ways
•	Very long, thin antennae

Habitat
• On submerged vegetation
• Under stones
• Slow or fast streams with low pH value

Question 8

Coleoptera

Hydraenidae - adults

Answer 8

Structure
• Minute in size
• Mouthparts longer than antennae
• Antennae club-shaped

Behaviour
• Active swimmers

Habitat
• Stagnant pools
• Wet rocks around waterfalls
• Amongst plants on the edge of streams

Question 9

Coleoptera

Hydrophilidae - adults

Answer 9

Structure
• Oval body with rounded back
• Short clubbed antennae, mostly hidden
• Mouthparts much longer than antennae

Behaviour
• Active swimming, using hind legs alternately
• They come to the surface with head first to break
surface film with tip of the antenna

Habitat
• Amongst vegetation
• In muddy patches along riverbanks
• Quiet shallow pools or slow edges of streams

Question 10

Coleoptera

Hydrophilidae - larvae

Answer 10

Structure
• Soft, worm-like
• Well-developed mouthparts

Behaviour
• Slow moving
• Creeping/crawling with head tilted upwards

Habitat
• Pools
• Quiet, shallow edges of streams

Question 11

Coleoptera

Psephenidae - larvae

Answer 11

Structure
•	Broad disc-like body, very flat
•	Head, legs and gills not visible from above
Behaviour
•	Move around in a slow gliding fashion
•	Entire body acts as a sucker to cling to rocks
Habitat
•	On rocks or other solid substrate
•	Shallow fast streams