Today whilst checking the garden pond I noticed how these Great Diving Beetle (Dytiscus Marginalis) larvae are growing bigger, and one was feeding off another. I managed to scoop one out to get some photos before releasing back into the pond. These are helping to keep the gnat larvae numbers down.
Photographs taken of Great Diving Beetle (Dytiscus Marginalis) larva in August 2016, rear garden pond, Staffordshire. © Pete Hillman 2016. Camera used Nikon D3200, with Sigma 105mm macro lens.
Great Diving Beetle (Dytiscus Marginalis) larva
I have observed quite a few of these aquatic beetle larvae scurrying over the surface of rocks beneath the water in my garden pond. I have also seen them catch prey and eat it. They appear to be feeding on gnat larvae, of which they have a plentiful supply of.
Aquatic beetle larvae are also called ‘Water Tigers’, such is their voracious appetite. They are long and slender, with sickle-shaped jaws, and when observing them for myself I can see they are pretty nimble and move quickly over the rocks and stones.
The larvae pumps digestive juices into its prey via canals located in its jaws. These juices dissolves the tissues into a kind of soup which it draws out and consumes.
Great Diving Beetle larvae are found in freshwater ponds, and they will eat anything from each other, other invertebrates, to tadpoles, and even small fish in its later stages. At the moment the photos show the larvae in an early stage.
Notice how in the top images it has its tail in the air like a scorpion. They use this to gather oxygen from the air by poking the tip through the surface of the water.
Photographs taken July 2016, rear garden pond, Staffordshire.