Pond dipping for wildlife

Posted: Thursday 20 June 2013
by Kate Bradbury

I spent most of last Sunday armed with a fishing net and a couple of jam jars, gawping into my mum’s pond.

Diving beetle

I spent most of last Sunday armed with a fishing net and a couple of jam jars, gawping into my mum’s pond.

This is the shallow pond I dug last year. After the ‘growling’ frogs in March, I wanted to see what else had moved in.

Pond dipping was never an activity I engaged in as a child. We didn’t have a pond at home and, after I attempted to walk on water at the local garden centre, my mum was reluctant to let me have a bath on my own, let alone wander off with a fishing net and a couple of jam jars.

Perhaps this denial in my early years fuelled my passion for ponds as a grown up. These days, I love a good pond dip. The only objection from my mother now, is that I’m making a mess of her lawn.

My mum has two ponds: the first I put in around 10 years ago, with the help of my then seven-year-old sister (we had to wait until she was of an age where she wouldn’t try to walk on water). For ease, we just bought a pre-moulded fish pond from the local garden centre, dug a hole, and plonked it in.

Being deep, the pre-formed pond attracts newts, which seem to like breeding in deeper water. There are always a few frogs there but they never spawn, and I occasionally find a pond skater on the surface. But its lack of gentle sloping sides and pond ‘shallows’ make it a pretty poor habitat for a lot of other wildlife, which is why I made the second pond differently.

Last Sunday, I sank my jam jar into the newer, shallow pond, and lifted it out. A rat-tailed maggot (the larvae of some hoverflies) floated in the water. There were a few water fleas and mosquito larvae, and lots of water boatmen. A couple of pond skaters remained on the surface of the pond, while frogs huddled together in the shallows - nothing too exciting.

But then, I saw it. There, rising to the surface of the water to take a gulp of air before returning to the muddy depths, was a diving beetle.

Diving beetles spend a lot time beneath the surface of the water, swimming up for air every few minutes, which they gather into a chamber under their wing covers to enable them to breath while submerged. My diving beetle was coming to the surface every five minutes. Poised with the net, I waited for it to return.

After a couple of failed attempts, I finally caught my quarry with a deft scoop of the net. I popped it in a jar, photographed it, and released it back into the water. It’s difficult to identify diving beetles without killing and dissecting them, but my trusty team of Twitter experts suspect that’s what it is.

Diving beetles (Agabus bipustulatus) are a common species, frequently seen in swimming pools. Although I’m slightly put out that the wonderful habitat I’ve created is only as good as an artificial, sterile body of water to these beetles, I’m reassured that diving beetles are top predators. This one is in my mum’s pond because there’s a lot to eat in there. I just need to get better at pond dipping, to find out what.

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Roy Hill 18/07/2013 at 23:56

Pond skaters are also a top predator in their own right. Diving beetles (so many species)? They do have this habit of using their neather regions to breathe :)