1 EAGLETON NOTES: Water Boatmen



Tuesday, 12 October 2010

Water Boatmen

I was cleaning the pond yesterday when something jumped on the path at the water's edge.  After a while it stopped jumping around and I discovered that I had a really attractive little creature - to photograph.  It was about 15mm (just over 1/2") long.  It's (leastways I hope it is) a Common Backswimmer or Water Boatman. 

 Common Backswimmer: Notonecta glauca 

This small (no more than 16 mm long) creature is an extremely potent hunters. They have three pairs of legs, two of which are used to “walk” underwater, while the third one serves as a kind of oars.   Although a water creature, the Backswimmer also has a pair of wings, which are covered under a layer of protective plates when the creature is not flying.

The Backswimmer uses the gel-like top layer of water by swimming under it, with the legs upside down, touching the water membrane. There the animal hunts everything that is small enough to catch.  They are one of the most aggressive water creatures hunting everything that comes near and is small enough – other bugs, larvae, small fish and tadpoles, as well as flying bugs that have fallen in the water.   These animals are so dangerous that they can even wipe out populations of fish completely, by hunting out all the young fish.

When the prey is close enough, the Backswimmer charges it at lightning speed and pierces the victim’s body with the small snout and injects a paralyzing substance, as well as digestion fluid which quickly dissolves tissue and turns it into a liquid substance, very much as spiders’ poison. does.  Afterwards, the Backswimmer sucks out all the feeding substance from the victim’s body and only an empty shell is left.

They are also competent fliers and often fly from one pond to another, in search of better suited surroundings – waters rich with oxygen and plants.

When I was in France recently I photographed another type of Water Boatman - not that I knew what it was until I asked my niece, Helen - which had flown into the swimming pool.  Plenty of bugs for it to eat but I'm not sure how long it would have survived the chlorine.

 [Thanks to www.itsnature.org for the information on which much of the text is based.]


  1. Thanks for giving the size. I got a little jumpy myself there suddenly coming face to face with it like this... (LOL)

  2. So interesting, and yet, so creepy! I tried not to let it, but it gave me the willies! Ha!

  3. Lovely images Geeb. I love the gold on the french one!

  4. So that's what a water boatman looks like. Doesn't look aggressive! Guess it's another case of looks being deceiving.
    I think yours looks more elegant than the French model. (Now there's one for the books!)

  5. Thanks for this I've never seen one the right way up. Nor have many other folk I warrant.

  6. Yea, Adrian, few people are prepared to get their camera wet and anyway one would be shooting up into the light!