Water Boatmen – Red in Tooth and Oar

By Ruth D’Alessandro, The Wildlife Gardener Nature’s cruel. Life’s unfair. The Wildlife Gardener gets it wrong sometimes. In the Wildlife Garden, a group of pond-dipping small children witnessed first hand how innocuous-looking bugs can be cold-blooded murderers… One net pulled up two 2cm beetle-like creatures with adapted ‘arms’ for rapid movement across water. Aah ” quaint little water boatmen (Notonecta glauca), like miniature rowing boats.

Notonecta glauca (c) Max xx

I picked them up and dropped them into a jar that already contained a large damselfly nymph. As I passed the jar round, one pounced on the damselfly nymph, punctured it with a spiked mouthpart and visibly sucked it dry within seconds. Cries of ‘Urgh! Gross!’ from assembled junior naturalists. For me, this triggered a traumatic childhood flashback of releasing some tiny fairground goldfish into our pond. A beetle-like creature shot up from the depths, grabbed a fish and pulled it, writhing and struggling, to the sludge at the bottom. Serves me right for introducing fish into a wildlife pond. I had always blamed a great diving beetle (Dytiscus marginalis) for abducting Goldie, but it may have been a water boatman.


The cast-off skins or exuviae of dragonfly and damselfly nymphs. These may have been shed by emerging adults, but they are also all that’s left after water boatmen have finished with their prey!

I needed to know more. My romantic Jerome K. Jerome notion of the water boatmen had been shattered. Further research revealed that water boatmen are true bugs: they have long spiked mouthparts for puncturing and sucking prey. Their bite is venomous and they have no hesitation in using that spike and venom if handled. Apparently it’s as painful as a bee sting. I’m glad I didn’t know this as I picked the water boatmen out of the net, and more relieved I hadn’t handed them round to the kids. And I vowed never to mix species in bug jars again. Now I know the nature of water boatmen, I watch the miniature dramas in the wildlife pond with new insight. A newt eft, swimming by, was buzzed by a swooping water boatman, but the little amphibian was just fast enough to evade it. Go eft, go! Thank goodness. I don’t know how much more shock and oar I can take.