Ranatra fusca “Brown Waterscorpion” Nepidae

Lake Inez, Lolo National Forest, MT
May 23, 2017
Robert Niese

There’s something genuinely unnerving about insects viciously preying upon vertebrates, and waterscorpions are superbly specialized for this terrifying task. They sit near the surface of the water, head down, with their elongated, raptorial front limbs outstretched, waiting. Their long paired “tails” remain in contact with the water’s surface like a snorkel, allowing them to breathe while fully submerged. When some unlucky fish or tadpole swims too close, they snap them up like a mantis and immediately stab them with their sucking mouthparts. Their saliva both subdues and begins to digest their prey, allowing them to suck out the animal’s insides. On a completely unrelated note, this individual looks worse for wear, which led me to discover that adults actually overwinter in lakes and ponds here in Montana – not an easy task considering that most bodies of water freeze-over completely at some point. So apparently they’re indestructible AND hyper-specialized predators. Thank goodness they’re only five inches long.