Water Scorpion from Australia

Giant Water Bug
Location: Queensland, Australia
January 26, 2012 12:50 am
Hi guys,
Hope you like these shots of a giant water bug that was hanging around banging into a shiny piece of stainless steel in my carport. They will often mistake a reflective surface for water and attempt to drop into it.
The bug played dead when I got close to it and it allowed me to turn it over for a shot of its piercing mouthparts. It was determined not to give itself away until I picked it up and took it over to some long grass. When I dropped it on the grass it quickly righted itself and flew away.
Signature: aussietrev

Water Scorpion

Hi Trevor,
The very flattened body and extremely long, posterior breathing tube indicates that this is a Water Scorpion, and not a closely related Giant Water Bug.  Interestingly, we found a photos of a Water Scorpion from Australia submitted by you in 2008 in our archive.  We decided to do a bit more research and we found the AusEmade website that has a photo of an Australian Water Scorpion from Simpsons Gap that is identified as
Laccotrephes tristis and contains this information:  “One of the interesting looking insects found swimming in the pools is the Water Scorpion, whose other common name is Toe-biter. These strange looking creatures are carnivores, feeding on other aquatic organisms that they can capture including tadpoles, small frogs and small fish. They swim with the tip of their long needle like tail breaking the water surface, acting as a breathing siphon.  With their large pincer-like forelegs used for seizing their prey, Water Scorpions can inflict a nasty nip, although they are also known to play dead when disturbed. Once they have grasped their prey, they inject a venom that liquefy the prey from the inside, which enables the Water Scorpion to suck out the prey’s body fluid.”  The Identification and Ecology of Australian Freshwater Invertebrates website also has some good information.  The Atlas of Living Australiahas a distribution map.

Water Scorpion

If you look closely at your close-up photos, you can see tiny red spots which we suspect are Mites.  Several sources indicate a common name of Toe-Biter which is shared with the North American Giant Water Bugs.

Water Scorpion


3 thoughts on “Water Scorpion from Australia”

  1. Thanks for the correction on the ID guys, too much Australia Day celebrating. Yes it had several mites on the underside. I don’t think I’d like to be stabbed by that hypodermic they have for a mouth either.

  2. The mites are probably parasitic larvae in the water-mite family Hydrachnidae, genus Hydrachna. Species in this genus are unusual for water-mites in that the larvae parasitize aquatic Hemiptera.


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