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Wasps Are Our Friends: Part III

The views expressed are those of the author and are not necessarily those of Scientific American.

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Megischus bicolor, a crown-of-thorns wasp in the family Stephanidae, photographed in Illinois, USA.

You might think an insect with an extra pointy derriere would pack a fearsome sting, but you’d be wrong. The extended rear appendage of the crown-of-thorns wasp is not a stinger but an egg-laying organ, the ovipositor, used to reach beetle grubs chewing through the wood below. Young wasps develop as ectoparasites of beetles in their burrows. Should this wasp take a stab at you, you’d feel as though tickled by a toothpick. Nothing more.

Why is this called a crown-of-thorns wasp? Have look at the head:

The function of the crown is not known, but it might help young wasps emerge from the beetle burrows.

Like the vast majority of wasps, Megischus is not aggressive. In fact, a challenge I faced photographing these delicate insects was their tendency to flee when the camera approached.

photo details (top):
Canon 100mm f2.8 macro lens on a Canon 6D
ISO 400, f/14, 1/160 sec
diffuse overhead speedlite

photo details (bottom):
Canon MP-E 65mm 1-5x lens on a Canon 6D
ISO 400, f/13, 1/160 sec
diffuse twin flash

More information about Stephanidae at the Tree of Life project.

Alex Wild About the Author: Alex Wild is Curator of Entomology at the University of Texas at Austin, where he studies the evolutionary history of ants. In 2003 he founded a photography business as an aesthetic complement to his scientific work, and his natural history photographs appear in numerous museums, books and media outlets. Follow on Twitter @myrmecos.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. rock johny 3:29 pm 06/24/2014

    So if it’s not a Yellowjacket or a hornet, is it generally non-threatening?

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  2. 2. DaveAlmquist 5:36 pm 06/24/2014

    I wouldn’t be too sure about the “tickled by a toothpick” feeling of their ovipositor unless you’ve actually messed with one of this species enough to have it attempt to defend itself. I grabbed a medium-sized ichneumonid awhile ago to show my kid that it wasn’t a stinging type of wasp and was shocked when it jabbed its ovipositor into me. No venom of course, but it did hurt in the same way a splinter or needle would.

    Link to this
  3. 3. Alex Wild in reply to Alex Wild 10:39 am 06/26/2014

    Thanks for your comment, Dave. Now I’m going to have to grab one and report back.

    Link to this

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