An Ovipositing Wasp in Russia - Observation of the Week, 5/3/19

Our Observation of the Week is this ovipositing Atanycolus wasp, seen in Russia by ropro!

In my experience, most people associate the word “wasp” with members of the Vespid family, such as hornets and paper wasps. And for good reason, as many of them are large, colorful, often found around humans, and can deliver a painful sting. But the world of wasps is endlessly fascinating, and that includes parasitoid ones such as the Atanycolus wasp seen above.

The photographer, Roman, tells me he came across this individual during mid-August, and it was one of several braconids he found on a fallen birch tree. Fallen birches, he says, are often great places to find wasps, “from Giant ichneumon wasps (Megarhyssa) to such small ones (the one in the picture, about five millimeters). Therefore, if I see a fallen birch, then I will definitely look at it.”

Why so many wasps around an old tree? Well, that’s where they can find food and a home for their young. Many other insects, such as long-horned beetles and some species of lepidoptera, lay their eggs here, and their larvae bore through the wood. Wasps like the Atanycolus photographed by Roman take advantage of this by using their long ovipositors to “drill” into the wood and lay their eggs on these larvae. The wasp larvae then parasitize the larvae of the other insects, either internally or from the outside, and usually wind up killing their hosts. This mother wasp, in fact, was so focused on her work, that Roman explains “it was easy to photograph, because the braconids did not react to my close presence and were inactive. The only difficulty was their small size.”

Always interested in nature, Roman says that ten years ago he bought a digital camera and, “after moving to a new place of residence, where was a large park nearby, I began to photograph insects, plants and birds there.

I have recently started to upload my own observations [to iNaturalist] and I [have] became interested in butterflies and moth of Central and South America here. They are very unusual there [and I am] trying to identify them.

- by Tony Iwane.


- PBS’s Deep Look has a nice video explaining Megarhyssa oviposition.

Posted by tiwane tiwane, May 03, 2019 20:43

Comments

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A really great image @rorpro!

Posted by susanhewitt 21 days ago (Flag)
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Wow! Great shot!

Posted by koinpro 21 days ago (Flag)
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Parasitoid wasps are fascinating. What a great photo. I'll definitely spend more time examining fallen birch trees in the future.

Posted by mws 21 days ago (Flag)
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Inspiring - thanks

Posted by dejaym 21 days ago (Flag)
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Amazing shot and a gorgeous individual!

Posted by whaichi 21 days ago (Flag)
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Any references on how the ovipositor evolved to drill wood? is crazy

Posted by langlands 21 days ago (Flag)
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Awesome!!

Posted by kkeivit 21 days ago (Flag)
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beautiful!

Posted by eightpanpeas 20 days ago (Flag)
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@langlands -- It's kind of a jackhammer action, not really a drill, and many kinds of fresh wood aren't *that* hard. The video shows the whole thing -- there's an amazing mechanical advantage she gets by coiling the ovipositor so that it's at a right angle to the wood, right under her body where she can put maximum pressure on it. For a wasp. :)

Posted by jennformatics 20 days ago (Flag)
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Fantastic!! Thank you!

Posted by alessandradalia 19 days ago (Flag)
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Fantastic!! Thank you!

Posted by alessandradalia 19 days ago (Flag)
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Wow. Brilliant photo

Posted by sandraf 19 days ago (Flag)
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Superb photo of a tiny insect. Congratulations and thanks for sharing.

Posted by pam-piombino 19 days ago (Flag)
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@jennformatics thank you! I formulated my question wrong though :) I meant how the behavior evolved, what intermediate forms would have been needed, maybe first they punctured on the opposite side of leaves, but to pass from leaves to trunks (even with slim cortex) looks amazing, it is mind-blowing

Posted by langlands 18 days ago (Flag)
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Wonderful image!

Posted by trobinson41 18 days ago (Flag)

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