Currently viewing the category: "Parasitic Hymenopterans"
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Subject: Strange wasp? Cape Cod
Location: Cape Cod, MA
July 21, 2014 5:56 am
My niece was in Cape Cod last year and couldn’t identify what this (wasp?) is. I’ve never seen anything like it. She asked several scientists that were there too and they couldn’t either. I don’t know if any were entomologists. It was just hanging out on a picnic table I believe.
Signature: Joe

Stump Stabber

Stump Stabber

Hi Joe,
We sincerely doubt that any of the scientists were entomologists, because even those that specialize in other insect orders should recognize a Giant Ichneumon or Stump Stabber in the genus
Megarhyssa.  Despite the formidable looking ovipositor, Giant Ichneumons are not aggressive and they are not capable of stinging humans.  With that stated, the ovipositor is used by the female to lay eggs beneath the surface of dead and dying trees and stumps that contain the wood boring larvae of Horntails and Woodwasps, so it might be possible for the ovipositor to pierce human skin, though we think it is highly unlikely for a Stump Stabber to mistake a human limb for an infested tree.  Several members of the genus look very similar, so we are reluctant to attempt a species identification.  Another distinctive member of the genus, Megarhyssa atrata, is our featured Bug of the Month for July 2014.

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Subject: What’s on the caterpillar?
Location: Southeastern Virginia
July 21, 2014 12:33 pm
A friend has a caterpillar in her garden and she found it like this today. It was fine a few days ago…What in the world is going on with it?
Signature: Crystal

Carolina Sphinx Before

Carolina Sphinx Before

Dear Crystal,
This caterpillar is a Carolina Sphinx or Tobacco Hornworm,
Manduca sexta, and they are frequently found feeding on tomato plants and related plants in the garden.  Your second image documents the results of a parasitization by a Braconid Wasp, Cotesia congregata.  The female Braconid lays her eggs inside the caterpillar using an ovipositor and the larval wasps develop inside the caterpillarfeeding on the caterpiller beneath its skin.  When the larvae mature, the make their way to the surface and spin cocoons, and that is what is shown in the second image.  The caterpillar will not live to maturity even if the cocoons are removed.  See BugGuide for additional information on the Braconid.

Carolina Sphinx parasitized by Braconids

Carolina Sphinx parasitized by Braconids

What's That Bug? does not endorse extermination

Subject: What is this?
Location: hamilton michigan united states
July 19, 2014 4:16 pm
This bug flew into our window when we drove into town …Kind of scary looking! what is it and should we be concerned?
Signature: Tammy Davis

Stump Stabber

Stump Stabber

Hi Tammy,
This Giant Ichneumon,
Megarhyssa atrata, is commonly called a Stump Stabber.  The female of the species possesses an ovipositor that can approach five inches in length which she uses to deposit her eggs deep beneath the surface of trees and stumps that are infested with the wood boring larvae of Wood Wasps like the Pigeon Horntail.  The larval Stump Stabber feeds on the Horntail larva and then pupates, emerging from the stump as a winged adult.  Male Stump Stabbers which lack the ovipositor, can sense the emergence of a female through the release of pheromones and will congregate and await her coming to the surface in order to mate.  You have nothing to fear from the Stump Stabber unless a female mistakes an arm or leg for an infested log.  Wasps do have mandibles, and since both male and female Stump Stabbers must chew their way to the surface of the stump they developed in, they might also bite a person, but we do not believe such a bite would hurt or cause any problem.

What's That Bug? does not endorse extermination

Subject: Slow flying wasp/dragonfly hybrid?
Location: Sammamish, WA
July 14, 2014 4:19 pm
Dear Bugman, we found this flying beauty in iut kitchen today. He/She is approx 2.5″ long in the body with slightly smaller wingspan and a 3″ long stingy stinger looking thing hanging from its rear end. Very beautiful and flies rather slow. Body is black and white with clear wings and bright orangish yellow legs (long and lanky legs with interesting joints). We contained it long enough to take a few photos and some video then let it free outside. Any guess on what it is- I’ve never seen one before?
Signature: The Joyce family

Ichneumon:  Rhyssa lineolata

Ichneumon: Rhyssa lineolata

Dear Joyce family,
This is a Parasitic Ichneumon Wasp in the family Ichneumonidae, and according to BugGuide, there are:  “About 5,000 described species in North America, possibly 3,000 more undescribed(2); arguably, the largest animal family, with the estimated 60,000 species worldwide (up to 100,000, according to some estimates.”  We believe we have correctly identified your Ichneumon as
Rhyssa lineolata based on this image posted to BugGuide.

What's That Bug? does not endorse extermination

Subject: What is it
Location: Minnesota
July 4, 2014 11:50 am
We saw this bug on our dying oak tree. He and his friends remind me of a scorpion but we live in Minnesota.
Signature: P.Pratt

Stump Stabber

Stump Stabber

Dear P.Pratt,
This is a magnificent image of a female
Megarhyssa atrata, commonly called a Stump Stabber.  The female Stump Stabber uses her lengthy ovipositor to place her eggs deep beneath the surface of dead and dying trees that are infested with the larvae of Pigeon Horntails and other Wood Wasps.  The larvae of the Stump Stabbers hatch and feed upon the larvae of the Wood Wasps.  They are considered parasitoids that parasitize and eventually kill the host insect.

What's That Bug? does not endorse extermination

Subject: Huge Bug on Mirror
Location: Vancouver, BC.
July 1, 2014 5:06 pm
Hi Bugman,
I’m trying to figure out what this is- it was in my friend’s house today and its HUGE! It looks like its some sort of Mantis or something- Any ideas?
Signature: Jonathan

Ichneumon startles residents

Ichneumon startles residents

Hi Jonathan,
The look on your face is quite startled.  This is some species of Ichneumon, a family of Parasitoid Wasps that are not aggressive, though we have occasionally gotten reports from folks who have been stung.  Female Ichneumons lay eggs on or near specific insect or arthropod hosts and the larval Ichneumon feeds on the host insect, eventually killing it.  We are unable to determine the species of Ichneumon that entered your friend’s home.  According to BugGuide, the family Ichneumonidae:  “About 5,000 described species in North America, possibly 3,000 more undescribed; arguably, the largest animal family, with the estimated 60,000 species worldwide (up to 100,000, according to some estimates).”

What's That Bug? does not endorse extermination