Currently viewing the category: "Horntails, Wood Wasps and Sawflies"
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Subject: Caterpillar swarm in Costa Rica
Location: Costa Rica higher elevation
October 31, 2014 9:12 am
These caterpillars(?) appear seasonally in the higher elevations in Costa Rica. (1500m/5000′ MSL). They are 3-4″ long and appear to burrow as a group in the ground (in our yard and surrounding farmlands).
We don’t know what they are (or whether they are a problem?) but they have a marvelous locomotion. They crawl on top of each other for awhile, then they all pause as if catching their breath, then resume. This video was taken on the road outside our house.
What are they and do they benefit or damage the plants and animals?
Signature: Bugged in Costa Rica

Sawfly Larva

Sawfly Larva

Dear Bugged in Costa Rica,
We do not believe these are Caterpillars.  We believe they are Sawfly Larvae, relatives of wasps and bees.  There are Australian Sawfly Larvae known as Spitfires that look similar.

Aggregation of Sawfly Larvae

Aggregation of Sawfly Larvae

Andrea Leonard Drummond, Nacho Gamboa liked this post
What's That Bug? does not endorse extermination

Subject: What is this bug?! Mutated wasp?!?! Please help!
Location: Windsor, ON Canada
October 27, 2014 12:49 am
Hi there! I’m from Windsor, ON Canada and I was raking leaves in my front yard today and this peculiar, very big and scary bug had landed on my arm. I immediately jumped and swatted it off and it landed on a leaf at my feet… My sister and I took a closer look because it appeared to be stunned or discombobulated so we took the opportunity to snap some photos and examine it. I have never seen a bug such as this, it looks like a mutated wasp and it bothers me to think there are more out there like this… I’m confused because it is now autumn and chilly where I live and most of the bees and wasps are no longer flying around for the season. I would really like to know what bug this is! It appeared to have a stinger, as well as some sort of tail? It did have black and yellow alternating stripes, long yellow legs and it was around 2 inches I would say.
Signature: Thanks so much!! -Sonia

Pigeon Horntail

Pigeon Horntail

Dear Sonia,
This Pigeon Horntail, which is sometimes called a Wood Wasp, is related to wasps, though Pigeon Horntails do not sting.  The female Pigeon Horntail uses her ovipositor to deposit eggs in dead and dying trees.

George Hilario, Ito Fernando liked this post
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Subject: Catapillar identification
Location: Rochdale-manchester-England
September 27, 2014 6:09 am
At home I have at least half a dozen catapillars and am feeding them apple at the moment but I am unsure of the species that the catapillar is;consequent not being able to feed them ther favourite food.if you can reply as soon as that would be fantastic so I can understand what to feed them :) also the catapillar has an orange tail and blue body with a black and orange head ,it also has random black spots speckled over its body
Signature: Alex:L

Gooseberry Sawfly Larva

Willow Sawfly Larva

Dear Alex:L,
Though it looks like a caterpillar, this is not a caterpillar, but rather a Sawfly Larva.  We believe we may have correctly identified it as a Gooseberry Sawfly Larva,
Nematus ribesii, thanks to this image on FlickR.  According to DownGardenServices:  “The caterpillar-like larva is light green with black dots and a shiny, black head. If disturbed it clings to the edge of the leaf while bending into a S-shape. All of the leaves can disappear with only the stalks and a few veins remaining. Check any leaves beyond them and the larvae will be there, so they can be rubbed off.  The lack of foliage weakens the bush and it produces a very poor crop the following year.”  An even closer match is the Willow Sawfly, , which is pictured on PBase and Wikimedia Commons.

 

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Subject: Large wood boring bug with oviduct
Location: Syracuse in
September 1, 2014 12:19 pm
We found this large black an yellow striped winged bug with oviduct …any thoughts
Signature: Mary b

Pigeon Horntail

Pigeon Horntail

Hi Mary,
This is a Pigeon Horntail, a species of Wood Wasp.  The egg laying organ is an ovipositor.

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Subject: Any ideas what this is?
Location: Buffalo, NY
August 17, 2014 9:10 pm
Does anyone have a clue what this flying bug is? Not sure if it came from the pine logs I was cutting but it also appears to have a stinger
Signature: Nick

Black and Red Horntail

Black and Red Horntail

Dear Nick,
Though we have no shortage of other Horntails on our site, including the Pigeon Horntail, this is the first example we are posting of a Black and Red Horntail,
Urocerus cressoni.  Horntails are Wood Wasps and the larvae bore in wood of dead and dying trees.  According to BugGuide:  “hosts include Fir, Spruce, and Pine (Abies, Picea, Pinus).”  

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Subject: Curious Large
Location: Hastings, MI
August 17, 2014 9:51 am
Hi,
My mom and I found this bug on a dead tree stump where there are a ton of Stump Stabbers around. The next day I found it dead on another area of the stump. I didn’t think it was a wasp since it does not have the separated thorax. It is a bit scary since it was so big, but I’m just wondering what it is since my 13 year old daughter has more curiosity than what is good for her.
Signature: Nervous Mom

PIgeon Horntail

PIgeon Horntail

Hi Nervous Mom,
You have no need to fear this Pigeon Horntail, because even though it is a Wood Wasp, they do not sting.  The female uses her ovipositor to deposit eggs beneath the surface of dead and dying trees and the larvae are wood borers.  Interestingly, the presence of Stump Stabbers makes perfect sense as the larvae of Stump Stabbers parasitize the larvae of Pigeon Horntails.  This particular female did not mature properly as her wings appear to have atrophied.

Thanks Daniel,
That is so incredibly interesting.  We see the Stump Stabber’s all the time but have never seen the Pigeon Horntail there.  We are around this stump all the time (it is huge) since my herb garden surrounds a small portion of it.  Now we don’t have to be afraid.
Thanks again,
Jenn

What's That Bug? does not endorse extermination