Great big, scary insect

paddyland

I posted this in AH, and was recommended to post it here.

I saw a great big, scary insect in Glendalough last week. I searched on Google, but cannot find anything resembling it. Someone said it was a wood wasp, but it was far larger, and didn't look like the images I found.

Basically, it was like a great wasp, about three or four inches long(!), vivid black and yellow, with stripes, and huge yellow eyes about the size of peas. It had a great big thing that looked like a stinger, about an inch long, although it may have been a thing for laying eggs.

It was like something that belonged in the Amazon rainforest! Has someone been importing dodgy crates of bananas recently?

I never saw an insect so big, it was half the size of the palm of my hand, if I dared go near it, let alone touch it!

Has anyone an image of it, or can anyone identify it?

Black Heart

Sounds like rhyssa persuasoria.

http://www.flickr.com/photos/8987340@N05/1206406956

They're harmless. The needle is an ovipositor. They parasitize giant wood wasps.

paddyland

Black Heart wrote: »

Sounds like rhyssa persuasoria.

No, didn't look like that at all. It may have been a form of wood wasp, but none of the images I found look exactly like it, and none do justice to the size of this thing!

Black Heart

Ok, not that, and definitely not this?

http://www.wildaboutbritain.co.uk/pictures/data/2/x10.jpg

I'm sure someone else will know.

Kess73

When I hear someone saying they saw something that looks like a big wasp, my first instinct is to think of a hornet.

A European hornet looks like this.

Hope I have the right pic.




But the size you described is way too big for a European hornet, even a queen.


The only thing I can think of even close to the size you say is a Giant Asian hornet like in this pic. But I don't think there could be one in Ireland unless it escaped from somewhere.





The best man in this forum to help you out is most likely Mothman, so keep an eye on the thread for when he spots it, or just send him a pm about it.

paddyland

Black Heart wrote: »

Ok, not that, and definitely not this?

http://www.wildaboutbritain.co.uk/pictures/data/2/x10.jpg

I'm sure someone else will know.

It may have been like that, yes, if the size matches. Except the yellow was much brighter than that picture and very vividly defined, with yellow eyes, yellow antennae, yellow stripes. How big do they grow to? Are they common in Ireland? I never saw one before.

Birdnuts

Could it have been Irelands largest species of Horsefly??

It is known to inhabit that area of Wicklow since deer are its main prey - Hard to get pictures of these things but this species is indeed huge and more the size of a large bumble-bee rather then the more common species of Horsefly. I know this because during a Dublin Naturalist FC outing to Laragh 10 years ago, one of these things landed on me and looked life a giant mutant wasp:eek:

Black Heart

paddyland wrote: »

It may have been like that, yes, if the size matches. Except the yellow was much brighter than that picture and very vividly defined, with yellow eyes, yellow antennae, yellow stripes. How big do they grow to? Are they common in Ireland? I never saw one before.

I've seen them, so they can't be that rare. Here's a pic for size.

http://www.flickr.com/photos/sam2cents/2836190417/

paddyland

It compares a lot with that photo, but over twice the size, maybe three times. When it flew off, it was like a small bird in the air.

Mothman

paddyland wrote: »

Basically, it was like a great wasp, about three or four inches long(!), vivid black and yellow, with stripes, and huge yellow eyes about the size of peas. It had a great big thing that looked like a stinger, about an inch long, although it may have been a thing for laying eggs.

With most of the above I was thinking Golden-ringed dragonfly but antennae would not be seen.

Allowing for the exaggeration regarding size, because it is an impressive beast in flight, I concur with it probably being Greater Horntail Wasp

paddyland

Yes, that seems to be the one. I made a guess at the size, I was sitting in a bus in Glendalough, and this thing landed on the windscreen wiper, and sat there for a few minutes, allowing close observation. Given the intimidating look of the thing, I was glad there was a large pane of glass between us...! Many thanks!

fryup

so is the Greater Horntail Wasp and the Giant Wood Wasp the same thing??

Mothman

fryup wrote: »

so is the Greater Horntail Wasp and the Giant Wood Wasp the same thing??

Yes, scientific name Urocerus gigas
Seems to be a number of english names.

artieanna

I came across a big wood wasp once it had a long stinger thingy attached to the tree, what is this for?

Black Heart

The 'stinger' is an ovipositor. It's used to lay eggs in to wood. The larvae live in the wood.

fryup

the giant wood wasp can't sting, right??

Black Heart

The giant wood wasp isn't actually a wasp, as far as I remember. It's a sawfly. They don't sting. The name sawfly comes from the fact that they cut into plants/trees with their ovipositor to lay their eggs. At least that's what I've read. I've seen sawfly larvae on the outside of plants, too, so I guess it's just a common name.

The wood wasp's ovipositor is large because they need to inject their eggs in to wood, which gives the larvae a certain amount of protection, though they have a very specialized foe in the parasitic giant ichneumon (Rhyssa persuasoria), which also has a very large ovipositor, with which it injects its eggs in to the larvae of the giant wood wasp, while they're in the wood.

Hope that makes sense