Sunday, 15 September 2013

It's a funny old world

Yesterday I was casting a satisfied look over my vegetable plot - deciding what to have for dinner - when I saw a good, clean specimen of the Silver Y moth, and dashed inside to get my camera:

Silver-Y moth

Silver Y moths are usually immigrant, although some breeding is known. Survival over winter is unlikely, so most specimens will be found after a warm southerly wind, just like we had on Tuesday and Wednesday.

Since I had my camera in hand, I had a quick look at the hoverflies and bumblebees that were busy pollinating my courgettes and I spotted movement on my broccoli leaves:

The Ichneumon wasp Hepiopelmus variegatorius
A quick glance told me that she was an Ichneumonid of some kind, and it was clear that she was investigating the larvae of the Large White butterfly under the leaves. She was moving at an incredible speed, scurrying over and under leaves, often disappearing completely from view.

The Ichneumon wasp Hepiopelmus variegatorius
I rattled off perhaps 50 shots, trying to catch her as she paused at the edge of a leaf long enough to get a decent image. Her antennae were rarely still as she constantly sampled the air and decided whether or not to look under a particular leaf:

The Ichneumon wasp Hepiopelmus variegatorius
From time to time I managed to get a glimpse of her through various holes in the leaves. You can just make her out in this shot:

The Ichneumon wasp Hepiopelmus variegatorius under a leaf

I 'massaged' that shot in the photo editing program and found that she was getting very close to the larvae (which can just be seen at the top of this shot):

The Ichneumon wasp Hepiopelmus variegatorius investigating a larva of the Large White butterfly

My next task was to try to get an identification, and I first turned to a list of known parasitoids of the Large White butterfly. The Large White has been very extensively studied, since it is seen as a pest species for crops, and methods of control are always being sought. A fairly quick search (perhaps 2 hours) revealed nothing like a match, so I went to the references (the most recent one is 1960!) and searched for identification via that unusual crescent on her thorax. Still no luck.

I decided to 'phone a friend' and NHM London in the guise of Gavin Broad came up with Hepiopelmus variegatorius, which fortunately is one of the few Ichneumons that can be accurately identified from a photograph. These are known to parasitise the larvae of Spilosoma sp. (Ermine Moths), so the Large White larvae were safe in this particular instance.

Back to the reference, to find that Hepiopelmus variegatus is described as rare in the UK, and a quick search of the Irish national database revealed no previous records for Ireland. So this seems to be a first Irish record (confirmed 16/09/2013).

If I hadn't seen the Silver Y, then I wouldn't have had my camera to hand, and that record would still not exist.

1508 Species, now.


The Weaver of Grass said...

Did you still find something to cook in the garden after all that mothery?

I like the sound of your mustard sauce - how do I make it - I have plenty of pork shops in the freezer.

Gill said...

Incredible photos, Stuart - and it just shows what you can find if you look carefully.

Weaver, you must have a very large freezer :-)

The Weaver of Grass said...

Sorry about the spelling mistake - very funny joke though!

This is my first Ian Rankin. He was recommended to me. The one I have read is 'Set in Darkness'. I usually like novels which are mainly in prose so didn't think I would enjoy this with so much dialogue, but I really enjoyed it. What interests me is how he manages to keep each character in character so to speak, so that by the end of the novel you can almost anticipate what reaction you are going to get. Also I liked the ending where the 'baddie' remains free to act again although we - and Rebus - know he is guilty. Shall certainly look for more.
I tried to get on to your site to leave a comment but it is all too complicated for me I am afraid.