Saturday, September 11, 2010

An Ichneumon wasp - Amblyteles armatorius

I am an amateur naturalist trying to learn something about everything living in my garden.

Hello! After a goodly absence I am back with some more of my garden wildlife. I hope there may be one or two of you out there still reading. Certainly my garden has not run short of new lifeforms to offer. Despite over a 100-species blogged so far, I have a long backlog of additional finds with more turning up all the time.

Photo 1 shows a magnificent insect I spotted resting on my hedge in late-summer of last year. The body was around a cm in length. Based on some similar images on the web I'm identifying it as an Ichneumon wasp - Amblyteles armatorius.


With tens-of-thousands of species of Ichneumon wasp worldwide and about 3200 in Britain alone, definitively identifying Ichneumons is a job for the specialist. Dr Gavin Broad is one such and has helpfully made available an online British checklist and a key to the sub-families of Ichneumonidae. You can download the entire 380-odd pages of the 1903-published Ichneumonologia Brittanica for free here. For any naturalist willing to grapple with the subject however, a supreme example of what can be achieved (and surely a candidate for "all-time greatest garden study") is given by Jennifer Owen. Her book, The Ecology of a Garden (Cambridge Uni. Press) records 15 years of painstaking cataloguing of the wildlife in a UK garden. During her studies Dr Owen discovered no fewer than 529 species of Ichneumon of which 15 were new to Britain and a staggering 4 were new to science!

From the comments above it will be understood my amateur's identification, based on a photograph alone, of my wasp as A. armatorius is to be treated with caution. It is certainly not the only European black -and-yellow striped Ichneumon as can be seen, for example, from the photo's here of species such as Ichneumon stramentor, I. xanthorius, Eutanyacra crispatoria and Diphyus quadripunctarius. For now I'm sticking with A. armatorius, as some of these others have yellow-striped antennae and other small differences, but I'm happy to be corrected by any of the experts out there.

Sadly, I have been able to uncover rather few details of the natural history of my Ichneumon. I have learnt that it is fairly common in the UK and the sole species in the genus Amblyteles. Adults apparently feed on pollen, that of umbellifers being a common target. In common with many other ichneumon's, the larvae are parasites of caterpillars, one target moth being The Yellow Underwing (Noctua pronuba). The larvae hatch inside the caterpillar and devour it from the inside. Other target moth species besides the Yellow Underwing are variously stated for A. armatorius. The scientific paper by Rolf Hinz (Entomofauna, 6(8), 1985, pp.73-77) disputes these claims however.

The paper above is in German incidentally, which is unfortunate if like me, you don't speak the language! (I found a free online copy of this paper some time ago, but have entirely failed to relocate it since. Anyone?). Since this was one of the very few learned articles I came across on A. armatorius however, I was determined not to be put off and came up with the idea of running the German text through Google's free, online automatic translation service. The results of computer translation are not always transparent. A German sentence that, in the original, I take to say something along the lines:
"I'm grateful to Messrs. G. and E. MannBausch Heidt of the Künanz Upland Bird-research Centre for supplying me with specimens"
gets translated as
"Messrs. G. and E. Mann Bausch
Heidt from the research Künanz bird-house in the mountain, the procurement of the material allowed, thanks.
"
Nevertheless, with patience it's generally possible to get the gist and I'll certainly consider using this approach in future.

I appear to have digressed! When starting today's posting it had been my intention to say something on the amusing topic of the religious debate sparked amongst Victorians naturalisists by the life-style of the Ichneumonidae. Since I have written enough for now however, and since, with another 3000-odd British Ichneumonidae out there, I feel confident I will have other chances to revisit this fascinating family of insects in the future, I will leave my somewhat cryptic last sentence hanging in the air and bid you farewell for now.

3 comments:

Blackbird said...

Good to hear from you again Henry. I look forward to more interesting facts and finds from your lawn!

Stewart said...

Hi Henry, this is my first visit to your blog. In one of your first posts I was very interested to see that you expect and estimated 250 species in your garden. I am sure you will have surpassed this by now?
This year is my first full year moth trapping in mine and have recorded 314 species so far. Along with about 80 birds, 5 mammals, 10 Butterflies, 2 amphibians the total is quite large. And I havent started on the plants that live wild or the other insects!

I think that in Oxfordshire you will be very suprised at the sheer quatity of wildlife you can find.

Keep up the great work.

Cheers Stewart.

Henry Walloon said...

Blackbird

Thanks for the encouragement.
I've only today discovered your splendid 'Rattling Crow' blog.
I love the concept!. I'm adding a link from this site.

Stewart,

Your comment gave me pause for thought and I am rapidly coming to the same conclusion! Looking at my 'Labels' section on my main page I'm realising I'll very likely find 20+ creatures for each of the sections 'plants', 'fungi','birds, 'lichens'.... For some such as 'beetles' and 'other insects' I'm realising I can probably double? quadruple?, sextuple?...that. At one and the same time daunting, yet wonderful to think just how rich is the life surrounding us.

Henry