Tuesday, June 22, 2010

Ruby-tail wasp

In my last post I outlined the gruesome breeding habits of the spiny mason wasp, that provisions its nest with paralysed weevil grubs for its larvae to feed on at a later date. In the spirit of Jonathan swift's famous observation, that....

 naturalists observe, a flea

Has smaller fleas that on him prey;

And these have smaller still to bite ’em;

And so proceed ad infinitum.

... here is the mason wasp's nemesis, the magnificently be-jewelled ruby-tail wasp Chrysis viridula. I watched this deadly little parasitoid's behaviour while I was photographing the mason wasp's nest, at the base of the cliffs at Hawthorn Hive on the Durham coast.
There are many species of ruby-tail wasp, also known as cuckoo wasps, each a parasite of a particular species of host wasp, and one thing that they have in common is relentless, restless activity, constantly using their downward-curving antennae to pick up a scent trail in the soil. Ruby-tail wasps have a thickly armoured, iridescent exoskeleton that's impervious to the stings of an angry victim. This species is less than a centimetre long and its colours are more exquisite than anything a jeweller could create.
Once it finds its host's nest hole it uses its antennae to explore the entrance, presumably testing for the specific scent that identifies its prey. Recent research suggests that ruby-tails can produce compounds in their exoskeleton that mimic the scent of their host and so avoid detection and counter-attack.
Next the ruby-tail crawls head-first into the nest hole, to make sure there's no one home, then ....
....... it climbs out and reverses in ....
... until only its metallic green head is visible in the entrance. Inside, it lays eggs that will hatch and produce larvae that will eat its host's young and their weevil grub food store. The hapless host , returning to seal its nest, will never know that the ruby-tail has visited and that its young are doomed.

26 comments:

  1. Absolutely wonderful stuff, Phil, a great story in these last two postings, and superb macro work also. I had no idea that we had colourful wasps like this. Thank you, again, for sharing all this with us.

    ReplyDelete
  2. Great posts Phil, I have watched Ruby tailed wasps before but knew nothing about their habits. I didn't realise how beautiful they are.

    ReplyDelete
  3. What an engrossing post! I have not seen these wasps hereabouts, but I have come across their prey. Absolutely marvellous pictures!

    ReplyDelete
  4. Superb sequence and story Phil. Looks like on the IoW the Spiny Mason Wasp has been recorded but not its bejewelled parasite.

    ReplyDelete
  5. Fantastic photos and writeup. Please do consider adding a this to the Magnified Nature Meme (http://naturemagnified.blogspot.com/p/meme.html).

    ReplyDelete
  6. Exquisite photos of an exquisite insect! Amazing. Thanks for sharing!!

    ReplyDelete
  7. Fasconating, Phil, and an interestingly attractive insect.

    ReplyDelete
  8. Been up & down those steps countless times, will be sure to take a closer look next time.

    ReplyDelete
  9. Great post and photos! thank you Phil.

    ReplyDelete
  10. Well, Phil, once again I am left gobsmacked by your blog. This stupendous beast has completely passed me by in spite of spending at least the last thirty years aspiring to be a really average naturalist when I grow up. Can't wait to find out the next thing I didn't know I didn't know about.... Cheers, Allan

    ReplyDelete
  11. Phil, what a stunner that Ruby-tail wasp is. Certainly lives up to its name; yet so deadly.
    A great post. I've learnt so much here.

    ReplyDelete
  12. Hi Richard, I had no idea there were so many different species - I thought there was just one, Chrysis ignita, until I started trying to ID it. fascinating insects.....

    ReplyDelete
  13. Hi Nigel, I've never really watched their behaviour before and didn't realise it was so complex.....

    ReplyDelete
  14. Thanks lotusleaf, I find all the hymenopteran insects really fascinating..

    ReplyDelete
  15. Thanks John, amazing what you come across when you lurk in the undergrowth........

    ReplyDelete
  16. Hi Rob,I remember finding one in Sussex the conservatory when I was a kid ........ slightly bigger species than this one though...

    ReplyDelete
  17. Hi Tom, thanks, will make the link (and Magnified Nature is a great site)

    ReplyDelete
  18. Thanks Ellen,I think it's the most colourful parasitoid I've ever come across...

    ReplyDelete
  19. Hi Emma, I suspect some of these insects have a rather short flight season, so I guess you need to be lucky and be in the right spot at the right time...

    ReplyDelete
  20. Hi Stevie, those steps don't get any easier do they? - quite treacherous about half way down, too

    ReplyDelete
  21. Thanks for the kind comments Blackbird - one of the wonders of digital photography is that you don't have to worry about the cost of taking a lot of photos to get a few good ones - in the old days it would have required about £25 worth of film to get a few usable pictures ....

    ReplyDelete
  22. Hi Nyctalus, there's a cost to all this - my family think I'm weird and my knees are shot, after all that kneeling on hard surfaces to take close-ups...

    ReplyDelete
  23. Hi Keith, natural history never fails to provide new wonders - always something new to explore. all the best, Phil

    ReplyDelete
  24. Fabulous photos of a fabulous creature. I don't associate such colouring with Uk wildlife.

    ReplyDelete
  25. I know what you mean John - they're the kind of colours you associate with tropical climates.

    ReplyDelete