Wednesday, September 15, 2010

Intimidation





If you're small, edible and confronted with a hungry carnivore your options are few. You can keep very still and hope you won't be noticed, run or take the bold option - stand your ground and try to intimidate your tormentor, which is exactly what this elephant hawk-moth Deilephila elpenor caterpillar did when I poked it with a grass stem. We found it in late afternoon (Deilephila means 'lover of evening') on the fellside near Blanchland in the Derwent valley, where it was climbing a rose-bay willowherb stem in preparation for another night's feeding.






















The caterpillar was over three inches long, close to being fully fed. Notice the curved tail spike (not very menacing) and the four distinctive eye spots at the other end, which begin to become more menacing when the caterpillar realises it's under threat.





















At that point it retracts its front three segments (that are longer and narrower than the others and have some resemblance to an elephant's trunk when it's feeding. This concertina-like contraction forces segments four and five, immediately behind and marked with the eye spots, to swell ............ and now those 'eyes' begin to look much more intimidating.....
.... especially when you look at it from this end, where you can compare its comparatively small real head with the false head formeed by swollen segment four.

Provoke it a little more and it will release its grip with the true legs at the front and, clinging on with pro-legs at the rear, wriggle violently like a snake. At this point its attacked will either be preparing to eat it anyway or will have been sufficiently intimidated to look elsewhere for a meal.

This is the commonest hawk-moth in the UK. You can find images of the adult insect at the excellent UK Moths web site.

23 comments:

  1. This is brilliant and well worth annoying it for the pictures alone. The text as usual is entertaining and informative.

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  2. Brilliant set of photos and a great explanation of the caterpillar's method of defence.

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  3. Beautiful macro shots Phil. It would certainly intimidate me!

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  4. When I first saw the photos, I thought it was a kiddie's balloon. I thought, "What's he doing playing around with balloons?!" :O) Absolutely amazing!

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  5. I found your comments on the Elephant Hawk-Moth very interesting. About 35 years ago when my children were young we found several caterpillars of the moth on the Rose-Bay willowherb and brought some home and kept them in a large empty fish tank, we replemised the leaves daily until the caterpillars pupated. On hatching the chyracises turned into beautiful pink and green moths but two of them turn into large parasitic black wasps.

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  6. I enjoyed looking at the pictures and reading your post.I couldn't stop giggling.

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  7. A great prototype for some alien creature in a film... though, in the last photo its even a bit goofy looking!

    Nice shots of the little terror.

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  8. Great post! I've never seen one of those.

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  9. Phil,

    Yet again a stunning infotale with brill pics.

    John

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  10. I've just followed the link you gave to see what the adult moth looks like. How beautiful! The colours are glorious. I'm off soon to a large patch of Rosebay Willowherb growing along the old railway line to see if I can spot the caterpillar for myself. :)

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  11. Hi Adrian, it's certainly one of the more entertaining caterpillars - a caterpillar with attitude, in fact....

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  12. Thanks Sheila, it put on a good performance for me..

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  13. Hi John, it's easy to imagine that it might deter a predator...

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  14. Hi Lesley, it looks a bit like a voodoo mask, doesn't it. The adult moth is exquisite. The best time to look for the caterpillars is late in the afternoon, when they climb up onto their food plant...

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  15. I once kept an elephant hawk-moth caterpillar, that was feeding on bogbean in our garden pond, until it pupated and it emerged as an adult very early in the year - sometime around February I think - and didn't survive until spring. Lovely moth though.... I guess no amount of intimidatory behaviour can protect the caterpillar from parasitic wasps

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  16. Hi lotusleaf, it's hard to take a caterpillar that does this seriously, isn't it...

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  17. Hi Valerianna, it looks like it would be more at home in a cartoon strip..

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  18. It's only the third one that I've seen in the last 30 years, Blackbird, but I hadn't realised that they spend most of the day concealed and emerge to feed late in the day..

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  19. Thanks John, I like wildlife with interesting behaviour...

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  20. Hi Phil,
    For the second year in succession the traffic to my blog in August (and probably September will follow suit) has doubled purely due to people coming from search engines looking for an elephant hawkmoth caterpilar - I haven't seen any recently, but now know to check out willowherb! It's nice to know that other people are enjoying finding them though! I'm going to edit the relevant post and put in a link to this, more informative one.
    Cheers
    Mark

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  21. Hi Mark, I've been keeping an eye open for them lately too - with no luck. They also eat fuchsia plants and bogbean. You'd think they wold be more common, wouldn't you, with so much rb willowherb around? All the best, Phil

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  22. I heard that about fuchsia but bogbean - how do they get to them, aren't they usually in shallow tarns?

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  23. That's an interesting point Mark - I used to have a garden pond with bogbean in the centre and on one occasion an elephant hawk-moth caterpillar turned up on the leaves - how do they get to dry land to pupate? I wonder if they float.....

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