Saturday, July 05, 2014

Wild spun-sugar...

When I discovered something whilst out walking in a local meadow, that at first glance you would be forgiven for thinking was wild spun-sugar, my interest was piqued.
Only small at around 5-7mm but beautifully formed, there seemed to be several of these miniature baskets adhered to both dock and sorrel plants.



Time for further investigation. I took some photographs and as I was wandering home, it dawned on me that I had actually seen something very similar a few years ago; but at that point, been unable to find an answer.
My research this time however soon provided a number of clues as to the identity of the creature that was responsible. To be 100% confident of the species would probably entail dissection, even so, I am reasonably happy that these enigmatic structures are actually the pupal cases of Hypera rumicis, a species of weevil.

Described as a pale-buff coloured weevil, with darker brown markings on the elytra (wing casing) of about 5mm in size. The weevil itself can be seen from late spring into summer, in areas that contain dock, or provide damp conditions.



If I didn't know better, I could make some kind of tenuous link with erstwhile England footballer David Beckham here; after all, world cup fever and all that? Lucky then that I do know better.
Whetted your appetite? Okay then, I'll elucidate-the intricate lattice-work of this cocoon, is sometimes referred to as a golden ball, or golden net ball (tenuous huh?) and is constructed by the larvae for its transformations. 

It resembles some of those made by caterpillars of moths. It's composed of loose threads, permitting the larva or pupa to be seen through the mesh.
Quite why nature has decided that this kind of protection from parasites is adequate escapes me; especially given that any movement in the leaf or stem the casing is attached to, seems to cause the larva inside to twitch and wriggle, drawing attention to itself.

I took a few shots of a larva beginning to make one of these fascinating creations...




I also managed a short video-well it wasn't that short actually, this is over half an hour's worth at its original timing. I have increased the speed to x8 to reduce the size for my blog and also...preventing boredom setting in.

The usual reminder here that videos don't show in the emailed version-you need to view this update directly on my BLOG

(The shiny-looking object bottom right is just my 'Plamp' to hold the plant steady)


A close up shot of this beautiful structure:



I don't know if this could be a similar, or even the same species but I found it recently on a birch leaf. Maybe it isn't a weevil at all?




That's about it for this update-I'll be back just as soon as time allows with another, my 137th I think..



7 comments:

  1. Absolutely fascinating! I've never seen anything like this before. Also quite surprised to see that the weevil larvae are like caterpillars.

    The only larva of a weevil that I have seen is from Curculio elephas which is the (sweet) chestnut weevil. This is a beauty of a weevil and the larva I've seen was cooked inside a chestnut! It looked like a little white maggot but poor thing obviously didn't get to mature..... :-)

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  2. Thank-you Mandy. Yes, they do have that appearance don't they. I think that weevil you have seen is very like our native nut, or acorn weevil?

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    1. Errrrrrrr I had to go check, yes they are both Curculio! Now I'll be searching amongst the fallen acorns this autumn..... ;-)
      Though I didn't find my one on chestnuts, it was on a flower in my garden!

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  3. Been so looking forward to this and I'm not disappointed! Wow! Absolutely fascinating to witness the creation of these amazing structures! Thank you!

    Intrigued by the second cocoon too! Wonder what it is! Will have to do some digging I think! Recking moth for some reason, but most likely wrong! Lol!
    A very quick search turned up the Apple leaf miner which apparently builds a 'hammock' coccoon! http://ukmoths.org.uk/show.php?bf=263 Never seen one of those either! Nature never ceases to amaze me!

    Best wishes

    Maria

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  4. Recking???? I mean 'reckon' of course! Lol! Never seem to see spelling mistakes until you've posted my comments either! I reread myself too... says a lot doesn't it? ;-)

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    1. Hi Maria-yes, frustrating that you can't edit comments isn't it. I do the same thing myself on blogs I follow sometimes! Anyhow..thank-you for once again being so kind and supportive here. I hadn't considered that could be a moth structure-I suppose because of the 'spun-sugar' around it but will check that suggestion out just as soon as I have a chance. (checks for spilling mistakes) ;-)

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  5. Amazing find and photos,always look forward to your posts as you have the knack of finding unusual insects and I enjoy your photography. Taken to wearing my reading glasses when I go out now, its amazing how much more I can see ! still looking for a Dock bug, even Mandy seen one in France !!!
    Amanda xx

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