Monday, September 5, 2011

Willowherb Blizzard

This diadem spider Araneus diadematus laboured to spin its invisible snare but made the mistake of weaving it downwind of a patch of Rosebay willowherb ....

... which made it instantly visible to insects that might otherwise have blundered into it. I watched the spider - perhaps driven by hunger after failing to catch any prey - meticulously trying to remove the cottony seeds from the web. It managed to clear the central  zone, but the outer sticky threads ....

.....collected more seeds faster than it could remove them, thanks ..

... to this large patch of willowherb upwind of the web, that released a blizzard of seeds with every puff of wind.

It's interesting to watch the willowherb seed pods open. First the four outer segments peel back like brittle banana skins, exposing ....

... a double row of seeds on each.  In still air they remain attached in rows....

.......pushed upwards on the cotton threads as they dry in the sun ....
.... until the slightest puff of wind whisks them away and up into the thermals. No wonder this plant is such a successful coloniser.
It's also the food plant of the elephant hawk-moth caterpillar 

Last Thursday's Guardian Country Diary was an account of pursuing this comma butterfly into a patch of willowherb.....and unleashing a blizzard of seeds in the process.


  1. You never fail to excite me. It's not so long ago i didn't know the I'm becoming knowledgeable on it's breeding habits. Many thanks...........A grand shot of the web.

  2. Wow. Cool site! I love the pictures in this, and the explanations. Poor spider!

    We have a praying mantis that's been living on some plants in a pot near the front yard for at least a month. She's become a friend.

    (Well how do you tell whether it's a boy or a girl? Besides, I think it's a girl.)

  3. What a perfect example of why there is so much pleasure to be had in going out and looking about. The psider's web is stunning and I now realise that I need to take a closer look at willowherb - it's amazing!

  4. I have always called Rosebay Willowherb 'Magic' because that's what it used to appear to be. I hope the spider won't starve.

  5. Wow. Great photos! Spiders are fascinating. I watched one that built a web in our climbing hydrangea that got covered in pollen. You could almost hear the spider muttering under her breath as she picked out each piece and flung it away.

  6. Wonderful shots. I pity the spider, though. Your article in the Guardian is very enjoyable. Thanks

  7. Hi Phil, Really enjoyed the country diary piece - it just struck a chord. The spider trying to clear the fluff from its web is a fascinating observation. Never seen that. It would have been better off giving up and starting again but I guess they are somewhat lacking in the brains department.

  8. Interesting! In Canada, it is called fireweed, as it is one of the first plants to establish itself in a burned area.

    1. in the US as well, or Alaska at least

  9. Thanks Adrian, it's a very attractive plant, thought i wouldn't want it to get a foothold in my garden!

  10. Hi Jessiethought,not sure how you tell the sex of a mantid - we don't have then in the UK - but maybe the arrival of baby mantids will confirm your suspicions!

  11. Hi Mark,I think a drift of Rosebay willowherb in full flower, or releasing its clouds of seeds,is one of the finest later summer flora spectacles

  12. I thnk the spider will be in for a lean time for a few days toffeeapple, until the plants have got rid of most of their seeds..

  13. Thanks zucchini mama, I'm very fond of spiders, especially the web sinners. The spiders' web season is about to arrive here, with their webs clovered in glistening dew drops at dawn.

  14. Thanks lotusleaf, there is a darker side to these spiders - this one was a female, and the females sometimes eat the much smaller males...

  15. Hi Allan, I think they often eat their old webs (natural recycling) but if it ate one of these it wold be full of fluff...

  16. Hi Karen, Rosebay willowherb famously grew all over the burned out areas of London ater the b;itz during the second world war - it turned bombsites purple...


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