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Friday, June 9, 2017

Master spinners of silk: the Orbweavers

The following article was published in Nature News, Midland Express, 6th June 2017.

Local writer Dr. Lynne Kelly shares her love of spiders and knowledge of two local species of Orbweavers commonly found in the Castlemaine region.



Left: Garden orbweaver in her web at night. Right: Golden orbweaver in her web by day with a tiny male approaching from above. Photos taken by: Dr Lynne Kelly

I adore spiders. I used to be an arachnophobe but knowledge cures an irrational fear, slowly at first. Then one day I watched an orbweaver spin her web from start to finish. That was the day I became a spider-obsessive. In the Mount Alexander Shire two varieties of orbweavers dominate – the large golden orbweavers who stay on their webs all day and the slightly smaller garden orbweavers that spin in the evening and scamper to hide in the foliage at dawn.

We have a few species of garden orbweavers. They are all in the Eriophora genus, distinguished by two prominent projections near the front of the abdomen. Garden orbweavers usually remove most of their web before dawn, re-absorbing the protein in the silk to use again. A single reinforced strand is left across the gap between bushes or trees in the hope that it will still be there the following evening. If that strand is broken, the spider will point her abdomen skyward and release a fine filament of silk. In even the slightest breeze, this silk will catch on foliage and she will rush across, back and forward, to reinforce the mainstay of her web. She will then drop to the ground and attach an anchor. She’ll rush up again to spin the radials and a spiral outwards. From the edge of her nearly complete web, she will then circle back towards the centre laying down the sticky spiral. Having worked tirelessly for nearly an hour, she will rest, head down, waiting for her prey.

Unlike the garden orbweavers, the huge golden orbweavers stay on the web all day, constantly repairing and reinforcing it. It is not the spider which is golden but the glow of the silk when it catches the sun. All the individuals I’ve seen locally are the Australian Golden Orbweaver (Nephila edulis). Discarded debris is left in the web above the spider to confuse the birds. Male garden orbweavers are only marginally smaller than their females but the males of the golden orbweavers are tiny by comparison [see above photo on right]. Although the males of most spider species will survive their sexual encounters, the Nephila males sacrifice themselves in their final act. Having produced a golden egg sac, the female will then die with the first frost.


For further reading, Lynne’s book, “Spiders: learning to love them” (Allen & Unwin, 2009) is an excellent resource for those interested in finding out more about these amazing creatures.

10 comments:

  1. Wow! Another person who likes spiders! Hi there!

    Say, what would things be like if we had spiders the size of ponies, and we could ride them like 8 legged horsies?

    And maybe they could be trained to flick their abdomen hairs at bad guys!

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    1. Great to meet you, CandF,

      Love your imagination. That sounds like the plot for a sci fi novel! Trained hair flicking massive spiders. I want one!

      Thank you!

      Lynne

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    2. Awwww thank you! I like the big spiders myself, because you can hold them and they're usually docile, and if you do mess up and they bite you, their venom won't liquefy your insides and kill you!

      Unless you're allergic...

      Then that would be bad...

      Anyway my pet Sammy likes to crawl up my arm and hang out on my shoulder. I showed him to my friend Laura and she kinda freaked out...

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    3. Now that comment will seem strange to many Australians. Can I assume that you are in America or England and have a pet tarantula?

      In Australia, we can't have your gentle tarantulas (if I am right in guessing the above) because they would be a disease threat to our local spiders. But our tarantulas are Old World, not New World, and far less docile than yours. So they aren't kept as pets and allowed to crawl up your arm.

      Large spiders are the huntsman (do Americans call them huntsman or giant crab spiders? They are fast and less predictable, so rarely kept as pets. Spiders as pets here are rare.

      Or have I got it all wrong? What sort of spider is Sammy?

      Great to meet another spider fanatic who also names them.

      Lynne

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    4. Yes I'm in America. Sammy is a Mexican Redknee Tarantula.

      I can't have a Huntsman... Well I could as I'm a cartoon, but I'm not allowed to have one.

      Say, I just remembered something... Australian Funnel-web spiders are really mean. They hate everybody, even other spiders.

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    5. Mexican Redknees are stunning creatures. Lucky you and lucky Sammy.

      Funnel-webs are not more nasty than other spiders. They just like being alone. I adore all spiders. :)


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  2. Yeah. Say if you get time stop by and say hello! This is where I live:
    https://caitandfriends.blogspot.com/

    And you can meet Laura too!

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  3. Looks good and very creative!

    Lynne

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  4. Can anyone help me identify the spider in this video?

    https://www.youtube.com/watch?v=YsTkaLUBHpo

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    Replies
    1. Not without a great deal more detail than that! Sorry!

      Lynne

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