The Spiders That Decorate Their Own Webs
Spider webs – possibly the most beautiful and intricate animal structures of the natural world. However, some spiders are not content with a simple web. They go one step further.
Some spiders decorate their own webs with even more elaborate and complex patterns than are necessary. Could they be the best exterior designers on the planet? Certainly from the look of these examples, they would be in the competition but the verdict is still out as to why they produce these extra web configurations. Some scientists argue that it is nothing more than ’spidey’ aesthetics. Take a look at some of these arachnid designs and come to your own conclusions.
In the early nineteen fifties the children’s author EB White was struggling to come up with ideas for his second novel. One day he noticed the additional decorations on the web of a Banded Garden Spider – much like the one above. It was from this natural inspiration that he would come up with the idea of a writing spider and would go on to write one of the world’s most cherished children’s books, Charlotte’s Web. Although anecdotal this story serves as a fine introduction to this most peculiar of insect habits.
As a certain Miss Aniston used to say, here is the science. The structures are known as web decorations but the more scientific name for one is stabilimentum. In the plural they are known as stabilimenta and the name came about because of a mistake. When first studied the decorations were believed to be used in stabilizing the web of a spider – and there you have the term stabilimentum – get it? However, this theory is generally dismissed these days – although it is obvious to one and all why early scientists may have thought this.
The truth be told, it is quite likely that the purpose and function of stabilimenta are manifold. It has been discovered that they evolved independently perhaps as many as ten times. Some spiders make their decorations purely out of their silk. Other spiders will make them from this and the remains of their egg sacs, not to mention any detritus that just happens to be close to their webs. The fact that they evolved independently does seem to point towards different functionality.
The web decorations can be found among a number of species of spider – but the best known example comes from the Argiope genus. The Saint Andrew’s Cross spiders are the most obvious if not resplendent of these web decorators. They are so called because of their habit of resting in their webs, legs outstretched in the shape of the cross of Saint Andrew. The decorations, often at almost mathematically precise forty five degree angles seem to extend the length of the spider and, potentially, make it a much less of an attractive target for those that predate it. Often, too, the decoration will be vertical and young spiders may even go for disc shapes.
Along with other things which seem to have a simple explanation, if you get five arachnologists in a room and ask them the purpose of web decorations then you may well get five different answers. Some think that the web decorations afford the spider and extra edge in terms of self protection. It may make spiders appear larger, as already seen, or make them more camouflaged. It may be the reverse of camouflage – by making the spider more visible then the web itself will be seen by animals like birds that are then less likely to inadvertently damage the web, partially wrecking or even destroying the painstakingly built structure. So it could well be a kind of ‘stop sign’ to other animals.
As science has progressed, so have the theories. One more modern idea posited is that the stabilimenta are used in order to attract more prey to the web. You have all seen insects at night flying towards lights? Ultraviolet light is often used to attract insects and then there is a sharp noise of insect flesh impacting and exploding under the influence of an electric current. It is now thought that the web decorations reflect ultraviolet light and this makes them attractive to a large number of insect species. Unwittingly they fly to their deaths. It is a pretty cool idea to think that spiders have for millions of years been using something as a weapon that we only recently discovered for ourselves.
Thermoregulation has also been put in to the ring to fight it out with the other ideas. The web decoration may well help the spider keep its body temperature to its optimum for survival, no matter what the weather is doing around the web. Perhaps the stabilimenta help it to create that all important dynamic state of stability between what goes on inside the spider and what is going on where it lives.
It could be that the spider has simply produced an excess of silk and that in order to divest itself of this it creates the web patterns. This could be argued against, as why should the spider simply not expel the excess rather than taking the time and energy to create these marvelous patterns? That returns us to the theory that the spider may well have a sense of web aesthetics – and as the ultimate web designer it wants its site to look the business. Is this perhaps a little too anthropomorphic? Maybe not, as many animals look to improving their environment – usually in pursuit of one thing.
Yes, you have it. The urge to reproduce may well be the reason that some spiders produce their web decorations. When the female is ready to reproduce she must attract a male and what better way than to enhance her already magnificent web? Above the female and male Argiope appensa with stabilimentum prepare to Disovery Chanel their way to the propagation of the species. One study in Spain did show that there was a definite correlation between the presence of a stabilimentum and the presence of a male looking to further the species by another generation.
The web decorations that are most noticeable are those that are made from silk though some spiders do in fact mix it up and include other items in their stabilimenta. Again, another theory indicates that these decorations will help to camouflage the spider – and give it protection. However, in the Nephila genus, spiders often attach lines of uneaten prey to their webs. As unlikely as this sounds, studies have indicated that this line of half eaten carcasses actually encourages more prey in to the web. And, yes, they always seem to be displayed in a straight vertical line. It does, however, somewhat detract from the much trumpeted aesthetics of stabilimenta.
Whatever the reason spiders construct their web decorations, it is certainly yet another astonishing feat that nature presents to us on a daily basis but which often we can overlook.
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60 Responses to “The Spiders That Decorate Their Own Webs”
On September 20, 2009 at 8:37 am
That is fascinating. Great photos too! I have never seen these web decorations before, and I do look at spiders’ webs as I think they are cleverly constructed. I didn’t know that about Charlotte’s Web either.
On September 20, 2009 at 9:05 am
cool article i’d never heard of this before.
On September 20, 2009 at 9:11 am
Stunning pictures & article!
On September 20, 2009 at 9:12 am
Wow these are kewl!
Spiders… icky of course, but interesting.
Back when I had Australian Bearded Dragon lizards I had to order boxes of crickets from a supplier and one box that came had the usual crickets …and some sort of tarantula (rose hair tarantula?) in the bottom of the box as well!
It was of course., well-fed.
I kept that as a pet for about a year (never touched it, just kept it in an aquarium.)
On September 20, 2009 at 9:34 am
A great article. Very informative and well illustrated, with a nice photographic..I really enjoyed reading this:) Thank you!!
On September 20, 2009 at 9:57 am
A novelty to me,spiders are creative designers as well.
On September 20, 2009 at 10:14 am
Clever spiders! Fascinating.
On September 20, 2009 at 12:18 pm
How extraordinary! these are splendid.
On September 20, 2009 at 7:46 pm
Although I can’t stand spiders, they do seem to be very creative. Great pictures and impressive article.
On September 20, 2009 at 7:47 pm
Pretty crafty spiders. That’s amazing that the web has the ability to use ultraviolet light. Interesting warfare.
On September 20, 2009 at 8:05 pm
I always enjoy your pieces and this is another one to enjoy.
On September 21, 2009 at 12:46 am
amazing! pictures are great!
On September 21, 2009 at 2:33 am
Amazing. I never heard of this before.
On September 21, 2009 at 8:02 am
Amazing work; by the spiders for such awesome designs and by you for such a great article!
On September 21, 2009 at 9:46 am
Lovely article with great photos. It seems that spiders should be consulting humans about the visual aspects of architecture.
On September 21, 2009 at 1:03 pm
This is really a fantastic article. And the pics made it even more interesting!
On September 21, 2009 at 6:59 pm
cool! didn’t know spiders could do that!
On September 21, 2009 at 10:21 pm
You always have amazing well-written articles and pics! Intriguing susbjects, too. I didn’t know there was a name for the little “extras’ spiders come up with.
On September 21, 2009 at 11:04 pm
Spider webs are my favorite things. I taught all my children and grands to appreciate them. I would bet the decorations are to attract a male. Almost everything a female does is for that purpose.
On September 21, 2009 at 11:06 pm
Beyond amazing. I truly loved reading this. I am a new fan to you now. =)
On September 22, 2009 at 12:48 am
Fascinating wonders of creation. I’ve never seen webs this close. Thanks for sharing this.
On September 22, 2009 at 5:00 am
Sorry to be posting as a guest with such a shakeup of a comment, but spiders grab these pieces of web to quickly throw them over their prey like a net. I’ve been fascinated by spiders for years and I’ve watched them do this. This is why most spiders have a leg holding on to the edges of most of these decorations. They grab it like a net and then throw it over their prey and wrap them up. I’ve watched this many many times. I find it hard to believe that entomologists haven’t documented this phenomenon.
On September 22, 2009 at 5:02 am
This is fascinating and so well researched – you have put hours into this article and it shows.
On September 22, 2009 at 10:11 am
This is by far the most fascinating thing I have learned in a while. It has always amazed me how these little buggers are able to create such beauty.
Totally awesome
On September 22, 2009 at 10:21 am
I’m amazed about the amount of things you can find on the web!
On September 22, 2009 at 1:17 pm
This is really cool! I have a deep rooted fear of spiders, but it is really neat to see how “artistic” spiders can be!
On September 22, 2009 at 2:00 pm
I very much enjoyed reading this article and seeing the fantastic web designs. It is no small coincidence that Navajos have grandmother spider myths and legends and that they believe grandmother spider taught them the art of weaving.
On September 22, 2009 at 2:13 pm
Wow, if we payed attention to things like that in our world we would be filled with great information. I loved the designs. Not to mention how pretty the spiders were, not that I would touch them unless they were tiny and lime green! lol
On September 22, 2009 at 4:02 pm
only one word for this article:
*pause for suspense*
AWESOME!!!
On September 23, 2009 at 1:55 am
Wow man some of those webs are supper Beautiful, i had no idea they decorated them like that. AMAZING
On September 23, 2009 at 2:03 am
Cool article and pics. Most fascinating.
On September 23, 2009 at 2:20 am
Very interesting.
On September 23, 2009 at 3:35 am
Very informative and interesting.
On September 23, 2009 at 11:05 am
I never knew spiders did such things,a very well written article with fascinating pictures.Will have to show this to my grand kids.
On September 23, 2009 at 1:59 pm
Your article is better than a National Geographic article! It is obvious you worked hard on this article. Thanks for taking the time to research, write and share this with your fellow writers! Good article!
On September 23, 2009 at 5:57 pm
I have an extensive fear of spiders, but this helps me see them in different light. Thanks for sharing this. It was interesting and some of the pics were really great.
On September 23, 2009 at 9:34 pm
Possibly where the idea of lace making and crochet came from?
On September 24, 2009 at 4:04 am
i am scared 2 death of spiders and this articles pics gave me the hee-bee-gee-bees. good info.
On September 24, 2009 at 1:04 pm
some cute some scary
On September 24, 2009 at 1:40 pm
The added “design” is to make it more visible to keep birds from flying into it. I learned that back in 5th grade science class.
On September 24, 2009 at 10:11 pm
Your articles never seize to amaze me.
On September 24, 2009 at 11:30 pm
personally, i’ve seen lots of spiders in their webs especially those “X” thing on the middle but not minding their beautiful creations. now, i learned something new. next time, i’ll try to be more attentive on their web’s design.
On September 25, 2009 at 11:12 am
These are beautiful..I just love nature!
On September 25, 2009 at 7:31 pm
That is cool – my Father has a huge one in his frontyard right now – it is forming one of those knit patterns in the middle…
On September 26, 2009 at 3:11 am
Wow. This is so random, but necessary. Great information
On September 26, 2009 at 6:16 am
Fasinating
On September 26, 2009 at 9:40 am
lovelycreatures
On September 26, 2009 at 10:48 am
Amazing! Those spiders are smart.
On September 26, 2009 at 8:41 pm
Dude…
On September 26, 2009 at 8:49 pm
Cool stuff except when I keep getting these webs all over me on hikes. Never knew I was wrecking such artwork.
On September 26, 2009 at 9:15 pm
They are the best Web designers
On September 26, 2009 at 10:27 pm
What an amazing piece!!! Lovely pictures and creative! Keep it up
On September 27, 2009 at 12:41 am
Goes to show that humans are not the only beings to demonstrate extreme arrogange when trying to attract a mate or show off the house–Love to see folks who appreciate the small beauties here on earth.
On September 27, 2009 at 3:01 am
I see the cross ones all the time in australia
On September 27, 2009 at 4:47 am
great article
:D ,, love your work .. please check out some of mine ? i would be very thankfull 
On September 27, 2009 at 6:15 am
This really is a well researched article.
The pictures show all the detail that goes into those decorations.
I’ve never really noticed them before and will have to look more closely at webs in the future.
That temperature control technology would be really useful inside the house in winter;-)
On October 4, 2009 at 11:38 am
i am wondering are spiders poisinus if they have a cross oon thier backs because i found 3 spiders and they have a realy big back one is orange and the other 2 are chocolate brown
thanks
On October 12, 2009 at 8:32 pm
Sure looks like camouflage to me.
On October 28, 2009 at 12:28 am
I do love spiders. I enjoyed this article and the pictures were great. I learned some things, too. Never heard of stabilimenta, and I love to learn things like that. Since I love spiders so much, I am trying to learn new things about them. I’d heard about birds not flying into the web with the designs, and that the designs might keep insects out of the web, so spiders tend to build the designs when insects are plentiful if the designs keep the insects at bay. Now, I know of other theories for this design as well. Pretty neat.
On November 5, 2009 at 10:25 am
I haven’t actually read the article, but if i were a spider waiting around all day for food to get caught in my net, i would decorate my web too. It’d get pretty lonely.
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