10 Super Silky Spider Facts
A Beautiful Bejewelled Spider's Web
Spiders: Nature's Spinning Wonders
For many humans, spiders are capable of putting not just the wind up them, but a force nine gale, such is the fear they can provoke. But the inventiveness of these abundant creatures lay claim to some amazing feats, even if they're not all completely palatable (to humans at least.)
These wonders of nature are helping scientists to formulate new materials. Love them or hate them, they may be helping us in the not too distant future.
1. Spiders Go to Great Lengths
All types of spiders have the ability to spin silk from glands in their body. Madagascar, that wondrous land of flora and fauna, is home to spiders that have the ability to spin a single silky strand that can span a river.
Webs up to 25 meters wide, created by Darwin's bark spider were discovered in Andasibe-Mantadia National Park by zoologist Ingi Agnarrson from the University of Puerto Rico. Research concluded that the web builders were nearly always female.1
2. Silky Variations
There are up to eight different types of spider silks and an individual spider is capable of spinning up to six. One type is used for the dragline, the strand from which a spider descends from a plant or a ceiling. Another is the stiff tubilform silk, excellent for winding round egg sacs for protection. The particularly sticky stretchy capture-spiral silk binds lines of the web while the minor-ampullate silk also is used for web construction At three times the strength of the dragline silk, anciform silk is used for capturing prey.2
We should take care of our spiders. They contribute to our eco-system by recycling dead animals and plants and are vital pollinators, and are food for other animals as well.
3. Spiders: Smooth-as-Silk Operators
An important consideration of a male spider's courtship is the use of silk depositions. This can take place on the female spider's own web or at the entrance to her burrow. It's thought the vibrations they produce can either enhance or reduce the chances of success.
In the case of black widow spiders this is especially vital. To avoid the chance of being cannibalised the male will perform his very best courtship signals to be accepted as mate, and escape any designs the female has on having her cake and eating it. In the case of the orb weaver spider, chemicals in the silk and even its colour may make the femme fatale rather less inclined to fatalism and increase the male's percentage of survival.
'Bridal veils' are the height of fashion for some spiders. Adding a touch of spice to their sex life, certain males will liven things up with a bit of judicial bondage. Enveloping his intended in silk may be crucial for the nursery spider, for while she fights her way out of her restraint, the male, having transferred his sperm, makes good his escape and flees from the possibility of being next on the menu.
As part of the bonding process, so to speak, some female spiders actually take the veil. Not that they enter a nunnery after having a bit of fun, but rather they consume the silk.3
Nursery Web Spiders in Bondage Ritual
4. Taking Silk and Judging Well
As we have learnt, life as a male spider can be a precarious occupation, so their web of intrigue must know no bounds. What better than to woo the object of your desire by bearing the equivalent of a bunch of roses?
Not that it's a bed of the red prickly flowers for all concerned. Spider rivalry can be deadly and the spider who doesn't come up to scratch can lose everything, including his life. Adding insult to injury, the victor gift wraps the opposition in his silk and offers it to the female. It's a smart move. Not all male spiders are quite that callous to his own kind. A twitchy spider may catch something on the usual diet and offer that to the female.
Whichever tactic is used, holding the grisly present between her jaws means he can get on with the serious business of sperm donation, safe in the knowledge her mouth is conveniently occupied and her choppers will not be tempted to take a bite in his direction.3
Despatching other would-be suitors is not the only tactic up a triumphant male spider's silky sleeve. Some leave a detachable palp, rather like a penis, as a sort of stopper, thwarting another male's desire for the same goal.4
A Male Spider Trades a Life Saving Gift
5. Spinning a Yarn For the Future
The amazing properties of spider silk has led to researchers developing synthetic versions for all manner of applications. It's very strong, more so than steel, and has tremendous elasticity. Potentially it could be woven into protective clothing, or braided to make sutures and other body repairs. The fibres have the added benefit of being manufactured at eco-friendly room temperature and is 98% water with the remaining 2% made up of silica and cellulose..5
Alas owing to the predatory nature of spider populations, it would be impractical to keep each one in solitary confinement to harvest the silk commercially, hence the hunt for a man made alternative.
The healing properties of spider silk were known hundreds of years ago when spider webs were applied to wounds. Unbeknown to our ancestors, it contains vitamin K which helps to stem bleeding.
6. Spiders Spin an Outsize Creepy Blanket
In October 2018 the unusually warm weather conditions caused a phenomenum on Lake Vistonida in the Xanthi region of north eastern Greece. Tetragnatha spiders spun a vast web covering 1000 square meters in an eerie silky film. Even nearby trees were engulfed. The previous month a lagoon at Aitoloko in the west of the country became inundated by tetragnatha spiders' webs. Mosquito larvae, which was in abundance due to the unseasonally hot conditions helped the Tetragnatha spider multiply and create this creepy covering..6 It really is the stuff of horror films.
Tetragnatha spiders are also known as stretch spiders due to their elongated body which they can fold down into a stick-like position. It camouflages them against plant stems in order to make it easier for them to catch their prey.3
7. Gossamer as the Holy Grail
Despite the extended Grecian silk blanket, harvesting spider silk is a highly laborious task, so much so, it has been dubbed 'The Holy Grail'. However the silk doesn't shine like the silk from silk worms and, despite its other qualities is less economically attractive.
In our high-tech world, the term 'The Holy Grail' is now applied to seeking its synthetic alternative.7
For more great facts about insects click here.
Some hummingbirds use spider silk to build their cup-shaped nests woven with other materials like moss and lichen, plant down such as dandelion clocks, feathers and leaves.
A Sun Hummingbird's Nest With Spider Silk
8. Spiders Go for Gold
In 2012 the Victoria and Albert Museum in London exhibited one of the rarest textiles in the world. It's the only known fabric to exist created from the silk of more than a million Madagascan golden orb spiders. To create just four meters of the precious material it took 80 weavers four years, spending five years collecting the spiders, enough to be made into an exquisite cape.
Producing spider silk garments is an exclusive business and has only been known since 1709 when the Frenchman François-Xavier Bon de Saint Hilaire fashioned gloves and stockings and apparently a suit for King Louis XIV. In the nineteenth century Napoleon and his wife Josephine were the beneficiaries of stockings and a shawl woven by Spaniard Raimondo de Termeyer. Hardly a large scale operation.
Spider Silk Cape
9. Sticky Spider Situations
We might assume, since webs are designed to trap prey, that the silk spiders secrete is sticky. In fact as they spin their webs tiny droplets of a protein glue-type substance cover the silk. How sticky it is varies with humidity. 8
Materials scientist Professor Ali Dhinojwala of the University of Akron in Ohio revealed that the glue needs water to keep it sticky. It is a feature that is exciting for scientists because the study of spider silk glue could aid the development of products such as bandages that do not come off under water.9
10. Spitting Spiders
Not all spiders spin webs or bundle up prey or eggs. Some spit. It's not a pleasant habit at the best of times. In the case of the spider family Scytodidae their table manners are distinctly disgusting.
These spiders fling out a venomous sticky silky gob from their mouth showering the prey in a criss-cross pattern. Often it's paralysed and rendered immobile, powerless against being further injected by another equally distateful fluid which dissolves the body and can be sucked up like a Scytodes smoothie.
4 Live Science
5 The Smithsonian/innovation
6 The Independent
9 BBC Earth Story
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© 2018 Frances Metcalfe