First published July 2010, updated January 2012
A fear of spiders isn't uncommon, although often unfounded. I know of far more
people who have been bitten by dogs or scratched by a cat than have been bitten
by a spider.
Sometimes fear can be turned into fascination once we understand more about
something.
A fascinating aspect of spiders is the webs they weave - not just the intricate
nature of the construction, but the silk used to spin the web, which is the
strongest natural or synthetic fiber known.
Spider silk is made up of complex proteins. Researchers have been keen to figure
out how to replicate spider silk, but have so far only decoded the silk's DNA
for a handful of species of spider. Spiders create different types of silk
depending on the application, with some species may create up to 8 different
silk types.
The interest in creating spider silk based products for applications such as
ropes and protective clothing becomes apparent when you look at the properties
of the silk.
According to Wikipedia, spider silk strength is better than that of high-grade
steel and is as strong as Kevlar; which is used in bullet proof body armor. It's
very lightweight and it would only take a strand of spider silk weighing around
a pound to encircle the entire planet. Some webs are strong enough to capture
small birds and bats.
Spider silk is able stretch up to 140% of its length without breaking and
retains its strength below -40 degrees Celsius.
Spiders are great recyclers too when it comes to their silk. After a couple of
days, the web strands lose their stickiness - so the spider eats that section
and weaves a new one.
While silkworms have been farmed for their silk for thousands of years, there
hasn't been much success in spider farming or harvesting spider silk as they can
be cranky little critters with have a tendency to eat one another. However, that
doesn't mean to say there hasn't been any success.
An example of just how beautiful spider silk can be as a fiber for textiles is
captured in this cloth, made from the silk of the golden-orb weaving spider.
From an embroider cape made of spider silk.
Crafted by Simon Peers and Nicholas Godley, 2011
Image credit: Victoria and Albert Museum
An image of the full spider
silk cape can be viewed here. I'm not one for fashion, but I found this to
be absolutely stunning. Aside from the amazing workmanship, what you see is the natural
color of the silk. According to the accompanying report on the ABC, 1
million female golden orb spiders contributed to the 4 metre (around 13
feet) cape. Spiders were capture in the highlands of Madagascar each morning,
harnessed in special equipment and their silk extracted; then returned to the
wild. I'm not sure how the spiders felt about the whole ordeal though - and if
they are the same golden orb spider we have here in Australia, the handlers
would have been risking a nasty bite.
Synthetic spider silk research is ongoing using genetically altered bacteria and
also, would you believe it, transgenic goats. These goats have been genetically
engineered to produce milk high in spider silk proteins.
Hmmm...
Anyhow, spiders play a very important role in the environment and we should
perhaps give them a little more respect. Someone who left a comment on another
article I published about spiders works in the pest control industry and had
this to say: ".. spiders do my job far better than i could ever hope to...I
urge everyone to think twice before stomping on our 8-legged friends because you
simply don't realize how many other creepy crawlies they are eliminating for
you."
Who knows, maybe there's a gregarious species of spider out there that can be
farmed for silk, just waiting to be discovered - another reason why pristine
habitats need to be preserved.
Trivia - there are well over 30,000 species of spider and only 200
species have bites that can cause health problems in humans (allergic persons
aside) - less than 1%. Three species of spider go extinct each year.
