Spiders make me feel uneasy. There’s just something about their eight legs and fat black hairy bodies that makes my skin crawl. But as I’ve discovered recently, there’s way more to spiders than the hideous funnelweb from my nightmares. Spiders are fascinatingly weird and fantastically resourceful.
Take for example, the little amber spider from the Peruvian Amazon, who grasped the internet’s attention recently when its mysterious circular picket fence web was discovered. Scientists figured out that a tower in the centre of the intricate corral holds a single egg from which a honey-coloured spiderling emerges. But there is still much to find out about this spidersilk Stonehenge, including its exact function, and the architectural arachnid remains nameless.
Another recent discovery from the Amazon is the so-called “decoy” spider; a sneaky little guy who uses insect corpses and other debris to fashion spider-shaped decoys in its web. These decoys are much larger than itself – it’s only a couple of millimetres across – and it hides out in a special pocket built into its creation’s abdomen. Amazingly, another decoy spider was also found around the same time, but this one was 18,000 kilometres away in the Philippines. Scientists are keen to sequence the genomes of these newly discovered spiders, to figure out exactly how they’re related and whether this is a case of convergent evolution: two unrelated species evolving to develop similar decoy systems. But what does the spider even use these decoys for? It’s still unclear whether they are lures for prey or anti-predator defences, and we don’t know how the spiders construct them either.
It’s not just spiders’ webs that are so awesome either – some spiders use their silk, which is stronger than steel (weight for weight), to construct parachutes. This phenomenon is known as “ballooning” or “dynamic kiting” and is usually exhibited by spiderlings. The young spider will climb as high as it can, stand on raised legs with its abdomen tilted to the sky, and eject silk threads from its spinnerets to automatically form a triangular parachute. Even the slightest breeze can lift the spider and its parachute and transport it anywhere from a few metres to five kilometres above sea level. It’s thought that this is how spiders reach new islands and mountaintops.
Spiders are not only your friendly neighbourhood flycatcher, they’re also a stunning example of the weird and wonderful biodiversity nature has to offer. These are just a few examples from the more than 43,000 spider species discovered to date – just imagine how many more crazy silk creations are out there!