Nobody can farm spider silk
SILK is the material engineers keep trying to copy: for its weight it absorbs more energy before snapping than steel or Kevlar, and it stretches a third of its length first. The obvious move would be to farm it the way we farm silkworms. It cannot be done, because spiders are territorial and will eat each other given the chance.
There is one famous exception. Between 2004 and 2012 a team in Madagascar had collectors catch golden orb spiders each morning, wind off the silk by hand and release them at dusk. Roughly 1.2 million spiders later there was enough for a single shimmering gold cape — eight years of work, and still the only garment of its kind.
Baby spiders fly
A spiderling that needs to leave home climbs to a high point, lifts its abdomen and releases several fine threads that fan out into a triangle. Then it lets go. This is called ballooning, and it works well enough that spiders arrive on ships hundreds of miles out to sea — Darwin recorded a mass landing on the Beagle and wrote it up, baffled, in his diary.
For a long time the assumption was pure wind. Then experiments in 2018 showed spiders will launch in still air inside a sealed box if an electric field is switched on, and that the threads repel one another as if charged. The atmosphere carries a weak electric field all the time, and a spider appears to be able to feel it through the hairs on its LEGS and ride it.
Why the spider does not stick to its own web
An orb WEB is not uniformly STICKY. The spokes running out from the middle are plain dry silk, and so is the spiral the SPIDER lays down first as scaffolding; only the capture spiral is beaded with glue. A spider crossing its own TRAP walks the dry lines, and that is the reason it always seems to take an oddly indirect route.
Even when it has to touch the sticky threads it gets away with it. The leg tips carry a dense brush of fine hairs that reduces the contact area to almost nothing, and there is evidence of an oily coating as well. Snip a spider's leg hairs in a laboratory and it starts having the trouble everyone assumes it should have.
They drink their dinner
A SPIDER has no teeth and a gut too narrow to pass a crumb, so it cannot eat solid food at all. What it does instead is inject the PREY with VENOM through a FANG to subdue it, then pump in digestive enzymes and wait while the meal dissolves inside its own skin.
Then it drinks, leaving a hollow shell — the reason the underside of a web collects neat empty husks of fly rather than fragments. Almost every spider is venomous and almost none is dangerous to people. The venom is a tool for turning an insect into soup.
Eight hundred million tonnes a year
A study in 2017 estimated what the world's spiders eat between them and arrived at 400 to 800 million tonnes of prey annually — in the same range as the total weight of meat and fish eaten by all of humanity. Every ARACHNID in every BURROW, NEST and hedge is part of that, and most of what they remove is insects.
The grid holds the rest of the toolkit: EIGHT LEGS and usually eight EYES, a HAIRY body built to CRAWL and SCUTTLE, the ability to SPIN and WEAVE, an EGG sac of silk, and the fact that if spiders stopped tomorrow the insect problem would be considerably larger than the spider problem ever was.