SPIDER SILK

SPIDER SILK IS one of the most versatile materials on Earth. Actually a protein created by special organs known as spinnerets, spider silk can be used for transportation, shelter, courtship, and all kinds of creative ways to trap prey.

Some spiders can produce more than one type of silk. A common orb-web, for example, may contain at least four different kinds, each adding a different component, such as strength, flexibility, and stickiness.

Equipped with such a versatile material, spiders have evolved to create a wondrous assortment of webs. There are horizontal sheet webs that catch falling prey and vertical latticework webs that intercept flying prey. Black widow webs are messy affairs, while funnel webs and lampshade webs can resemble three-dimensional sculptures.

Some spiders produce a silk that is low in UV reflection and is also translucent, so insects can’t see it. On the other side of the spectrum, there are spider silks that reflect ultraviolet light and appear blue at certain angles. In the tropics, there are even spiders in the Nephila genus that infuse their silks with carotenoids, which, when the sun hits them, makes the webs seem as if they were dipped in liquid gold.

Bolas spiders skip web-building altogether. These clever creatures lure moths in close with pheromones and then swat the insects out of midair with a single piece of sticky, weighted silk that they swing around like a mace. Gnaphosids shoot silk at their prey like Spiderman.

Of the close to 50,000 spider species known to science, most do not produce webs at all. But all spiders produce silk. The ways in which they use this material are as varied as they are fascinating.

Spider silk is incredibly strong and flexible. It also tends to be very clean and have anti-microbial properties, because spiders don’t want molds and microbes growing on their webs.

While silk is an excellent building material, it can also be used for transportation.

Jumping spiders are constantly leaping across chasms, for instance. They protect themselves against falls by anchoring a silk safety line to their perch. This allows jumping spiders to crawl back to where they started if they miss their mark. It even allows change directions once they’re airborne with a quick tug of the drag-line.

Most spiders are tiny, but they can travel between trees or across enormous gaps through a process known as “bridging.” All the spider needs to do is let out a line of silk into the wind and then pull it taut once it connects to something out in the world.

Similar to bridging, numerous spider species are able to “balloon” up into the sky by releasing strands of silk that get picked up by the wind and Earth’s electrical fields. Ballooning spiders have been found floating more than two miles high and thousands of miles out at sea.

Spider silk isn’t just strong, stretchy, and sticky—it can be stinky, too. Female spiders have pheromones on their silk.

“Silk is a communication method,” : “It works chemically, using pheromones, but then for web-building spiders, it is also a dance floor used for male courtship displays.

Partly to woo the female and partly to convince her he is a suitor rather than dinner, males of many species will tap, pluck, and otherwise send vibrations throughout the female’s web. Males may also remodel the female’s web by laying down silk of his own or destroy whole sections of it, perhaps in an attempt to hide the female from other males in the area.

Elsewhere in the mating and reproduction game, spiders use silk to safeguard their eggs and build nursery webs to protect their spiderlings. Males of some species use silk to gift-wrap food items, which they then give to females in an attempt to woo their favor, though sometimes a spider will try to cheat the female by wrapping up a rock or seed instead.

Silk can also be used to tie a female up during courtship. This is called “mate binding” or the “bridal veil.” And while it may sound strange, this behavior may make the female more receptive to mating by bringing her sensory hairs into contact with the male’s pheromone-laden silk. Physically restraining her can also prevent cannibalism.