Even-More-Gigantic Giant Orb Spider Discovered

• By Hadley Leggett

Scientists have found the world’s largest species of golden orb-weaver spider in the tropics of Africa and Madagascar. The discovery marks the first identification of a new Nephila spider since 1879.

Females of the new species, Nephila komaci, measure a whopping 4 to 5 inches in diameter, while the male spiders stay petite at less than a quarter of their mate’s size. So far, only a handful of these enormous arachnids have been found in the world.

“We fear the species might be endangered, as its only definite habitat is a sand forest in Tembe Elephant Park in KwaZulu-Natal,” ecologist Jonathan Coddington of the Smithsonian’s National Museum of Natural History said in a press release. “Our data suggest that the species is not abundant, its range is restricted, and all known localities lie within two endangered biodiversity hotspots: Maputaland and Madagascar.”

The first potential specimen of the new species was uncovered by Coddington and his colleague Matjaz Kuntner of the Slovenian Academy of Sciences and Arts in 2000. They found a huge female orb-weaver among a museum collection of spiders in Pretoria, South Africa, and she didn’t match the description of any known spider. Although they hoped the unusual-looking giant represented a new species, several dedicated expeditions to South Africa failed to find any live spiders of a similar description.

Then, in 2003, a second specimen from Madagascar was found at a museum in Austria, suggesting that the first spider hadn’t been a fluke. But despite a comprehensive search through more than 2,500 samples from 37 museums, no additional specimens turned up, and the researchers assumed the biggest of all orb-weavers was probably extinct.

Finally, three live spiders have been found to prove the scientists wrong: A South African researcher found two giant females and one male in Tembe Elephant Park, proving that the new species was not extinct, just incredibly rare.

“Only three have been found in the past decade,” Kuntner wrote in an e-mail to Wired.com. “None by our team, despite focused searches. Only an additional two exist in old museum collections. Compared to thousands of exemplars of other Nephila species in museums, that is disproportionately rare.”

The two biologists named the new species after Andrej Komac, a scientist friend of Kuntner’s who died in an accident near the time of the discoveries.

Like all Nephila spiders, females of the new species spin huge webs of golden silk, often more than 3 feet in diameter. In the report of the discovery of this rare spider, published Tuesday in PLoS One, the researchers also addressed the evolution of the dramatic size difference between male and female orb-weavers.

By mapping out the evolutionary tree of all known orb-weaver species, the scientists discovered that as the spiders evolved, females got bigger and bigger, while males stayed roughly the same size.

“It is good for females to be big, because they can lay so many more eggs,” Coddington wrote in an e-mail. In addition, large size probably helps females avoid being eaten by predators.

“Relatively few groups can safely pluck an orb-weaving spider from its web,” he wrote, “because you have to be able to hover to do so (hummingbirds, wasps, damselflies come to mind). None of these are large enough to tackle an adult Nephila, or even a large juvenile.”

Males, on the other hand, are better off staying small and reaching sexual maturity at a young age. Because males spend most of their time underground, hunting for a mate is one of the most dangerous activities they undertake.

“So males risk everything to find, probably, just one, huge female, inseminate her, and probably do not willingly leave her web to search for another,” Coddington wrote. “Nothing about sex says males must be big.”

Image 1: Tiny male Nephila spiders are dwarfed by their female counterparts. Matjaz Kuntner and Jonathan Coddington/PLoS ONE.
Image 2: A giant golden orb-web exceeding 1 meter in diameter, spun by a Nephila inaurata spider. M Kuntner.

1 Million Spiders Make Golden Silk for Rare Cloth

• By Hadley Leggett

A rare textile made from the silk of more than a million wild spiders goes on display today at the American Museum of Natural History in New York City.

To produce this unique golden cloth, 70 people spent four years collecting golden orb spiders from telephone poles in Madagascar, while another dozen workers carefully extracted about 80 feet of silk filament from each of the arachnids. The resulting 11-foot by 4-foot textile is the only large piece of cloth made from natural spider silk existing in the world today.

“Spider silk is very elastic, and it has a tensile strength that is incredibly strong compared to steel or Kevlar,” said textile expert Simon Peers, who co-led the project. “There’s scientific research going on all over the world right now trying to replicate the tensile properties of spider silk and apply it to all sorts of areas in medicine and industry, but no one up until now has succeeded in replicating 100 percent of the properties of natural spider silk.”

Peers came up with the idea of weaving spider silk after learning about the French missionary Jacob Paul Camboué, who worked with spiders in Madagascar during the 1880s and 1890s. Camboué built a small, hand-driven machine to extract silk from up to 24 spiders at once, without harming them.

“Simon managed to build a replica of this 24-spider-silking machine that was used at the turn of the century,” said Nicholas Godley, who co-led the project with Peers. As an experiment, the pair collected an initial batch of about 20 spiders. “When we stuck them in the machine and started turning it, lo and behold, this beautiful gold-colored silk started coming out,” Godley said.

Father Comboué, who one historical text erroneously calls Father Comboné, had a partner in designing his machine, M. Nogué. Together, they got quite a spider silk fabric industry going in Madagascar and even exhibited “a complete set of bed hangings” at the Paris Exposition of 1898. That fabric has since been lost, but the exhibition brought them some attention, excerpted below.

“It should be said that the female halabe allows herself to be relieved of her silken store with exemplary docility and this in spite of the fact that she is distinguished for her ferocity; her usual treatment of the males who pay her court is to eat them and she feasts without compunction on members of her own sex weaker than herself. M Nogue’s apparatus consists of a sort of stocks arranged to pin down on their backs a dozen spiders. The spiders accept this imprisonment with resignation and lie perfectly quiet while the silken thread issuing from their bodies is rapidly wound on to a reel by means of a cleverly devised machine worked by hand.” — Great Britain Board of Trade Journal

“The first experiments of Father Comboné were made in the simplest manner. The spiders were imprisoned in match boxes and by slightly compressing the abdomen he managed to extract and wind upon a little reel turned by hand it thread that sometimes attained a length of 500 yards… it is to the ingenuity of M. Nogue, one of the sub directors, that we owe the apparatus which permits the thread to be wound mechanically and to be twisted and doubled in the quickest and most practical manner. This is done by means of a curious little machine, not easy to describe, in which the spiders are imprisoned by the throat while undergoing the operation. Young Malagasy girls go daily to a park near the school to gather three or four hundred spiders which they carry in osier baskets with wooden covers to be divested of their webs… Generally after having submitted to the reeling operation the spiders are put back in the park for a couple of weeks… [The silk's] color when first spun is a beautiful gold and it requires no carding or preparation of any sort before being woven. Will this be the silk of the future?” — The Literary Digest

But to make a textile of any significant size, the silk experts had to drastically scale up their project. “Fourteen thousand spiders yields about an ounce of silk,” Godley said, “and the textile weighs about 2.6 pounds. The numbers are crazy.”

Researchers have long been intrigued by the unique properties of spider silk, which is stronger than steel or Kevlar but far more flexible, stretching up to 40 percent of its normal length without breaking. Unfortunately, spider silk is extremely hard to mass produce: Unlike silk worms, which are easy to raise in captivity, spiders have a habit of chomping off each other’s heads when housed together.

To get as much silk as they needed, Godley and Peers began hiring dozens of spider handlers to collect wild arachnids and carefully harness them to the silk-extraction machine. “We had to find people who were willing to work with spiders,” Godley said, “because they bite.”

By the end of the project, Godley and Peers extracted silk from more than 1 million female golden orb spiders, which are abundant throughout Madagascar and known for the rich golden color of their silk. Because the spiders only produce silk during the rainy season, workers collected all the spiders between October and June.

Then an additional 12 people used hand-powered machines to extract the silk and weave it into 96-filament thread. Once the spiders had been milked, they were released into back into the wild, where Godley said it takes them about a week to regenerate their silk. “We can go back and re-silk the same spiders,” he said. “It’s like the gift that never stops giving.”

Of course, spending four years to produce a single textile of spider silk isn’t very practical for scientists trying to study the properties of spider silk or companies that want to manufacture the fabric for use as a biomedical scaffold or an alternative to Kevlar armor. Several groups have tried inserting spider genes into bacteria (or even cows and goats) to produce silk, but so far, the attempts have been only moderately successful.

Part of the reason it’s so hard to generate spider silk in the lab is that it starts out as a liquid protein that’s produced by a special gland in the spider’s abdomen. Using their spinnerets, spiders apply a physical force to rearrange the protein’s molecular structure and turn it into solid silk.

“When we talk about a spider spinning silk, we’re talking about how the spider applies forces to produce a physical transformation from liquid to solid,” said spider silk expert Todd Blackledge of the University of Akron, who was not involved in creating the textile. “Scientists simply can’t replicate that as well as a spider does it. Every year we’re getting closer and closer to being able to mass-produce it, but we’re not there yet.”

For now, it seems we’ll have to be content with one incredibly beautiful cloth, graciously provided by more than a million spiders.

Images: 1) AMNH/R. Mickens 2) Nicholas Godley and Simon Peers