Spiderman 3 Moves Inspired By Spider Web Facts

By Emilie Lorditch

American Institute of Physics

COLLEGE PARK, MD (April 25, 2007) -- What can stop a Boeing 747 in flight? What can be stronger than bullet-proof Kevlar and more elastic nylon? Why it's spider silk! While these facts sound more like science fiction than science fact, audiences are anxiously waiting to see Spider-Man 3 opening in theaters on Friday, May 4. Even though Spider-Man's web is the creation of special effects, biologists and mechanical engineer inspired or "inspidered" by the webbed wonder are caught in the web of mystery surrounding spider silk.

"There are over 39,000 species of spiders," said Cheryl Hayashi, a biologist at the University of California-Riverside. "All spiders spin at least one kind of silk and some spiders can produce 7 different types." Depending on which spider spins it, even these silks have unique properties.

The kind of silk usually determines its use. "Most spider silks vary in their strength and elasticity," said Randy Lewis, a molecular biologist at the University of Wyoming. "Dragline silk is the strongest silk because it supports the weight of the spider." This silk attaches the spider to the web and provides support just like a rapeller's rope as the spider drops below the web to avoid prey.

"When most people think of spider silk, they envision an insect-catching orb web," said Hayashi. An orb-web is a wagon-wheel shaped net with its spokes made from strong silk. The center of the wheel is the capture spiral which is made from flagelliform silk that is covered with sticky adhesive droplets. Once dinner is caught, spiders use achniform silk to wrap and immobilize their prey.

"Spiders are incredibly fascinating in the way they make and are able to manipulate their silks," said Hayashi. "They can even recycle their silk by eating it--it's a good source of protein."

Growing spider silk to study has created its own challenges. Because one spider can produce several types of silks, collecting silk from live spiders makes it difficult to study a specific variety of silk. By cloning spider silk genes and then adding them to genetically engineer E. coli bacteria, Hayashi and Lewis have found that the bacteria can produce chemically identical spider silk proteins for experiments. "By combining different genes, we can create spider silk proteins with novel properties," said Hayashi.

While there still are many things for researchers to learn about spider silk, sometimes the truth is even stranger than fiction. Hayashi and Adam Summers, an ecology and evolutionary biologist at the University of California at Irvine, were studying Costa Rican zebra tarantulas and discovered that these tarantulas not only spin silk from their abdomen, but also from their legs. This new kind of silk helps the tarantulas cling to surfaces, showing that Spider-Man's webbed locomotion might not be too far off the truth.