for National Geographic News
The oldest known fragment of spiderweb has been found entombed in a piece of 110-million-year-old Spanish amber, scientists announced today.
The fossil web was found complete with several entangled insects and other small creatures.
Its discovery seems to cement arguments that spiders living in the age of dinosaurs already wove complex aerial webs like those snagging bees and butterflies today.
Experts believe the earliest spiders probably made silk to line burrows or to help pick up vibrations from prey crawling past them.
But no one is sure exactly when so-called orb weaving spiders evolved and began suspending their iconic spiral webs in the air (see a spiderweb photo gallery).
"When you look at the piece, the striking thing is that the geometry of the web and the prey type and size in it are like what one would see today," said David Grimaldi, an invertebrate biology specialist at the American Museum of Natural History in New York City.
"Spiders have been fishing insects from the air for a very long time."
Grimaldi and colleague Enrique Peñalver, along with Xavier Delclòs; of the University of Barcelona in Spain, will publish their findings in tomorrow's issue of the journal Science.
A separate study by a team based at the University of California, Riverside, which also appears in this week's Science, analyzed genetic diversity within two groups of living orb-weaving spiders.
That study concludes that orb-weavers probably first appeared around 136 million years ago, a date that reinforces the amber evidence.
Spiders and many other small creatures are often found trapped in ancient amber. The hard, yellowish material is a fossil form of the sticky sap that oozes from trees such as pines and other conifers.
SOURCES AND RELATED WEB SITES