SCIENCE

Two researchers report finding two perforated snail shells unearthed in the 1930s in what is now Israel. (Courtesy Of Marian Vanhaeren And Francesco D'errico)

A total of 119 new champs and co-champs were named this year, including an American elm in Fountain Creek, Va., that was declared to be equally as large as the incumbent elm champ in Tennessee. All told, Virginia has 54 national champion trees, including the largest white oak, white mulberry and red buckeye.

Maryland boasts the biggest box elder and southern crab apple trees and a co-champion poison sumac (which is tied with a Virginia specimen), among others.

The District has a single national champion tree: a huge common jujube, 61 feet tall with a 93-foot circumference, shading a nice patch of the U.S. Capitol grounds.

-- Rick Weiss

Webcasting's Ancient Origins

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Two very different kinds of spiders make the same kind of orb spider web -- the ingenious wheel-shaped contraption that has been trapping flies, beetles and wasps through the ages. Biologists once assumed this was an example of convergent evolution, the independent emergence of the same useful traits in different species.

New research published last week in Science, however, suggests that the complex architecture involved in spider webs may have been devised by a single common ancestor that dates back about 136 million years.

DNA analysis by Jessica Garb and her colleagues at the University of California at Riverside showed that spiders known as Deinpoidea , such as the net-casting spiders, and Araneoidea, which include the golden silk spiders, both inherited certain key proteins from this common ancestor.

Both kinds of spiders build the radial structure of webs in similar ways, but they use different substances for the silky nets that trap flying prey. The nets have to be enormously strong to absorb the kinetic forces of a hurtling insect: Deinopoids use dry silks to create a mesh and to trap prey using electrostatic forces. Araneoids use a gluey silk that traps prey by being sticky.

Araneoid silks have been extensively studied. Garb and her fellow researchers genetically analyzed deinopoid silks and showed that they shared a common genetic lineage with araneoid silks.

-- Shankar Vedantam