Forever (Almost) Amber

Celeb-watchers keep tabs on their idols’ indecorous antics via TV, tabloids, and raunchy websites. We natural history buffs, on the other hand, enjoy tracking the lives, loves, and calamities of brute creation down the ages through a more wondrous medium--amber. A sticky resin that seeped from trees in distant millennia, amber trapped all sorts of small plants and animals. Hardening into yellowish-brown, translucent “caskets,” it preserved and carried these remnants of life through millions of years into the museums and biological laboratories of today.

A news item distributed the other day by the Associated Press was a reminder of amber’s priceless service to science. An amateur fossil-hunter had found a lump of amber on a British beach and turned it over to a paleobiologist at Oxford University. The amber turned out to be from the early Cretaceous, about 140 million years ago, at a time when the dinosaurs were just beginning to flex their muscles. Preserved in the amber among some plant debris was a tiny silken orb web, the oldest spider snare ever found.

“You can match the details of the spider’s web with the spider’s web in my garden,” the scientist reported.

That the web was orb-shaped must be of special interest to araneologists--people who study spiders. For years they have theorized that simple orbs came early in the evolution of webs, before the horizontal sheets and tangled cobwebs that characterize the snares of many spiders now extant. And there, in that lump of coral washed up on England’s shore, the scientist found an image that was not simply the impression of a web in a rock, nor a fossilized artifact. It was the web itself.

Such finds are invaluable, though not rare. No other kind of fossil preserves such perfect specimens. Ancient trees, especially conifers, exuded masses of resinite through openings in the bark of trunks and branches. (The substance served to heal wounds in the trees’ “skin,” just as scabs form over scratches on our bodies.) Insects, spiders, and other small animals, plus bits of local plants, were often trapped in the gooey ooze. When the material hardened, it preserved these organisms for as close to forever as anything can get.

Often it’s all there in the amber. Nerves, organs, even cellular material, remain intact. Colors sometimes appear as vividly as they did on the day the creature became entombed. Stingless bees still clutch blobs of resin, harvested for their nests, in miniscule claws. A lucky pair of leafhoppers is caught for all time in the act of mating. Eggs stream from the ovipositor of a gall midge, while parasites burst through the abdomen of a midge found in Cretaceous amber.

All of these remains, perhaps even an assemblage of a dozen or more kinds of insects and spiders in a single lump of amber, help scientists study life as it was in past epochs.