October 15, 2012 9:44 am
A rare fossil uncovered by researchers from Oregon State University captured a 100-million-year-old moment in time, a spider attacking an insect trapped in its web.
Researchers call the fossil “extraordinarily rare” for its remarkable detail. It’s also the first and only fossil evidence of a spider—an orb weaver—attacking prey in its web. (Its victim was a parasitic wasp.) As an extra bonus, the fossilized piece of amber also contains 15 unbroken strands of spider silk and the body of a small male spider in the same web, providing early evidence of social behavior in spiders.
The amber dates back to the Early Cretaceous period, which took place between 97-110 million years ago, and was recovered from the Hukawng Valley of Myanmar, where dinosaurs once wandered. Spiders themselves likely evolved around 200 million years ago, though the oldest spider fossil dates back just 130 million years.
The wasp in question, a male, belonged to a species known to parasitize spider and insect eggs. In that context, the researchers say, the spider’s attack may be considered payback.
“This was the wasp’s worst nightmare, and it never ended,” said zoologist George Poinar, Jr., in a press release. “The wasp was watching the spider just as it was about to be attacked, when tree resin flowed over and captured both of them.” Its large and probably terrified eyes now stare for eternity at its attacker, moving in for the kill, he said.
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