To avoid being swallowed by sap, a frightened stick bug jumped out its skin, leaving its exoskeleton forever entombed. Photo by George Poinar, Jr./Oregon State University
CORVALLIS, Ore., July 14 (UPI) -- Fifty million years ago, one lucky -- and frightened -- insect avoided amber entombment. Though the stick bug wasn't embalmed, the remnant of its close call was.
Researchers recently unearthed a piece of ancient amber containing the exoskeleton of an insect similar to a modern walking stick -- skin only, no bug. The sticky sap also captured a mushroom, the first found in Baltic amber, and a mammalian hair.
"From what we can see in this fossil, a tiny mushroom was bitten off, probably by a rodent, at the base of a tree," George Poinar, Jr., a researcher and amber fossil expert at Oregon State University, said in a news release. "An insect, similar to a walking stick, was probably also trying to feed on the mushroom. It appears to have immediately jumped out of its skin and escaped, just as tree sap flowed over the remaining exoskeleton and a hair left behind by the fleeing rodent."
The amber was recovered from the coast of the Baltic Sea in Scandinavia. Some 50 million years ago, Northern Europe featured a vast subtropical forest. The dinosaurs had just died out and mammals were quickly diversifying.
Plant life was in flux, too. Cone-bearing evergreens, or gymnosperms, were giving way to flowering plants, or angiosperms.
The insect in the Baltic amber was a member of the Phasmatodea order, a group commonly known as stick insects -- insects that resemble sticks and leaves.
"It would have shed its skin repeatedly before reaching adulthood, in a short lifespan of a couple months," explained Poinar. "In this case, the ability to quickly get out of its skin, along with being smart enough to see a problem coming, saved its life."
Researchers know the sap didn't simply swallow up a week-old discarded exoskeleton, as the bug skin still featured fine filaments when it was entombed. The filaments would have been quickly weathered away had they been exposed to the elements.
Poinar and his colleagues detailed their discovery in the journal Fungal Biology.