Amber-trapped beetle shows chemical warfare 100 million years ago

Tyrannosaurus rex wasn't the only killer walking the Earth 100 million years ago.

Bugs infected with diseases and parasites could have devastated dinosaur populations, and insects also impacted plant food sources, according to an upcoming book by Corvallis scientists George Poinar Jr. and Roberta Poinar, whose research served as the inspiration for "Jurassic Park."

"What Bugged the Dinosaurs" will be released in January. The book is being published by Princeton University Press.

"We think insects played an important role in determining the fate of the dinosaurs, and a lot of people haven't considered that yet," said George Poinar Jr., a zoology researcher at Oregon State University, and one of the world's foremost experts on organisms trapped in amber.

John Ruben, chairman of OSU's zoology department, said he wasn't sure his colleague was on the right track, but didn't discount his suggestion entirely.

"I don't know of any particular evidence that would point to a link," said Ruben who teaches dinosaur biology. "It was probably a lot of things working together to cause their extinction. … Extinctions are very complicated. We don't know why animals that lived at the same time people lived went extinct. Dinosaur extinction, we're talking about 65 million years ago."

Poinar said bug problems were just one factor in the extinction of dinosaurs. Combined with climate change, ocean regressions and volcanic activity, insects may have led to the end of the prehistoric giants.

Even 100 million years ago, bugs were pests. Poinar studied bugs trapped in amber that bore diseases and even pathogens from cold-blooded vertebrates. And some of those vertebrates likely were dinosaurs, he said.

Poinar also said that insects also would have competed for the same plant food sources, and led to the rise of flowering plants, which pushed aside species such as ferns that some dinosaurs relied on.

Ruben said many dinosaurs flourished after the rise of flowering plants, however. "There's no evidence that dinosaurs were dying from disease based on the bones," he said.

Poinar, 71, is a courtesy professor at OSU. He isn't paid, but he is a member of the zoology department and gets to use OSU facilities for his research.

He's been studying amber for about 30 years, and he and his wife have worked on two previous books about the orange, often translucent substance, and he also wrote another book solo.

In a separate development, Poinar and OSU researchers recently identified a soldier beetle, preserved almost perfectly in amber, that was using chemical repellents to fight off an attacker when an oozing flow of sap engulfed it.

"This was a really interesting find, because it not only doubled the age of this particular group of beetles, but it showed that insects had already developed chemical warfare 100 million years ago," Poinar said.

The findings were just published in the Journal of Chemical Ecology.

"We're investigating the ancient life, what the ancient ecosystem was like, by looking at various bugs and flowers from various parts of the world," Poinar said.

Kyle Odegard covers Oregon State University. He can be contacted at kyle.odegard@lee.net or 758-9523.