A 230-million-year-old mite preserved in amber
An insect trapped in amber, perfectly preserved for millions of years: the image is familiar to fans of Jurassic Park, but in fact, few insects got stuck in sticky tree resin until about 130 million years ago—long after the Jurassic period ended. That’s when trees first began to produce enough of it to ensnare flies and mites.
Or so paleontologists believed. Three newly discovered bugs in amber may force a revision of that timeline. As a new study reports in Proceedings of the National Academy of Sciences, these specimens are 230 million years old.
The researchers discovered the creatures while doing a survey of the lifeforms encased in 70,000 droplets, each just a few millimeters in diameter. The amber comes from the Heiligkreuz Formation in northeastern Italy, and it contains plenty of microorganisms, such as bacteria and algae, that make it clear that the droplets formed during the Triassic era, 250 to 200 million years ago.
Within three pieces of amber, researchers were delighted to find three tiny creatures: an ancient nematoceran fly and two eriphyoid mites, the ancestors of modern plant parasites. While these ancient specimens help clarify insect and mite evolution, they also muddy up the timeline of tree development. If 230-million-year-old trees at this site could produce enough resin to ensnare these fellows, does this mean that other Triassic trees had that capability?
Not necessarily. Because bugs this old have only been found in amber at a single location, it’s more likely that an unusual local change stimulated the trees to make extra resin. Perhaps, the paper’s authors suggest, there was a shift in local climate, or perhaps an infestation of mites, like these ones, triggered the tree’s resin production.