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.
Heliconius numata (top) mimics the wing
pattern of Melinaea mneme (bottom).
What’s the News: A single species of butterfly in the Amazon is able to copy the wing patterns of several neighboring species to avoid being eaten by hungry birds—a wide-ranging talent that has long perplexed evolutionary biologists. Now, an international team of scientists studying the mimicking butterfly Heliconius numata has finally solved this puzzle that plagued even Charles Darwin.
Writing in the journal Nature, researchers found that a specific supergene—a cluster of genes that is passed on to offspring as one big chunk—controls the different elements of wing patterns, allowing related butterflies to display distinct markings despite having the same DNA. “These butterflies are the ‘transformers’ of the insect world,” lead researcher Mathieu Joron said in a prepared statement. “But instead of being able to turn from a car into a robot with the flick of switch, a single genetic switch allows these insects to morph into several different mimetic forms.”