46-million-year-old mosquito filled with blood is a scientific first (+video)
Scientists have described the first-ever fossil to be found with a blood meal inside its abdomen - a highly improbable find.
In 1993, a fictional scientist plucked dinosaur DNA from an amber-wrapped mosquito flush with its last victim’s blood. He used it to furnish an entire island with dinosaurs and called it, of course, Jurassic Park. Cinematic chaos ensued.Skip to next paragraph
Subscribe Today to the Monitor
This scenario is not possible, outside of cinema, for two reasons. The first is that DNA has a half-life of 521 years and degrades to be un-readable after about 1.5 million years. So, the upshot is that dinosaur DNA in a mosquito’s fossilized blood meal has been reduced to nil millions of years before humans even existed. There is no getting around this.
The second is that no real life scientist had ever even found a fossilized mosquito bloated with blood. In fact, the odds of that happening are so infinitesimal, and the set of circumstances that would have to occur is so peculiar, that such a find was thought to be as good as impossible.
But a new paper published this week clarifies that finding a blood-filled mosquito is not, in fact, impossible – it’s just improbable. Writing in Proceedings of the National Academy of Sciences, scientists have described the first ever fossil to be found with a blood meal inside its abdomen. The 46-million-year-old mosquito contains heme, a chemical compound found in hemoglobin, the protein in red blood cells, and it is the first conclusive, direct evidence of blood feeding in ancient insects.
“It’s a one in a billion chance,” says Dale Greenwalt, a researcher at the Smithsonian Institution National Museum of Natural History, in Washington, DC, and the lead author on the paper.
Blood feeding, or hematophagy, is found in five orders of modern insects that, combined, include some 14,000 species. Though scientists have long known that insects practiced hematophagy at least some 100 million years ago, the evidence had been circumstantial: fossilized mosquitoes had been found with long proboscises – the tubes that females use to dip into an animal’s veins – in a morphological indication that the species fed on blood. Just four described insect fossils offer evidence of blood feeding more direct than morphological clues, including a 95-million-year-old sand fly from Myanmar, which had parasites in its gut that associated it with blood feeding.
“We’ve known for a long time that blood feeding is very ancient,” says Dr. Greenwalt. “We just we haven’t been able to prove it.”
That’s because the odds that an insect would have died with a blood feast inside it are slim. And the odds that such an insect would die in just the right place that it could be preserved for millions of years and then, in a critical last step, be found, are preposterously slim.