Bedbugs sucked blood in the age of dinosaurs
Despite the moniker, bedbugs evolved long before mattresses and even survived the K-T extinction.
- Scientists originally thought bedbugs evolved on bats roughly 50 million years ago.
- New research used DNA to map the bedbug ancestry and found the species evolved as far back as the Cretaceous.
- The researchers hope that understanding how bedbugs evolve will help us curb their ability to spread and transmit diseases to people.
An international team of scientists have been on a quest. They have traveled to Africa, South America, and South East Asia. They have scaled cliff faces, explored shadow-stained caves, bushwhacked through sweltering jungles, and dodged dangerous wildlife. What treasure did they seek: a golden idol, an ancient codex, a city lost to time?
Nope. They endured all this to procure a blood-sucking parasite that most of us can't wait to be rid of: bedbugs. For 15 years, these scientists traveled the world collected specimens of the family Cimicidae. Their goal was to create a molecular phylogeny — essentially a bedbug ancestral tree mapped through DNA analysis.What they found surprised them.
Bedbugs: Our Mesozoic bedfellows
A bedbug ingests its bloody meal on a human host. Though we do all we can to be rid of them, bedbugs survived the extinction event that wiped out the dinosaurs. (Photo: CDC/Wikimedia Commons)
Bedbugs were previously thought to have evolved with bats, their most common, and long-assumed first, hosts. This origin story kick-starts the bedbug lineage roughly 50 million years ago.
To learn more about these infectious pests, researchers began collecting as many bedbug species they could. Natural history museums and colleagues donated some specimens, but others had to be obtained in the field.
Over the course of 15 years, the scientists traveled the world collecting bedbugs from their natural hosts. These travels took them in proximity to dangerous wildlife like buffalo and leopards, not to mention a few wadings through knee-high guano. In the end, they collected 34 Cimicidae species from 62 locations.
After mapping their molecular phylogeny, the team discovered that bedbugs evolved about 115 million years ago. This new lineage predates bats by about 50 million years, stretching back into the Cretaceous period. Bedbugs roamed the earth alongside dinosaurs such as Triceratops, Velociraptor, and Tyrannosaurs rex.
The team published their results in Current Biology earlier this month.
"To think that the pests that live in our beds today evolved more than 100 million years ago and were walking the earth side by side with dinosaurs was a revelation. It shows that the evolutionary history of bedbugs is far more complex than we previously thought," Professor Mike Siva-Jothy, study co-author from the University of Sheffield's Department of Animal and Plant Sciences, said in a release.
This also means that bedbugs survived the K-T extinction event, the cataclysmic end of the Mesozoic era that saw the extinction of approximately 70 percent of all species living at the time, including, of course, dinosaurs. This puts bedbugs in league with nature's other K-T survivors and all-around badasses sharks, crocodiles, cockroaches, and the platypus.
Did bedbugs nosh on T-rex?
Probably not. While bedbugs evolved alongside the king of the thunder lizards, they likely didn't feed on its blood or any other dinosaur species. As the researchers point out, bedbugs and their relatives favor hosts who have "homes": birds with their nests, bats with their roosts, and humans with their beds. Dinosaurs likely employed a drifter lifestyle, and so wouldn't have been a favored host.
But if neither bats nor dinosaurs were the bedbug's original host, who was? We don't know. The species original host remains elusive.
If that answer is unsatisfactory, take heart that avian dinosaurs — or, as they are commonly known, birds — remain a potential candidate.
Others believe bats, or a bat ancestor, are still in the mix. "The fossil record for [both bed bugs and mammals] are patchy…that makes it hard to make definitive statements," Jessica Ware, an entomologist and evolutionary biologist at Rutgers University, told PBS. "It's possible bats are older, and we've just underestimated."
Evolving pest control
The researchers then used their data to explore the frequency at which bedbugs jump from one host to another. Broadly speaking, some bedbugs become specialized to a single host, but others are more generalized and able to jump between hosts.
The bedbugs that pester humans, Cimex lectularius and Cimex hemipterus, are just two of more than 100 Cimicidae species. These human-gorging bedbugs were thought to have diverged around the time our species entered the game of life — as is true of other human parasites such as lice.
However, the data showed that these bedbugs had evolved already, likely on bats. They opportunistically began snacking on slumbering humans when our species began using caves as dwellings. Throughout our shared history, a new bedbug species has jumped to human hosts about every 500,000 years. However, the way humans have reshaped our environments may speed up that pace.
"These species are the ones we can reasonably expect to be the next ones drinking our blood, and it may not even take half a million years, given that many more humans, livestock, and pets that live on earth now provide lots more opportunities," Professor Klaus Reinhardt, study co-led and bedbug researcher at Dresden University, said in the same release.
According to Siva-Jothy, the team hopes their findings will allow us to better understand the history and abilities of these pests. Understanding their evolution may help us control their ability to spread and transmit diseases to humans.
A large new study uses an online game to inoculate people against fake news.
- Researchers from the University of Cambridge use an online game to inoculate people against fake news.
- The study sample included 15,000 players.
- The scientists hope to use such tactics to protect whole societies against disinformation.
Researchers hope the technology will further our understanding of the brain, but lawmakers may not be ready for the ethical challenges.
- Researchers at the Yale School of Medicine successfully restored some functions to pig brains that had been dead for hours.
- They hope the technology will advance our understanding of the brain, potentially developing new treatments for debilitating diseases and disorders.
- The research raises many ethical questions and puts to the test our current understanding of death.
The image of an undead brain coming back to live again is the stuff of science fiction. Not just any science fiction, specifically B-grade sci fi. What instantly springs to mind is the black-and-white horrors of films like Fiend Without a Face. Bad acting. Plastic monstrosities. Visible strings. And a spinal cord that, for some reason, is also a tentacle?
But like any good science fiction, it's only a matter of time before some manner of it seeps into our reality. This week's Nature published the findings of researchers who managed to restore function to pigs' brains that were clinically dead. At least, what we once thought of as dead.
What's dead may never die, it seems
The researchers did not hail from House Greyjoy — "What is dead may never die" — but came largely from the Yale School of Medicine. They connected 32 pig brains to a system called BrainEx. BrainEx is an artificial perfusion system — that is, a system that takes over the functions normally regulated by the organ. The pigs had been killed four hours earlier at a U.S. Department of Agriculture slaughterhouse; their brains completely removed from the skulls.
BrainEx pumped an experiment solution into the brain that essentially mimic blood flow. It brought oxygen and nutrients to the tissues, giving brain cells the resources to begin many normal functions. The cells began consuming and metabolizing sugars. The brains' immune systems kicked in. Neuron samples could carry an electrical signal. Some brain cells even responded to drugs.
The researchers have managed to keep some brains alive for up to 36 hours, and currently do not know if BrainEx can have sustained the brains longer. "It is conceivable we are just preventing the inevitable, and the brain won't be able to recover," said Nenad Sestan, Yale neuroscientist and the lead researcher.
As a control, other brains received either a fake solution or no solution at all. None revived brain activity and deteriorated as normal.
The researchers hope the technology can enhance our ability to study the brain and its cellular functions. One of the main avenues of such studies would be brain disorders and diseases. This could point the way to developing new of treatments for the likes of brain injuries, Alzheimer's, Huntington's, and neurodegenerative conditions.
"This is an extraordinary and very promising breakthrough for neuroscience. It immediately offers a much better model for studying the human brain, which is extraordinarily important, given the vast amount of human suffering from diseases of the mind [and] brain," Nita Farahany, the bioethicists at the Duke University School of Law who wrote the study's commentary, told National Geographic.
An ethical gray matter
Before anyone gets an Island of Dr. Moreau vibe, it's worth noting that the brains did not approach neural activity anywhere near consciousness.
The BrainEx solution contained chemicals that prevented neurons from firing. To be extra cautious, the researchers also monitored the brains for any such activity and were prepared to administer an anesthetic should they have seen signs of consciousness.
Even so, the research signals a massive debate to come regarding medical ethics and our definition of death.
Most countries define death, clinically speaking, as the irreversible loss of brain or circulatory function. This definition was already at odds with some folk- and value-centric understandings, but where do we go if it becomes possible to reverse clinical death with artificial perfusion?
"This is wild," Jonathan Moreno, a bioethicist at the University of Pennsylvania, told the New York Times. "If ever there was an issue that merited big public deliberation on the ethics of science and medicine, this is one."
One possible consequence involves organ donations. Some European countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood throughout the body, but use a "thoracic aortic occlusion balloon" to prevent that blood from reaching the brain.
The system is already controversial because it raises concerns about what caused the patient's death. But what happens when brain death becomes readily reversible? Stuart Younger, a bioethicist at Case Western Reserve University, told Nature that if BrainEx were to become widely available, it could shrink the pool of eligible donors.
"There's a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs," he said.
It will be a while before such experiments go anywhere near human subjects. A more immediate ethical question relates to how such experiments harm animal subjects.
Ethical review boards evaluate research protocols and can reject any that causes undue pain, suffering, or distress. Since dead animals feel no pain, suffer no trauma, they are typically approved as subjects. But how do such boards make a judgement regarding the suffering of a "cellularly active" brain? The distress of a partially alive brain?
The dilemma is unprecedented.
Setting new boundaries
Another science fiction story that comes to mind when discussing this story is, of course, Frankenstein. As Farahany told National Geographic: "It is definitely has [sic] a good science-fiction element to it, and it is restoring cellular function where we previously thought impossible. But to have Frankenstein, you need some degree of consciousness, some 'there' there. [The researchers] did not recover any form of consciousness in this study, and it is still unclear if we ever could. But we are one step closer to that possibility."
She's right. The researchers undertook their research for the betterment of humanity, and we may one day reap some unimaginable medical benefits from it. The ethical questions, however, remain as unsettling as the stories they remind us of.
Many governments do not report, or misreport, the numbers of refugees who enter their country.
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