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Why Mosquitoes Evolved to Like Us
Humans weren't a part of the mosquito's diet thousands of years ago, and researchers have isolated the genes to prove it.
You may be surprised to hear that mosquitoes didn't always rely on human blood for nourishment—they evolved to sniff out your scent not too long ago (by evolutionary standards). Steve Connor of The Independent wrote on the recent study that explains how the parasite transitioned thousands of years ago from furry mammals to us.
Researchers have found 14 genes in the mosquito genome that are directly linked to a love of human blood and odor. One particular receptor, Or4, is highly active in mosquitoes with a taste for humans. This receptor is able to pick up unique chemical vapors our skin releases. Researchers were able to isolate the chemical sulcatone as one of the scents that attracts the bugs when we step a foot outside our door. Mosquitoes learned to recognize this smell and knew they were near a food source.
The study noted there was a divergence in the evolutionary line that exists today in Rabai, Kenya where one set of black-bodied mosquitoes that feed on furry forest animals have no preference for the sulcatone smell. But brown-bodied mosquitoes that inhabit villages in Africa are quite receptive to the stuff. These two subspecies live just hundreds of meters apart.
Leslie Vosshall of Rockefeller University in New York, led the study that was published in the journal Nature. She explained why the mosquitoes adapted to humans as a food source all those years ago:
“It was a really good evolutionary move. We provide the ideal lifestyle for mosquitoes. We always have water around for them to breed in, we are hairless and we live in large groups.”
“There’s a whole suite of things that mosquitoes have to change about their lifestyle to live around humans. This paper provides the first genetic insight into what happened thousands of years ago when some mosquitoes made this switch.”
Read more at The Independent
Photo Credit: mycteria/Shutterstock
A Mercury-bound spacecraft's noisy flyby of our home planet.
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
Erin Meyer explains the keeper test and how it can make or break a team.
- There are numerous strategies for building and maintaining a high-performing team, but unfortunately they are not plug-and-play. What works for some companies will not necessarily work for others. Erin Meyer, co-author of No Rules Rules: Netflix and the Culture of Reinvention, shares one alternative employed by one of the largest tech and media services companies in the world.
- Instead of the 'Rank and Yank' method once used by GE, Meyer explains how Netflix managers use the 'keeper test' to determine if employees are crucial pieces of the larger team and are worth fighting to keep.
- "An individual performance problem is a systemic problem that impacts the entire team," she says. This is a valuable lesson that could determine whether the team fails or whether an organization advances to the next level.