From schools of fish, to herds of antelope and even human societies, one of the group’s many advantages is its inherent safety. Surrounded by their peers, individuals can lower their vigilance and calmly engage in other activities, such as foraging, or watching youtube videos.
But the Safety in Numbers rule has more to it than just being together. In many cases, communication also plays a big role. Social cues of danger are fairly well known. Just think about the different ways animals use to convey the presence of a threat. Shrieks, yelps and barks immediately come to mind.
Now, how about naming a few examples of social cues of safety? After all, knowing that the danger has passed is important for lowering one’s defences and resuming other activities. The reason this task is more challenging is because it’s actually a trick question – no social safety cues have been identified until now.
Remarkably, the discovery of the first social safety cue was made thanks to a tiny insect: the fruit fly. These results, published (August 21st) in the scientific journal Nature Communications, mark a new phase in our understanding of how social communication works.
A silent sign of danger
“When people think about social communication of danger, they normally think about alarm calls”, says Marta Moita, a principal investigator at the Champalimaud Centre for the Unknown in Portugal. “But we are interested in a different type of threat cue, the expression of the defensive behaviours themselves.”
Freezing is one of the three universal defence responses, together with fight and flight. This response is the best course of action in situations where escape is either impossible or less advantageous than just staying still with the hope of remaining unnoticed.
“Freezing may actually be a safer way of conveying the existence of danger to others”, Moita points out. “This manner of social communication does not require the active production of a signal that may result in drawing unwelcome attention. Also, freezing may constitute a public cue that can be used by any surrounding animal regardless of species”, she explains.
Moita’s team has recently demonstrated that individual fruit flies freeze in response to an inescapable threat. This finding triggered their curiosity, would this behaviour change if there other flies were around?
Safety in (exactly how many) numbers
To answer this question, Clara Ferreira, the lead author of the study, proceeded with a systematic set of experiments, beginning with one fly, then two, three, and so forth, up to groups of ten.
“We placed the flies in a transparent closed chamber and repeatedly exposed them to an expanding dark disc, which mimics an object on a collision course. Just imagine the visual effect of an approaching open palm”, Ferreira explains. “Many visual animals that are exposed to such a stimulus respond defensively, including humans. If they freeze, they often stay motionless for quite some time, even after the threat is gone.”
Their results revealed that group size matters. “All groups – from two to ten – froze less than individual flies. However, we were surprised to find a complex effect of group size on the flies’ behaviour”, says Ferreira.
In groups of six and more, the flies froze transiently when the threat appeared and then resumed movement once it was gone. On the other hand, the flies’ response pattern in groups of five or less was more similar to that of individual flies.
“Flies in those groups still froze less than single flies. However, their freezing time increased as the experiment progressed. The more repetitions of the threatening stimulus they experienced, the longer they would remain motionless when it reappeared”, Ferreira explains. “These results were very intriguing”, she adds. “This was the first time the effect of group size on freezing was systematically characterised in any species and it revealed a fascinating and intricate relation.”
Should I stay or should I go?
These findings clearly demonstrated that flies change their defensive responses when others are present. This novel observation raised a pressing question – what social cues were the flies responding to? To find the answer, Ferreira and Moita meticulously analysed their previous results and conducted additional experiments using blind flies and controllable magnetic “dummy flies”.
The results revealed a two-part answer. “The first part describes the flies’ response to the appearance of the threat”, Ferreira recounts. “We learned that an individual fly was more likely to enter freezing if its peers (magnetic or otherwise) froze in response to the threat. We were somewhat expecting to see this. Previous studies in the lab showed that in specific situations, freezing is a social cue of danger in rats. Here, we witnessed a similar behaviour in flies.”
The second part of the answer, however, caught the researchers by surprise: flies were more likely to exit freezing if others began to move. “This means that flies were using the resumption of movement as a social cue of safety!”, Ferreira points out.
“This is a completely novel phenomenon”, Moita adds. “There are many types of recorded social alarm cues, but this is the first social safety cue to be identified in any animal species. It also pins down movement as the social cue we were searching for. In a sense, this cue ‘kills two birds with one stone’: the sudden cessation of movement signifies danger, whereas its resumption signifies safety.”
Next stop – the brain
Moita and Ferreira’s series of striking discoveries opens a unique opportunity to learn how the brain perceives and responds to social cues. “The fruit fly is one of the most powerful animal models used in scientific research nowadays”, says Ferreira. “It offers specialised tools to study neurobiology in a very specific and targeted manner.”
Indeed, the authors have already begun unraveling the neural basis of this behaviour. “In this project, we identified a set of visual neurons that are crucial for perceiving the movement of others as a safety cue”, Ferreira explains. “And we are planning to continue investigating the neural circuits involved.”
As Moita points out, even though flies and humans are different, there are parallels across these and other species that may make findings in the fly relevant for revealing general principles. “Since we are studying a fundamental behaviour spanning almost all of animal life – the tendency to seek safety in numbers – we believe that our work paves the way for understanding conserved mechanisms in other animals”, she concludes.
Ferreira et al. Behavioral and neuronal underpinnings of safety in numbers in fruit flies, Nature Communications (2020). DOI: 10.1038/s41467-020-17856-4
This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.
Tla'amin Nation COVID-19 survivor warns virus spreads easily and recovery is difficult – Yahoo News Canada
Brandon Peters was keeping his bubble small this summer.
The Vancouver resident planted a “COVID garden” and planned on playing it as safe as possible during the pandemic. Those plans were derailed, and so was his health, after attending the funeral of a loved one on Tla’amin Nation territory on the north Sunshine Coast near Powell River, B.C.
Peters, a member of the nation, was diagnosed with COVID-19 within days of the visit. After spending most of September in bed fighting the virus, he is now speaking out publicly to warn people just how hard that fight can be.
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content=""I opened myself up for just a minute, a couple people hugged me, and I got sick within a couple of days," said Peters Thursday on On The Island.” data-reactid=”15″>”I opened myself up for just a minute, a couple people hugged me, and I got sick within a couple of days,” said Peters Thursday on On The Island.
He said when he left the north Sunshine Coast, he was so overcome with fatigue he could not complete the 80 kilometre drive to the Langdale Ferry Terminal to catch a ferry to the Lower Mainland. Instead, he had to pull over and sleep.
Peters did make it back to Vancouver though, only to have a horrible night where he said he felt “deep pain” throughout his body and had an excruciating headache.
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Down for the count” data-reactid=”18″>Down for the count
The next day he got tested for COVID-19. The day after that, he learned he was positive.
For the next few weeks, Peters lay in bed so overcome with exhaustion he said he couldn’t eat anything and drank only water.
“The fatigue was so intense I would have to gather my gumption just to go to the washroom,” he said.
In a recently uploaded video on the Tla’amin Nation’s Facebook page, Peters says he wondered every day while bed-ridden if he was going to make it to see another week.
Fortunately, Peters was never hospitalized and says he now has about 80 per cent of his strength back. Now he wants to tell others his story to try and prevent anyone from going through the harrowing ordeal he did — or worse.
The video is part of sharing that story.
“People might look at me like a leper over the next little while but I think if I help a couple people it will make the video worthwhile,” said Peters.
He said it is important to him that people take the risks of the virus seriously and stop engaging in activities that could put themselves or others at risk.
“This is going to be with us for a while and we need to make those responsible decisions.”
According to a media release from the Tla’amin Nation, there have been 36 positive COVID-19 cases reported in the nation since September 7.
The community is currently in a state of local emergency and non-approved visitors are restricted from Tla’amin land.
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="To hear the complete interview with Brandon Peters on On The Island, tap here.” data-reactid=”30″>To hear the complete interview with Brandon Peters on On The Island, tap here.
NASA says bus-sized asteroid safely buzzed Earth | TheHill – The Hill
NASA reported that an asteroid roughly the size of a school bus passed by Earth early Thursday morning, traveling from about 13,000 miles away.
According to the government space agency, the rock made its closest approach to Earth around 7 a.m. EDT on Thursday, passing over the Southeastern Pacific Ocean.
NASA first reported on the asteroid on Tuesday, saying that scientists estimated the space rock was about 15 to 30 feet wide. Scientists predict that the asteroid will now travel around the sun and not make its way back into the Earth’s vicinity until 2041.
A small near-Earth asteroid about the size of a small school bus will safely zoom past our planet around 13,000 miles (21,000 km) above the surface. The space rock will then make its way around the Sun, passing Earth again at a farther distance in 2041. https://t.co/z6uDogXn52 pic.twitter.com/c9Xv4PhNFi
— NASA JPL (@NASAJPL) September 23, 2020
Paul Chodas, director of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in Southern California, said Tuesday that space rocks such as these are relatively common and are not considered a threat to life on Earth.
“There are a large number of tiny asteroids like this one, and several of them approach our planet as close as this several times every year,” Chodas said. “In fact, asteroids of this size impact our atmosphere at an average rate of about once every year or two.”
He added that “the detection capabilities of NASA’s asteroid surveys are continually improving, and we should now expect to find asteroids of this size a couple days before they come near our planet.”
2020 SW, discovered by @Catalina_sky, is about 15 to 30 ft. wide and will pass by Earth Thurs., Sept. 24, at a distance of about 13,000 miles (22,000 km). Tiny asteroids like 2020 SW approach Earth this closely several times every year and aren’t a threat: https://t.co/xKWtzxLI7Q pic.twitter.com/FpkY77zibw
— NASA Asteroid Watch (@AsteroidWatch) September 23, 2020
NASA said that while Thursday’s asteroid was not on a trajectory to hit Earth, it would have likely broken up in the atmosphere and become a bright meteor, known as a fireball, before causing any damage.
This comes a month after NASA reported that an asteroid is on a path toward Earth one day before the U.S. presidential election, although the agency said that the chances of it actually hitting the Earth’s surface are less than 1 percent. NASA confirmed in a statement to The Hill last month that the rock would not pose a threat.
“If it were to enter our planet’s atmosphere, it would disintegrate due to its extremely small size,” a spokesperson said in the statement. “NASA has been directed by Congress to discover 90% of the near-Earth asteroids larger than 140 meters (459 feet) in size and reports on asteroids of any size.”
UM physicists part of international team for historic first – UM Today
September 24, 2020 —
UM researchers on an international team of physicists have made the first precise measurement of the weak force between particles in the universe, verifying a theory of the Standard Model of Particle Physics.
Using a device called the the Spallation Neutron Source at the U.S. Department of Energy’s Oak Ridge National Laboratory, the scientists were able to measure the weak force exerted between protons and neutrons by detecting the miniscule electrical signal produced when a neutron and a helium-3 nucleus combined and then decayed moving through a target.
The Standard Model describes the basic building blocks of matter in the universe and fundamental forces acting between them. Calculating and measuring the weak force between protons and neutrons is an extremely difficult task.
Their finding yielded the smallest uncertainty of any comparable weak force measurement in the nucleus of an atom to date, which establishes an important benchmark.
UM physicist Dr. Michael Gericke said:
“When a neutron and a helium-3 nucleus combine, the reaction produces an excited, unstable helium-4 isotope, decaying to one proton and one triton (consisting of two neutrons and one proton), both of which produce a tiny but detectable electrical signal as they move through the helium gas in the target cell.”
Gericke led the group that built the combined helium-3 target and detector system designed to pick up the very small signals and led the subsequent analysis.
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