How Flies See The World
The neural code in the fly brain continuously adapts to environmental conditions
Our visual system is extremely good at recognizing objects under the most diverse conditions. For example, we can detect people on the side of the road in bright sunlight as well as on cloudy days. We can also see the direction they are moving in, no matter if they are walking in front of a white wall or a crowded bus stop. However, what the eye and the brain seem to do with apparent ease is a great challenge for automated systems with computer-aided image processing. Researchers from the Max Planck Institute of Neurobiology in Martinsried have now discovered how the fly brain tackles this problem: The neurons constantly change their sensitivity depending on the contrast of the current environment. A comparison between neighboring cells then reveals an optimum that allows for the best possible transmission of visual information.
The fly brain uses a simple but effective algorithm to calculate movement under varying contrast conditions.
A fly brain consists of about 100,000 nerve cells, of which approximately 25,000 are involved in the perception of motion. Compared to brains of vertebrates, the number is rather small. Nevertheless, many parallels have been found between visual systems of such distinct animals as flies and, for example, mice. The great advantage of a fly brain is, however, that neurobiologists are able to decipher the system cell by cell.
Male House Flies Are Constantly Looking For A Date
Remember, in Fact 6, when we discussed the compound eyes of a fly? Well, they also play a role in how houseflies find a partner.
Studies show that theres a specific region within the eyes of a male fly called the “love spot.” It is pretty much used for detecting and chasing female flies. This “spot” is located within the dorsofrontal region of their eyes. This is typically used to detect small target motion, however, males also use it to stay locked onto potential mates during aerial pursuit.
The Bottom Line: Do Insects Feel Pain
This article, for me, was one of those really weird articles where I think my opinions changed while doing research for the article. The typical position of entomologists is that insects feeling pain is pretty unlikely. In the past, Ive argued a position stronger than the one that Bova argues in his pieceone which was based upon the information similar to what Bova received during his undergraduate training.
However it now appears to me that a lot of the pathways insects use to not only sense injury, but interpret these experiences, and respond to that injury are a lot more similar to my pathways than I had originally realized. The paper on hornworm responses to pain was something I was unaware of, and have never had the opportunity to observe in person. The grooming behavior is what interests me, and it doesnt seem to have been addressed further in the literature.
So based on all of this new information, my response has gone from outright skepticism to something more akin to:
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Do Flies Dream At Night
Around the turn of the last century, it was discovered that flies have a period of several hours a day when they are inactive.
What wasnt known was what this inactivity truly meant. Was it sleep in the way we know it?
When humans sleep, our brain activity changes. We cycle back and forth through phases of deep sleep and a wake-like sleep .
Dr van Swinderen wanted to know whether flies also have sleep stages. But studying sleep in flies presented another interesting set of challenges.
Unlike humans, you cant watch for the droop of an eyelid flies dont have eyelids. You cant wait until they curl up somewhere to know they are asleep flies dont have a typical sleeping posture. If a fly is standing around not moving, it could be asleep, or quietly awake contemplating the universe.
So, how can we know that a fly is asleep?
Dr van Swinderens solution was the DART machine.
Specially designed by his team, the Drosophila ARousal Tracking system uses cameras and small motors to track the movement of several individual flies, each contained in its own glass tube.
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Watch the video tracking fly movements in the DART machine.
Watch the video tracking fly movements in the DART machine.
We found flies that were still for 1520 minutes were harder to wake up than flies that had been immobile for five minutes, Dr van Swinderen said.
Flies were looking more and more like us with every discovery.
Information Processing Is Teamwork
As an important part of their investigation, the researchers presented the flies with rotating movies of landscapes at varying contrasts. Thanks to an innate behavior, flies react to the optic flow of such images by following with a rotation of their own, matching the speed and the direction of the scene. “By observing the rotation of the flies, we can see how well they can resolve the movement and the speed of the surrounding image,” explains Drews. “Using this information, we were able to investigate the reactions of individual neurons to different contrast ratios.”
The investigation demonstrated that the fly brain has a built-in feedback loop for contrast comparison, implemented right at the beginning of light stimulus processing. If a neuron perceives a high contrast, it first compares this value with the value from its neighboring cells. If the ambient contrast is low in comparison to the center contrast, the nerve cell responds strongly. If the ambient contrast is higher, the response of the cell is weaker.
The fly visual system thus encodes contrast only in relation to the ambient contrast. “Through this mechanism, the visual system constantly adapts its contrast sensitivity to the given environmental contrast,” explains Leonhardt. “This results in a robust information transmission that works equally well under almost all conditions.”
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Interesting Facts About Flies You Never Knew
can be a big nuisance to anyone and their constant buzzing around can really get on your nerves. For businesses, particularly those in the food and pharmaceutical industries, they can be a huge concern due to the impact they can have on consumer health.
However, flies can be quite fascinating creatures. Their breeding, feeding, and even moving habits are quite different from ours and can actually be quite interesting.
If you have a problem with a fly infestation around your business or home, contact to discuss fly removal and fly prevention solutions.
Structure Of A Compound Eye
Compound eyes are made up of thousands of individual visual receptors, called ommatidia. Each ommatidium is a functioning eye in itself, and thousands of them together create a broad field of vision for the fly. Each ommatidium is a long, thin structure, with the lens on the outer surface of the eye, tapering to a nerve at the eye’s base. When the ommatidium receives light, it is filtered through the lens, then a crystalline cone structure, pigment cells and visual cells. Every ommatidium has its own nerve fiber connecting to the optic nerve, which relays information to the fly’s brain.
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Screening For Sleep Mutants In Drosophila
The demonstration that Drosophila sleeps is very important because it supports the notion that sleep fulfills some fundamental functions in many divergent animal species. However, Drosophila can also benefit sleep research by offering a powerful tool for the genetic dissection of sleep, just as it has benefited research on circadian rhythms. Over the last 7 years our laboratory has embarked on a large-scale mutagenesis screening in search for flies that need little sleep and/or do not show a sleep rebound after sleep deprivation. The final goal is to screen as many single-gene mutations as there are fly genes. So far, we have screened >15,000 mutant lines, many of them carrying a mutation in one single gene. The mutation was caused either by the insertion of a transposon in the fly genome , or by ethyl methanesulfonate . Insertional mutagenesis usually allows rapid identification of the mutated gene by sequencing the flanking sequences from one or both ends of the transposon insertion. However, transposons do not insert at random into the genome, but have preferred hot spots . Chemical mutagenesis with EMS, on the other hand, randomly induces small mutations over the entire genome at a reasonable rate, but the molecular characterization of the gene of interest may be not as straightforward.
House Flies Defecate A Lot
And they arent too worried about where they do it either!
As you know, house flies like to live off a liquid diet. Because of this, their digestive system can move quite quickly, which means they defecate often. It is speculated that house flies defecate every time they land, even if its on their next meal!
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Fruit Flies And Mosquitos Are Brainier Than Most People Suspect Say Scientists Who Counted The Bugs Brain Cells
Findings provide baseline number of brain cells likely needed for complex behaviors
Whole brain of a fruit fly. Nuclei of neurons in fruit fly brain tissue. Credit: Joshua Raji and Christopher Potter, Johns Hopkins Medicine.
In research made possible when COVID-19 sidelined other research projects, scientists at Johns Hopkins Medicine meticulously counted brain cells in fruit flies and three species of mosquitos, revealing a number that would surprise many people outside the science world.
The insects tiny brains, on average, have about 200,000 neurons and other cells, they say. By comparison, a human brain has 86 billion neurons, and a rodent brain contains about 12 billion. The figure probably represents a floor for the number needed to perform the bugs complex behaviors.
Even though these brains are simple , they can do a lot of processing, even more than a supercomputer, says Christopher Potter, Ph.D., associate professor of neuroscience at the Johns Hopkins University School of Medicine. They enable the insects to navigate, find food and perform other complicated tasks at the same time, and our study offers one answer to the question of how many brain cells come together to conduct these behaviors, Potter adds.
Results of the research are summarized May 14 in PLOS ONE.
Raji and Potter found that the brain cells in each species contained mostly neurons about 90%. The rest are most likely supportive cells called glia, they say.
Functions Not Controlled By The Brain
The;insect;brain controls only a small subset of functions required for an insect to live. The stomodaeal nervous system and other ganglia can control most body functions independent of the brain.
Various ganglia throughout the body control most of the overt behaviors we observe in insects. Thoracic ganglia control locomotion, and abdominal ganglia control reproduction and other functions of the abdomen. The subesophageal ganglion, just below the brain, controls the mouthparts, salivary glands, and movements of the neck.
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Big Data And Your Brain
You may have heard about how big data is helping scientists come to terms with things they could have never realized so quickly without the collective resources and efficient approach that big data offers.
Scientific initiatives that previously would have been mere what if scenarios, are now becoming realities, thanks to what big data can do.
Recently, scientists in Taiwan have proven the capabilities of this emerging technology, using it to reverse-engineer the brain of the fruit fly by focusing on individual neurons. Lets take a look at this particular project and how it could offer insight for ongoing similar research for human brains.
Understanding More About How Fruit Flies Brains Operate
The brain mapping project, led by neuroscientist Ann-Shyn Chiang at the National Tsing Hua University, allows scientists to target individual brain cells and zoom back out to see how the cells relate to complex nerve bundles. They can do all this using nothing more than computer mice and web browsers. Even better, the resulting brain diagrams are detailed enough that scientists can tell which clusters of cells are responsible for specific behaviors in a fruit fly.
Then, they can hone in on a specific neural circuit and trigger a fruit fly to turn its head or flap a wing. These feats were recently showcased to the scientific community at the yearly meeting for members of the Society for Neuroscience.
The brain mapping process has not been a speedy one. The team of scientists has created images for 60,000 neurons, and each cell is one gigabyte in size. Although thats quite an achievement, it has required a decade of hard work and the scientists have not even tackled half the nerve cells in the fruit flys brain.
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Can We Make Anaesthetics Even Safer
Dr van Swinderen does not wish people to be alarmed by this finding, emphatically supporting that todays anaesthetics are safe. His findings could explain, however, why the anaesthetics of 100 years ago were much less so.
The hypothesis were working on is that the safe anaesthetics we use today put you to sleep nicely first, as a courtesy in a way, then they hit you on the head to allow surgery to proceed, he said.
In contrast, it could be that the dangerous anaesthetics of old, like chloroform, just hit you on the head. A significant number of people didnt recover from chloroform.
His findings are being welcomed by those in the medical community, and he was invited to share his findings at the 2018 International Society for Intravenous Anaesthesia in Malaysia.
I think many of the anaesthetists were interested to find out what the drugs they were administering actually do, he says.
Weve been using general anaesthetics for almost 200 years, but we still didnt really know.
Dr van Swinderens team is now working to better understand which general anaesthetics cause more of a sleep effect and which cause more of the neural communication effect.
Alongside reducing side effects like nausea or recovery complications, this change could make general anaesthetics even safer for people whose neural communication is vulnerable like children whose connections are still growing, or those with dementia who are losing connections.
What Flies And Worms Have In Common
- ETH Life
- Researchers have, for the first time, compared the proteomes of two different multi cellular organisms. They found surprising correlations between two animals that, at first sight, couldn’t be more different.
Researchers at ETH Zurich and the University of Zurich have, for the first time, compared the proteomes of two different multi cellular organisms. They found surprising correlations between two animals that, at first sight, couldnt be more different.
In a new publication in PloS Biology, researchers at the University of Zurich and ETH Zurich have, for the first time, undertaken a comparison of the proteomes of two different multi cellular organisms. The researchers compared the protein catalogue of the tapeworm Caenorhabditis elegans with that of the fruit fly Drosophila melanogaster.
This comparison was possible because, over the past few years, the researchers have been cataloguing the flys proteins, with the data being systematically collected in Zurichs specialist centre for proteome analysis, the Center for Model Organism Proteomes at the University of Zurich.
Investigating the worm
The protein catalogue for the fruit fly was also sourced from a previous study published in 2007. In this study, an international team of researchers, including members of the University of Zurich and ETH Zurich, were able to record and index nearly two thirds of the predicted Drosophila melanogaster proteome a total of over 9,100 proteins.
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They Are Smart And Have A Considerable Ability To Memorize
- B.A., Political Science, Rutgers University
Even tiny insects have brains, though the insect brain does not play as important a role as human brains do. In fact, an insect can live for several days without a head, assuming it does not lose a lethal amount of hemolymph, the insect equivalent of blood, upon decapitation.
Time Passes More Slowly For Flies Study Finds
Flies avoid being swatted in just the same way Keanu Reeves dodges flying bullets in the movie The Matrix by watching time pass slowly.
To the insect, that rolled-up newspaper moving at lightning speed might as well be inching through thick treacle.
Like Reeves standing back and side-stepping slo-mo bullets, the fly has ample time to escape. And it is not alone in its ability to perceive time differently from us. Research suggests that across a wide range of species, time perception is directly related to size.
Generally the smaller an animal is, and the faster its metabolic rate, the slower time passes.
The evidence comes from research into the ability of animals to detect separate flashes of fast-flickering light.
“Critical flicker fusion frequency” the point at which the flashes seem to merge together, so that a light source appears constant provides an indication of time perception. Comparing studies of the phenomenon in different animals revealed the link with size.
“A lot of researchers have looked at this in different animals by measuring their perception of flickering light,” said Dr Andrew Jackson, from Trinity College Dublin in the Republic of Ireland. “Some can perceive quite a fast flicker and others much slower, so that a flickering light looks like a blur.
“It’s tempting to think that for children time moves more slowly than it does for grownups, and there is some evidence that it might,” he said.
The Lifespan Of A House Fly Isnt That Long
On average, the life cycle of a house fly only lasts for around 30 days, which means they dont live for long at all.
However, in their short lifetime, they manage to accomplish quite a lot. House flies can lay up to 500 eggs in their lifetime which are usually in batches of around 75 to 150. So, although they dont live long, an infestation can quickly arise through new generations.