Why Do Flies Rub Their Hands?

Why do flies throw up in their hands?

From poop to plate – When it comes to passing on pathogens, it’s not necessarily the fly itself but where it’s come from that matters. Flies don’t just visit freshly made sandwiches. They spend far more of their time in rotting animal and plant waste. Among this waste can be a range of pathogens and parasites.

House flies don’t bite. Unlike mosquitoes that transmit pathogens of human health importance in their saliva, house flies transmit pathogens on their feet and body. As well as leaving behind pathogen-filled footprints, the flies leave their poop on our food. They vomit too. Flies don’t have teeth. They can’t take a bite out of our food, so they have to spit out some enzyme-rich saliva that dissolves the food, allowing them to suck up the resulting soup of regurgitated digestive fluids and partially dissolved food.

If a fly has plenty of time to walk around on our food vomiting up, sucking in and defecating out, the chances of leaving behind a healthy population of pathogens are high.

Why do flies keep touching you?

O They are attracted to carbon dioxide which human beings breathe out. o They are attracted to the heat of the warm body, to sweat and salt, and the more the person sweats the more flies they attract. o Flies feed on dead cells and open wounds. o Oil is an important food for flies.

Why do flies like to annoy you?

Identifying the Flies – When you think of flies buzzing around your home (or your head), the most common culprit is usually the housefly. These flies are merely a few millimeters long and black in color. But why does the housefly love you and your home? Houseflies LOVE the scent of food, garbage, feces, and other smelly things like your pet’s food bowl.

Why do flies fly up to your face?

Maggie Hardy, The University of Queensland You know the drill. A picnic in the park, a walk in the bush or a barbecue with friends and family – all perfect summer activities that can be ruined by annoying flies that never leave you alone. So why do they do it and what do they want ? Flies are one of the most diverse insect orders, with more than 150,000 species described worldwide in more than 150 different insect families. Pinned down: That’s one way of killing a blowfly. CSIRO, CC BY There are two main types of fly: the Nematocera (which includes mosquitoes and non-biting crane flies) and the Brachycera (which includes house flies, fruit flies, and horse flies). In Australia, there is only one type of fly that’s attracted to us, rather than our blood: the bush fly ( Musca vetustissima, Diptera: Muscidae), which is a non-biting fly and close relative of the house fly ( Musca domestica ).

1. These flies are after the proteins, carbohydrates, salts, and sugars naturally present on your skin.
2. All the other flies around you are probably after your blood, and that includes mosquitoes and horse flies.
3. And yes, unfortunately some people are more attractive to mosquitoes than others.
4. Although mosquitoes and other blood-feeding insects are attracted to the carbon dioxide we exhale, we know the insect sensory system also helps find exposed skin,

Since the skin near our faces is often exposed, that’s one reason flies are always buzzing around your face and hands.

Do flies feel pain?

Other pain indicators – The framework we used to evaluate evidence for pain in different insects was the one that recently led the UK government to recognise pain in two other major invertebrate groups, decapod crustaceans (including crabs, lobsters, and prawns) and cephalopods (including octopuses and squid), by including them in the Animal Welfare (Sentience) Act 2022.

1. The framework has eight criteria, which assess whether an animal’s nervous system can support pain (such as brain-body communication), and whether its behaviour indicates pain (like motivational trade-offs).
2. Flies and cockroaches satisfy six of the criteria.
3. According to the framework, this amounts to “strong evidence” for pain.

Despite weaker evidence in other insects, many still show “substantial evidence” for pain. Bees, wasps, and ants fulfil four criteria, while butterflies, moths, crickets, and grasshoppers fulfil three. Beetles, the largest group of insects, only satisfy two criteria.

1. But, like other insects that received low scores, there are very few studies on beetles in this context.
2. We found no evidence of any insect failing all the criteria.
3. Our findings matter because the evidence for pain in insects is roughly equivalent to evidence for pain in other animals which are already protected under UK law.

Octopuses, for example, show very strong evidence for pain (seven criteria). In response, the UK government included both octopuses and crabs in the Animal Welfare (Sentience) Act 2022, legally recognising their capacity for pain. The UK government set a precedent: strong evidence of pain warrants legal protection.

At least some insects meet this standard, so it is time to shield them. For starters, we recommend including insects under the Animal Welfare (Sentience) Act 2022, which would legally acknowledge their capacity to feel pain. But this law only requires the government to consider their welfare when drafting future legislation.

If we want to regulate practices such as farming and scientific research, the government needs to extend existing laws. For example, the Animal Welfare Act 2006, which makes it an offence to cause “unnecessary suffering” to animals covered by the act.

This may lead to insect farms, like conventional farms, minimising animal suffering and using humane slaughter methods. The Animals (Scientific Procedures) Act 1986 regulates the use of protected animals in any experimental or other scientific procedure that may cause pain, suffering, distress or lasting harm to the animal.

Protecting insects under this act, as octopuses already are, would regulate insect research, reducing the number of insects tested and ensuring that experiments have a strong scientific rationale. Finally, pesticides are a huge welfare concern for wild insects.

Do flies have feelings?

For decades, the idea that insects have feelings was considered a heretical joke – but as the evidence piles up, scientists are rapidly reconsidering. O One balmy autumn day in 2014, David Reynolds stood up to speak at an important meeting. It was taking place in Chicago City Hall – a venue so grand, it’s embellished with marble stairways, 75ft (23m) classical columns, and vaulted ceilings.

• As the person in charge of pest management in the city’s public buildings, among other things, Reynolds was there to discuss his annual budget.
• But soon after he began, an imposter appeared on one of the walls – a plump cockroach, with her glistening black body contrasting impressively with the white paint.

As she brazenly sauntered along, it was as if she was mocking him. “Commissioner, what is your annual budget for cockroach abatement?” one councillor interrupted, according to a report in The Chicago Tribune, Cue raucous laughter and a mad scramble to eradicate the six-legged prankster.

No one would question the cockroach’s impeccable, though accidental, comic timing. But the incident is partly funny because we think of insects as robotic, with barely more emotional depth than lumps of rock. A cockroach that’s capable of being amused or playful – well, that’s just plain absurd. Or is it? In fact, there’s mounting evidence that insects can experience a remarkable range of feelings.

They can be literally buzzing with delight at pleasant surprises, or sink into depression when bad things happen that are out of their control, They can be optimistic, cynical, or frightened, and respond to pain just like any mammal would. And though no one has yet identified a nostalgic mosquito, mortified ant, or sardonic cockroach, the apparent complexity of their feelings is growing every year.

When Scott Waddell, professor of neurobiology at the University of Oxford, first started working on emotions in fruit flies, he had a favourite running joke – “that, you know, I wasn’t intending on studying ambition”, he says. Fast-forward to today, and the concept of go-getting insects is not so outrageous as it once was.

Waddell points out that some research has found that fruit flies do pay attention to what their peers are doing, and are able to learn from them, Meanwhile, the UK government recently recognised that their close evolutionary cousins – crabs and lobsters – as sentient, and proposed legislation that would ban people from boiling them alive. For insects, golden tortoise beetles are unusually good at making their feelings clear (Credit: Alamy) An evolutionary imperative Insects are a jumbled group of six-legged invertebrate creatures with segmented bodies. There are more than a million different types, encompassing dragonflies, moths, weevils, bees, crickets, silverfish, praying mantis, mayflies, butterflies, and even head lice.

The earliest insects emerged at least 400 million years ago, long before dinosaurs took their first tentative plods. It’s thought our last common ancestor with them was a slug-like creature which lived around 200 million years before that, and they’ve been diversifying ever since. Initially they ruled over the land as giants – some dragonflies were sparrowhawk-sized, with 2.3ft (70cm) wingspans – before evolving into the extraordinary array of arthropods around today, from flies with fake scorpion tails to fuzzy moths that resemble winged poodles,

As a result, they’re strikingly similar to other animals, and yet vividly different. Insects have many of the same organs as humans – with hearts, brains, intestines and ovaries or testicles – but lack lungs and stomachs. And instead of being hooked up to a network of blood vessels, the contents of their bodies float in a kind of soup, which delivers food and carries away waste.

The whole lot is then encased in a hard shell, the exoskeleton, which is made of chitin, the same material fungi use to build their bodies. The architecture of their brains follows a similar pattern. Insects don’t have the exact same brain regions as vertebrates, but they do have areas that perform similar functions.

For example, most learning and memory in insects relies on “mushroom bodies” – domed brain regions which have been compared to the cortex, the folded outer layer that’s largely responsible for human intelligence, including thought and consciousness.

Tantalisingly, even insect larvae have mushroom bodies, and some of the neurons within them remain for their whole lives – so it’s been suggested that adult insects that went through this stage might be able to remember some things that happened before they metamorphosed.) There’s mounting evidence that our parallel neural setups power a number of shared cognitive abilities, too.

Bees can count up to four, Cockroaches have rich social lives, and form tribes that stick together and communicate. Ants can even pioneer new tools – they can select suitable objects from their environment and apply them to a task they’re trying to complete, like using sponges to carry honey back to their nest,

Do animals suffer from post-traumatic stress? Why so many of us are casual spider-murderers The intelligent monster you should let eat you

However, though insect brains have evolved down an uncannily familiar path to our own, there is one crucial difference: while human ones are so engorged they sap 20% of our energy and drove women to evolve wider hips, insects have compacted their wits into packages several million times smaller – fruit flies have brains the size of a poppy seed, Asian honeybees scream with their bodies, by vibrating them (Credit: Alamy) So, even at first glance, it seems like insects would have the intellectual capacity for emotions. But does it make sense that they would have evolved them? Emotions are mental sensations that are usually linked to an animal’s circumstances – they’re a kind of mental programme that, when it’s set off, can change the way we act.

It’s thought that different emotions have emerged at different points in evolutionary history, but broadly they turned up to encourage us to behave in ways that will improve our ability to survive or reproduce, and ultimately, maximise our genetic legacy. Geraldine Wright, a professor of entomology at the University of Oxford, gives the example of hunger, which is a state of mind that helps you to alter your decision-making in a way that’s appropriate, such as prioritising food-seeking behaviours.

Other emotions can be equally motivating – rumblings of anger can focus our efforts on rectifying injustices, and constantly chasing happiness and contentment nudges us towards achievements that keep us alive. All these things could also apply to insects.

• An earwig that’s thrilled when it finds a nice damp crevice filled with delectable rotting vegetation will be less likely to starve or dry out, just as one that panics and plays dead when it’s disturbed has a better chance of escaping the jaws of a predator.
• Let’s say you’re a bee that ends up in a spider web, and a spider is swiftly coming towards your across the web,” says Lars Chittka, who leads a research group that studies bee cognition at Queen Mary, University of London.

“It’s not impossible that the escape responses are all triggered without any kind of emotions. But on the other hand, I find it hard to believe that this would happen without some form of fear,” he says. A heretical idea When Waddell first started his own research group in 2001, he had a fairly simple goal in mind. It’s difficult to study pain in fruit flies because they don’t respond to morphine. However, they are partial to cocaine (Credit: Alamy) To begin with, Waddell cautiously chose the word “motivation”, rather than “hunger”, to describe the flies’ state of mind – he suggested that they were more motivated to find food if it had been withheld.

• And people found it a little problematic,” says Waddell.
• Some other scientists felt that this was too anthropomorphic and preferred the term “internal states”.
• So I often had arguments that I thought were essentially meaningless, because they were just playing with that word,” he says.
• Then in a matter of years, studying insect intelligence became significantly more fashionable – and all of a sudden the term “motivation” was abandoned, with researchers making the case for insects having “emotional primitives”, says Waddell.

In other words, they experienced what looked suspiciously like emotions. “I had always thought of these physiological changes that occur when animals are in deprivation states – deprived of sex, deprived of food – as subjective feelings of ‘hunger’ and ‘sex drive’,” says Waddell.

I’ve never really bothered labelling them as ’emotions’, pretty much because I thought it was going to get me into trouble. But before I knew it, everyone seemed to be more comfortable using that,” Now that the suggestion insects have feelings is slightly less scandalous, the field has exploded in popularity – and this strange group of animals is becoming more relatable by the day.

But proving that an insect can experience an emotion remains tricky. Take the humble bumblebee. In humans, those who have experienced trauma are especially wired to expect the worst – and this has also been demonstrated in a number of other vertebrate animals, including rats, sheep, dogs, cows, cod and starlings. Cockroaches are highly sociable and copy the behaviour of their peers, just like humans do (Credit: Alamy) First, the researchers trained a troupe of bees to associate one kind of smell with a sugary reward, and another with an unpleasant liquid spiked with quinine, the chemical that gives tonic water its bitter taste.

1. Then the scientists divided their bee participants into two groups.
2. One was vigorously shaken – a sensation bees hate, though it’s not actually harmful – to simulate an attack by a predator.
3. The other bee crowd was just left to enjoy their sugary drink.
4. To find out if these experiences had affected the bees’ mood, next Wright exposed them to brand new, ambiguous smells.

Those who had had a lovely day usually extended their mouthparts in expectation of receiving another snack, suggesting that they were expecting more of the same. But the bees who had been annoyed were less likely to react this way – they had become cynical.

1. Intriguingly, the experiment also hinted that the bees weren’t experiencing some alien, unrelatable form of pessimism, but a feeling that might not be too dissimilar to our own.
2. Just like humans who are feeling exasperated, their brains had lower levels of dopamine and serotonin.
3. They also had lower levels of the insect hormone octopamine, which is thought to be involved in reward pathways.) Wright says many of the chemicals in our brains are highly conserved – they were invented hundreds of millions of years ago.

So an insect’s emotional experiences could be more familiar than you would think. “So from that perspective, yes, they may have diverged a little bit in terms of what they signal in which animal lineage, but it’s quite interesting,” she says. For example, Waddell’s research on fruit flies has found that their brains use dopamine just like ours do, to elicit feelings of reward and punishment.

“So it’s very, very interesting that those things have, you know, convergently evolved and are sort of similar,” says Wright. “It means that that’s the best way of doing it.” Wright explains that her bee experiment doesn’t necessarily mean that all insects can experience pessimism or optimism, because bees are unusually social – community life at the hive is particularly cognitively demanding, so they’re considered intelligent for insects.

“But other insects probably do too,” she says. A clear message However, it would be surprising if insects could feel emotions but not express them at all. And tantalisingly, there are some hints that insects might be more relatable than you’d think here too. Industrial farming has turned much of the earth’s surface into a hostile environment for insects (Credit: Alamy) The problem is something Charles Darwin first considered in the late 19th Century. When he wasn’t pondering evolution or eating the “strange flesh” of the exotic fauna he discovered, he spent much of his time thinking about how animals communicate their feelings, and wrote up his findings in a little-known book.

• In The Expression of the Emotions in Man and Animals, Darwin argues that – just like every other characteristic – the ways humans express their feelings would hardly have appeared out of nowhere in our own species.
• Instead, our facial expressions, actions and noises are likely to have evolved via a gradual process over millennia.

Crucially, this means that there’s probably some continuity among animals, in terms of the ways that we display our emotional state to others. For example, Darwin noted that animals often make loud noises when they’re excited. Among the loud chattering of storks and the threatening rattling of some snakes, he cites the “stridulations”, or loud vibrations, of many insects, which they make when they’re sexually aroused.

• Darwin also observed that bees change their hums when they’re cross.
• This all suggests that you don’t need to have a voice box to express how you’re feeling.
• Take the golden tortoise beetle, which looks like a miniature tortoise that’s been dipped in molten gold.
• It’s not actually covered in the element, but instead achieves its glamorous look by reflecting light off fluid-filled grooves embedded in its shell.

However, pick one of these living jewels up – or stress it out in any way – and it will transform before your eyes, flushing ruby-red until it resembles a large iridescent ladybird. Most research on the beetle has focused on the physics of how it achieves the colour switch, but intriguingly, it’s thought that the response is controlled by the insect, which may choose to change depending on what’s going on around it – rather than something that just happens passively. Insects have diversified to fill almost every conceivable niche, but they all share similar brains – so emotions in insects may be universal (Credit: Alamy) Then there’s the Asian honey bee. Around October each year – during what’s ominously referred to as the “slaughter phase” – they run the gauntlet of gangs of bee-decapitating giant hornets, also aptly known as “murder hornets”.

The wasps have a wide native range in Asia, from India to Japan, but scientists suspect they’re slowly invading other areas, with occasional sightings in North America, Their raids on bee hives can last for hours, and wipe out entire colonies – first, they cut up their worker bee victims into pieces, then they go for their offspring.

But the bees don’t go quietly. In work released earlier this year, scientists revealed that they scream – using an amplified, frantic version of their usual buzz. And though no one has conclusively tied the shrieks to an emotional response in the bees, the study’s authors noted in their paper that these “antipredator pipes” share similar acoustic features to the alarm calls of many other animals, from primates to birds to meercats, and might suggest that they’re fearful.

1. A n uncomfortable truth However, the most contentious aspect of the inner lives of insects has to be pain.
2. There’s lots of evidence in fruit fly larvae that they feel mechanical pain – if we pinch them, they try to escape – and the same is the case for adult flies as well,” says Greg Neely, a professor of functional genomics at the University of Sydney.

As always, proving that these unpleasant experiences are interpreted as emotional pain is another matter. “The issue is really the higher order aspect,” says Neely. However, there’s emerging evidence that they can indeed feel pain as we know it – and not only that, they can experience it chronically, just like humans.

One basic clue to the former is that, if you train fruit flies to associate a certain smell with something unpleasant, they will simply run away whenever you present them with it. “They link together the sensory context with the negative stimulus, and they don’t want that – and so they go away from it,” says Neely.

When fruit flies are prevented from escaping, they eventually give up and exhibit helpless behaviour that looks a lot like depression. But perhaps the most surprising results have emerged from Neely’s own research, which has found that injured fruit flies can experience lingering pain, long after their physical wounds have healed. Insect populations are declining accross the whole planet (Credit: Alamy) And though pain hasn’t yet been studied in a wide variety of insects, Neely thinks its likely that it would be similar across the board. “If we look at the overall architecture of how the brain is set up – the receptors, the ion channels and the neurotransmitters are all pretty similar,” says Neely, who points out that you can find examples of insects that are blind to these sensory signals, such as larvae that are in the middle of their transition to adulthood, but this is unusual.

• A question of numbers All this research has some unsettling implications.
• At the moment, insects are among the most persecuted animals on the planet, routinely killed in almost-incomprehensibly large numbers.
• This includes 3.5 quadrillion – 3,500,000,000,000,000 – poisoned by insecticides on US farmland each year, two trillion squashed or slammed by cars on Dutch roads, and many more that have gone uncounted.

But though there isn’t much data on the full extent of our insecticide, one thing is widely accepted – the numbers we’re despatching are so vast, we’re living through an “insect Armageddon”, an era where insects are vanishing from the wild at an alarming rate. During “slaughter season” gangs of giant Asian hornets launch ferocious attacks on honeybees, decapitating the adults and eating their offspring (Credit: Alamy) The discovery of insect emotions also poses a slightly awkward dilemma for researchers – especially those who have devoted their careers to uncovering them.

Fruit flies are the archetypal research animal, studied so intensively that researchers know more about them than almost any other. At the time of writing, there are around 762,000 scientific papers that mention its Latin name, ” Drosophila melanogaster “, on Google scholar. Equally, studies into bees are growing in popularity, for the insights they can provide into everything from epigenetics – the study of how the environment can influence the way our genes are expressed – to learning and memory,

Both have endured more than their fair share of experimentation. “I like to watch bees and I’ve studied behaviour for a lot of my career, so I empathise quite a lot with them already,” says Wright, who has been a vegetarian for decades. However, the numbers used in research are tiny compared to those sacrificed elsewhere, so she feels that it’s easier to justify.

“It’s this sort of disregard of life in general that we have – you know, people just wantonly take life and destroy it and manipulate it from humans to mammals, insects to plants.” But while using insects for research is still largely uncontroversial, the discovery that they may think and feel raises a number of sticky conundrums for other fields.

There’s already a historical precedent for banning pesticides to protect certain insects – such as the EU-wide embargo on nicotinoids for the sake of bees. Could there be scope for moving away from others? And though insects are increasingly promoted as a noble and environmentally friendly alternative to meat from vertebrates, is this actually an ethical win? After all, you’d have to kill 975,225 grasshoppers to get the same volume of meat as you would from a single cow.

• Perhaps one reason we don’t tend to think of insects as emotional is that it would be overwhelming.
• Zaria Gorvett is a senior journalist for BBC Future and tweets @ZariaGorvett – Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram,
• If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”.

A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.

Should you let flies land on you?

3. But, if a fly does land on you, wash yourself. And don’t eat anything that it touches. – “The biggest concern a person should have is that when a fly lands on your counter, it was probably on something decaying before,” says Tommy. Yikes, According to Tommy, the most concerning part about flies is not knowing where they’ve been, but knowing what they’re attracted to.

Is it bad if a fly touches you?

Food hygiene expert Dr Cameron Webb has explained that any germs transferred by a fly are unlikely to make you ill. A single touch down is unlikely to affect the average healthy person. In most cases, our immune system is able to repel any nasty bugs.

Can flies sense you?

Failed to save article – Please try again If an outdoors, socially-distanced gathering is part of your Thanksgiving plans, beware of uninvited guests. I don’t mean friendly neighbors who might invite themselves to a piece of pie. A blowfly feeds on an apple with its straw-like proboscis. (Josh Cassidy/KQED) I’m talking about flies. Buzzing around curiously, they’ll help themselves to whatever food you leave unattended. As they walk all around they could spread hundreds of types of bacteria they carry on their legs. So you try sneaking up on one and it skedaddles. Why, oh why, is it so hard to swat a fly? Now you see me, now you don’t. A blowfly escapes a swatter in the nick of time. (Josh Cassidy/KQED) Flies are formidable opponents, with an arsenal of tools they carry all over their bodies. For starters, their hair and antennae help a fly sense us as we walk up to them. A fly can see you coming from nearly every angle. (Josh Cassidy/KQED) Not only can they feel us, they can see us too. “They have a very small blind spot in the back of their head,” Fox said, “but a lot of flies can see almost 360 degrees around their heads.” And a fly’s eyes and tiny brain process information 10 times faster than human eyes and brains. Quick, sharp turns help a fly dodge your swatter. These aerobatics are possible thanks to a pair of tiny club-shaped limbs called halteres, nestled below the fly’s two wings. (Josh Cassidy/KQED) Once the fly escapes your swatter and is in the air, it’s in its element and your job is even tougher.

• Seen up close and slowed down, a fly’s aerobatics are impressive: It makes razor-sharp turns with ease and at great speed.
• What makes this possible is a pair of modified wings called halteres, a Greek word for dumbbell, which describes their shape.
• All of the 200,000 species of flies that scientists have described have a pair of halteres and a pair of wings.

(That includes mosquitoes, which, wouldn’t you know it, are flies too.) Most other insects — bees, butterflies, dragonflies — have four wings and no halteres. The relatively large halteres of a crane fly are easier to spot than most. The halteres are the small, club-shaped parts beating below the fly’s wings. (Jessica Fox/Case Western Reserve University) As a fly turns, its halteres sense the rotation. In a split second, neurons at the base of the halteres send information to the fly’s muscles to steer its wings and keep its head steady.

Houseflies flap their wings about 200 times per second, which means they really only have five milliseconds to figure out what the next wingbeat is going to be like. And if you’re using vision that takes too long to do,” Fox said. “They really need a mechanical receptor in order to be able to sense their body rotations and correct them on the timescale that they need.” Though flies are a pesky pest and we are constantly in their pursuit, they likely evolved halteres to escape other animals besides us.

“Flies hang out on the backs of cows,” said Sane. “The tail of a cow trying to flick insects off, it’s likely to kill the fly if it doesn’t fly off fast.” Lizard tongues are also quick-moving threats. And then there’s flies themselves. In lightning-fast chases, males compete for the ability to mate.

“These chases are among the most aerobatic chases that I’ve ever seen; there’s nothing that comes even close,” said Sane. “And if flies did not turn very fast they’ll get caught and slammed to the ground.” When researchers remove a fly’s halteres, it can no longer control its flight. It loses all sense of where its body is in space.

In slowed-down videos, flies without halteres give the impression of being drunk. A fly whose halteres have been removed by researchers can’t control its flight and falls down. (Katie Jordan, Alex Yarger and Jessica Fox/Case Western Reserve University) “They don’t seem to know; they just keep flapping,” said Fox. “They just keep pitching and rolling and eventually they fall. A fly can stay out of reach by hanging upside down on the ceiling. (Josh Cassidy/KQED) It hangs there with tiny hooks and sticky pads on its feet. The pads, called pulvilli, have microscopic hairs that excrete a liquid that sticks to the surface under pressure, sort of like suction. The pads on a fly’s feet, called pulvilli, have microscopic hairs that excrete a liquid that sticks to the surface. The photo on the right shows an extreme close-up of the hairs. (Stanislav Gorb/University of Kiel, Germany) Despite the fly’s slick tools, Sane recommends one trick next time you try to nab one.

What do flies fear the most?

video: A single fly walks back and forth, and briefly grooms, before a shadow moves overhead. The fly jumps and freezes in place, its wings and other appendages held motionless. After about 5 seconds, the fly suddenly breaks its freezing posture, and escapes.

• View more Credit: William T.
• Gibson When fruit flies respond to the threat of an overhead shadow, are they afraid? That’s a hard question to answer, say researchers reporting in the Cell Press journal Current Biology on May 14.
• However, their studies do show that flies’ response to visual threats includes many essential elements of what we humans call fear.

David J. Anderson of the Howard Hughes Medical Institute and the California Institute of Technology and his colleagues say that their findings in flies are a step toward dissecting the fundamental neurochemistry, neuropeptides, and neural circuitry underlying fear and other emotion states.

• No one will argue with you if you claim that flies have four fundamental drives just as humans do: feeding, fighting, fleeing, and mating,” says William T.
• Gibson, a Caltech postdoctoral fellow and first author on the study.
• Taking the question a step further-whether flies that flee a stimulus are actually afraid of that stimulus-is much more difficult.” To ask the question in a different and less problematic way, the researchers dissected fear into its fundamental building blocks, which they refer to as “emotion primitives.” First, fear is persistent, Gibson explains.

If you hear the sound of a gun, the feeling of fear it provokes will continue for a period of time. Fear is also scalable; the more gunshots you hear, the more afraid you’ll become. Fear is generalizable across different contexts, but it is also trans-situational.

Once you’re afraid, you’re more likely to respond in fear to other triggers: the clang of a pan, for instance, or a loud knock at the door. The question then was this: In terms of these building blocks of emotions, does a fly’s response to shadows resemble our response to the sound of a gun? Very much so, the new study shows.

Anderson and colleagues came to that conclusion after enclosing flies in an arena where they were exposed repeatedly to an overhead shadow. In collaboration with Pietro Perona’s computer vision group, also at Caltech, the team carefully analyzed the flies’ behaviors as captured on video, which showed that shadows promoted graded and persistent increases in the flies’ speed and hopping.

• Occasionally, the insects froze in place, a defensive behavior also observed in the fear responses of rodents.
• The shadows also caused hungry flies to leave a food source, suggesting that the experience was generally negative and generalized from one context to another.
• It took time before those flies would return to their food following their dispersal by the shadow, suggesting a slow decay of the insects’ internal, defensive state.

Importantly, the more shadows the flies were exposed to, the longer it took for them to “calm down” and return to the food. In other words, when flies flee in response to a shadow, it’s more than a momentary escape. It’s a lasting physiological state much like fear.

• And, if that’s true, it means that flies could help us understand in a very fundamental way what fear and other emotions are made of.
• The argument that this paper makes is that the Drosophila system may be an excellent model for emotion states due to the relative simplicity of its nervous system, combined simultaneously with the behavioral complexity it exhibits,” Gibson says.

“Such a simple system, leveraged with the power of neurogenetic screens, may make it possible to identify new molecular players involved in the control of emotion states.” The next step, the researchers say, is to dissect the neural circuitry involved in the flies’ shadow response.

### Current Biology, Gibson et al.: “Behavioral responses to a repetitive shadow stimulus express a persistent state of defensive arousal in Drosophila” http://dx.doi.org/10.1016/j.cub.2015.03.058 Current Biology, published by Cell Press, is a bimonthly journal that features papers across all areas of biology.

Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. For more information please visit http://www.cell.com/current-biology,

Do flies have a purpose?

Eat shit and fly – Flies quite literally eat poo but they also clean up other waste too, helping clean-up after us humans. They can eat our household waste and divert it from going into landfill. The black soldier fly, for example, can have up to 600 larvae, with each of these quickly consuming half a gram of organic matter per day.

• This small family can eat an entire household green waste bin each year.
• Flies act as scavengers consuming rotting organic matter so we don’t have to deal with it which is a very important role in the environment.
• If it wasn’t for flies, there would be rubbish and dead animal carcasses everywhere.
• A lovely thought to mull over while you’re grilling.

Flies turn poo and rotting carcasses into stock feed, and live bird, frog and lizard food for free. Pretty cool if you think about it.

Why am I so disgusted by flies?

4. Negative connotation – A few insects simply remind of negative situations or something filthy. Take flies for instance. These insects swarm around garbage, dead and rotting carcasses and excrement. The mere sight of them makes you think of something putrid.

Why do flies sit on humans?

Why do flies sit on humans? I checked into an ayurvedic centre in Haryana for a week. Clean, spartan and strict, it was the ideal place for me. Except for the flies. I was covered with oil or mud for the better part of the day and showered three times but it seemed to me that I had become a target for all the flies of the district.

No one else seemed to have a problem. But walking, sleeping, being massaged or eating, I was brushing away the House Fly, Musca domestica, and its more ubiquitous cousin the Bush Fly, Musca Vetutissima. Why do flies sit on humans? It is so energy expensive for them. They are brushed away a thousand times, swatted, hurt, killed.

Why don’t they sit on animals, or furniture? (They do sit on animals, but only those that are hurt and cannot defend themselves.) Since the common housefly doesn’t have any interest in sucking blood, (feeding on open wounds is a different story), you think they’d fly away from humans.

1. After all, we’re a lot larger and more intimidating swatters.
2. The Fly has a very soft, fleshy, sponge-like mouth and when it lands on you and touches your skin, it won’t bite, it will suck up secretions on the skin.
3. It is interested in sweat, proteins, carbohydrates, salts, sugars and other chemicals and pieces of dead skin that keep flaking off.

This type of fly also gets its nutrients from sitting around the eyes of livestock. It is hard to get it from anywhere else on hairy animals, which is also why they land more often on human skin which is comparatively less hairy. Here are some reasons why they land on humans: * They are attracted to carbon dioxide which human beings breathe out.

• They are attracted to the heat of the warm body, to sweat and salt, and the more the person sweats the more flies they attract.
• Flies feed on dead cells and open wounds,
• Oil is an important food for flies,
• Oily hair is an attractant.
• Less hairy skin gives the fly spaces to vomit.
• A fly vomits on solid food to liquefy it.

The house flies taste with their feet so if there is food on the skin, and space to liquefy it, they will land there. * Some body-odours are more attractive to flies than others. This is apart from the quantity of carbon dioxide that is emitted. Houseflies are scavengers,The human body, like some of their favourite food sources – faeces, food and rotting flesh – radiates a sense of warmth and nourishment.

1. With a voracious appetite, aided by an excellent sense of smell and a pair of complex eyes that covers half its head, the fly lands on us because it is constantly on the hunt for a warm place to eat, defecate, vomit and lay eggs.
2. In order to make the area in and around your home a “no fly” zone take basic preventative measures.

If you have a dog make sure you do not leave its faeces out in the open, as dog faeces serves as both buffet and egg depository. Don’t leave food out for too long, pay special attention to kitchen utensils and surfaces, empty your garbage cans regularly and keep an eye out for organic rotting matter.

1. Don’t leave food in pet bowls after they have eaten.
2. Wipe down trash cans from the outside as well.
3. Net all the windows and shut the doors.
4. Check for cracks and holes (particularly around window screens) that they might be using.
5. Unhygienic rubbish tips are a prime fly-breeding site, but if garbage is covered by a layer of soil, preferably daily, this can be avoided.

But why are certain people singled out? Could it be the scent in the soap or shampoo? Apparently, sweet fruity smells attract flies because they like sugar. Maybe your skin, mouth and nostrils are moister than others. It is also claimed that flies and gnats migrate to the taller persons in a group.

1. You don’t have to sweat a lot – just more so than the rest of the people in your house to make it more likely for them to land on you.
2. Fruit flies are slightly smaller than the common house fly.
3. They are not interested in human smells but in yeast, so they are attracted to things that are fermenting and can ferment, like sugar, fruit and, of course, actual yeast.

So, if you drink alcohol and hang around with people who don’t, or if you use grooming products with alcohol in them, you will attract fruit flies. Don’t eat fruit outside? Switch your soap if it is fruit smelling. But apart from swatting and waiting for winter, there is little you can do.

Blowflies, also known as bottle flies, have metallic green or blue bodies, are large, and make a buzzing sound when they come near. They are really a nuisance for me because they lay their eggs on animals, and my hospitals get thousands of animal patients every week suffering from maggot infestation.

There are other flies as well: the Drain fly found in sewage beds whose wings are densely covered in hair and held tent–like over the body when at rest; the Flesh Fly, whose three-striped body looks like a chequer board, lays its eggs on decaying meat or fish or animal flesh.

Swatting a fly is so difficult. Their eyes allow them to see all around and they have a sixth sense about danger. According to the California Institute of Technology flies fly within 100 milliseconds of recognizing a threat. Flies have been around since before humans. In the Biblical plague of Egypt, flies represent death and decay.

The Philistine God Beelzebub’s name, (often equated with Satan), means Lord of the Flies. In Greek mythology Zeus sent a fly to bite Pegasus, the winged horse, causing his rider Bellerophon to fall back to earth when he was attempting to fly to Mount Olympus the home of the gods.

• In the Red Indian Navajo religion Big Fly is an important spirit.
• Many scientists have tried to find out how to use flies constructively.
• Suggestions range from mass rearing them and using them on animal manure garbage dumps.
• Flies are recyclers.
• They eat scraps and then excrete and turn it into a substance plants can use).

Or harvesting their maggots and feeding them to animals. Both these ideas seem insane to me. Ogden Nash’s poem sums up our irritation with this being “God in His wisdom made the fly / And then forgot to tell us why.” Perhaps to keep human populations down by spreading diseases that range from dysentery to typhoid and cholera.

During the Second World War the Japanese, under Shiro Ishii, used special Yagi bombs on China. The bombs contained flies coated with cholera bacteria. The bombs thrown in Baoshan in 1942 and Shandong in 1943 killed over 4 lakh people. Anyway now that I am back, my fly demons seem to have lessened. So maybe it was the oil.

To join the animal welfare movement contact [email protected], www.peopleforanimalsindia.org : Why do flies sit on humans?

Do flies feel pain when you crush them?

By Dr. Shelley Adamo, Dalhousie University Do insects feel pain? Many of us probably ask ourselves this question. We swat mosquitoes, step on ants, and spray poison on cockroaches, assuming, or perhaps hoping, that they can’t – but can they? As someone who studies the physiology behind insect behaviour, I’ve wondered about it myself. Are these crickets angry? In pain from being whipped by antennae? How would we know? To find out whether insects feel pain, we first need to agree on what pain is. Pain is a personal subjective experience that includes negative emotions. Pain is different from nociception, which is the ability to respond to damaging stimuli.

1. All organisms have nociception.
2. Even bacteria can move away from harmful environments such as high pH.
3. But not all animals feel pain.
4. The question, then, is do insects have subjective experiences such as emotions and the ability to feel pain? We’ve probably all observed insects struggling in a spider’s web or writhing after being sprayed with insecticide; they look like they might be in pain.

Insects can also learn to avoid electric shocks, suggesting that they don’t like being shocked. However, just as I was appreciating how much some insect behaviour looked like our pain behaviour, I realized that Artificial Intelligence (e.g. robots and virtual characters) can also display similar behaviours (e.g.

• See ( https://www.youtube.com/watch?v=YxyGwH7Ku5Y ).
• Think about how virtual characters can realistically express pain in video games such as “The Last of Us” (e.g.
• Https://www.youtube.com/watch?v=OQWD5W3fpPM ).
• Researchers have developed circuits allowing robots and other AI to simulate emotional states (e.g.

‘joy’, ‘anger’, ‘fear’). These circuits alter how the robot/virtual character responds to its environment (i.e. the same stimulus produces a different response depending on the AI’s ‘emotion’). However, this does not mean that robots or virtual characters are ‘feeling’ these emotions.

1. AI shows us that behaviour may not be the best guide to an insect’s internal experience.
2. Given that behaviour seemed an unreliable guide, I then looked for neurobiological evidence that insects feel pain.
3. Unfortunately, the insect brain is very different from the human brain.
4. However, once we understand how our brains perceive pain, we may be able to search for circuits that are functionally similar in insects.

Research in humans suggests that pain perception is created by complex neural networks that link up the necessary brain areas. These types of networks require massive bidirectional connections across multiple brain regions. Insect brains also have interconnections across different brain areas.

• However, these interconnections are often quite modest.
• For example, the mushroom bodies in the insect brain are critical for learning and memory.
• Although the mushroom bodies contain thousands of neurons, in fruit flies, for example, they have only 21 output neurons.
• In humans, our memory area, the hippocampus, has hundreds of thousands of output neurons.

The lack of output neurons in insects limits the ability of the insect brain to sew together the traits that create pain in us (e.g. sensory information, memory, and emotion). Finally, I considered the question from an evolutionary perspective. How likely it is that evolution would select for insects to feel pain? In evolution, traits evolve if the benefits of a trait outweigh its costs.

1. Unfortunately, nervous systems are expensive for animals.
2. Insects have a small, economical, nervous system.
3. Additional neurons dedicated to an ‘emotional’ neural circuit would be relatively expensive in terms of energetics and resources.
4. If it is possible to produce the same behaviour without the cost, then evolution will select for the cheaper option.

Robots show that there could be cheaper ways. The subjective experience of pain is unlikely to be an all-or-none phenomenon. Asking whether insects feel pain forces us to consider what we would accept as a subjective experience of pain. What if it was devoid of emotional content? What if cognition is not involved? If insects have any type of subjective experience of pain, it is likely to be something that will be very different from our pain experience.

It is likely to lack key features such as ‘distress’, ‘sadness’, and other states that require the synthesis of emotion, memory and cognition. In other words, insects are unlikely to feel pain as we understand it. So – should we still swat mosquitoes? Probably, but a case can be made that all animals deserve our respect, regardless of their ability to feel pain.

Adamo, S. (2019). Is it pain if it does not hurt? On the unlikelihood of insect pain. The Canadian Entomologist, 1-11. doi:10.4039/tce.2019.49 (Paper made available to read for FREE until Sept.16, 2019 in cooperation with Cambridge University Press) Post Views: 5,422

Why do I feel bad killing insects?

Megan Cox A shoe begins to step on a spider as it roams the ground it walks on. Digital illustration by Megan Cox. Imagine you are laying on your bed struggling to fall asleep on yet another sleepless night when you notice a tiny shadow skitter across your bedroom ceiling.

• Upon closer inspection, the shadow turns out to be an arachnid, a spider.
• Lifting up a slipper as a single shiver runs down your spine, you find yourself pausing with criminality, moments before its execution.
• You think of its family, the spiderlings it may have, with the haunting feeling lingering over your head.

If a tiny being like this one causes you to feel much repugnance, why does it feel so wrong to take your slipper and crush it? Guilt when killing household spiders can be largely attributed to introquite psychological phenomenons and the knowledge of their biological impact on the planet.

Though spiders have limited emotional capabilities, the humans often personify them to have much more complex feelings often leading to cognitive dissonance. Cognitive dissonance is a psychological concept surrounding the uncomfortable feeling of contradicting beliefs conflicting with each other. Murder is frowned upon around the world, but the same feeling of wrongdoing applies to insects, small rodents, and sometimes inanimate objects.

This phenomenon can be largely attributed to a part of the brain discovered in the early 1990s known as Mirror Neurons. “When seeing others experience emotions, mirror neurons make us take on their feelings,” says Palatine High School psychology teacher Andrea Guthrie when explaining the function of the brain’s ability to mirror the feelings of other living organisms.

As it turns out, many household insects such as the ones hiding in your room this very second are much more beneficial to their food webs than they are perceived to be. Some of these roles include prevention of disease spread and being predators of invasive species. Entomologists say that many spiders eliminate many harmful insects in homes such as blood-filled mosquitoes.

Being a part of an extensive food web, spiders make up a large majority of their bottom tier. Food webs are made up of tens of layers of predators all depending on each other in order to keep equilibrium. A single food web makes up the entirety of food chains within an ecosystem.

“If you’re looking at one food chain, if one component is removed, it’s going to have a pretty drastic effect,” says Biology teacher Mrs. Dahl. “One small change can have a domino effect on everything else in the area.” If every person in one area killed a spider every day, one billion spiders would be removed from the world, possibly causing its predators to prey on different species.

Because different species already have another predator, their population begins to decrease as a result of having two predators. The collapse of one food web kickstarts the collapse of those around it, over time wiping out other food chains around it.

• While the impact of killing every spider you see can be detrimental, it is difficult to know exactly just how many people out there annihilate spiders on a daily basis.
• For every spider that is actually seen lingering, tens or hundreds more hide in places that can’t be seen.
• The reality of things is removing a spider from your home is not going to make seeing another one any less possible.

Feeling guilt towards killing spiders is perfectly rational despite their initial seemingly worthless qualities that send shivers down the spines of many. Next time a spider crawls on your bedroom ceiling, attempting to capture it in a cup and letting it out into the world may be a better option.

What are flies scared of?

3. Natural and Essential Oils – Certain scents are great for repelling insects and for keeping flies away. Create a spray by mixing two cups of water or vodka and several drops of your chosen essential oil. Eucalyptus oil is a good option, but you can also use lavender, citrus, pine, clove, peppermint, and thyme essential oils.

Most flies hate these scents, so the oils will act as a fly repellent. You can also smear some essential oils on the window and door frames — just make sure it’s out of reach of any pets, since some essential oils might be toxic to them, too! NOTE: If you don’t want to use essential oil, you can use dried versions of herbs and spices.

Dried cloves, lavender, and thyme will also create a smell that will keep flies away. They make great decorations, too!

Can flies get angry?

Flies also like to feed on dead cells and open wounds. When trying to figure out why flies are angry, research showed that Drosophila produces a pheromone, and this chemical messenger promotes aggression, directly linked to specific neurons in the fly’s antenna.

Can flies be friendly?

Harmless to Humans – Friendly flies like to land on people, but cannot bite. The DEC does not release these flies. Friendly flies are also called government flies because some people believe that the government released the flies to control forest tent caterpillars. This is a persistent and inaccurate rumor, as the flies are native to New York.

1. Their populations are not usually noticed until there is a tent caterpillar outbreak.
2. Once the population of the forest tent caterpillars increases, so does the population of friendly flies.
3. After an outbreak of the forest tent caterpillars ends, the friendly fly population also collapses.
4. In fact, the flies are likely the main reason for the caterpillar outbreak collapse.

This is a natural part of the cycle of biological activities that regularly occur in New York’s forests. These flies do not have biting mouthparts and are not interested in human flesh or blood. They do however like to land on humans, probably seeking moisture and perhaps salt on the skin’s surface.

Do flies show fear?

Do flies have fear (or something like it)? A fruit fly starts buzzing around food at a picnic, so you wave your hand over the insect and shoo it away. But when the insect flees the scene, is it doing so because it is actually afraid ? Using fruit flies to study the basic components of emotion, a new Caltech study reports that a fly’s response to a shadowy overhead stimulus might be analogous to a negative emotional state such as fear – a finding that could one day help us understand the neural circuitry involved in human emotion.

• The study, which was done in the laboratory of David Anderson, Seymour Benzer Professor of Biology and an investigator with the Howard Hughes Medical Institute, was published online May 14 in the journal Current Biology,
• Insects are an important model for the study of emotion; although mice are closer to humans on the evolutionary family tree, the fruit fly has a much simpler neurological system that is easier to study.

However, studying emotions in insects or any other animal can also be tricky. Because researchers know the experience of human emotion, they might anthropomorphize those of an insect – just as you might assume that the shooed-away fly left your plate because it was afraid of your hand.

1. But there are several problems with such an assumption, says postdoctoral scholar William T.
2. Gibson, first author of the paper.
3. There are two difficulties with taking your own experiences and then saying that maybe these are happening in a fly.
4. First, a fly’s brain is very different from yours, and second, a fly’s evolutionary history is so different from yours that even if you could prove beyond any doubt that flies have emotions, those emotions probably wouldn’t be the same ones that you have,” he says.

“For these reasons, in our study, we wanted to take an objective approach.” Anderson and Gibson and their colleagues did this by deconstructing the idea of an emotion into basic building blocks – so-called emotion primitives, a concept previously developed by Anderson and Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology.

• There has been ongoing debate for decades about what ’emotion’ means, and there is no generally accepted definition.
• In an article that Ralph Adolphs and I recently wrote, we put forth the view that emotions are a type of internal brain state with certain general properties that can exist independently of subjective, conscious feelings, which can only be studied in humans,” Anderson says.

“That means we can study such brain states in animal models like flies or mice without worrying about whether they have ‘feelings’ or not. We use the behaviors that express those states as a readout.” Gibson explains by analogy that emotions can be broken down into these emotion primitives much as a secondary color, such as orange, can be separated into two primary colors, yellow and red.

“And if we can show that fruit flies display all of these separate but necessary primitives, we then may be able to make the argument that they also have an emotion, like fear.” The emotion primitives analyzed in the fly study can be understood in the context of a stimulus associated with human fear: the sound of a gunshot.

If you hear a gun fire, the sound may trigger a negative feeling. This feeling, a primitive called valence, will probably cause you to behave differently for several minutes afterward. This is a primitive called persistence. Repeated exposure to the stimulus should also produce a greater emotional response – a primitive called scalability; for example, the sound of 10 gunshots would make you more afraid than the sound of one shot.

1. Gibson says that another primitive of fear is that it is generalized to different contexts, meaning that if you were eating lunch or were otherwise occupied when the gun fired, the fear would take over, distracting you from your lunch.
2. Trans-situationality is another primitive that could cause you to produce the same fearful reaction in response to an unrelated stimulus – such as the sound of a car backfiring.

The researchers chose to study these five primitives by observing the insects in the presence of a fear-inducing stimulus. Because defensive behavioral responses to overhead visual threats are common in many animals, the researchers created an apparatus that would pass a dark paddle over the flies’ habitat.

• The flies’ movements were then tracked using a software program created in collaboration with Pietro Perona, the Allen E.
• Puckett Professor of Electrical Engineering.
• The researchers analyzed the flies’ responses to the stimulus and found that the insects displayed all of these emotion primitives.
• For example, responses were scalable: when the paddle passed overhead, the flies would either freeze, or jump away from the stimulus, or enter a state of elevated arousal, and each response increased with the number of times the stimulus was delivered.

And when hungry flies were gathered around food, the stimulus would cause them to leave the food for several seconds and run around the arena until their state of elevated arousal decayed and they returned to the food – exhibiting the primitives of context generalization and persistence.

“These experiments provide objective evidence that visual stimuli designed to mimic an overhead predator can induce a persistent and scalable internal state of defensive arousal in flies, which can influence their subsequent behavior for minutes after the threat has passed,” Anderson says. “For us, that’s a big step beyond just casually intuiting that a fly fleeing a visual threat must be ‘afraid,’ based on our anthropomorphic assumptions.

It suggests that the flies’ response to the threat is richer and more complicated than a robotic-like avoidance reflex.” In the future, the researchers say that they plan to combine the new technique with genetically based techniques and imaging of brain activity to identify the neural circuitry that underlies these defensive behaviors.

Their end goal is to identify specific populations of neurons in the fruit fly brain that are necessary for emotion primitives – and whether these functions are conserved in higher organisms, such as mice or even humans. Although the presence of these primitives suggests that the flies might be reacting to the stimulus based on some kind of emotion, the researchers are quick to point out that this new information does not prove – nor did it set out to establish – that flies can experience fear, or happiness, or anger, or any other feelings.

“Our work can get at questions about mechanism and questions about the functional properties of emotion states, but we cannot get at the question of whether or not flies have feelings,” Gibson says. The study, titled “Behavioral Responses to a Repetitive Stimulus Express a Persistent State of Defensive Arousal in Drosophila,” was published in the journal Current Biology,

In addition to Gibson, Anderson, and Perona, Caltech coauthors include graduate student Carlos Gonzalez, undergraduate Rebecca Du, former research assistants Conchi Fernandez and Panna Felsen (BS ’09, MS ’10), and former postdoctoral scholar Michael Maire. Coauthors Lakshminarayanan Ramasamy and Tanya Tabachnik are from the Janelia Research Campus of the Howard Hughes Medical Institute (HHMI).

The work was funded by the National Institutes of Health, HHMI, and the Gordon and Betty Moore Foundation. : Do flies have fear (or something like it)?

Why do flies throw up when they eat?

A fly regurgitating digestive juices. Carlos Ruiz, CC BY-ND Ravindra Palavalli-Nettimi, Florida International University and Jamie Theobald, Florida International University Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected], Do flies really throw up on my food when they land on it? – Henry E., age 10, Somerville, Massachusetts Imagine you’re at a picnic and just about to bite into your sandwich.

• Suddenly you spot a fly headed your way, homing in on your food with help from its compound eyes and antennae.
• It manages to escape your swatting, lands on the sandwich and then seems to throw up on it! It can look kind of gross, but the fly might be just airing out its own digested food, or spitting on yours,

Most of the over 110,000 known fly species have no teeth, so they cannot chew solid food. Their mouthparts are like a spongy straw. Once they land on your food, they need to release digestive juices to liquefy it into a predigested, slurpable soup they can swallow.

1. In short, some flies are on a liquid diet,
2. A fly slurping its liquid meal.
3. To fit more food in their stomachs, some flies try to reduce the liquid in what they have already eaten.
4. They regurgitate food into vomit bubbles to dry it out a bit.
5. Once some water has evaporated they can ingest this more concentrated food.

Human beings don’t need to do all this spitting and regurgitating to get nutrients out of our food. But you do produce a digestive juice in your saliva, an enzyme called amylase, which predigests some of the sandwich bread while you chew. Amylase breaks down starch, which you can’t taste, into simple sugars like glucose, which you can taste. Bristles and hair on a Tachinid fly. Maria Cleopatra Pimienta, CC BY-ND Did you know flies can taste food without their mouths? As soon as they land, they use receptors on their feet to decide whether they’re on something nutritious. You may have noticed a fly rubbing its legs together, like a hungry customer getting ready to devour a meal.

Why do flies take their heads off?

Female flies lose their heads to sing like a male Video: Gene switch causes female flies to sing like males Female fruit flies have a hidden talent: the ability to sing like a male. All you have to do is switch on one gene – and chop off their heads. The headless, singing females have been nicknamed “flyPods”.

These decapitated flies flutter their wings to create a male mating song, a key part of courtship. Odd as it seems, the result suggests that males and females have a lot in common. Lurking in females is the ability to act just like a male – and presumably vice versa, says, a neuroscientist at the University of Oxford, who led the study.

“You have a system that’s more or less unisex in most of its parts, and you have a few key nodes that you set to male or female,” he says.

Why do flies look like they are washing their hands?

In the world of flies, tiny particles, like pollen grains, dust – which is mostly bits of dead skin, bits of dead insects etc, can become stuck to the fly’s body, and especially the feet, when the fly is walking around. Flies, by rubbing their legs together can clean off these tiny particles.

Is it safe to drink something a fly landed in?

(Holloway/Getty Images) You pour a chilled glass of your favourite sauvignon blanc and are about to take a sip when a fruit fly lands in it. The fly is clearly dead. But given what you know about where flies hang out, you wonder if it’s safe to drink. Despite their salubrious sounding name, fruit flies ( Drosophila species), eat food that is decaying.

1. They inhabit rubbish bins, compost heaps or any place where food is present, including drains.
2. Rotting food is rich in germs, any of which a fly can pick up on their body and transfer to where it next lands.
3. These bacteria include E coli, Listeria, Shigella, and Salmonella, any of which can cause a potentially serious infection in even healthy people.

The fruit fly, you realise, may have just deposited potentially lethal microbes in your wine, so you toss it in the sink and pour a fresh glass. However, the scientific evidence suggests you may have just wasted a good glass of wine. Wine has typically between 8 percent and 14 percent ethanol and has a pH of around 4 or 5 – a pH below 7 is considered acidic. Wine is known to inhibit the growth of germs, such as E coli, ( Science Photo Library/Canva Pro ) Whether the germs transmitted by the fruit fly into the wine can cause an infection depends on the number of bacteria deposited (the “infectious dose”) and how metabolically fit the germs are.

• The wine the fruit fly entered was also chilled, which some food poisoning bacteria find shocks their metabolism so profoundly it stops them growing.
• As all types of wine (red, white or rosé, whether chilled or room temperature) are naturally antibacterial, germs in wine are likely to become damaged, which will reduce their infection fitness.

This suggests that while the germs deposited into wine by the flies might be present in a dose high enough to cause illness, they are not likely to cause an infection as they are too damaged. So, in all likelihood, the contaminated wine could be drunk without ill effect – whether it was chilled or not.