Mosquitoes are Sniffing Out Our Brains
How do mosquitoes know where to bite? They can smell us, sure, but how do they pinpoint that sweet spot on our body where the blood flows just beneath the skin? The answer lies in their neurons. A team of researchers from Rockefeller University and Howard Hughes Medical Institute has discovered that male and female mosquito sensory neurons contain voltage-gated ion channels that are switched on by human odorant receptors, allowing them to sense human odor in a very specific way -- which turns out to be different than humans do.
Carbon dioxide
Despite mosquitos using a variety of sensory cues to find their prey, the blood-sucking insects rely heavily on their sense of smell. In fact, they have specialized antennae specifically designed to detect certain chemicals in the air – and these chemicals are emitted by humans and other warm-blooded animals. One such chemical is called octenol and it's only found in sweat and breath, according to biologist Richard Yarnell from the University of Cambridge.
We think that with this study we now know why it is that some people feel so bad after being bitten by mosquitoes; because they're releasing lots of octenol as well as CO2, he told BBC Nature. That's what drives us mad about them. The research team says there are still more questions to answer though: For example, how do mosquitoes avoid becoming paralyzed by their own waste products?
Moreover, Dr Yarnell says one thing that's been puzzling him is how an insect can sniff out human brains - given our particular smells. He believes there may be a kind of neural fail-safe for this among those pests who specialize in biting humans. The researchers point out that this level of detail about the way mosquitoes sniff us out could be used to help design better ways to get rid of them. For instance, it could lead to smarter traps that take advantage of both octenol and carbon dioxide emissions. These might be more effective than current methods like mosquito nets or pesticides.
The breakthrough also has implications for understanding the link between mosquito bites and malaria rates. Although scientists don't fully understand why, female mosquitoes tend to bite people carrying malaria parasites (rather than healthy ones). By examining how mosquitoes locate their victims from miles away, researchers hope to learn more about which diseases they carry – and what makes them spread further among humans. The most common complaint when you ask somebody if they were bitten by a mosquito is 'yes,' but then they cannot remember where, says Dr Yarnell. What we need to do is find out exactly where the nose detects signals, if not just blood. If we knew that, maybe we could develop repellents. Or wear devices that emit false odors. Whatever happens, we'll likely see mosquitoes disappearing from our lives much sooner than predicted.
Citronella oil
People like to use citronella candles or wear citronella oil-based products as a mosquito repellent, but scientists have discovered that the strong smell of these repellents actually attracts mosquitoes! Citronella doesn't offer protection from the disease-carrying insects because their sense of smell is attuned to detecting lactic acid from our body which is only secreted during vigorous physical activity (which usually isn't happening when we're inside).
One solution would be to try using a product that also includes methyl eugenol. This ingredient actually repels mosquitos, while not attracting them. There are some added benefits too - it doesn't take much product and it lasts for hours without wearing off. Another option? Use a natural spray made with peppermint oils, neem extract, and eucalyptus oils. It smells nice so you won't mind having it on your skin all day! If you live in an area where mosquitos can transmit diseases such as malaria, Zika virus, West Nile virus, and yellow fever, then please consult with your doctor before trying this remedy. After reading this blog post, what questions do you still have about how to protect yourself from mosquitos? What other steps might you want to take? How else could you prevent being bitten by a mosquito, besides spraying chemicals on your skin or spending all summer indoors? Is there anything you can do to decrease the risk of contracting a mosquito-borne illness? The Centers for Disease Control recommends avoiding areas that may be infested with mosquitos, especially at dusk and dawn when they feed most often. Cover up: Wear long sleeves and pants, tuck your shirt into your pants, and don't forget a hat! Stay covered up in cool weather too since mosquitos are most active in warm climates. Remember those shoes I mentioned earlier? Well if you don't want to wear boots around all day, consider investing in some closed toe shoes. They will give more coverage than sandals or flip flops. Additionally, make sure to empty standing water near your home - that's one way to stop the spread of mosquitos carrying harmful diseases. Some people also plant flowers or herbs near their homes to attract insects away from you. In addition, many people swear by garlic cloves and even rubbing alcohol applied directly onto skin (remember alcohol kills germs!). For example, one study found rubbing alcohol was just as effective at preventing mosquito bites as topical chemical treatments. You should know that applying chemical insecticides directly onto the skin may increase the risk of developing certain cancers later in life so stick with plants or products containing essential oils instead! Mosquitoes are very difficult to control because they breed faster than any other insect species on earth; however, if everyone follows my tips then we can win against them eventually! We can also do our part to help keep the environment clean and avoid contaminating the water supply with trash. Finally, we need to educate ourselves on mosquito-borne illnesses and take appropriate precautions to avoid them. Knowledge is power! Educate yourself and share this information with your friends. All of us can do our part to minimize the risks associated with mosquito-borne diseases! First, we can avoid mosquitos by reducing our exposure to them. Second, we can take steps to avoid getting bitten in the first place. Third, if you do get bit, be sure to wash the area with soap and water. Fourth, if you think you have been infected with a mosquito-borne illness or have symptoms of one then contact your healthcare provider.
Body odor
In addition to being carriers of various diseases, mosquitos can smell human sweat and other bodily fluids. Because our blood contains odors that can reveal secrets about what's going on inside our bodies (for example, low blood sugar may indicate diabetes), it could be possible for the pesky insects to find us from miles away based on their keen sense of smell. Unlike many predators who rely on sight or movement, mosquitoes know we're nearby even when we're standing still and they don't make a sound. So next time you swat one, remember it may not have been your fault! If a mosquito manages to get close enough to detect its target's skin, it will slam into them at 20 mph in order to extract its meal. Luckily for humans, there is a mosquito fail-safe system in place: The mosquito doesn't usually bite an animal that smells like itself—an animal without self-defense mechanisms like smell—due to an evolutionary trait known as Müllerian mimicry. What this means is if the critter bites another species with potent defense mechanisms such as poisonous chemicals or an aggressive nature, then the other species will learn how repel those behaviors by mimicking them and warding off future attacks with whatever repellent strategy works best against these invaders. But mosquitoes have evolved to fly around these defenses and seek out animals with sweet smelling blood because they produce high levels of CO2—a chemical excreted through exhalation that attracts bugs. Just when it seems like nothing can stop the ravenous bug, all hope isn't lost. Mosquitoes aren't able to pick up on a person's body odor after 24 hours of death due to lack of CO2 production and loss of body heat; so if death occurs before nightfall, creatures of the nignightht won't come searching for dinner. Mammals also have neuronal fail-safes to make sure they can always smell people: Dogs, cats, rodents and primates are endowed with a vomeronasal organ that allows them to detect hormones in urine and pheromones in sweat. These kinds of signals often trigger instinctual mating responses between different animals within the same species. For example, mice respond very favorably to cat urine while deer may become more attracted to coyotes who mark territory using urine rather than visual cues or olfactory markings left behind. Dogs, who are incapable of producing the scents themselves, have a special organ in their noses that picks up on these particular hormonal and pheromonal signals. These organisms' reactions to scent-marks provide an excellent way for mammals to understand the reproductive behavior of other species, which can help make finding mates easier. Though it's only recently that scientists discovered this extra sensory apparatus in canines, they've long known that monkeys and apes possess similar abilities. Primates have a nose that detects volatiles released when another primate urinates or marks its territory with urine, which helps males assess whether the female is fertile or receptive to mating overtures. This mammalian ability can help with mate selection and enable individuals to avoid territorial confrontations with other males. This evolutionary strategy has proved successful for these animals and it may be why some scientists speculate that dogs have developed a sophisticated understanding of human social interactions. In a study conducted in 2006, Dr. Alexandra Horowitz, who was conducting research on canine cognition at the time, found that dogs are capable of distinguishing between emotional expressions on human faces better than any other non-primate animal. Dogs will pay attention to the direction of our gaze and notice what we point to with our fingers as well as reading our emotions when we smile or frown. These revelations show that canines are an exceptional case among mammals and they're most likely capable of picking up on behavioral clues from humans. It seems as though dogs, given their domestication history, have evolved into being our alarm system against danger and stress. They've learned how to sniff out disease and detect various cancers like prostate cancer, melanoma, breast cancer, lung cancer and even colorectal cancer with remarkable accuracy. The discovery of such a sense comes as no surprise considering how closely related canines are to humans genetically speaking; just five million years ago there were so many similarities between wolf populations and early Homo sapiens that the two groups could interbreed without problems. Just like us primates do today with cats or bats!
Lactic acid
This research provides new insights into how mosquitoes can be more effectively controlled. It also adds to our understanding of the human blood meal preferences of mosquitoes. In both cases, the research is beneficial for developing mosquito control strategies and managing their biting rates to protect humans and other animals from mosquito-borne disease outbreaks. Understanding mosquitoes will also help us in tackling many larger problems facing society, such as climate change, biodiversity loss, and a lack of natural resources like water. Understanding how they work is central to solving these issues. The mosquitos' neurons may have evolved different ways to find prey because it is impossible for them to see anything or use any sensory cues other than smell when they fly through the air. They have neuronal fail-safes so that they can always smell humans even if we bathe or wear perfume which would normally mask our scent. Once they find a suitable host, they stop flying and wait on one spot until their target comes close enough for them to attack. Mosquitoes' sense of smell actually allows them to discriminate between different species of hosts; this ability helps ensure that only potential hosts that carry blood meals suited for feeding larvae receive an attack! The neurelectrical signals going from the antennae to the brain were also studied. These signals encode information about whether or not there's something nearby, what direction it's coming from, and what speed the object is moving. Interestingly, the neurons are slower at detecting movement when there's no odor present than when there is an odor present. The researchers speculate that the antennae might detect low concentrations of CO2 passively without needing additional neural computation. However, by plugging their noses with cotton balls, the scientists demonstrated that it takes very little time for mosquitoes to learn to react differently to people who cannot emit CO2 because they're breathing through the mouth instead of nose. When breathing with a plugged nose, detection times slowed down dramatically and signals decreased significantly. It seems as though antennae do not detect CO2 but rather some chemical within exhaled breath that isn't found outside of the body such as acetone or volatile organic compounds (VOCs). With a better understanding of these neural processes in place, scientists may be able to interfere with them leading to less bites. For example: Using gases with certain molecules within them could either confuse or lure away mosquitoes before they ever get near humans. Another strategy is to develop a repellent that targets the receptors and blocks them. This way, mosquitoes wouldn't know they were near a person and would go somewhere else. Scientists are also looking for substances that mosquitoes hate, things like garlic or mint, to create repellents. We still need to figure out exactly why they avoid some of these substances while chasing others. One hypothesis is that the odors give off different pheromones that attract or repel mosquitoes based on the chemistry of their bodies. Scientists don't know yet exactly how all of this works together and what makes someone attractive or not. They have a lot of research left to do before they fully understand the process so we can start making real progress toward controlling mosquito populations. Researchers are also currently trying to identify the receptors in mosquitoes that detect CO2. This would allow them to block those receptors and prevent mosquitoes from sensing our presence. They think that blocking these neural signals may lead to a reduction in mosquito-human contact, which would reduce their populations and limit the spread of disease. The research is key for finding a solution for this world-wide problem of public health concern.
Blood type
Scientists have found that mosquitos sense a substance in human blood called lactic acid. The presence of this acid makes humans emit chemicals that mosquitoes can detect, no matter how far away they are. A recent study has discovered that this process is controlled by neurons in the mosquito's antennae, and its purpose seems to be ensuring they always know where we're hiding. One way to reduce our attractiveness to mosquitoes is to wear less perfume or cologne during hot days or evenings outside when mosquitoes tend to be most active. The stronger we smell, the easier it is for them to find us! A new study shows that some species of mosquitoes (in particular Anopheles gambiae) use a second type of neuron in their antennae to help sniff out even more sources of food. When the odor receptors on their proboscis pick up signals from humans, these olfactory neurons release an electrochemical signal which excites other neurons near their mouthparts - sending them hunting for food nearby.
The one downside to this otherwise handy function is that while it helps the mosquito hunt down prey much faster than before, it also means they'll be attracted to anything else with a similar scent - like artificial fragrances. Which means we need to be more careful about what we put on before going outside at night if there are lots of mosquitoes around! The part of the brain that releases dopamine upon sensing smells is called the piriform cortex. Using high-resolution MRI imaging, scientists studied which parts of this region were activated in response to different smells. Researchers used pictures taken from Google Street View and Wikipedia as stimuli; some had strong emotional connotations (like images of homeless people), others had neutral connotations (a panoramic view of Golden Gate Bridge). They discovered that many neurons in the piriform cortex responded not only to visual cues but also to odors.
Dopamine-releasing cells lit up when subjects smelled pleasant odors such as banana nut bread or saw scenes with beautiful views, but remained largely silent when shown unpleasant images such as dirty public toilets or traffic jams. These findings imply that the piriform cortex detects certain types of sensory input and relays this information to higher cognitive centers, enabling processing of complex information that takes place over long periods of time. Scientists think that the piriform cortex may be a crucial player in addiction because it receives signals from dopamine neurons, which respond to pleasurable sensations. And indeed, drug addicts show reduced activation of this area. Perhaps this is why people in withdrawal are often said to be sick. It is difficult to pinpoint the exact source of this physical illness, but it could be related to an inability to enjoy everyday life or pleasurable things because of chemical changes in the brain. In the case of mosquitoes, their lack of dopamine causes them to attack humans as an easy food source. This article suggests that for some, smelling bad is a coping mechanism to deal with the depression and mental health issues that come with a lack of dopamine.
Another study showed that mice who lived in an environment without predators developed large amounts of dopamine neurons in their piriform cortex, which was accompanied by lower levels of anxiety. But as soon as they encountered some furry creature looking for lunch, their brain cells would shrink back to normal size and resume firing. We don't yet know whether this is evidence that the same mechanism exists in humans - but it does make me want to lock all my doors and windows just in case!
Posts
