Mosquitoes The most dangerous animals in the world Mosquitoes have an incredible ability to spread disease by feeding on blood, which is why they do so. A team of scientists has discovered that mosquitoes may be able to detect human heat signatures using infrared detection. When emitted from an infrared source that is roughly the same temperature as human skin, the number of hosts a mosquito can seek out doubles. In experiments, mosquitoes detect body odor and carbon dioxide (CO2) They’re already known to be able to smell the carbon dioxide we exhale, but this could be another tool to help them track prey that targets humans. The study was published in the journal Nature on August 21. Nature.
“The mosquitoes we study Aedes aegypti“They’re very good at finding human hosts,” said study co-author Nicholas DeBaubian, a molecular biologist at the University of California, Santa Barbara (UCSB). It said in a statement“This study sheds new light on how they accomplished this.”
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Sense the blood
Mosquito species Aedes aegypti It is known for spreading viruses that cause more than 100,000 cases of Zika, yellow fever, dengue fever, and more each year. Anopheles mosquito Spreads the parasite that causes malaria. World Health Organization estimatesMalaria alone kills more than 400,000 people each year.
Male mosquitoes are harmless, but females need blood for the development of their eggs. Over the past 100 years, scientists have spent time and effort trying to understand how mosquitoes find hosts. There doesn’t seem to be a single cue that mosquitoes rely on. Mosquitoes actually integrate environmental information collected from multiple senses at different distances.
“This includes CO2 The breath, the smell, the sight, [convection] “Heat from the skin and moisture from the body,” said study co-author Avinash Chandel, a postdoctoral student at UCSB. It said in a statement“But each of these clues has its limitations.”
Mosquitoes have poor eyesight, and sudden human movements or strong winds can throw them off track, so the team wondered if they could develop a more reliable directional system.
Applying heat
Mosquitoes sense heat rising from the skin within about four inches of the ground, and sense skin temperature directly when they land. These two senses correspond to two of the three types of heat transfer. ConvectionOne is “conduction,” where heat is removed by a medium such as air, and the other is “conduction,” where heat is removed by direct contact.
Thermal energy can travel longer distances when it is converted into electromagnetic waves. Heat is usually converted into waves in the infrared (IR) range of the light spectrum. These IR waves are capable of heating up anything they hit. Mamushi can sense thermal infrared rays From warm prey.
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To test Aedes aegypti The research team placed female mosquitoes, which have the same infrared sensing abilities, in cages and Host-seeking activity was measured in two zones.Each zone contains human odor and CO2 Other zones emitted infrared light at the same concentration as human exhalation. One zone emitted infrared light at body skin temperature. A partition separated the infrared source from the chamber to prevent heat exchange by conduction and convection. The team counted the number of mosquitoes that began roaming around the cage, as if searching for a vein.
When thermal infrared radiation is applied at a temperature of 93 degrees Fahrenheit, roughly the same as skin temperature,Insect host-seeking activity doubledThe team found that using infrared light was effective up to about 2.5 feet.
“What struck me most about this study was how powerful an IR cue can be,” says DeBeaubien. “Once all the parameters were set properly, the results were unmistakable.”
TRPA1 effectively extends the range of the mosquito’s infrared sensors to about 2.5 feet.”
Not only did the team find that mosquitoes can sense this heat, but they also identified which parts of their bodies and the biochemicals they use to do this. At the tips of mosquito antennae, there are peg-in-pit structures that are well suited to sensing radiation. The pits work by protecting the pegs from conductive and convective heat, allowing highly directional infrared light to penetrate and heat up the structure. The mosquito then detects the infrared light using a temperature-sensitive protein, TRPA1, which acts as a temperature sensor.
A growing problem
Climate change and global travel Extension Aedes aegypti range Mosquitoes live outside of tropical and subtropical countries too, making it even more important to prevent mosquito bites. Currently available across the United States It’s a place where it’s never been found before. The largest concentrations are in parts of Florida, Texas, Arizona and California. Louisiana and Texas Gulf CoastWashington DC, New York, Indiana and Kentucky.
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this study One way to improve methods for controlling mosquito populations is to incorporate a heat source into mosquito traps that is closer to human skin temperature to make them more effective. Loose-fitting clothing helps prevent bitesIt prevents mosquitoes from getting close to your skin and the infrared light spreads between your skin and clothing, making it undetectable to mosquitoes.
“Despite their small size, mosquitoes are responsible for more human deaths than any other animal,” said Debeaubian. “Our study improves our understanding of how mosquitoes target humans and offers new possibilities for controlling the transmission of mosquito-borne diseases.”