Another way mosquitoes track people

Male mosquitoes are harmless, but females need blood to develop their eggs. Although a mosquito bite is often no more than a temporary nuisance, in many parts of the world it can have serious consequences, causing diseases such as fevers and malaria.

The ability to transmit diseases has earned mosquitoes the title of the world’s deadliest animal, so it’s no surprise that for more than 100 years, careful research has been conducted into how they find their victims. Recently, another way in which these insects hunt for humans was discovered, the press service of the University of California, Santa Barbara (USA) reports.

Scientists have previously established that there is no single sign that these insects rely on. At the same time, they combine information from many different senses at different distances, in particular:

• CO2 from the victim’s breath;
• smells;
• vision;
• convection of heat from the skin and moisture of the victims’ bodies.

However, each of these signals has limitations, the article notes. Insects have poor vision, and strong winds or rapid human movement can throw off the tracking of their chemical senses.

So the researchers wondered whether mosquitoes could detect a more reliably directed signal.

As a result, scientists, having conducted research with Aedes aegypti mosquitoes, which are very good at finding their victims, added another sense to the mosquitoes’ well-known “repertoire” – infrared detection.

Infrared radiation from a source whose temperature is approximately equal to the temperature of human skin, in combination with CO2 and human odor doubled the overall activity of insects aimed at finding a host, the university press service notes. Mosquitoes overwhelmingly focused on this infrared source when searching for a host.

It is noted that:

• At about 10 cm, mosquitoes can detect the heat rising from human skin and they can directly feel the temperature of our skin as soon as they land;
• But energy from heat can also travel long distances when converted into electromagnetic waves, typically in the infrared range of the spectrum. It turns out that for mosquitoes, infrared remains an effective way to detect prey at distances of up to 70 cm.

The fact that previous studies did not observe any effect of thermal infrared exposure on mosquito behavior is explained by the researchers’ methodology:

• Scientists only sent an infrared signal without any other signals. However, the signal alone does not stimulate insects to search for victims;
• The researchers found that for mosquitoes, infrared radiation is only meaningful in the context of other cues, such as elevated CO2 levels and human odor.

The researchers also found out where the infrared detector is located and how it works at the morphological and biochemical levels. It was already known that the tips of mosquito antennae contain heat-sensing neurons. It turned out that removing them also eliminated the mosquitoes’ ability to detect infrared radiation.

According to scientists, this discovery, in particular:

• may help improve mosquito population suppression methods. For example, adding a thermal infrared signal may make mosquito traps more effective;
• also helps explain why loose-fitting clothing is particularly good at preventing bites—not only does it block the mosquito’s ability to reach your skin, it also allows the infrared radiation to diffuse between your skin and your clothing so that mosquitoes can’t detect it.

Source: Racurs

David

I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.