Introduction:
Did you ever wonder why mosquitoes seem to be more attracted to certain individuals? Recent research has shed light on the specific reasons behind this phenomenon. In this episode, we delve into the chemistry of skin odors and explore the molecules that make some people more appealing to these bothersome insects. Additionally, we uncover effective products that can help deter mosquitoes. Join us as we unravel the secrets of mosquito attraction.
Video Transcript:
Are you constantly bothered by mosquitoes?
I can relate—I’m a mosquito magnet myself. It seems like no matter where I am or who I’m with, mosquitoes always single me out for a bite. It’s like I’m their personal barbecue, although I wouldn’t recommend hosting indoor barbecues as suggested by the American Chemical Society.
If you’re also a mosquito magnet, you’re not imagining it. There are genuine reasons why certain individuals are more attractive to mosquitoes than others.
Before we explore why mosquitoes have a preference for specific people, let’s understand what happens when these tiny vampires feast on our blood.
When a female mosquito lands on you (only females bite), it pierces your skin with its proboscis—a mouthpart consisting of six tiny needles. Two of these needles have serrated edges, similar to a saw blade, which aid in pain reduction and prevent immediate swatting.
The proboscis is designed to minimize discomfort by starting with a soft touch and combining a sawing action with gentle vibrations. Interestingly, scientists are even studying these structures to develop painless microneedles for medical injections. So mosquitoes may be unintentionally contributing to society after all.
Mosquitoes not only extract blood from us but also inject their saliva into our bodies. Although researchers are still uncovering the exact role of each chemical in mosquito saliva, some act as numbing agents to prevent us from sensing the bite. Others function as vasodilators and anticoagulants, ensuring that our blood flows freely and doesn’t clot.
There are more than 100 proteins in mosquito saliva, and not all of their functions are fully understood. However, we do know that the cocktail of chemicals triggers an allergic reaction in our bodies, leading to itchiness. Our immune system recognizes the foreign proteins from mosquito saliva, prompting a histamine response that causes itching and attracts white blood cells to the area.
As someone who despises mosquito bites, I find the entire process incredibly frustrating. Not only do they find me easily, but the bites often linger for weeks.
So, how do mosquitoes locate us in the first place?
Mosquitoes use various sensory clues to track us down. They can detect our body heat, follow the scent of carbon dioxide (CO2) from our breath, and sometimes even spot us due to our size disparity. These broad sensory cues provide a general sense of where humans are located. However, once they find a gathering like a barbecue, how do they choose whom to bite?
This is where skin odor comes into play.
Numerous studies have been conducted over the years to determine why some individuals emit scents that are more appealing to mosquitoes. Some studies suggest that blood type or the consumption of certain foods or drinks may play a role. Pregnancy and the presence of a malaria infection have also been linked to mosquito attractiveness.
While these studies suggest intriguing connections between malaria infection and mosquito preference, they often yield different results or conflicting findings, leading to confusion.
Fortunately, in recent years, groundbreaking research has shed new light on mosquito attraction. These studies have left me feeling vindicated and excited to share their findings.
The first study, published in the fall of 2022, focused on the fatty acids present on our skin, specifically carboxylic acids exuded in our sebum—a waxy, oily substance that helps moisturize our skin. The researchers devised an ingenious experiment in which participants wore nylon stockings on their arms to collect their sebum. They then created a chamber where Aedes aegypti mosquitoes could choose between differently scented nylons.
The results were remarkable.
Mosquitoes were significantly more attracted to the scent of individuals who are often targeted by these insects. Finally, scientific evidence supports what many of us mosquito magnets have long believed. The study revealed several carboxylic acids, including pentadecanoic, heptadecanoic, and nonadecanoic acids, that were present in higher levels on the skin of those highly attractive to mosquitoes. Additionally, they identified ten other unidentified compounds within the same chemical class.
The study spanned three years, ensuring that external factors such as food consumption or recent alcohol intake did not skew the results. These attractant compounds were proven to be consistent and stable.
Why do these compounds vary between individuals?
Several factors could contribute to the differences observed. Genetic predisposition may influence the production of distinct skin compounds, and variations in our skin microbiomes could also impact the presence of specific fatty acids. As a geneticist, I eagerly await follow-up studies to delve deeper into this area.
I didn’t have to wait long for more mosquito magnet research. In May 2023, another study emerged, focusing on Anopheles gambiae, another common mosquito species. Using an innovative camera setup, the researchers observed mosquitoes landing on warm targets scented with various substances, including isolated attractants like CO2 and whole body odor from six different humans.
The experimental setup was impressive. Mosquitoes were placed in a large caged outdoor arena, and tubes connected to the arena led to tents containing the targets—the humans. Fans facilitated the transmission of human scents through the pipes into the central arena, allowing mosquitoes to choose their preferred destination.
To add a touch of humor, they even placed a fan next to a sleeping human to attract mosquitoes. Truly delightful.
This study also highlighted the significance of car
