A recent study published in the journal Nature Communications has revealed an interesting reason why Aedes aegypti, a common mosquito species, seeks out and bites human skin.
As we are in the midst of a cold winter, many are looking forward to warm summer days, yet they dread the pesky mosquitoes. So, who are the “favorite” targets of these mosquitoes? This is a question that scientists are still trying to answer.
The new research shows that Aedes aegypti, after detecting human breath, is attracted to specific colors including red, orange, black, and light blue.
Red is the color that attracts mosquitoes.
The researchers believe that this discovery will help explain how mosquitoes locate their hosts, as human skin, regardless of overall pigmentation, sends a strong “signal” of red-orange to mosquito eyes.
“There are three main factors that attract mosquitoes: human breath, sweat, and skin temperature. In this study, we have identified a fourth factor: the color red. This color is not only found on your clothing but can also be present on each person’s skin,” said Jeffrey Riffel, a biology professor at the University of Illinois, USA, and the lead author of the study.
In the experiments, the research team observed the behavior of Aedes aegypti mosquitoes. They sprayed specific scents into a small test chamber and displayed various visual patterns, such as colored dots or human hand shapes.
In the absence of any scent stimuli in the room, the mosquitoes essentially ignored the colored dots, regardless of their color.
After spraying carbon dioxide into the room, the mosquitoes continued to overlook the colored dots, whether they were green, blue, or purple. However, if the dots were red, orange, black, or light blue, the mosquitoes would fly towards them.
The researchers noted that most people can see different colors at various light wavelengths, such as 650 nanometers for red and 450 nanometers for blue.
However, it remains unclear whether mosquitoes perceive colors in the same way that the human eye does. Most of the colors that attract mosquitoes after detecting carbon dioxide are red, orange, and black—all corresponding to longer light wavelengths. Meanwhile, human skin also emits long-wavelength signals in the red-orange spectrum.
This study sheds light on how the olfactory senses of mosquitoes influence their responses to visual cues. Understanding the colors that attract mosquitoes could aid in designing more effective mosquito repellents and insecticides.
