Mosquitoes, those pesky bloodsuckers, rely on more than just our scent to find their next meal. New research reveals their surprising ability to use thermal infrared vision to pinpoint a tasty spot on your skin, leaving you itchy and potentially exposed to disease.
A recent study published in Nature sheds light on the infrared detection system of the Aedes aegypti mosquito, a species known for transmitting diseases like dengue, yellow fever, and Zika. Scientists already knew that mosquitoes use a combination of cues to locate their hosts, including exhaled carbon dioxide (CO2), body odors, visual cues, convective heat, and humidity. “However, each of these cues has limitations,” explained Avinash Chandel, a biologist at UC Santa Barbara and co-lead author of the study.
This new research delves into the specific role of thermal infrared in a mosquito’s host-seeking behavior. The team conducted experiments where female mosquitoes were exposed to human odors and exhaled CO2 levels in two separate zones. One zone also emitted thermal infrared radiation mimicking human skin temperature. The results were striking: the mosquitoes in the zone with the infrared source exhibited double the host-seeking activity.
Previous research has shown that mosquitoes can detect the rising heat from human skin within about 4 inches (10 centimeters) and can directly sense skin temperature upon landing. This new study, however, demonstrates their ability to detect thermal infrared from a greater distance, extending their range to approximately 2.5 feet (70 centimeters) when the infrared source is active.
“Any single cue alone doesn’t stimulate host-seeking activity,” said Craig Montell, a biologist at UCSB and the study’s senior author. “It’s only in the context of other cues, such as elevated CO2 and human odor, that IR makes a difference.” This suggests that mosquitoes integrate multiple sensory inputs to effectively target their hosts.
The researchers believe this discovery could lead to new mosquito control strategies. For instance, loose-fitting clothing might offer some protection by allowing the thermal infrared radiation from the skin to dissipate, making it harder for mosquitoes to detect a potential host.
The Aedes aegypti mosquito, once primarily found in tropical and subtropical regions, has expanded its range in recent years, including to parts of the United States like California. As the geographic distribution of these disease-carrying insects grows, so does the importance of understanding their host-seeking mechanisms. This new research on their infrared vision provides valuable insights that could contribute to developing more effective methods for controlling mosquito populations and reducing the spread of mosquito-borne illnesses.
