Mosquitoes Track Humans Using Infrared, Finds US Study

Researchers at UC Santa Barbara have found that the mosquito species Aedes aegypti is highly attracted to infrared sources when seeking hosts. This species is responsible for spreading viruses like dengue, yellow fever, and Zika, causing millions of cases annually. The study, published in Nature, reveals that these insects do not rely on a single cue but integrate multiple sensory inputs over various distances.

Mosquitoes like Aedes aegypti use several cues to locate hosts from afar. These include carbon dioxide from exhaled breath, body odours, visual signals, heat from skin convection, and body humidity. "However, each of these cues has limitations," said Avinash Chandel, a postdoctoral researcher at UCSB. Poor vision and environmental factors like wind or rapid human movement can disrupt their chemical tracking abilities.

Within approximately 10 cm, mosquitoes can detect heat emanating from human skin. They can also sense skin temperature directly upon landing. These abilities correspond to two types of heat transfer: convection and conduction.

The research team speculated whether mosquitoes could detect a more dependable directional cue such as infrared radiation. "The mosquito we study, Aedes aegypti, is exceptionally skilled at finding human hosts," said Nicolas DeBeaubien, co-lead author and former UCSB graduate student and postdoctoral researcher in Professor Craig Montell’s lab. "This work sheds new light on how they achieve this."

The study highlights the complexity of mosquito host-seeking behaviour by showing that they integrate various sensory information rather than relying on a single cue. This integration helps them navigate effectively despite the limitations of individual senses.

Understanding these mechanisms could lead to better strategies for controlling mosquito populations and reducing the spread of diseases they transmit.

With inputs from WAM