A groundbreaking study from UC Santa Barbara has revealed that mosquitoes possess an unexpected sense: infrared detection. This new discovery, published in Nature, significantly enhances our understanding of how mosquitoes locate their hosts and opens new avenues for mosquito control.
Mosquitoes, particularly the species Aedes aegypti, are known for their sophisticated host-seeking abilities. They rely on a combination of cues—carbon dioxide (CO2), human odours, visual signals, convective heat from skin, and humidity—to find their targets. However, recent research has shown that these insects also use infrared radiation to guide their search.
EXPERIMENT SETUP AND FINDINGS
In their study, the researchers exposed female mosquitoes to human odours and CO2 in two separate zones. One zone also emitted infrared radiation from a source at approximately human skin temperature. Despite the barrier preventing direct heat transfer, mosquitoes were significantly more attracted to the infrared zone, demonstrating that infrared radiation plays a crucial role in their host-seeking behaviour.
INFRARED SENSOR MECHANISM
Unlike visible light, infrared radiation cannot be detected by rhodopsin proteins, which are sensitive to light. Instead, mosquitoes use a different method to sense IR. The researchers identified heat-sensitive neurons located at the tips of the mosquito’s antennae, which are activated by infrared radiation. These neurons use the TRPA1 protein to detect temperature changes.
BIOCHEMICAL INSIGHTS
The study also found that two rhodopsin proteins, Op1 and Op2, in addition to TRPA1, play roles in extending the sensitivity of mosquitoes to infrared radiation. While TRPA1 directly responds to higher IR levels, Op1 and Op2 assist in detecting lower levels of IR, broadening the mosquito’s detection range.
IMPLICATIONS FOR MOSQUITO CONTROL
The discovery of infrared detection could revolutionize mosquito control strategies. Incorporating infrared sources into mosquito traps might improve their effectiveness, while understanding how mosquitoes use thermal IR could enhance personal protection methods. For instance, wearing loose-fitting clothing can help dissipate IR and reduce mosquito attraction.
ADDRESSING MOSQUITO-BORNE DISEASES
With mosquitoes responsible for spreading diseases affecting billions globally, this new insight is crucial. The ability to target and control mosquito populations more effectively could help combat diseases such as dengue fever and Zika virus, particularly as mosquitoes expand their range due to climate change and global travel.
FUTURE RESEARCH DIRECTIONS
The researchers plan to further investigate the mechanisms of infrared detection and its implications for mosquito behaviour and control. By refining our understanding of mosquito sensory biology, future interventions could become more targeted and effective.
The UC Santa Barbara team’s discovery of infrared detection in mosquitoes provides valuable new knowledge about how these insects locate their hosts. This breakthrough not only enhances our understanding of mosquito biology but also offers promising avenues for improving mosquito control strategies and reducing the spread of mosquito-borne diseases.
