An international research team has discovered intriguing insights into how mosquitoes mate, which may enhance malaria control strategies and could inform advancements in precision drone technology. According to their findings, when a male Anopheles coluzzii mosquito perceives the distinctive wingbeat sound of females, his vision becomes activated, enabling him to search for a potential partner nearby. This connection between males detecting female-specific sounds and visually targeting objects could lead to innovative mosquito control methods, particularly targeting the Anopheles species responsible for malaria transmission.
If you hear a high-pitched buzzing sound, it’s a telltale sign that a female mosquito is nearby looking for blood – this task is performed by females, not males. While this noise might prompt you to swat at the insect, for a male mosquito, it signals mating time.
A team led by researchers from the University of Washington has made fascinating discoveries about mosquito mating behavior, which may improve malaria management and assist in developing precision drone technologies. In their paper released on August 30 in Current Biology, the team disclosed that a male Anopheles coluzzii mosquito’s eyes become active upon hearing the frequency of female wingbeats.
Many mosquito species, including Anopheles coluzzii, a primary malaria vector in Africa, typically have limited vision. However, the team observed that when males hear the characteristic sound of female wings, their vision is engaged, allowing them to search their surroundings for a mate. Remarkably, even in the midst of a crowded, buzzing swarm, males can focus on a potential female target, maneuvering swiftly through the group without colliding into others.
“We discovered a robust connection between male mosquitoes searching for mates: they hear specific frequency wingbeats made by females, triggering their visual system,” explained lead author Saumya Gupta, a postdoctoral researcher in biology at UW. “This highlights the complex interaction among various sensory systems in mosquitoes.”
This significant correlation between male mosquitoes hearing female-like wingbeats and moving toward visual stimuli may pave the way for the creation of new traps that specifically target Anopheles mosquitoes, the carriers of malaria.
“The appeal of this sound is so compelling for males that it prompts them to move toward what they perceive as the source, whether that’s an actual female or possibly a mosquito trap,” added senior author Jeffrey Riffell, a biology professor at UW.
Like many Anopheles species, Anopheles coluzzii mates in expansive swarms during sunset, predominantly consisting of males with only a few females present. To the naked eye, these swarms appear chaotic with mosquitoes darting past one another. Males need to skillfully utilize their senses to avoid collisions while searching for the rare female.
Gupta, Riffell, and their collaborators—including experts from Wageningen University in the Netherlands, the Health Sciences Research Institute in Burkina Faso, and the University of Montpelier in France—aimed to study how mosquitoes’ sensory systems work together in these swarms. They created a miniature arena resembling a flight simulator with a curved, pixelated screen to recreate the visual disarray of a swarm. Within this arena, a tethered male mosquito could not fly freely but could still see, smell and hear, mimicking flight behavior.
In tests with multiple male Anopheles coluzzii mosquitoes, the researchers found that males reacted differently to an object in their line of sight based on the sound they were exposed to. When a tone at 450 hertz, the frequency of female wingbeats, was played, males were directed toward the object. Conversely, if a tone at 700 hertz, closer to the frequency of male wingbeats, was played, they did not respond in the same way.
The proximity of the object also played a role. Males would not adjust their direction toward an object if it appeared to be more than three body lengths away, even when female-like tones were present.
“The resolving power of a mosquito’s eye is approximately a thousand times less than that of a human’s,” noted Riffell. “They generally rely on sight for passive tasks, like navigating around obstacles.”
In addition to their strong response to female flight tones, arena tests showed that males made minor flight adjustments around other objects even without specific sounds. They changed the amplitude and frequency of their wingbeats in response to visual stimuli, suggesting these actions might be instinctual maneuvers to avoid collisions. The team further examined male-only swarms in the lab and observed that males tended to accelerate away from one another upon nearing another male mosquito.
“Our findings suggest that males utilize close-range visual cues to prevent collisions within swarms,” stated Gupta. “However, the presence of female wingbeat sounds seems to greatly modify their behavior, indicating the importance of combining auditory and visual information.”
This research could offer a fresh approach to mosquito control by focusing on how mosquitoes integrate auditory and visual signals. The males’ consistent attraction to visual clues triggered by female buzz might be an exploitable weakness that researchers can leverage for the next generation of mosquito traps—especially for Anopheles species, which play a significant role in spreading malaria pathogens.
“Focusing on mosquito swarms is an effective strategy for control efforts, as it can significantly decrease overall biting,” said Riffell. “However, current methods, particularly insecticides, are becoming less effective as mosquitoes develop resistance. We need innovative strategies, such as lures or traps designed to attract mosquitoes with high effectiveness.”
Co-authors on the study include Antoine Cribellier, Serge Poda, and Florian Muijres from Wageningen University, along with Olivier Roux from the University of Montpelier. Roux and Poda are also associated with the Health Sciences Research Institute in Burkina Faso. Funding for the research was provided by the Human Frontiers Science Program, the National Institutes of Health, the Air Force Office of Scientific Research, and the French National Research Agency.
