Mosquitoes listen for a specific buzz to find mates

Have you ever wondered how mosquitoes, those pesky little buzzing creatures that keep you up at night, choose their mates? Interestingly, it’s all about listening for the right buzz.

Researchers from the esteemed Nagoya University in Japan have recently decrypted the mystery behind how the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus), differentiate their own kind from others.

How do they do it? By tuning into the unique frequencies of sound generated by the flapping wings of opposite-sex mosquitoes from their own species.

Dusk ritual, swarm and mosquito buzz

During twilight, male Aedes mosquitoes congregate in large flying swarms. It’s like a buzzing singles bar where they wait patiently for fertile females to fly in.

Study co-author Dr. Matthew Su noted that as soon as a female enters this airborne gathering, the male mosquitoes – equipped with an exceptional sense of hearing – listen for her distinctive wing-sound, approach her and attempt to woo her.

“In the past few decades, the territories of the two types of mosquitos have increasingly overlapped,” said Dr. Su. “Mainly at dusk, male Aedes mosquitoes form a swarm, a large group of flying males waiting for fertile females to fly in.”

“When a female enters the group, the male uses his excellent hearing to hear her wing sound, approach her, and attempt to mate. But females of other species could enter the group too, so we became interested in how males avoid mating with the wrong species.”

Art of listening to the buzzing mosquitos

This curiosity led the team to investigate further. They installed microphones in mosquito breeding cages to capture the frequencies of wingbeats from both sexes, and compared these frequencies between species.

An intriguing pattern was discovered – both the males and females of the Asian tiger mosquito produced higher wing sound frequencies than their yellow fever counterparts.

The researchers hypothesized that this difference in sound frequency is the secret behind how mosquitoes avoid misdirected romance.

To prove this theory, synthetic female wing sounds were played back to male mosquitoes. Without fail, the Asian tiger mosquito males responded to higher frequencies than the yellow fever males, clearly demonstrating species-specific sound recognition.

“We believe the males have optimized the vibratory properties of their ‘ears’ to match the frequencies of females of the same species,” said Professor Azusa Kamikouchi, the joint corresponding author of the study.

“This suggests that males are finely tuned to the specific wingbeat frequencies produced by females of their species.”

Tuning into the right frequency

“Mosquito mating depends on male hearing of female sounds,” noted Dr. Su. “Even though the difference in female sounds may sound small at 40 Hz, for mosquitoes – and humans in fact – this gap is huge.”

“They modulate their hearing function via signals sent from their brains to their ears to listen for the right frequency. Humans actually do something similar to help tune out background noise to sleep or hear a friends’ voice in a noisy bar.”

New approach to mosquito control?

Understanding this wing-sound phenomenon could open a new avenue for mosquito control. Currently, most traps are designed to attract females to lay eggs, which are then killed off.

However, the Nagoya researchers have an additional idea. By playing specific flight sounds, these traps could also lure in male mosquitoes.

“I could see our research being used to combine oviposition and sound traps,” said Dr. Su. “Oviposition traps exist, but they mostly catch females, so we thought why not capture males at the same time?”

“It’s good to plan ahead for potential outbreaks especially as the effects of climate change are increasing the number of people affected by mosquitoes.” 

Symbiotic coexistence with buzzing mosquitos

The researchers underscore the fact that completely eliminating mosquitoes would harm the ecosystem. Despite being a nuisance to humans, these creatures play important environmental roles as pollinators for plants and feeders for amphibians.

“Elimination may not be a good idea because we don’t know the effects on the ecosystem. Instead, we feel that limited biocontrol is better,” Dr. Su explained.

“Ultimately, we will have to live together with mosquitoes, ideally separately. Therefore, we have to understand them and drive numbers down to levels where diseases are less likely to be transmitted.” 

So the next time you’re bugged by a mosquito’s incessant buzz, remember that it’s not just noise, it’s intricate insect communication at work.

The study is published in the journal iScience.

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