For those who aren’t inclined to trudge through the technical, scientific article, we’ve broken down the basics here so you can learn all about mosquito courtship.
What Did We Already Know About Mosquitoes Buzzing?
Before we dive in, it’s important to understand that scientists have long-since established that mosquitoes can perceive sound, and many studies have been done on this topic since the original discovery of Johnston’s organ (the mosquito’s ear) in 1855. It is also accepted that the buzz of a female flying mosquito is a mating signal. It alerts males to the female’s presence and attracts them to her.
Despite decades of research, scientists still don’t fully understand mosquito biology, namely mating behavior (we’ll explain why cracking the mosquito’s mating secrets is so important in a bit). This study is notable because it uncovered new information that revised the current understanding of mosquito mating behavior.
What Have New Information We Learned About a Mosquito’s Buzz?
Typically, the frequency created when mosquitoes fly at an established tone, and that tone is between 300 and 600 Hz, depending on the species. However, this study uncovered that the process of attracting a mate is not just the male hearing and following a female’s tone.
Among the different types of mosquitos, certain species can change their wing beat frequencies to match each other, thus creating a harmonic duet (or love song!).
The A. aegypti species, i.e. the mosquito that spreads the Zika virus, modulate their flight tones when they are within a few centimeters of each other. Surprisingly, they do not change their sounds to meet the already established fundamental frequency of 400 Hz for a female or 600 Hz for a male, but a shared harmonic frequency of 1200 Hz, which is much higher.
This is shocking because it was previously concluded that male mosquitoes could only hear frequencies between 300 Hz and 800 Hz, and nothing higher. After discovering this harmonic mating frequency, an in-depth neurophysiological examination was performed, and the researchers found that both males and females can detect sounds up to 2000 Hz.
The study is also significant because it reveals that both sexes of mosquito can hear and respond to sounds. Females were previously thought to be deaf.
How Do We Know Mosquitoes Can Hear?
This study included a series of behavioral experiments, in which the researchers tethered mosquitoes to the end of an insect pin. The mosquitoes were then suspended in midair, which caused them to flap their wings and fly.
The fundamental flight tones were established and recorded, and then the scientists moved the mosquitoes (on their tethers) past mosquitoes of the opposite sex and observed the changes. The researchers performed multiple 10-second “fly-bys,” moving the female mosquitoes in and out of the male hearing range.
Why Are Mosquito Mating Habits Worth Studying?
Aside from the fact that this is an intriguing study, these findings are quite significant in solving many of the public health issues caused by mosquitoes.
Mosquito-borne diseases like malaria, yellow fever, dengue, and most recently, Zika, continue to affect millions of people around the world. The more we know about the mosquito as a disease vector, the better chance we have at containing them and finally putting an end to these outbreaks.
Mating behavior is an especially important topic for scientists to understand, as it gives them valuable tools to limit mosquito reproduction, and therefore limit the spread of disease.
This particular study found that females are less responsive to male flight tones after having mated, and they are less likely to match the male’s tone. This is in line with previous findings, and it gives us an important clue about how to interfere with mosquito reproduction. One strategy is to release sterile mosquitoes into the wild so that mating potential is diminished. This has been shown to work with other insects in the past.
The study authors hypothesized that a male’s ability to change its flight tone is a measure of the male’s reproductive readiness. So, they believe that developing this ability for lab-raised, sterilized, or genetically modified males could be a viable way to hinder species reproduction.
In a larger sense, this study was an important step in understanding mating behavior and could bring us closer to stopping diseases like Zika from spreading.