Certain male flies perform love songs that female flies find irresistible, and now you can hear one of these songs, thanks to new research.
Click here to have a listen.
(Two of the fruit flies and an image showing the neural cirtuitry that drives the singing and courtship process; Credit for the image and recording: Anne von Philipsborn and Tibor Kulcsar)
To produce the song, he extends and then vibrates a wing. What you hear is the pulsating acoustic signal created by this exercise. To the human ear, it sounds like humming or crackling.
To female fruit flies, it’s magic and leads to arousal and mating.
(A fun aside here is that these are the small flies you often see swarming around ultra ripe or rotten fruit. You’ve probably had a bunch of them in your kitchen at some point, perhaps going through their elaborate courtship process right next to your produce.)
Researchers aren’t just being voyeurs with the flies. Because the flies are tiny and easy to study, the scientists are using them as models for decision-making, action selection, and motor pattern generation in all living organisms. In short, the researchers want to find out how meaningful behavior is orchestrated.
Neurobiologist Anne von Philipsborn and IMP director Barry Dickson have reached the point where they can cause a male fly to start singing and get “in the mood” even without having a female around. It’s a bit like turning a fly into a robot, controlled by a remote.
They do this using a method called thermal activation. The researchers fit defined sets of fly nerve cells with temperature-sensitive ion channels. The channels open up when the temperature reaches 86 degrees Fahrenheit. At that heat, the channels also become permeable for certain small molecules. This incoming flow of ions, in turn, activates the nerve cell and triggers an impulse.
By switching on and off targeted nerve cells, the neurobiologists identified two centers in the fly’s nervous system that control singing. According to an =1&tx_ttnews=1293836400&tx_ttnews=31535999&tx_ttnews=1&cHash=01779b6677']IMP press release outlining the new research, “the command to sing comes from a center located in the brain. This network of cells receives input from various sources. The most important of these are sensory organs and other regions of the brain. What the fly sees, hears and smells is channeled to this circuit and, together with pre-existing information obtained from prior experience, a decision is made to court or not to court the female.”
“The second neural circuit is located in the chest and is connected to the muscles that move the wings. This network is a so-called pattern generator. It coordinates the movement of the muscles and produces their rhythmic pattern.”
Given the above information, the next step for the researchers is to look deeper into the mechanisms that control behavior.
“We now need to figure out exactly how this circuit works under normal conditions, when the male is naturally aroused by a virgin female,” Dickenson said. “And we are also now starting to use the same method to look for neurons that trigger other components of mating behavior, such as copulation itself.”