Fruit Flies Have Neurons For Late-Night Lovin', And You Might Have Them Too
Sleep is great, but sometimes other activities—reading a dramatic page-turner, finishing up an art project, getting to know someone a bit better, if you catch our drift—take precedence. That's no different for fruit flies. They can keep themselves awake if there's lovin' to be had, and now researchers have discovered the brain cells responsible. It's an important step to understanding how humans stay "up all night to get lucky," too.
All Night Long
For a 2017 study published in the journal eLife, scientists set out to find the neurons responsible for balancing a fruit fly's drive for sleep with that for sex. In the past, researchers had noticed that fruit flies vary in the amount of sleep they need: flies sleep less when they're starving, probably because they need to find food; female flies sleep less after mating, probably so they can lay eggs; and groups of male and female flies sleep less than single-sex groups, probably because there's some hanky panky going on. Still, they didn't understand the underlying mechanism.
The researchers screened for neurons that might be responsible for keeping fruit flies awake for love, and stumbled upon a small number of a type they called MS1, which are responsible for releasing octopamine, a chemical similar to human noradrenaline. MS stands for "male specific," and that's because when they activated it, it kept isolated male fruit flies awake, but not isolated females. That's a clue that they're the neurons responsible for helping males stay up all night for mating—they don't control male sexual behavior, but they do communicate with the mating neurons to help males stay awake and court females.
Is this what's at work keeping humans awake until last call at the singles bar? Unfortunately, it's unclear, but the researchers can muse. "The noradrenergic system in humans, which is similar to the Drosophila octopaminergic system, may function in an analogous manner to allow important motivational factors such as sex drive, fear, and hunger to overcome sleep drive," they write.
Why the heck are scientists doing this research on fruit flies? You're not the only one who's wondering. In 2008, U.S. vice-presidential hopeful Sarah Palin famously said, "...sometimes these [tax] dollars go to projects that have little or nothing to do with the public good. Things like fruit fly research...I kid you not."
It led to a flurry of op-eds from science proponents, and for a good reason: fruit fly research has led to a wide range of important discoveries, especially in the realm of genetics. Fruit flies are what's known as a model organism. Like a model of, say, a solar system, model organisms are smaller and simpler than organisms like us, so they're easier to study. At the same time, they still have many of the same characteristics as more complex organisms. Plus, they procreate like gangbusters: you can watch a fruit fly's entire lifespan in just a few weeks, and breed several generations in a matter of months.
That's why when you hear that scientists have discovered something in fruit flies, instead of laughing, you should pay attention. There's a good chance that if they found it in fruit flies, they could find it in us.
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