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These Fighting Fruit Flies Are Superheroes of Brain Science | Deep Look

August 19, 2019

This episode is supported by the Great Courses Plus. Go to to learn
more. These fruit flies are throwing down. They’re like fruit fly gladiators. They lunge. Flip each other over. Roll around. And even toss each other, sumo-wrestler style. Normally, fruit flies don’t get this worked
up over a drop of apple juice. But these guys have had their genes manipulated,
something scientists have been doing to fruit flies for more than a century. Yep, these little insects that we only notice
when they get into our kitchen are unsung heroes of science. In 1910, biologist Thomas Hunt Morgan noticed
a rare white-eyed fly among his normal red-eyed ones. The discovery led to our fundamental understanding
of how genes get passed on from generation to generation. Since then, fruit flies have been key to figuring
out how human diseases work. That’s because, when it comes down to it,
fruit flies are more like us than you might think. They have about the same number of genes: 20,000 or so. In fact, 75 percent of the genes that make
humans sick are found, in a very similar form, in fruit flies. They’re a simpler version of us, a kind
of genetic mirror that scientists have used to learn about cancer, Parkinson’s, Alzheimer’s. And the fighter fruit flies? They’re helping researchers learn about
conditions that tap into our emotional states, like depression or addiction. Neuroscientist Eric Hoopfer – who studies
fruit flies in David Anderson’s lab at Caltech – flashes them with a red light. He has altered these research flies to be
sensitive to this light. It activates a cluster of neurons in the flies’
brains. And they fight. But change the intensity of the light, and
they do something very different. See how they’re vibrating just one wing? That’s fruit fly flirting. The researchers were surprised to see that
the same neurons controlled such different behaviors. What do fighting and “flirting” have in
common? In both, flies are pretty hot and bothered. These neurons control something like emotional
arousal. Pinpointing these circuits in their brain
could help us figure out where trouble starts in the human brain… and maybe one day, lead
to better treatments for mental illness. So the next time you see one of these guys
on your leftover piece of banana, you might want to think twice about swatting it. A little thanks might be in order instead. Thanks to the Great Courses Plus for sponsoring
this episode. The Great Courses Plus is a digital learning service providing a range of topics from educators. Start your one-month trial by clicking the
link below or going to Hey guys. It’s Lauren. These flies seem to be having fun. If you’re curious about the amorous habits
of other animals, check out our video on newts. Every year they travel back to the pond where
they were born to get some underwater lovin’. And watch how garden snail babies are made. It involves a tiny spear called a “love
dart.” Thanks for watching.


  • Reply It's Okay To Be Smart March 28, 2017 at 5:29 pm

    Cool! They made Drosophila melee-nogaster

  • Reply PillsWontHelpYouNow February 4, 2019 at 2:51 pm

    Hmmm, I don't think it's fair to say that mice or fruit flies have the same diseases humans have.

  • Reply CovetableMean YT February 8, 2019 at 7:44 pm

    0:23 DROPKICK!
    0:40 SUPLEX!

  • Reply Michael Tran February 15, 2019 at 5:32 am

    PETA is probably angry

  • Reply RKO - Gaming February 17, 2019 at 5:53 am

    Kills Fruit flies while watching this in end you might think twice oh rip -_- i'm monster

  • Reply The game master February 18, 2019 at 11:59 pm

    I never thought I would see a fly suplex another fly.

  • Reply Scarlet BloodMoon February 20, 2019 at 6:30 pm

    Mind control

  • Reply June February 23, 2019 at 4:35 am

    rainbow wings,epic

  • Reply Jessie Amalli February 23, 2019 at 5:57 am

    0:12 when me and my brother fighting over food

  • Reply Tigee Shark February 23, 2019 at 12:02 pm

    Probably my only chance to swat them

  • Reply Rrezarta Meti February 23, 2019 at 8:34 pm

    flip each other

  • Reply Dewan Covers February 24, 2019 at 4:32 am

    Most exploited insects in Biotechnology studies.
    I am a biotechnology student and i love experimenting with this little friends.

  • Reply Exo Phase February 24, 2019 at 5:27 am


    Top 1 Best anime fight

  • Reply MARIO SONIC/Bukunmi February 24, 2019 at 9:35 pm

    Super Smash Flies

  • Reply •corgi weirdo!• February 26, 2019 at 3:54 am

    fruit fly flirting is SOOO innapropiate

  • Reply Gayatri Kulkarni February 26, 2019 at 5:11 am

    0:21 more like"Melanogangster"

  • Reply QTee February 27, 2019 at 9:42 am

    Omg these little hideous critters are impossible to stop watching… hey. Im up!

  • Reply Hello sir February 28, 2019 at 6:37 am

    It has more than four legs so I hate it.

  • Reply Leah Ceri March 4, 2019 at 3:41 pm

    Now I know what to do the next time I see a fruitfly. Just don't know where to get a red light

  • Reply yellowhammerheath March 6, 2019 at 10:11 pm

    FOR HONOR in a nutshell

  • Reply The GamerYT March 10, 2019 at 12:20 pm


  • Reply Chan Ho Woo March 19, 2019 at 5:42 am

    MK Flytra

  • Reply Cosmic Carma March 22, 2019 at 9:46 pm

    I have never seen flies fight, but it’s so funny😂😂

  • Reply Bobs o r Vegana March 26, 2019 at 2:24 pm

    That bass part was pretty epic. 0:40

  • Reply Naruto & sasuke Funny moments March 31, 2019 at 12:15 pm

    These Fighthing Fruit Flies are Mating Season Attack

  • Reply 뭘 하면 좋으려나? what should i do?何をすればいいかな?. March 31, 2019 at 2:53 pm

    It would have been much intriguing if that red light was capable of affecting on us lol.

  • Reply queenlover123 lps April 1, 2019 at 3:23 am

    Yay lai

  • Reply Potatoes Kween April 1, 2019 at 3:59 am

    I'm that third fly in the background screaming " Worldstar"

  • Reply Adeline Chong April 3, 2019 at 3:08 pm

    Hahahaha the mini John Cena

  • Reply Fortnite Sabrlese April 5, 2019 at 5:51 pm

    i hate those yheir coming on my food😠😠😡😡😡😡

  • Reply Jason Zheng April 6, 2019 at 4:31 pm

    next time i see one, ima think twice of how to hit it

  • Reply Rismay Habibi April 10, 2019 at 12:56 am

    This video reminds me about my last semester's project. The project was about genetic mapping… i got 3 strains of fly. One strain have vestigial wings, then the normal strain also the black body strain… then my friend got the project about this "flirting" process…. suddenly i feel grateful because i don't need to babysit 5 strains at once…😑😑😑

  • Reply Lilith [Alien hybrid goddess] {SCP-5002} April 13, 2019 at 3:47 am

    Fruit fly: on back hoomun halp meh pls

  • Reply LilithCatsLol(*-*) April 18, 2019 at 1:27 am

    0:23 Y E E T

  • Reply lorenzo jackson April 24, 2019 at 3:49 pm

    The power of Red Kryptonite

  • Reply Scare League April 25, 2019 at 2:15 am

    are you not entertained

  • Reply Pretty Ricky April 27, 2019 at 3:57 am

    You did not just compare me to a fruit fly…

  • Reply s a n i y a *—* April 28, 2019 at 8:24 pm

    “what do fighting and fu-flirting have in common?”

  • Reply Deeep Gagan April 30, 2019 at 2:51 pm

    2:50 this is what pure witchcraft looks like

  • Reply Nikki M May 1, 2019 at 12:59 am

    Sooo cool!
    Still gonna swat'em though…

  • Reply Letz Talk May 1, 2019 at 6:40 am

    Relationships be like:

  • Reply Owen Digity May 3, 2019 at 1:26 pm

    All of these videos are ambiguous, vague, poorly informed loads of garbage. Good job pbs.

  • Reply Semira and Aydin Nikocevic May 4, 2019 at 4:28 pm


  • Reply Marvelous Mary May 7, 2019 at 12:26 am

    I’ll say thanks and then kill it heh…3:38

  • Reply Badd Mouth May 10, 2019 at 1:51 am

    Woah!!! They are legitimately wrestling.

  • Reply KingØJack May 10, 2019 at 2:23 am

    Thanks fruit flies, thanks for helping to find me anxiety meds that actually work 😀

  • Reply ??? waluigi May 10, 2019 at 5:35 am

    these flys say what sup what sup and Square each other up

  • Reply ??? waluigi May 10, 2019 at 10:16 pm


  • Reply zocoly ice May 21, 2019 at 11:29 pm

    This is the best wrestling fight ever😂😂😂😂😂

  • Reply MrFishBreath God May 22, 2019 at 6:35 am

    They should make a fruit fly WWE

  • Reply jeff namw May 22, 2019 at 11:13 pm

    I'm half a furit fly? Then why i don't have wings?

  • Reply Zaihas Syakhir May 25, 2019 at 12:11 pm

    S U M O F L I E S

  • Reply •Fader• May 28, 2019 at 10:46 pm

    imagine a fruitfly and john cena wrestling each other.

  • Reply Frappelychee May 29, 2019 at 11:36 pm

    Oh no I regret watching this. Now when I'm in a house with fruit flies I'm gonna have panic attacks thinking about them "doing it" all around me and possibly me accidentally squishing some in the middle of it and then I have their body parts and goup stuck on me 😷😷😷🤢🤢🤢🤮🤒

  • Reply GreyCloud The Weird OC XD June 4, 2019 at 12:20 am

    Me as a scientist: lol i wonder what would happen if i- oops
    makes danger flys

  • Reply Dark Soul June 4, 2019 at 3:01 pm


  • Reply Amine Boukhriss June 5, 2019 at 10:54 am

    a little thanks for making my food NASTY 😒

  • Reply Subscribe To Me For No Reason June 6, 2019 at 7:41 pm

    I showed a fruit fly this video and it started waving a right wing at me..

  • Reply animageekgurlfan1346 June 7, 2019 at 5:26 am

    No…. I’ll still swat it

  • Reply that awkward loner June 12, 2019 at 1:23 pm

    Cool, now I know that we are identical to these annoying monstrosities.

  • Reply King Fantastic June 13, 2019 at 2:00 pm

    Right!!! Tryna find ways in which the human brain can also be controlled… No red light is gonna bother me that much, in your face scientists!!! Hahahaha

  • Reply ERROR June 20, 2019 at 12:15 pm

    If this research gets to humans, and gets into the wrong hands, it could turn into kingsman.

  • Reply Nandanie July 4, 2019 at 9:13 pm

    The quality tho 😍😍

  • Reply Araceli Miguel July 5, 2019 at 2:47 pm

    2:43 sweet flip bro

  • Reply ??? July 5, 2019 at 11:30 pm

    No, I'm still gonna swat it

  • Reply Jacob Mo-Middilly-Morin July 6, 2019 at 4:16 am

    I must know the music

  • Reply Yusuf Suharyadi July 7, 2019 at 3:17 am

    very cute when a seen closely , I want one

  • Reply Kaiman Nesbitt July 7, 2019 at 3:20 am

    I thought they made up the thing about fruit flies with white eye as part of the lesson

  • Reply Eric VandenAvond July 7, 2019 at 2:37 pm

    Wow what an amazing video. Keep it up.

  • Reply seatbelttruck July 7, 2019 at 9:54 pm

    …The flirty flies are a male and a female, while the fighting flies are both male. I hope they tried both scenarios with different combinations of sexes, or it really throws their findings into question, if indeed the cause of the behavior was different frequencies of light.

  • Reply ming yew July 8, 2019 at 2:43 pm

    0:46 attitude adjustment fruit fly style

  • Reply Bazooka Llama Productions July 9, 2019 at 3:57 pm

    chevelle sings "SEEING RED AGAAAAAIN!!!!!"

  • Reply Max Amazing July 10, 2019 at 5:55 am

    When they fight it looks like you and your brother or sister are fighting for the last pizza

  • Reply KamiSam July 11, 2019 at 8:48 am

    I will destroy all these flies if they enter my home. But I love their science lol

  • Reply NoirKami July 13, 2019 at 6:36 am

    Haha imagine if they could find a link to do this to humans 😂

  • Reply ALIEN SIGNALS July 13, 2019 at 7:12 pm

    Genes don't make people sick, diseases which effect the genes, cells, body systems make people sick.

  • Reply ACiD_ ReinX July 14, 2019 at 8:00 pm

    World star!!!

  • Reply vorniceanu ionut July 15, 2019 at 11:40 am

    Better treatment or manipulation. With the way humain are ,,evolved,, right now, surely the latest…

  • Reply Requiamas Roach July 16, 2019 at 11:57 pm

    0:24 that back flip though

  • Reply Frank Blangeard July 17, 2019 at 4:02 am

    On a battlefield, shine the correct intensity of red light at the enemy and the enemy would want to flirt instead of fight. 2:48

  • Reply eb verge July 17, 2019 at 6:22 pm

    They are super cute.

  • Reply *LaDY* *L0VE* July 18, 2019 at 2:36 pm

    So cute in this video😍
    Not so cute in clusters in someone's kitchen 😝

  • Reply PYRO_SKELETRON plays July 19, 2019 at 2:22 am

    Why would we thank them when they are on our food. They are the ones free and not in the laboratory working.

  • Reply Tanki The T-34-85 July 20, 2019 at 4:12 pm


  • Reply Machine_Gun_Kelly July 21, 2019 at 7:13 am

    come on college boy

  • Reply Z E July 23, 2019 at 7:50 pm

    I will use fruit flies flirting techniques to flirt with the female.

  • Reply Vishnu Prasad July 25, 2019 at 1:23 am

    Wait, but didn’t they say they where both males

  • Reply Funky Monkey July 26, 2019 at 3:05 am

    I mean there’s bdsm so I’m not surprised

  • Reply LegendaryRalts July 28, 2019 at 7:09 am


  • Reply Freedom Pirate UK Audit Law July 30, 2019 at 4:41 pm

    Watches vid then goes into kitchen and kills the remaining flies without a thought

  • Reply simply shubh August 4, 2019 at 1:37 am

    I need to install red headlamp to my bike

  • Reply simply shubh August 4, 2019 at 1:37 am

    I need to install red headlamp to my bike

  • Reply Rayna LeFevre August 8, 2019 at 5:00 am

    These animals really know how to duke it out.

  • Reply Maximilian Weinzierl August 8, 2019 at 3:59 pm

    I love them 🙂

  • Reply C A N A D A :P August 9, 2019 at 11:12 pm

    Who has been binging this series🙋‍♀️

  • Reply latrennidy hollis August 11, 2019 at 4:23 am

    You should try different color lights

  • Reply Semira and Aydin Nikocevic August 11, 2019 at 9:59 pm


  • Reply Yummy Memes August 12, 2019 at 12:29 pm

    0:24 YEET

  • Reply JustA ChocolateMan August 16, 2019 at 6:14 pm

    Hubert mmmmms in the background.

  • Reply Jy'ron Flanders August 17, 2019 at 2:40 am

    Where those two males

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