by Matthew Cobb
This is a picture of a male vinegar fly, Drosophila melanogaster, which both Jerry and I have studied for the whole of our lives (in fact I’ve spent much of mine studying fly maggots). This was the insect that was chosen by Morgan in 1908 to study evolution – he didn’t hold with the new-fangled ‘genetics’ that had just been named. Morgan wanted to get his flies to mutate by subjecting them to all sorts of environmental stresses, but instead he discovered a white eyed fly that just popped up in the stocks.
Over the next few years, Morgan and his students – principally Sturtevant, Muller and Bridges – laid down the basis of genetics, showing that genes are on chromosomes, and constructing intricate chromosome maps showing the precise location of different genes, for which Morgan won the Nobel Prize in 1933. Muller went on to show that mutations could be induced by X-rays, for which he won the Nobel Prize in 1946.
Drosophila kind of went out of fashion in the second half of the 20th century, as molecular genetics swept the board – for over three decades, this was an approach that was limited to bacteria and viruses. However, in the 21st century ‘the fly’ has undergone a bit of a renaissance, as all sorts of techniques have become available for identifying and manipulating genes. Most satisfying for Jerry and I, many of our colleagues have realised that other Drosophila are available. There are dozens of Drosophila species, each with a different evolutionary history, and therefore different genes, anatomy and behaviour.
There’s a fantastic set of fly pictures available at this site, run by two French researchers, Benjamin Prud’homme and Nicolas Gompel of the CNRS in Marseille. What is striking in looking at these images is quite how varied these flies are, and above all the realisation that although we may know a great deal about D. melanogaster, we know very little about why it is the way it is. Its natural history remains obscure.
In a way, the fly was turned into a piece of laboratory equipment by Morgan and his colleagues. Now we are turning it back into a proper organism. Here are three questions we do not know the answers to, some of which are being studied by the Prud’homme/Gompel lab:
– Why do males of some species have ‘sex combs’ (those little black dots on the front legs), while others do not?
– Why do some species have patterned wings while others do not? (Here are just three species: D. melanogaster, D. biarmipes and D. guttifera (note that D. guttifera does not have sex combs)
– And finally, why does the closely-related African genus Zaprionus have these funky go-faster stripes?
Science isn’t primarily about knowing stuff. It’s about finding out new stuff. Uncovering the answers to these questions will be part of 21st century biology, and while they might seem quite unimportant to most readers, the answers will undoubtedly tell us something important about how species evolve and adapt to their environment, and how new characters arise.
If any of you are unsure as to how big (or rather small) these insects are, this will give you an idea:
All photos except the final one (c) Prud’homme and Gompel. The final photo is from here.
The unanswered scientific question I have about fruit flies is how to get these bastards out of my house! They are driving me nuts.
Clean your bins, look under fridge for rotting fruit, clean fruit bowl. Flies will disappear. They are only there because it smells good to them. I like having them in the house, myself.
Come over and get some! 😉 Bring along a couple pints of good Manchester ale and we’ll call it even.
The ale is also an attractant. So no luck! 🙁 Drosophila are really feeding on yeasts growing on rotting fruit. D. melanogaster especially likes to hang around breweries and wineries.
And pubs with carpets!
* Chop peeled banana & other fruit
* Place a few pieces in the bottom of small, open container such as a cup
* Cover opening with cling film
* Pierce once with sharp point
* Ensure hole large enough for target flies to crawl through
* Make one for each fly-afflicted room
* Eat leftover fruit
Put a few ounces of apple cider vinegar in a small glass. Put a drop of dish detergent (manual kind) in and stir, to break the surface tension. Watch in amazement as the bottom becomes blanketed by dead fruit flies over a matter of days.
Best place to keep it is right next to the fruit bowl, if you have one.
You are telling us how to kill live animals!
No point in killing dead ones!
…unless they’re Jesus, of course. I mean, he’s dead, right? And he flies, no?
Still haven’t figured out how to do it. I tried unholy water, chopping off his feet, and driving a steak (medium rare) through his…erm…well, the obvious place. No joy.
Any suggestions?
b&
I often over etherized mine in science class. Ooops.
You do not have too many flies. You have too few spiders.
The wicked nom-web we weave!
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I seem to remember being taught that it isn’t what we know that’s important, it’s what we believe that is not true that’s important
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Are you thinking of the Roy Rogers quote? “It isn’t what he doesn’t know that scares me – it’s what he knows for sure that just ain’t so”.
I think that quote is usually attributed to Will Rogers.
Oops!! Thanks. I guess I must have been hungry.
I consider myself lucky to have been absorbing the advances made possible by research in E. coli & D. melanogaster as an undergrad. Which is a reason why I bemoan when politicians such as this bean-brain from Wasilla use it to shore up their ignorant base.
Gorgeous pics!
“in the 21st century ‘the fly’ has undergone a bit of a renaissance” – a sort of Renaissance Fly?!
That last bit chimes with Nature’s Henry Gee today on his ‘blog’ –
“What’s the one thing about science you wish the public understood better?
That science isn’t about knowledge – it’s about ignorance.”
http://occamstypewriter.org/cromercrox/
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Beautiful. I have a mancrush at Richard Feynmann. I think it has to do with his brain and communication skills.
Yeah… I love his terse but lucid description of chloroplasts.
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Right on. Feynman was real genius.
He’s so simple, so direct and so right.
Thanks! 🙂
Feynman left a big hole 🙁
I prefer to think of it as a massive black hole. Yes, it sucks.
Frankly, I think he’d have found a massless black hole to have been a much more interesting option for a legacy….
b&
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This to me is the example of beautiful scientific thinking.
It’s not so much the answers that are interesting, but the questions.
A good well thought out question can often lead to new completely surprising answers….and ultimately to more good questions.
what I great geeky site this is.
“Drosophila kind of went out of fashion in the second half of the 20th century”
This surprised me. In high school biology class in the mid-70’s we spent a lot of time working with these lil buggers. I guess our teacher wasn’t very up to date, or maybe he was ahead of his time. 😉
Yes, we did!
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I don’t think I believe this claim that fruit flies ever went out of fashion.
Story 1:
Back in grad school, there was a fly lab down the hall. We sometimes had fruit flies at home, buzzing the bananas. I assumed the two facts were unrelated… until I noticed that I was squashing white-eyed flies. I think of this whenever I go into a BSL-3 facility.
Story 2:
I had a professor of population genetics in college here in Texas who did wild Drosophila studies in Hawaii, on the big island. Fly populations are isolated by lava flows (kapuki?), and are then subject to founder effect and drift. I remember thinking (at the time) that getting paid to wander Hawaii was a sweet deal. This is before I actually saw what field work entailed.
Just sharing.
Kipuka. Islands of habitat not affected by surrounding lava flows:
http://en.wikipedia.org/wiki/K%C4%ABpuka
Drosophila – Ode to a Fruit Fly
Drosophila Melanogaster, you sexy little fly.
Your universe is in a bottle; you never saw the sky.
You never had the chance to fly, free as God made you.
Your firmament was made of glass, all you ever knew.
A slice of apple or an orange would have been your wish.
A ripe banana is your heaven in a little dish.
Instead you existed under glass just for me to see,
to reproduce and be bred by a human deity.
I watched you copulate, lay eggs to my delight;
I watched as your larva pupated in plain sight;
I watched your offspring hatch and spread their tiny wings;
I etherized your whole brood and examined the little things.
With a little brush, I selected a few mutations,
and then bred them once again to make some new creations.
Playing God sure felt good for some unholy reason.
Creating little mutants was supernatural treason.
What I did in college lab with deliberate resolution
happens all the time in nature, its called evolution.
But there are those of little wit that still cannot conceive
that what we did together should really be believed.
I finished my genetics course and passed the final tests.
I never could have done it without my fruit fly pests.
Playing God is bad enough; some think it a holy crime.
But, it was fun proving evolution by my design.
Bravo! Well done. 🙂
+1!
All these recipes for trapping flies are simply going to attract them into your house! Remove potential breeding sites (look under cupboards etc), clean places that smell, rinse out old alcohol containers, and flies will miraculously disappear outside, I promise!
That is the best suggestion. I learned about drosophila when I worked at a winery here in California. They swarmed by the thousands to the barrel bungs of fermenting grape juice, or spills of grape juice or wine. But cleaning fastidiously was the most efficient answer.
Because the winemakers studied at UC Davis, everyone referred to the flies as Drosophila (and no other name), and other flies as just “flies”, to differentiate. Whenever known, the scientific name was employed for such things.
I believe one of those flies has different regulatory DNA controlling expression of the paintbrush gene.
Wasn’t the HOX complex first described in Drosophila as well?? My greatest epiphany in appreciation of evolution was discovering that there was a common toolkit for animals as far apart as fruitflies and [people+cats]. Later of course, the story deepens, back to flatworms and jellyfish, and incorporating eyes and the CNS. But the HOX story is what brought me back!
As an undergraduate in the later 50’s,
I had the pleasure of working in
Th. Dobzhansky’s lab at Columbia University on
sexual isolation in Drosophila paulistorum.
There were a whole bunch of people involved,
including other undergraduates. The results
were published in a 10 author paper in American Midland Naturalist. Dobzhansky was always a gracious and caring professor and his
courses help me develop a lifelong interest
in evolutionary biology, so I have always had a broad tolerance for fruit flies buzzing around my open wine bottles and fruit. I
expect and hope that Drosophila will remain a major animal in the study of speciation and evolution.
I did my PhD thesis on molecular genetics of Drosophila in the late 80’s. Drosophila was where the development genetics was tested at the time. It was very cool, very advanced, and drove a lot of insights on how genes interact to develop organism through morphogenesis. Unless we consider the 80’s and 90’s part of the 21st century, I have a strong disagreement with Dr Cobb assessment about Drosophila being out of fashion on the second half. Maybe on the late 90s early 2000’s, as all development genetics was busy replicating all learning from the two past decades to other organisms.
I do fully agree the golden age started by TH Morgan and his successors is unique, and the lighthouse that illuminated the path of our research.
I remember I did use a lot of the different species of the genus to do comparative molecular analysis, and was amazed with the variety of shapes patterns and sizes they display. And guess what, Hawaii is a hbig hub of speciation. Why would it be?…
Great article, brough very fond memories. I can’t smell yeast and not think of the little flies.
“Hawaii is a hbig hub of speciation. Why would it be?…”
Unless you are tongue-in-cheek, see comment #11.
IIRC, Morgan was too busy to go to Stockholm to collect his Nobel in 1933. I see that his medal & diploma were just donated to Woods Hole.
If you like good insect photography, check out AntWeb (http://www.antweb.org/). Their images are all Creative Commons licensed. Most – if not all – are from the collections at the California Academy of Science and using their Big Kahuna camera set-up. It takes close-up images at multiple focal points to create an image in complete focus throughout.
Great post Matthew, thanks! Succinct and very interesting. And it’s generating lots of comment.
Time flies like an arrow;
Fruit flies like a banana.
Steve Jones
I’ve wondered. Has anybody actually seen a time fly? And how do we know that they have an affinity for arrows?
b&
Good point. Maybe time flies like a turkey vulture.