Catching Flies With Honey

About a month ago Dr. Mrs. Dr. F and I developed fruit fly problem in the kitchen. Working as I do in a mixed research university it seemed natural to walk down the hall and ask some of those overfunded fruit fly experts how they deal with escapees. As it turns out the old saw is actually pretty useful – flies love honey, and vinegar doesn’t help. The solution endorsed by nine out of ten fruit fly geneticists worked well enough that I’ll recommend it here.

You need some tape, a small square of stout paper (try a business card), honey and a small flask-type container with a narrow mouth. Researchers use erlenmeyer flasks, I used one a one-serving cognac bottle.

Roll the stout paper into a cone, leaving a hole in the bottom just big enough for two fruit flies to crawl through back-to-back (if you don’t know how big that is, you don’t need a honey trap). Cover the bottom of the bottle/flask with honey, then add an equal measure of red wine and mix. Push the paper cone into the flask pointy end first and tape it in place. That’s it! You’re done. Flies will chase the honey/wine smell like guys after football and beer, but the geometry of the inverted cone makes it nearly impossible to find a way out.

Another tip from my geneticist friends: if your can’t figure out whether related mutations act through the same pathway, try epistasis! No need to thank me.

***Critical Update***

Per the comments, it appears that you can catch about the same number of flies with vinegar. Add that to my earlier look at the boiling frog parable and this blog has become something of a graveyard for folk biology.

Use the thread to list any other scientifically bogus folk sayings that come to mind.






47 replies
  1. 1
    bago says:

    No thanks given.

  2. 2
    Bumper says:

    Ok, I have to delurk here. We’ve had fruit fly incidents here too and vinegar does work, and our method is a lot simpler. Just get a small bowl, like a ramekin, put some dish soap in the bottom and pour about 1/2 inch of vinegar over the that. I used cider vinegar. Leave it on the counter and before long you will have a bowlful of drowned fruit flies. We’ve caught hundreds of flies like that. Thankfully they’re all gone now.

    So, do all you scientists keep red wine in the lab for just such emergencies?

  3. 3
    Jeff Berardi says:

    "Dr. Mrs. Dr. F"? Was that a Venture Brothers reference?

  4. 4
    Talisker says:

    Like Bumper says, cider vinegar works waaaaaaaaay better than honey. Your fruit fly experts steered you wrong.

    …unless you’re looking for an excuse to crack open a bottle of wine, of course :)

  5. 5
    rawshark says:

    I thought fruit flys lived for like 8 minutes? Can’t you just wait them out?

  6. 6
    MarkusB says:

    @rawshark:
    Can’t you just wait them out?

    You can, but you just end up covered in flies.

  7. 7
    bago says:

    they breed in two. Worse than Palins I tells ya!

  8. 8
    bago says:

    I feel that comrade reproductive vigor is obliged to comment

  9. 9
    Ninerdave says:

    I have never been so well informed in my life since I started reading this blog 3ish years ago

  10. 10
    Ninerdave says:

    @Talisker:

    …unless you’re looking for an excuse to crack open a bottle of wine, of course :)

    Posted by a someone with a handle of Talisker. Lawlz!

    Talisker is currently my favorite, by far, scotch.

  11. 11
    Ninerdave says:

    Serious question (that I could google but am to lazy to):

    What makes fruit flies so attractive to scientists.

    P.S. I feel guilty about checking work email at home, Tim and spouse doing research at home, in their kitchen, brings this to a whole new level.

  12. 12
    bago says:

    Rapid breeding means many generations. Perfect for studying genes.

  13. 13
    JGabriel says:

    @bago: Bingo. Perfect for studying how genes evolve, to be more precise.

    .

  14. 14
    TenguPhule says:

    Use the thread to list any other scientifically bogus folk sayings that come to mind.

    All things being equal, people will make independently rational decisions to maximize efficiency.

    Oh wait, that bogus economic folk sayings…

  15. 15
    TenguPhule says:

    Per the comments, it appears that you can catch about the same number of flies with vinegar.

    Even simpler, use a bit of overripe fruit.

  16. 16
    NutellaonToast says:

    The commonly held belief that wings work because the curved upper surface causes air to move faster than the flat lower surface is wrong. Bernoulli’s principle is at work to make planes fly, but the fluid dynamics (air is technically a fluid) involved are a lot more complicated than just the simplistic over-under model people usually quote. Otherwise, planes wouldn’t be able to fly upside down.

  17. 17
    Steve T. says:

    I’m sure this works, but there is also some satisfaction in countering biological threat with biological defense: carnivorous plants. I’ve had great success with several varieties of pitcher plant. They gobble up the flies in short order, without looking quite so vicious as venus fly traps.

    But you have to have a cheery bright house friendly to plants, and I don’t, so they tend to die out. I’ll try to remember this honey-wine trick, as I’ll probably need it.

  18. 18
    bago says:

    Nutella: that’s just thrust and deflection. You can make a brick fly with enough thrust.

  19. 19
    Lesley says:

    Bugs that looked a lot like fruit flies (though I couldn’t verify this) were breeding in the bathroom and kitchen drains. I tried everything, including setting out bottles filled with a mixture of water, vinegar and honey, but more kept appearing. I ended up pouring first baking soda down each drain and then a couple of cups of vinegar. I let that sit for a couple of hours, then I flushed the drains with scalding hot water. Over the next few days a few flies appeared but they were greatly reduced. I repeated the measure three times and presto, no more fly larvae.

  20. 20
    geemoney says:

    I can’t find a picture, but there are nice glass vessels available here commercially in Europe that do basically what the Erlenmeyer does. It is basically a glass cone that you can stopper at the top. The bottom of the cone has a lip on the inside; you can then fill a bit of liquid in the cone. The whole thing is supported so that the flies can get in through the bottom.

    We have always used vinegar and it becomes a total fruit fly motel. Interestingly (okay not really), the couple of times that normal house flies have found their way in, they have managed to find their way out. The fruit flies, not so much.

    As I think about it, this is exactly like those wasp catchers that you sometimes see, and with which people might be more familiar.

  21. 21
    MikeJ says:

    Use the thread to list any other scientifically bogus folk sayings that come to mind.

    "The British government has learned that Saddam Hussein recently sought significant quantities of uranium from Africa. "

  22. 22
    robertdsc says:

    Speaking of science, John made a thread about stem cell research and the quickest way to get the ball rolling.

    The President (tee hee) says he prefers a legislative approach first:
    Steve Benen has the details.

  23. 23
    R-Jud says:

    Y’all know about Ben Goldacre, right? His "Bad Science" column in the Guardian is super. Column is on Saturdays; his blog (and mini-blog) point to a whole bunch of other wonderful sites.

  24. 24
    iain says:

    Use the thread to list any other scientifically bogus folk sayings that come to mind.

    Did you know that we only use ten percent of our brains?

  25. 25

    I am totally flattered that I’m the link to "over-funded fruitfly experts".

  26. 26
    MikeJ says:

    As I think about it, this is exactly like those wasp catchers that you sometimes see, and with which people might be more familiar.

    Unrelated to flies, honey or vinegar, a school in TW made a trap for mosquitos using co2 as bait.

  27. 27
    harlana pepper says:

    Completely OT, but since this is the top thread, what do folks think about this? Does it really mean anything? I keep hearing about how there will be rash of whistle-blowers coming out of the woodwork after today. Wonder what the leadership knows. And yes, I know Pelosi was complicit in the torture debacle. But that is what makes this all the more curious. Esp. considering her "no impeachment" pledge. I realize she was just talking about Bush, but I interpreted that to mean, "we’re just going to leave the whole thing alone, forever. I get the feeling the leadership is checking out the public’s appetite for justice at this time, "floating" the idea. But considering members of Congress have so much to hide (aside from complicity in Bush’s crimes, god only knows what’s on all the surveillance tapes and wiretaps), I wonder where this will go. And Conyers, for all his efforts, has produced nothing we have been able to work with thus far, unless the by-product of all those hearings will be a solid foundation for prosecution. Hmm.

  28. 28
    estamm says:

    I get fruit fly problems ever summer (thanks produce guys at Meijer grocery stores!). I will try these tricks next summer. In the past, I used to take recently emptied frozen OJ containers and put them on the counter. A few hours later, I’d come back and quickly cover the top with plastic wrap. Typically I’d get 6 or 8, but there could be more. Then I’d put scalding water in a large pot and submerge the container and drown/scald them. Worked great, but the key word here is "WORK". I love the vinegar in the bowl solution, which I will try.

  29. 29
    HeartlandLiberal says:

    I had a friend years ago whose family were Nazarene, so there was absolutely zero alcohol in their household.

    He had a severe problem one year with slugs in his vegetable garden.

    I dropped by with a can of cheap beer, borrowed a saucer from his kitchen, showed him how to open the beer bottle (while wife and child stood by in horror), and how to pour to cover the bottom of the saucer, and place it on the ground near the plants being attacked.

    I did not stick around to explain the technique of emptying the saucer and the collection of bloated and dying slugs he would find every morning after their night of sinful carousal. But he figured it out.

    Oh, and I snuck him off with me to see the theater opening of the second Star Wars movie, this was back in the 70’s. Movies were also forbidden fruit to the Nazarene church.

    What are friends for if not to help friends indulge just a little bit?

  30. 30
    harlana pepper says:

    HeartandLiberal: no drinkies? That is dowright sad.

  31. 31

    I just heard one of my favorites as I flipped through the channels to see if anyone was going to cover the inauguration. It’s from Faux News–of course: "Where’s all that global warming in DC this morning? It’s only 25 degrees out here."

  32. 32
    KyCole says:

    Beer always works for me too- plus its really easy. Just drink most of the beer, then set the bottle on the counter. Many flies enter, no flies leave.

  33. 33
    tavella says:

    Fruit flies do breed quickly, but the reason they are beloved of scientists among the many quick-breeding insects is that their salivary glands have oversized chromosomes that made it easy, presequencing days, to see transcription activity.

  34. 34
    Gravenstone says:

    @Ninerdave:

    Serious question (that I could google but am to lazy to):

    What makes fruit flies so attractive to scientists.

    P.S. I feel guilty about checking work email at home, Tim and spouse doing research at home, in their kitchen, brings this to a whole new level.

    Collegiate biology class fruit fly studies also gave rise to one of my favorite perjoratives – calling someone a NDBF (Needle Dicked Bug Fucker). Rises right up there with my nerd buddy’s preferred, "you sir, are a poikilothermic myxomycete" (cold blooded slime mold).

    Nerds! FTW

  35. 35
    phil says:

    Also important is that fruit flies are really fucking small, so scientists can comfortably fit hundreds in a container the size of a small flask.

  36. 36
    TheFountainHead says:

    Barack Obama becomes President today, and BJ is engrossed in a discussion regarding the mass genocide of a small insect. There’s so much symmetry in this.

  37. 37
    calling all toasters says:

    You know what works well for catching flies? Flypaper.

  38. 38
    Punchy says:

    I’m just glad fruit fly research has given us the terms like bent wing and sepia eye. I’m always trying to work "sepia" I’m into a romantic convo….

  39. 39
    Face says:

    If I wanted to catch flies I’d just grab my baseball mitt.

  40. 40

    @bago: I am Legion.

    Anyway, we use wine. The flies get drunk and drown. The survivors join AA or something. All I know is one half-full glass of wine gets rid of an infestation in less than a week.

    It also helps if you check the entire fruit section of your grocery store before you buy fruit. If you see the little fuckers anywhere, don’t buy fresh fruit at at that store.

  41. 41
    Kirk Spencer says:

    @HeartlandLiberal: Turns out that yeast in a bit of sugar water is as good as beer for attracting slugs.

    I did a semi-controlled experiment for a couple of years in a row mixing placement of the yeast-water and the beer. Certain locations were better than others, certain containers worked better, some evenings slugs were more active than other evenings. Over time, however, and mixing which containers had which liquid and where they were located, the end result was that there was no significant difference in results.

    Which means you don’t have to waste good beer or pay money for bad beer if you don’t want to do so.

  42. 42
    demimondian says:

    Since FDDD’s PhD is in fruit fly genetics — you could still see Hermann Muller’s doodles on the desk at which she sat in grad school — and since she and I were talking about just this yesterday, I can answer the various questions with some authority. As Tim has already said, in fact, fruit flies are *more* attracted to cider vinegar than they are to honey. They don’t actually consume the sugar in the fruit; they actually consume the yeasts and molds which grow on the fruit. Vinegar smells of rotting fruit; ergo, it’s a better attractant.

    So, yes, contrary to widely held myth, you will catch catch more flies with vinegar than with honey.

    As to the transcription stuff. D. melanogaster was readily available and easily raised in Ithaca when Muller and de Morgan were there. The ready availability on ones own coffee cup in a fine upper New York State morning is often the best reason to select an experimental subject. The polytene chromosomes in their salivary glands were actually interesting because they made basic cytology possible, which is critically important when looking at X-ray induced mutations, many of which are actually due to chromosome rearrangements. Transcription measurement is a more recent thing; it’s post Watson-Crick.

  43. 43
    Adolphus says:

    I also work in a large research university and we did some work on a canine based aphorism last year I’d like to share.

    We found, contrary to the folk saying, that 95.789% of the time, that dog will indeed hunt. The important variable here is what, in fact, the dog is asked to hunt.

  44. 44
    Ed in NJ says:

    To piggy-back on the vinegar solution, what I’ve always done is put the vinegar in a cup and covered it with clear plastic wrap. Make a small hole in the plastic, and the flies find their way in, but they can’t get out before dying. You’d be surprised at how many of those things appear when they smell vinegar.

  45. 45
    RSA says:

    the geometry of the inverted cone makes it nearly impossible to find a way out.

    The cone entryway is also a feature of crab and lobster traps. Bugs is bugs, I guess.

  46. 46
    magisterludi says:

    The local lore is house flies are kept at bay when you hang a plastic bag of water with a penny in it above the door.

  47. 47
    tinat says:

    when in High School taking advanced biology and doing a fruit fly study us evil teens let the suckers free…the High School had fruit flies in it for ages, LOL, I guess they couldn’t leave glasses of wine around for them, huh

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