Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Interesting Phenomenon

  1. Dec 15, 2009 #1
    I'd purchased a http://en.wikipedia.org/wiki/Mosquito_bat" [Broken] recently. These things are very handy for swatting mosquitoes in the rainy season. A little while ago, I noticed something curious while swatting: after I hit the creature, it falls on the floor and begins to spin rapidly. Many a time I have tried to get this on video, but by the time I run back with the camera, it stops spinning. This time, I happened to have a cell phone camera on me and recorded it.

    Can anyone explain why this happens? If additional information is required to explain this, please let me know. I would guess that a jolt of current does something, but what exactly?
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Dec 15, 2009 #2

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You would spin too if you were in that much pain. Get a more efficient swatter to kill the mosquito instantly.
  4. Dec 15, 2009 #3
    You do realise this is the equivilant to asking why a freshly tasered man twitches.
    Last edited by a moderator: May 4, 2017
  5. Dec 15, 2009 #4
  6. Dec 15, 2009 #5
    Well, the fly is seriously injured and is trying to get to a different location.
    It thus beats its wings to try and fly away. Being injured it is unable to fly away, and likely its wings are injured.
    So, instead of lifting off and away, the wings are so screwed up the fly just spins around. As well, the fly probably is trying to crawl away at the same time, leading to further chaotic motion.
  7. Dec 15, 2009 #6
    @Meir Achuz, xxChrisxx and pallidin -

    The mosquito is dead. I've checked this plenty of times when this happens as I myself was curious to see why this happens. You can't see it, but when it does the sliding toward the end of the video, no body parts move individually. It moves as a rigid body. Having seen half-dead mosquitoes before, I am quite sure they at least twitch their feet also.

    Secondly, the camera doesn't show the rate at which the mosquito is spinning. It is spinning VERY fast. It certainly couldn't move this fast when it was alive. It is most certainly not going to do so if it is injured.

    I was thinking that the bat sets up some sort of current running through the thing so that it is orienting towards some magnetic field? Or maybe the current is doing something else.

    And lastly, please don't pity the damned thing. We get so many of them here that you get eaten alive after 6 PM. It's terrible.
  8. Dec 16, 2009 #7
    Well, if it's dead it won't move beyond the complex air patterns produced by the swatter.

    If you have an electric swatter, things are slightly different, but in no way accounts for 'spin'. I still believe that the motion you see is from something not yet dead.
  9. Dec 16, 2009 #8

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Some dead animals go though all sorts of reflexive motion. I have seen a headless chicken run around for several minutes. I didn't eat chicken for years after that.
    If the dead fly started to spin with parts extended, it would speed up as the extended parts contracted.
  10. Dec 17, 2009 #9
    Related to this thread, I'm just wondering:
    Has the "headless chicken running around for several minutes" been somehow scientifically described? OK, I'm a nerd. Just wondering. We don't see that happen with humans.
  11. Dec 17, 2009 #10
    No. It is spinning far faster than mosquitoes move when alive. And most of the time, regardless of how I hit it, the ones that DO spin all spin in the same spot like the one above. All of them spin in the same fashion.

    I wouldn't expect that if it was half-alive and simply trying to get away.
    Last edited: Dec 17, 2009
  12. Dec 17, 2009 #11
    Let me make this more cogent:

    Reasons for my belief that the mosquito is dead:

    1. Their body is stiff when it spins and completely unlike mosquitoes when they are half dead and trying to escape. From my observations while swatting mosquitoes (which spans my entire life), they twitch when they are half dead. They DO NOT remain stiff.

    2. They spin abnormally fast, and all of them in the same fashion. If this was a random thing that occurred for wont of getting away from me, I'd expect a more random motion depending on what parts of the mosquito I've destroyed.
    Last edited: Dec 17, 2009
  13. Dec 17, 2009 #12
    I shall try this tonight if any of them happen to spin. I have a large magnet ( part of my Levitron ), using which I shall try to see if I can induce a change in this spinning motion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook