Why is it so hard to swat a fly? • Hacker News Board

Re: Why is it so hard to swat a fly?

#31

Post by japhyr » Sun, Sep 17, 2017, 2:03 PM UTC

It's really easy to pick up flies with a hose attachment on a vacuum.

Every once in a while we get a number of flies in the house during the summer when the doors and windows are open. They tend to gather in the sides of our windows, looking for a way out. I used to catch them one by one, and then I tried a vacuum. It was easy, once they are aware of the vacuum it's too late to fly away, and they get sucked right up. It's probably not worth while for one or two flies, but if you're going after a few a vacuum can be really effective.

Re: Why is it so hard to swat a fly?

#32

Post by zomg » Sun, Sep 17, 2017, 2:06 PM UTC

after watching karate kid, i now catch flies exclusively with chopsticks. i'm 3,285 for 3,285!

Re: Why is it so hard to swat a fly?

#33

Post by ximeng » Sun, Sep 17, 2017, 2:13 PM UTC

zeotroph wrote: post #18

delinka wrote: post #10

Where’s the video of the killer fly catching a fruit fly? I want to see that .

Also, what is the scientific name of the killer fly? There is no such article on wikipedia. And some more references on how compount eyes see mechanically , as opposed to chemically, would be interesting.

https://en.wikipedia.org/wiki/Asilidae maybe this one, although this video explicitly names killer fly: https://www.youtube.com/watch?v=ukiTGsvFP1Y

Re: Why is it so hard to swat a fly?

#34

Post by [deleted] » Sun, Sep 17, 2017, 2:18 PM UTC

zomg wrote: post #32

after watching karate kid, i now catch flies exclusively with chopsticks. i'm 3,285 for 3,285!

[deleted]

Re: Why is it so hard to swat a fly?

#35

Post by agumonkey » Sun, Sep 17, 2017, 2:19 PM UTC

apl wrote: post #12

As someone who works in visual neuroscience, this article's a tough read. Lots of statements that are semi-accurate at best. 1) Eyes don't work like cameras; there's no real "exposure" phase as such (even though there's lots of thresholds). So it's misleading to talk about discrete images that we sample at some fixed frequency. Instead, it's much more helpful to think of photoreceptors and subsequent processing stage…

Still what about non escape reflex sense of "time" ? Say like landing. Don't they perceive the world at a faster (or I should say systemically adequate for them) rate ?

Re: Why is it so hard to swat a fly?

#36

Post by agumonkey » Sun, Sep 17, 2017, 2:20 PM UTC

adekok wrote: post #5

If you want to catch a stationary fly, it's pretty easy to do so with your bare hands. The key thing to know is that they jump backward before taking flight. Aim for a spot about 1-2" behind the fly, and about 1-2" above the fly. Try to catch it there , and your success percentage will be high.

Also depends on the fly species. Some are just uber slow I could play tennis with them.

Re: Why is it so hard to swat a fly?

#37

Post by agumonkey » Sun, Sep 17, 2017, 2:20 PM UTC

i_feel_great wrote: post #9

Three techniques: 1. Move your open hand towards the fly very slowly until you are 5cm (2 in) away then slap. 2. Move both hands slowly towards the fly and "clap" to catch it. 3. Blow gently downwards onto the fly, then slowly increase the force of the blowing. You might then be able to pin its wing to the surface. Yes, I have a lot of time on my hands.

Proper scientist

Re: Why is it so hard to swat a fly?

#38

Post by ximeng » Sun, Sep 17, 2017, 2:25 PM UTC

adekok wrote: post #5

If you want to catch a stationary fly, it's pretty easy to do so with your bare hands. The key thing to know is that they jump backward before taking flight. Aim for a spot about 1-2" behind the fly, and about 1-2" above the fly. Try to catch it there , and your success percentage will be high.

https://www.youtube.com/watch?v=otqcVG-nJGI apparently they plan their escape

Re: Why is it so hard to swat a fly?

#39

Post by dagaci » Sun, Sep 17, 2017, 2:26 PM UTC

You will notice that flies do not generally flee from things swaying (plants branches, curtains) in the wind, if you make a sway movement with your swatting implement the fly will ignore you when your too close for it to escape.

Re: Why is it so hard to swat a fly?

#40

Post by throwitawayday » Sun, Sep 17, 2017, 2:27 PM UTC

apl wrote: post #12

As someone who works in visual neuroscience, this article's a tough read. Lots of statements that are semi-accurate at best. 1) Eyes don't work like cameras; there's no real "exposure" phase as such (even though there's lots of thresholds). So it's misleading to talk about discrete images that we sample at some fixed frequency. Instead, it's much more helpful to think of photoreceptors and subsequent processing stage…

On 3), the giant fiber is fast but not faster than other descending fibers. If anything, it is more reliable in its ability to signal.

See: https://www.nature.com/neuro/journal/v17/n7/full/nn.3741.htm...

Short abstract snippet (the "parallel circuits" are other, non-giant descending neurons that also trigger the escape behavior upon a looming stimulus):

"Intracellular recording of the descending giant fiber (GF) interneuron during head-fixed escape revealed that GF spike timing relative to parallel circuits for escape actions determined which of the two behavioral responses was elicited. The process was well described by a simple model in which the GF circuit has a higher activation threshold than the parallel circuits, but can override ongoing behavior to force a short takeoff. Our findings suggest a neural mechanism for action selection in which relative activation timing of parallel circuits creates the appropriate motor output."