# If a flying butterfly or housefly is hit by a falling raindrop what happens?
**URL:** https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740
**Category:** Factual Questions
**Created:** [April 10, 2008, 6:50am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740 "2008-04-10T06:50:01Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@astro](https://boards.straightdope.com/u/astro)
#### Post date: [April 10, 2008, 6:50am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/1 "2008-04-10T06:50:01Z")
I never really thought about this, but in considering the kinetic impact of a large raindrop on a small or delicate insect I would think it could be devastating. Are they knocked to the ground? Injured? Unharmed?
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### Author:  [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)
#### Post date: [April 10, 2008, 7:29am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/2 "2008-04-10T07:29:15Z")
No answers really, but just wanted to say this is a great question. I’ve wondered it myself. Even if the impact didn’t injure the critter (which I suspect it might not, because bugs and things are quite robust in some ways) they’d be messed up with the surface tension of the water and I can’t imagine anything happening but a quick interface with the ground (even a drop of water on an ant when I’m having a shower renders the thing helpless in this way - and it’s already on the ground).
I guess instinct must take over - you don’t tend to see any flying things much, even in light rain. I suspect they head for cover pretty sharpish.
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### Author:  [@NunOfTheAbove](https://boards.straightdope.com/u/NunOfTheAbove)
#### Post date: [April 10, 2008, 7:56am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/3 "2008-04-10T07:56:42Z")
Here is what the straight dope has to say about it.
[http://www.straightdope.com/mailbag/mbugs\_in\_rain.html](http://www.straightdope.com/mailbag/mbugs_in_rain.html)
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### Author:  [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)
#### Post date: [April 10, 2008, 12:54pm UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/4 "2008-04-10T12:54:19Z")
I’ve seen butterflies get hit and they did fine. Flies did ok too. Only during a deluge are they in trouble.
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### Author:  [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)
#### Post date: [April 10, 2008, 4:59pm UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/5 "2008-04-10T16:59:36Z")
Ever seen a housefly fly headfirst into a bathroom mirror, bounce off, and repeat the same procedure over and over again 20 times in a row? I think that if a fly can ignore that sort of intentional abuse, a little raindrop isn’t going to phase it much.
Remember, muscle/bone/exoskeleton strength generally goes up by diameter squared, whereas mass/volume (and thus kinetic energy and weight) goes up by diameter cubed, so handling objects many times your diameter size (as well as flying yourself straight into a mirror) is a lot easier when you are insect-scale.
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### Author:  [@Chez\_Guevara](https://boards.straightdope.com/u/Chez_Guevara)
#### Post date: [April 11, 2008, 10:31am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/6 "2008-04-11T10:31:18Z")
[QUOTE=astro]
I never really thought about this, but in considering the kinetic impact of a large raindrop on a small or delicate insect I would think it could be devastating. Are they knocked to the ground? Injured? Unharmed?
[/QUOTE]
The answer to your question is as elusive as the butterfly itself.
[Here](http://www.sciam.com/article.cfm?id=what-do-butterflies-do-wh&ref=rss) is a piece from _Scientific American_ written by Michael Raupp, professor of entomology at the University of Maryland. He opines as follows:
> [@](#):
>
> Imagine a monarch butterfly searching for nectar or a mate in a meadow on a humid afternoon in July. Suddenly, a fast-moving thunderstorm approaches, bringing gusty winds and large raindrops. For the monarch and other butterflies this is not a trivial matter. An average monarch weighs roughly 500 milligrams; large raindrops have a mass of 70 milligrams or more. A raindrop this size striking a monarch would be equivalent to you or I being pelted by water balloons with twice the mass of bowling balls.
This entertaining analogy suggests to me that a butterfly caught in a deluge is toast. However, [a team of French physicists](http://physicsworld.com/cws/article/print/168) reporting on the hydrodynamics of droplet impact on various surfaces offers this view:
> [@](#):
>
> Other examples of this non-wetting approach can be found in duck feathers and butterfly wings. These corrugated surfaces also provide air pockets that prevent water from completely touching the surface. As a result of the limited contact that the drops have with the surface, there is very little friction against drop motion. This means that water can bounce or roll off duck feathers and butterfly wings quite easily.
This doesn’t really get us very far since I have no way of verifying Professor Raupp’s bowling ball conclusion. He also fails to discuss specifically the impact of a raindrop on the butterfly’s wings, while the physicists don’t refer to the impact of a raindrop on the butterfly’s body.
It’s a good question.
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### Author:  [@mwbrooks](https://boards.straightdope.com/u/mwbrooks)
#### Post date: [April 11, 2008, 9:13pm UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/7 "2008-04-11T21:13:41Z")
[QUOTE=astro]
I never really thought about this, but in considering the kinetic impact of a large raindrop on a small or delicate insect I would think it could be devastating. Are they knocked to the ground? Injured? Unharmed?
[/QUOTE]
The critter might be better off flying than sitting on something. I say this because I once tried (please forgive me) killing houseflies by shooting them point blank with a CO2 pistol, using just the blast (no pellet). If there was nothing on the other side of the fly, it was usually just displaced rapidly by a few inches and flew off. If I angled the gun so the fly was propelled into something (like a window frame), the fly usually did _not_ survive.
Those critters are pretty tough.
I think a butterfly wouldn’t fare as well flying in a hard rain as a fly or bee would, simply because the butterfly’s wings aren’t as compact.
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### Author:  [@panache45](https://boards.straightdope.com/u/panache45)
#### Post date: [April 12, 2008, 12:48am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/8 "2008-04-12T00:48:07Z")
Many times, when watering the garden, I’ve directed the hose toward a flying insect. This is much more serious than a single drop of water, yet it merely slows them down for a few seconds, then they’re on their merry way. Of course if I hit them with the full force of the jet of water, it’d probably do serious damage.
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### Author:  [@SmackFu](https://boards.straightdope.com/u/SmackFu)
#### Post date: [April 12, 2008, 2:44am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/9 "2008-04-12T02:44:42Z")
According to “Bee Movie”, bees can’t fly in the rain.
Does that count as a cite?
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### Author:  [@Kozmik](https://boards.straightdope.com/u/Kozmik)
#### Post date: [April 12, 2008, 3:00am UTC](https://boards.straightdope.com/t/if-a-flying-butterfly-or-housefly-is-hit-by-a-falling-raindrop-what-happens/444740/10 "2008-04-12T03:00:35Z")
This is a good chaos theory question.