Mosquitos Have Little Trouble Flying in the Rain

sciencehabit writes with an interesting article about the (surprisingly not well studied) effects of rain on flying insects. From the article: "When a raindrop hits a mosquito, it's the equivalent of one of us being slammed into by a bus. And yet the bug will survive and keep flying. That's the conclusion of a team of engineers and biologists, which used a combination of real-time video and sophisticated math to demonstrate that the light insect's rugged construction allows the mosquito to shrug off the onslaught of even the largest raindrop. The findings offer little aid in controlling the pest but could help engineers improve the design of tiny flying robots." Bats, unfortunately, aren't so lucky: "...these furry fliers need about twice as much energy to power through the rain compared with dry conditions."

Re:Impact energy not the same for small objects

[zero.kalvin]

AIUI, you assume wrong.

I am aware of that, but I didn't want to complicate things, in case the reader was not a physicist. Sometimes simple assumptions can still give you a clear indication of what is going on.

Re:Impact energy not the same for small objects

[zero.kalvin]

Give me a break, I wanted to write that comment that was as short, as quick, and as simple as possible. My conclusion isn't wrong ( in the literal sense ), I just made a "very" conservative estimation ( we do that in physics ). The whole point was to show, that the difference between a mouse and horse isn't small, but rather gigantic. I was not going into assumptions of density and its uniformity, or whether we can assume animals as spherical or not, or of buoyancy and drag factors. Now I agree with http://science.slashdot.org/comments.pl?sid=2894703&cid=40216663 [slashdot.org] , I should have mentioned that I was doing a very conservative estimation and the number is actually much higher.

Matter of chance

[dutchwhizzman]

If mosquitos weren't able to deal with rain, there wouldn't be a lot of mosquito's. They need water to reproduce in so they live in predominantly wet areas. Evolution made the rain resistant mosquito's breed and the non resistant ones extinct. Horses don't often fall down steep cliffs, nor do humans, so there isn't a lot of reason for them to develop a resistance against that. Mice reach their terminal velocity rather quick, so if they survive a 2m drop, they are much more likely to survive a 200m drop, since the difference in velocity isn't that much.

Tiny Flying Robots?

[guttentag]

The findings offer little aid in controlling the pest but could help engineers improve the design of tiny flying robots.

Great! Because I was just thinking to myself, "we really need more tiny flying robots. If I have to wait 20 years for the CIA to solve the raindrop problem and weaponize these things, I'll die of boredom before videos of them assassinating people with them show up on YouTube."

Too heavy on the sarcasm? Fortunately I don't say stuff like this out loud.

Re:Impact energy not the same for small objects

[Zorpheus]

Yeah but if you assume that they touch the floor at the same speed, the amount of energy to be absorbed per body weight is the same for mouse and horse. The force per body weight is even lower for the horse since it has longer legs and therefore more time to slow down. But also the ratio of the cross section of the legs to the body weight is worse, which makhttp://science.slashdot.org/story/12/06/05/0112252/mosquitos-have-little-trouble-flying-in-the-rain#es it worse for the horse again.

Terrible analogy

[LordNimon]

When a raindrop hits a mosquito, it's the equivalent of one of us being slammed into by a bus. And yet the bug will survive and keep flying.

In other words, it's definitely not the equivalent being slammed by a bus.

Re:Impact energy not the same for small objects

[Anonymous Coward]

Simplify the experiment.
F=M*A
Given two objects of equal velocity, the more massive imparts more force.
The determining factor in the bounce vs. splash is how much energy is required to destroy the cellular bonds.
Assume both objects are spherical with the same composition and density, and no outside forces such as gravity or air resistence, etc. This also allows us to assume the same amount of force applied to a given surface area upon impact.

If the velocity is low enough, neither object will impact with enough force to break the structural bonds of the object.
If the velocity is high enough, both will break.
There is a "sweet spot" in the middle where the smaller will bounce while the larger breaks.
This is because the force required to break the structural bonds does not increase with the volume or mass of the object... it's essentially a fixed constant.

Now, when we're talking about dropping an actual mouse and an actual horse, things get vastly more complex. You not only have to worry about surface area, terminal velocity, impact angle, surface area of impact, but also the elasticity of each organism, and whether or not PETA gets wind of the experiment and interferes.

So how does the mouse vs. horse debate apply to this story, or the claim about getting hit by a bus?

"The team concluded that the raindrops deform and largely bypass the much smaller bodies of the mosquitoes."
Oh, it doesn't fucking apply at all.