Or at least not survive?
No wings, no web or any other means of softening the fall.
I don’t think there’s any height, even if the bug doesn’t have wings. The atmosphere would slow them down, just as it would slow you down. However, bugs are much smaller, so they fall much more slowly than you would.
Probably can’t happen for small insects. Don’t forget terminal velocity. Whether you drop a small bug from 10 feet or 1000 feet, the terminal velocity is likely to be the same (you’d have to do calcs for each critter, which can be quite complicated. In any event, event if you or I fall 10 feet, we’re hurting, whereas a bug is totally unaffected [apparently].)
Someone will pop along here soon with a more exact answer, but remember that thing called “terminal velocity”. Assuming that a bug can survive a fall at its terminal velocity, the distance of the fall will have no effect on its survival.
If the bug’s exoskeliton is strong that is also a great advantage, bugs survive even when masses much greater than their own fall on them. I suspect nearly all exoskelital bugs will survive a fall at their own terminal velocity. Snail slugs and caterpillas on the other hand might -Splat- quite nicely.
P.S. I don’t know why but I read the OP as "From what height would a bull have to fall to -SPLAT-
To clarify terminal velocity:
As an object accelerates, the wind resistance against it increases.
As an object falls, it accelerates.
Terminal velocity is when the force of wind resistance against an object exactly matches that of gravitational force pulling it towards the ground. This stops the object from accelerating.
I believe for an average human this is around 110mph. So you could fall from 28,000 feet or 1,000 feet, and you’ll still hit the ground at the same speed.
For lickle buggies, I have no idea, but think like a peanut or summat.
cheers, jjimm, I was just wondering about why terminal velocity existed at all. (As in, why there was a limit to falling speed)
Bippy, I dunno about the Bull, but I vote you’re cleaning it up! 
ok, insects are pretty simple creatures really, not a huge amount there to keep a shrink busy, but they do have a brain, could that not be rattled around or jarred to the extent it might cause fatal brain damage even if the exoskeleton survived the fall intact?
Same kind of issue: a human brain - or say, a bull’s brain - has much more mass (therefore, much more inertia) than a cockroach’s. In a fall, a bull’s brain is going to “keep going” with more force than a bug’s. It’s this momentum that slams the brain into the inside of the skull causing a concussion or other brain damage. The bug’s brain has significantly less mass, so At the sudden-stop phase of the fall the effect is much less.
That’s even assuming that a bug’s brain is significantly akin to a mammalian brain. In actuallity it’s more of an over-developed nervous system, so there isn’t really a central mass that can slosh around in brain-fluid.
This is a good example of scale effect. Start with the incredible shrinking man at 1/100 of his previous height or 6/10" tall. His shape is unchanged so coefficient of drag will be the same as before. I know I’m ignoring Reynolds number but let’s keep this simple. His frontal area to calcuate drag is 1/10,000 of what it was at full size, remember area is 1/100[sup]2[/sup]. His mass is now 1/1,000,000 of what it was before. The ratio of mass to drag from full size to small has changed by a factor of 100.
What would happen if a bug tried to reenter the atmosphere? That would be so much cooler than a magnifying glass.
I think it depends on what kind of bug we’re talking about…
Many insects (e.g., ladybugs) will die if you throw them at a wall hard enough. This process does not visibly crush them, so they must have some sort of internal parts that will break due to the shock. While something like an ant is small and light enough for terminal velocity to come into effect, there is no way something like a stag beetle will survive a fifty foot drop.
I can’t recall the source, but I read a discuss of this once. Apparently, a critter as large as a mouse can fall an indefinite distance under Earth gravity and one atmosphere, without serious harm. Somewheres after that, the amount of energy built up in momentum is too great.
That’s an invalid comparison. The force of your throw can be much greater than the force of gravity on the ladybug’s mass.
I doubt that a bugs “brain” can even be found except by an expert in bug brains. My father and I once tried to find a catfish’s brain. All we could find was a slightly enlarged knot on the end of its spinal cord. No mass that could bang against the skull at all.
I believe that the wind resistance scales as the square of the velocity. The kind of scaling argument that Padeye just mentioned then means that the incredible shrinking man will have a terminal velocity that’s roughly sqrt(100) = 10 times slower than the full-sized man’s terminal velocity, which works out to about 10 mph. Now think about how many bugs you get splattered on your windshield when you’re driving down the highway at about 10 mph.
But as long as she’s throwing the ladybug through the air, once it leaves her hand, air resistance will quickly slow it down to its terminal velocity anyway.
Okay, let’s remove the terminal velocity factor.
How high could a bug be dropped in a vacuum until it kills it?
Not only do bugs not go splat, but if you keep scaling down you eventually reach a size where the bug floats along in the atmosphere like a speck of dust with little effect from gravity. These have been found in the upper atmosphere, blown there by updrafts. Wasn’t there a column about the terminal velocity of cats here a while ago?
Yup, here it is. If a cat dosn’t have a fatal terminal velocity, a bug sure as heck doesn’t either.
If you figure out how fast a bug has to impact in order to die, I will tell you how far it has to fall from. I will leave the testing up to you though.
I know the plural of anecdotes is not data, but I’ve read on these boards that your larger “bugs” like tarantulas and such (yes, I know they’re not “bugs,” they’re arachnids, an entirely different thing) don’t survive a fall from any appreciable distance very well at all. Something like a drop from as little as 5 feet (perhaps less?) can kill a monster spider because their larger size (and thus weight) and structure makes them ill equipped to deal with the sudden forces of deceleration.