I assume these and similar insects can only get up to a certain height, and that anyone whose windows are above that height would not need screens to keep them out.
Is this correct? And if so, what is that height?
I would think strong updrafts could take them up fairly high in the sky whether they like it or not…
I seem to remember that back when I lived in New York City, apartments above the 6th floor were not furnished with window screens. No central air either as it was the 60’s. I was only 17 or so and might be remembering incorrectly.
I was on the uppermost floor of the Empire State Building a few years ago and lots of bees could be seen outside the windows. The presence of multiple bees makes me think there must have been a hive up in the sky, and that they would have to descend quite far to find flowers and then ascend home.
I always heard that it was the 5th floor.
You mean height above local terrain, or altitude above sea level? Because they seem to do fine in the mountains (well above 10,000 feet)
As far as height above local terrain…there’s this. Sounds like some species naturally include 40-foot-high airspace as their stomping grounds. Breezes can take them much higher, but I imagine that’s an uncommon thing.
Insects will mostly stay where the food is. What I have typically heard is that if you are above the tree level in your area, you are mostly safe from bugs coming in through your window.
The key word there is “mostly”. I’ve heard of people who live 20 or more stories up who have had insects occasionally fly in through their windows. It’s nowhere near as common as someone who lives on the 4th floor, but it happens.
Insects have been found up in the 15,000 to 20,000 foot range. At these heights, bugs start running into the same problems that humans do, extreme cold combined with a lack of oxygen.
I don’t know what the world record is for insect altitude, but I imagine it’s pretty high. Poking around on google, I found that bees have been found at about 20,000 feet on Mt. Everest. Scientists tested the bees in a vacuum chamber and found that they could survive and continue flying at simulated altitudes up to close to 30,000 feet.
I work in the Bank of America Plaza, in Atlanta. I’ve seen insects on the 47 floor window. I didn’t think they could get that high, but there you go.
I was told that when the American settlers first moved west, they could keep food away from flies by hanging it trees. True or myth? No idea.
Interesting question the OP poses, and appreicate everybody’s feedback. I can say at 8,750’ where I have my log cabin in the Sangre de Christo mtns, I often go the whole year without seeing a single mosquito, and I’m covered with old thick forest growth of 100’ trees, so the wind really isn’t all that strong either.
I do have some flies, only time they are a nuisance is when I’m cooking meat outside. There is a very small moth population about half the size of a dime, that seems to do fine though. I suppose the several dozen bats that come out at dusk spend most of their time feeding off of them, since the mosquito population is almost nil. The few mosquitoes I have seen at this altitude, were slow as hell.
Since where I’m at all of the water is from natural springs and a creek that keeps the water moving, that also is a good deterent not having any standing water for the mosquitoes to lay their eggs in.
Wouldn’t think so myself. Did they give the reasoning behind that?
I wonder if updrafts play a role, as well. I know that I’ve frequently seen spiders in webs just outside of the windows in skyscrapers in Chicago; there must be enough bugs in the vicinity for them to survive and thrive.
I thought that was bears.
Apart from ballooning, AIUI spiders just set up shop wherever they are and hope for the best. Their presence outside high windows doesn’t necessarily mean they are surviving and thriving there; they may just land there on a random breeze, build a web, and then shrivel and die over the course of several days for lack of prey.
I have seen a fly at about 35,000 feet. He had no trouble flying around the cabin of that plane.
I bet if they suddenly decided to depressurize the cabin that no tiny little oxygen mask would descend from the ceiling for him though.
I didn’t write that right. The small moths actually do have a fairly good population, I misrepresented that with their small size.
Spiders (& other insects) like the smell of mercaptan (the odor that is added to propane). We’ll occasionally see one a few thousand feet up.
I guess they’re occasionally stowaways on other kinds of aircraft, too. 
Insects have been found at insanely high altitudes:
In addition, they can live at very high altitudes (although they are “only a few feet off the ground” at that altitude)
One of the many effects of global warming is that ** warmer climate threatens malaria spread in Ethiopia** and other locales where communities developed above the altitude that shielded them from the mosquitoes that deliver that deadly disease.