Nicely explained... As for the last remark about evolution, indeed, it's not the reason. In fact, its funny to see how difficult flight is for them because of their huge wings.

I wonder if insects that breed near roads now have larger wings.

@Frank: Motor vehicles haven't existed nowhere near long enough for evolution to kick in and enlarge wings, we are several orders of magnitude out. However, it may be correct from a purely observational standpoint that the average wingspan (relative to body weight) has gone up near roads, simply because there was a normally distributed population which is now big-wing-heavy because of a significant amount of the small-wing population having gone splat.

@Flater That's actually a myth about evolution taking so long. Still...it would be interesting to check. One of those things that if you collected lots of flies near roads and lots of flies away from roads and found a difference, you could probably publish the results and end up with a brief moment of fame as the mainstream media run with the fascinating headline of "Roads create giant insects"

@Frank: Collecting flies does not differentiate between flies near roads having evolved to have larger wings, or simply that only the flies with larger-than-average wings are the only ones left after the smaller-than-average winged ones went splat.

@Flater You'd have to look at the maximum wingspans or something like that. Or even better, breed flies in jars and kill off the little ones and wait for a few generations until you have butterfly sized mosquitoes and then release them near roads and then send findings to Reuters

@Frank: See you in a million years.

@Flater Doesnt matter. You could collect bumble bees and glue little bits of tissue paper onto their wings. Then release them near roads and send photos to the newspapers.

@Flater Counterxample: domesticated cat. No idea where 1 million years comes from.

I don't think the "extra speed of air over the wings is small" argument is completely accurate, I think it's simply a matter of wing area vs mass. The bigger the wings compared to the mass of the insect are, the more immediate the reaction to the redirected air current in front of the windshield will be. Sure, small wings happen to have higher speed to counterbalance their lack of size, but if a small bug "magically" was able to fly at butterfly wing speed, I'm pretty sure it would still go splat.

@MaxD fair point - the two things are closely related. The wings can only move slowly because they are large. So yes, in the end it’s an area/inertia type of argument. There’s an interesting corollary for this as it relates to filters: Large particles get stuck (trapped), medium-sized ones travel through the “maze” (not enough inertia for their drag, so they follow the air flow), tiniest ones get stuck by electrostatic force.

Antibiotic resistance is evolution. The shorter the whole replication cycle, the faster it happens.

@Frank Also Homo sapiens, 100s of thousands of years, not millions between different hominids. Many island species phenotypically differentiate in only 10,000 years (such as species of insect and lizard), species with fast reproductive rates even faster. Maybe chromosomal changes that stop interbreeding between species don't take place on average until 1,000,000 years later, but that has no effect on actual species phenotype.

@Flater: Evolution of insects doesn't take all that long. The classic example is the British peppered moth that evolved a nearly black form in the mid-1800s to deal with urban pollution, then re-evolved the lighter form after emissions control laws cleaned up things: bbc.com/news/science-environment-36424768

Inset evolution may be fast, but not nearly fast enough, something (likely something we are doing) is killing them. theatlantic.com/science/archive/2019/02/…

@Frank This reminds me of an article I read (Scientific American perhaps) about some study of the wing-length of some species of scavenging bird. The upshot is that the birds that were feeding from roads had wings that better allowed them to get off the road quickly.

@jamesqf It’s debatable whether that was really “evolution” or natural selection of the color variant that existed before (but was rarely seen). Either way - the color variant becomes the predominant specimen when environmental pressures favor it.

@Floris: And that isn't evolution?

It should be noted that there is a range of heights for each and every car and bug, including butterflies, within which the bug will go splat. However, due to the much lower wing loading of butterflies, the fatal height range of butterflies is much smaller than that of fleas and such.

@StianYttervik the ground effect comes into play when there is air flow over the wings. Not sure to what extent that is the case for the butterfly wing.

@Flater What you described is precisely natural selection! The gene pool of the population of butterflies would change, tending towards larger wing sizes. That's one mechanism of evolution.