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Comment by Gys | Hacker News Reader

A 26 page research report with a clear conclusion:

> The results show that the number of insects sampled on vehicle number plates in the UK decreased by 58.5% between 2004 and 2021, and that these differences were statistically significant. A comparison of the 2004 national data with the 2019 data from Kent showed a 53.7% decrease. The greatest decreases in splat rate between 2004 and 2021 occurred in England (65%) whilst journeys in Scotland recorded a comparably smaller decrease (27.9%), with intermediate decreases in Wales (55%).

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It could be evolution - insects with traits that kept them from cars were selected for. Perhaps changes to the license plates? Changes in the design of cars? Or a general decline of insect population?

Yes, it could be that, but anecdotally I see significantly less bugs on cars during summers than during my childhood. The grill, windshield, etc would have dozens of lovebugs after a short drive on an early summer day. Now they're rare.

Completely anecdotal but I seem to remember flies banging their heads on windows a lot more when I was younger.

Now they seem to be able to navigate their way out with comparative ease. Open a door or window and waft them in the general direction and they seem to be able to escape.

I've been wondering for a few years if this was evolution.

Please tell me where you live so I can move there. My flies are as dumb as ever, I can't even get them to go out the window with me actively trying to kill them. They rather take their chances with the swatter or get tangled behind the curtains.

The UK. Maybe you stress them out :)

From an evolutionary perspective it would seem wrong to actively go towards the source of stress when the opposite direction clearly leads to safety. But then again what do I know. Perhaps my flies are adrenaline junkies.

I've had two birds fly into my living room window this week. I haven't even cleaned it recently. The flies may be evolving but robins have a ways to go yet.

The more aerodynamic the car is the less splats there should be, as the bugs are more likely to be carried by the flow of air around the car, correct?

Still, there is no doubt that the insect population is in a massive decline.

>The more aerodynamic the car is the less splats there should be, as the bugs are more likely to be carried by the flow of air around the car, correct?

It depends on what the nature of the airflow around a specific car looks like. Bugs have a harder time than air making a "hard corner" but the mass of air stuck at a hard corner can cause other air to go around in a more graceful way and carry the bugs with them.

Coefficient of drag hasn't improved much since the 90s and most of those improvements have been with regard to the vacuum behind the car so aerodynamics is probably only a contributing factor either way.

> The more aerodynamic the car is the less splats there should be, as the bugs are more likely to be carried by the flow of air around the car, correct?

incorrect

As I've pointed out in another comment, research has shown [0] that counter-intuitively "modern cars actually hit slightly more insects."

It's a reasonable hypothesis, however what this research shows is that we would have expected to see more dead insects on cars had populations remained stable.

0. https://www.theguardian.com/environment/2020/feb/12/car-spla...

Research is research, but anecdotes are anecdotes. And anecdotally, I can tell you that having done the same drive in the same conditions many times with both a Jeep Wrangler and a Toyota Prius, the Wrangler consistently has far more bugs on it, and requires multiple cleanings per leg of the journey. The Prius requires no cleanings for the duration of the trip.

I've worn the same brand and model of motorcycle helmet (Nolan flip-up) for probably 20 years. Granted, I'm sure Nolan has made some minor changes over the years, but the aerodynamics of my massive noggin haven't changed, and I clean far, far fewer bugs off my face shield than in years past. Just my imagination? No, I have records of when I buy Honda Spray Cleaner and Polish (the pro's choice for cleaning face shields), and I don't buy as much as I used to for the same miles ridden. And old post of mine from six months ago when the topic came up, and everyone's all like "cars are more aerodynamic than they used to be" (yeah, well, my head's not), basically saying the same thing:

https://news.ycombinator.com/item?id=29006969

Reasonable questions to ask. But a fairly well-known German study based on traps that catch flying insects had a 75% reduction over 27 years:

[1] https://journals.plos.org/plosone/article?id=10.1371/journal...

Just anecdotally, I see almost no bugs swarming street lights anymore, and have personally experienced the windshield phenomenon on several road trips.

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