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Comment by PheonixPharts | Hacker News Reader

This is the classic "this is fine" response whenever someone posts this observation about declining insect populations and cleaning dead bugs off of cars.

However a tiny bit of investigation into this will lead you to realize that this hypothesis is false.

More than just being false, research has discovered that modern cars hit more insects than less aerodynamic cars [0]:

> The research included vintage cars up to 70 years old to see if their less aerodynamic shape meant they killed more bugs, but it found that modern cars actually hit slightly more insects.

So, given what research has shown us, we should expect there to be more insects observed if it were the case that insect populations remained stable while cars became more aerodynamic.

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

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Right, the quote from the linked paper is:

> This is contrary to a suggestion that finding fewer insects on number plates in recent years might be attributed to increasing streamlining of vehicle aerodynamics over time. Our data show that newer vehicles sample more insects than older vehicles, and we have observed pattern of fewer insects on number plates more recently than in the past in spite of this effect of vehicle age, which is assumed to be correlated with aerodynamics.

In fact the researchers posit a few more possiblities other than collapse of insect populations that could explain their data. For example they can't eliminate the possibility that there's some change in the management of roadside verges that specifically decreases the insect population in those environments, without reducing the population in other environments.

The challenge for all the explainations which involve something other than population change is that there's now an increasing nubmer of studies using different techniques which consistently show declining populations. For example [1] uses Malaise traps in nature reserves, which presumably wouldn't be affected by roadside management practices, and finds a ~75% decrese in flying insect biomass over 27 years, whereas [2] uses light trap data to look at moths specifically and finds a ~40% decline in biomass over 50 years (and ~50% in woodlands).

Whilst it's possible to find studies that show increases in insect numbers e.g. as a result of site-specific conservation work, there's a lot of data suggesting that in Europe at least numbers are in significant decline. As far as I can tell (and I'm really not an expert) we don't understand the reasons all that well, but habitat fragmentation and pesticide use are leading theories. We at least know that common pesticides (notably, but not exclusively, neonicotinoids) are toxic to bees, and will reduce populations even at sub-lethal doses (e.g. [3]). So changing our agricultral practices to eliminate these chemicals looks like a necessary, but perhaps not sufficient, part of the solution.

[1] https://journals.plos.org/plosone/article?id=10.1371/journal... [2] https://resjournals.onlinelibrary.wiley.com/doi/10.1111/icad... [3] https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.66...

I drive over 100 Km daily. My '15 Impreza would get bugs on the windshield, but my '22 Model 3 is covered with them every evening. The first thing that I do after plugging it in is to clean the windshield, headlights, and other front-facing parts every evening. I'd do that maybe once every week or two in the Impreza.

Not if the aerodynamic cars from a decade ago significantly impacted insect populations.

Less than half of 1% of the land area in the United States is covered by roads of all kinds, not including rights-of-way, parking lots, and driveways.

National Academies of Sciences, Engineering, and Medicine. 2005. Assessing and Managing the Ecological Impacts of Paved Roads. Washington, DC: The National Academies Press. https://doi.org/10.17226/11535.

There is every reason to expect that the flying insects near paved roads today are less likely to die in encounters with cars than the flying insects near roads of 40 years ago.

But it would be very difficult to measure that effect.

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