Hacker News Reader

Comment by vlovich123 | Hacker News Reader

To everyone replying “aerodynamics”, I’ve had the same car for about 9 years now and the drive along the 5 from Bay Area to LA feels like there’s fewer bugs on my windshield (granted not recorded diligently for scientific purposes but whereas before I’d need to scrub the windshield at least once halfway these days I can drive all the way and still don’t need a wash at the end)

Same goes for the argument that bugs have evolved to migrate away from the roads - the 5 has been a busy thruway for a long time with lots of cars and trucks.

The article is short but says scientists have clear data that populations have plummeted and the larger vehicle consumer trend + more people on the road means that there’s fewer bugs to encounter per windshield on top of that.

View on HN

I actually find it rather interesting how many people here, in a forum I generally assume to be better informed than elsewhere, seem wholly unaware of the dramatic decrease in insects over the last few decades.

Strong "I am very smart" contrarian energy here.

People who think they know better are more likely to comment than those who will simply say "huh, interesting!" You will often get a somewhat biased set of comments.

I also find it rather interesting to see talks about insect decline while it's only one part of the larger issue, rated by some as important as the climate crisis: the biodiversity crisis. Dramatic decreases are happening for way more species than just insects.

But is it “only one part” or more like a reliable indicator of the overall ecological health?

Both?

> Both?

I see. It just sounded like you were dismissive of that one metric based on this part of your original response:

> I also find it rather interesting to see talks about insect decline while it's only one part of the larger issue.

Which is why I asked.

I mean, hop into any threat remotely related to COVID and you'll see people come out in swarms of common science denial.

Just because people might be knowledgeable about certain technologies doesn't make them knowledgeable about anything else. In fact I'd argue that it heavily biases them to making more mistakes in other fields, especially considering that many tech problems are 'solved' by going to a search engine -- that's not a good way to do science.

> Same goes for the argument that bugs have evolved to migrate away from the roads

There are many studies in all kind of environments, even in the middle of the woods, in natural reserves; insects are going down both in term of diversity and numbers everywhere

They're being evolved away by pollution

NY state has a long running study where on July 15th every year they would put up a super bright lighthouse bulb in the middle of the woods and put it over a tarp. After they night they'd weigh the physical mass of insect life that had come to the light, and died, overnight.

I forget the exact %, but they'd seen a 50 or 60 percent reduction in mass since the 70's, some depressingly high number.

I don't think this would stop anyone from using the evolution argument, since in their mind this would just show that they evolved to not fly towards the deadly light.

One bulb, one night, once a year wouldn't be enough to select for light avoidance.

What about a thousand lit streets and a million cars every night swashing bugs? What about night lights helping predators see the bugs to weed out those light lovers?

I’m not saying these are true. But your response lacked imagination :)

Same tests have been run on licence plates. As they have remained in a similar position for decades, aerodynamics is clearly not the major contributing factor.

> To everyone replying “aerodynamics”, I’ve had the same car for about 9 years now and the drive along the 5 from Bay Area to LA feels like there’s fewer bugs on my windshield (granted not recorded diligently for scientific purposes but whereas before I’d need to scrub the windshield at least once halfway these days I can drive all the way and still don’t need a wash at the end)

Hasn’t California had extremely climate events over the last decade (wildfires, ongoing drought)? Given that bugs tend to be sensitive to air quality, this would likely local population decline which would then lead to the effect you’ve observed.

I welcome anyone to come to Prince Edward Island and enjoy the many, many mosquitos and midges our Island has to offer. They can be heard as small “pops” while driving.

A boom of one particular species is not necessarily indicative of a healthy ecosystem. We don't welcome algal blooms as signs of life bouncing back; rather, they are brutally disruptive to ecosystems. They leave mass death in their wake. Without a closer study of which species you're observing (they might be human-borne invasive species after all), it's not really easy to say if what you're seeing is healthy at all. And the timescales are important. This year or this decade might be a boom and 20 years from now they've managed to deplete their environment of resources and crash.

Yeah, I certainly don't doubt that there are global changes going on, but that particular drive along I-5 is confounded by many other local variables.

I too notice changes in the amount of bugs having driven that route periodically for about 30 years. Due to economic and weather conditions over decades, there are very obvious changes in whether you are driving by grassland, irrigated crops and orchards, defunct and desiccated crops and orchards, or graded and developed human environments. The road has also widened and gotten much more traffic.

The general trend is more human presence year over year, but the agricultural activity is more cyclic. As I understand it, these areas are only viable to irrigate in wet years, because the senior water rights are held and used much further north and east along the CA-99 corridor. In droughts, these more recently developed farms dry up first.

It's also of course very seasonal, with bug populations booming and then disappearing much like wild flowers and migrating bird flocks along the same route. In the heaviest bug carnage periods, driving this section of I-5 can be like driving through the US midwest during a grasshopper or cicada boom.

Also, the "bugs evolve away" would need evolutionary pressure being involved. But the explanation I got was the available biomass for bugs is such that any chunk of bugs killed on the road was easily filled by other bugs eating their lunch and procreating.

> Also, the "bugs evolve away" would need evolutionary pressure being involved

I do not claim that evolution is the reason for the reduction in dead bugs, but if "go near road" has a increased risk of death due to automobiles, there absolutely is selective pressure to not "go near road". Bugs that get killed by cars don't procreate (again) after all.

I read last week about mooses avoiding certain hunting spots during hunting season.

Link in Swedish, not sure how scientific this is but…

https://www.aftonbladet.se/nyheter/a/mQQWbO/algarna-overlist...

Is "moose" a word like "sheep", that is it's own plural? (I honestly don't know, but "mooses" sounded odd).

My guess would have been meese. Luckily, all the information is out there.

> "plural moose or (dated, rare) mooses or (non-standard, jocular) meese" [0]

[0] https://en.m.wiktionary.org/wiki/moose

Many much moosen

https://youtu.be/CafPNEWnDhk

Yes but the pressure is weaker than one might intuitively guess. There are billions of bugs. Even near roads, very few of them are going to be hit by cars, comparatively. Near roads there often are ditches with some water or moisture, making an environment otherwise beneficial for bugs.

Also, decreased road side windshield bug smashing coincides with measured loss of insect biomass:

https://en.wikipedia.org/wiki/Decline_in_insect_populations

Disputing that feels more and more like disputing global warming being a thing.

> Disputing that feels more and more like disputing global warming being a thing.

There's a reason I started my comment with "I do not claim that evolution is the reason for the reduction in dead bugs". I was just nitpicking and not trying to be the devil's advocate.

Also note that "species are evolving to adapt to XYZ" really means "everything that can't deal with XYZ is dying". If the ecosystem just doesn't have any species that can deal with XYZ, then that part of the ecosystem just dies.

What if, with more cars and bigger windshields, we're just grabbing less and less of these bugs due to more of them being killed by other cars / trucks?

The environment around those roads contains millions of other insects. The amount killed by cars is a tiny percentage. That would obscure any affect from the small increase in automobiles or their windshields.

The last time this was discussed I found some articles showing that the more boxy and angular windows of older vehicles were less likely to have bugs smashed on them. This is why these studies often use license plate splatters to get a better count -- that really hasn't changed.

> some articles showing that the more boxy and angular windows of older vehicles were less likely to have bugs smashed on them

Do you mean "more likely"?

> This is why these studies often use license plate splatters to get a better count -- that really hasn't changed

Do you claim the amount of license plate splatters remains consistent today as, say, 30 years ago, or some other time frame? I think this claim really needs to be sourced, can you produce these studies you allude to? Thanks

No, I absolutely meant "less likely". The bugs don't hit as often against the old vehicles. The older boxy vehicles were more likely to push the insect away, while the modern aerodynamic vehicles allowed the bug to hit the windshield more frequently. I'll see if I can find the study, I don't have it handy at the moment.

As for the license plates, they are no more aerodynamic than they were 30 years ago, which makes them a better source for insect measurement.

Edit: relevant discussion from a few months ago: https://news.ycombinator.com/item?id=31275879

> As for the license plates, they are no more aerodynamic than they were 30 years ago, which makes them a better source for insect measurement.

I agree with this, but not the claim that there are studies showing this number is consistent with the past. The linked discussion also seems to imply that sampling rate corresponds with the decline in insect populations, unless I missed something.

I've not said that they (bug splatters) are consistent with the past. Perhaps my wording wasn't the best, but I was trying to say that the aerodynamic properties of a license plate have not changed.

I see, "that really hasn't changed" was a statement on aerodynamics and not volume of insect collisions. Thanks, I agree with what you're saying, good tidbit about the more aerodynamic cars leading to lower probability of insect survival.

Reply on news.ycombinator.com