Bugs Matter: counting insect ‘splats’ on vehicle number plates [pdf](cdn.buglife.org.uk)
cdn.buglife.org.uk
Bugs Matter: counting insect ‘splats’ on vehicle number plates [pdf]
https://cdn.buglife.org.uk/2022/05/Bugs-Matter-2021-National-Report.pdf
57 comments
It used to be—80s and early 90s—that a couple hundred mile drive down the Oregon coast would need at least one or two stops for bug splat removal. I made that drive last July and there were perhaps two splats for the entire 400-mile round trip.
This was the case in the Midwest in our basically-the-same-shape-as-modern-cars 90s family cars. We'd use the windshield cleaner thing next to the gas pump nearly every time we stopped, when on road trips, and for good reason—there'd be a few large splatters and a bunch of smaller ones, every time. And that's if it wasn't particularly buggy out that day—there were some times we stopped for the windshield, not for gas.
I think I've done that like... four or five times, total, since the year 2000. And I think every time it was for a single big bug-splatter.
[EDIT] I also recall there being tens of times more large insects—butterflies, large moths, grasshoppers, katydids—around in general back in the late 80s and early 90s, even in the 'burbs, like they were just all over the place in the Spring and Summer, you'd walk through lawn-length grass at the school playground and tons of them would be all around you, hopping away or taking to the air, and now I have to try pretty hard to find even one... but surely that can't be right, can it? That'd be super noticeable by scientists who track that kind of thing. Right?
I think I've done that like... four or five times, total, since the year 2000. And I think every time it was for a single big bug-splatter.
[EDIT] I also recall there being tens of times more large insects—butterflies, large moths, grasshoppers, katydids—around in general back in the late 80s and early 90s, even in the 'burbs, like they were just all over the place in the Spring and Summer, you'd walk through lawn-length grass at the school playground and tons of them would be all around you, hopping away or taking to the air, and now I have to try pretty hard to find even one... but surely that can't be right, can it? That'd be super noticeable by scientists who track that kind of thing. Right?
There might be a perception thing involved as well. Insects tend to emit sound in high frequencies and adults get worse in hearing those as they age. When I was in my early 20s, my mother once swore there were no crickets around while I was like "how can you not hear them? They're so loud...". Nowadays, I wonder were the crickets have gone...
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I’ve been driving all over the midwest and my car is covered in splats after each trip. This seems really surprising to me.
I’ve driven a lot over Kansas, Oklahoma, and Texas in rural areas since the 60’s. The number of bug splats now is just a fraction of what it was in the 60’s and 70’s.
I don’t doubt that; I was just remarking about the “1 splat” figure.
I remember being at minor league baseball games in the 90s, waiting for dark to see fireworks after the game, and getting absolutely rained on by moths falling from getting cooked in the stadium lights. The cloud of moths would be so thick it would partially obscure the lights. The girls would scream and the boys would scoop up handfuls from the ground to throw at the girls.
... Not me. Other boys.
Anyway. I don't think the mosquitoes got the memo. I feel like I get more and more bites every year.
... Not me. Other boys.
Anyway. I don't think the mosquitoes got the memo. I feel like I get more and more bites every year.
'80s cars are not exactly known for their aerodynamics...
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'( )------( )=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...
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...
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...
> 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.
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.
But it would be very difficult to measure that effect.
I have been driving the exact car from this drawing for the last 25 years: Volvo 940, square as a brick.
In the 90s, it needed a weekly scrub to keep the headlights and plate visible.
I have literally not washed my car a single time over the last year. It has moss and pollen all over, but there are hardly any bug splats.
This frightens me _so_ very much.
In the 90s, it needed a weekly scrub to keep the headlights and plate visible.
I have literally not washed my car a single time over the last year. It has moss and pollen all over, but there are hardly any bug splats.
This frightens me _so_ very much.
The majority of US cars are huge SUVs and pickup trucks. I would dare say 80's cars are more aerodynamic simply by having a smaller cross section.
Not necessarily. Windshields were less curved and more vertical, body panels were much less contoured, and features like sealed-beam headlights, mirrors (if equipped), and windshield wipers were more protuberant. A 1980s Mercury Grand Marquis had a drag coefficient of 0.46, while a 2018 Ram 1500 is listed at 0.357 (less is better). Obviously some 80s cars fared better, mostly compacts like my '83 SAAB 900 (3.7, not on the list below) or sports cars. I just picked the Mercury as a typical full-sized family sedan.
Here's a big list, for anyone interested in some numbers: https://en.wikipedia.org/wiki/Automobile_drag_coefficient
Here's a big list, for anyone interested in some numbers: https://en.wikipedia.org/wiki/Automobile_drag_coefficient
Coefficient of drag normalizes relative to cross sectional area. Pointing out that a modern Ram 1500 has a lower Cd than an old Mercury doesn't mean the Ram has less drag. If the Ram's cross sectional area is 30% larger, it will have more drag than the Mercury despite having a more aerodynamic shape.
I have heard that a Spoon Sports modified F20c can do 11k reliably. The engine has a very long stroke for its size, and stock, the piston speeds are already higher than almost any other car engine, so that it can spin as fast as it does is pretty amazing.
Motorcycle engines, however… Some of those are 14-16K stock.
Motorcycle engines, however… Some of those are 14-16K stock.
Thanks for pointing this out; I was unaware. There's also a table of cross-sections later in the linked Wikipedia page, but I hadn't paid much attention to it because of not knowing how to perform a meaningful comparison.
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The article's title specifically mentions "number plates". All cars in the UK are required to display number plates (license plates) at the front and back. They have a standard size. They are nearly all (99% or more) in the centre and are roughly the same height off the ground, depending on model.
My first Mark 1 Ford Fiesta from 198something had its plate at about the same place as the Honda S2000 I had in 200something and the Renault CLio I have now and the Ford Transit van I also drive.
The S2000 did the best doughnuts though. Rear wheel drive, variable valves, 13,500 RPM red line and quite a lot of welly.
My first Mark 1 Ford Fiesta from 198something had its plate at about the same place as the Honda S2000 I had in 200something and the Renault CLio I have now and the Ford Transit van I also drive.
The S2000 did the best doughnuts though. Rear wheel drive, variable valves, 13,500 RPM red line and quite a lot of welly.
What kind of mods did you put on your S2000 for it to do 13500 RPM and not blow up immediately? That redline would be 3000 above any other production car sold, with the 2nd place being a motorcycle engine in an Ariel Atom 500 redlining at 10'500 RPM.
My eyes are dim, my memory is ... Whoops. Perhaps 9000 RPM is a bit closer to when the bloody thing stuttered when I overdid it a bit. It got there rather rapidly in 1st and getting into 2nd and 3rd on time took a bit of fast twiddling. No paddle flapping nonsense, just a stick that has to be moved rather fast in conjunction with the clutch.
I live in Yeovil, Somerset - the Ariel mob are from down the road - Crewkerne (pronounced something like Kruken!)
I live in Yeovil, Somerset - the Ariel mob are from down the road - Crewkerne (pronounced something like Kruken!)
I have heard that a Spoon Sports modified F20c can do 11k reliably. The engine has a very long stroke for its size, and stock, the piston speeds are already higher than almost any other car engine, so that it can spin as fast as it does is pretty amazing.
Motorcycle engines, however… Some of those are 14-16K stock.
Motorcycle engines, however… Some of those are 14-16K stock.
Your s2000 had a 13.5k redline? Did you happen to have one with a Spoon engine that went 2k beyond any other Spoon engine?
Not doubting you just genuinely interested as an enthusiast. edit: saw your other reply
Not doubting you just genuinely interested as an enthusiast. edit: saw your other reply
Somewhat off topic - Did you draw that car yourself, or did you copy it from somewhere? It's great!
This happens on my home Debian box when I mistype `git`:
$ gti
,---------------.
/ /``````|``````\\
/ /_______|_______\\________
|] GTI |' | |]
= .-:-. |________| .-:-. =
` -+- -------------- -+- '
'-:-' '-:-'There's this assumption, not explicit, but floating around this thread, that aerodynamics somehow makes splats more difficult.
I can't really refute it, but it doesn't ring true to me either.
Insects don't even touch the car before exploding, mind you.
I can't really refute it, but it doesn't ring true to me either.
Insects don't even touch the car before exploding, mind you.
Last summer's trip was in a Mercedes GLK, not exactly the paragon of slipperiness.
[deleted]
Ingenious. A similar method has been employed for monitoring species’ density using roadkill as a metric [1]
[1] https://www.ucf.edu/news/new-study-shows-impact-of-roadkill-...
[1] https://www.ucf.edu/news/new-study-shows-impact-of-roadkill-...
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%).
> 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%).
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?
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.
[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.
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.
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.
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.
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?
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...
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.
>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.
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.
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
https://news.ycombinator.com/item?id=29006969
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I must say, what an ingenious way to measure insect counts. It's clever ideas like these that I come to hacker news for.
I wonder if it is a matter of there simply being more cars on the road - population increase. i.e. fewer bug impact per car. Traffic? Can (higher) velocity have an effect? Off topic: same goes for “power density” in gas vs electric vehicles. What is power density in oxygen free environments like underwater or space?
Could this in any way be related to the increase of wifi, cellular or any other EM waves that got a huge boom since the early 2000s? I ask this as in, is there any research on how the EM waves we've been using the past 20-25 years interact with arthropoda in general?
https://en.wikipedia.org/wiki/Decline_in_insect_populations
There are a lot of very plausible explanations to work through before you have to consider something exotic like EM sensitivity.
There are a lot of very plausible explanations to work through before you have to consider something exotic like EM sensitivity.
Probably going to regret asking this, but is there any evidence that EM waves interact negatively in anything in the animal kingdom? Outside of literally cooking something.
For the "any other EM waves" portion sure, ionizing radiation damages in a very different way than heating something up. It's unrelated to things like Wi-Fi and celluar though and such non-ionizing radiation has not been found to have some other negative interaction.
Extremely high power extremely low frequency radiation can also cause electrical flow but it's not been found to be problematic in humans at least. I doubt anyone has done a study on extremely low frequency radiation for arthropods in the specific time frame specified by the GP but I also doubt this portion of the EM landscape has changed significantly enough compared to before that time frame to be a relevant explanation.
Extremely high power extremely low frequency radiation can also cause electrical flow but it's not been found to be problematic in humans at least. I doubt anyone has done a study on extremely low frequency radiation for arthropods in the specific time frame specified by the GP but I also doubt this portion of the EM landscape has changed significantly enough compared to before that time frame to be a relevant explanation.
If the (important/compelling/disturbing) science content wasn't enough, definitely open the article for terms like "Splatometer" and "Splats-per-mile".