
No net insect abundance and diversity declines across US - jbotz
https://www.nature.com/articles/s41559-020-1269-4
======
blakesterz
"Some taxa and sites showed decreases in abundance and diversity while others
increased or were unchanged, yielding net abundance and biodiversity trends
generally indistinguishable from zero. "

That's very interesting, and REALLY surprising. Even the citations listed
there has this one: "More than 75 percent decline over 27 years in total
flying insect biomass in protected areas."

Hoping to see the details on how they did things.

~~~
joshvm
Ecology is incredibly difficult because everything is horrendously under-
sampled. Essentially all ecology reduces to counting species over time and
somehow extrapolating to huge areas. So-called total count surveys are
extremely expensive.

I can only speak from a megafauna perspective (eg not insects), but there were
recently some results that suggested that animal decline in Africa was
overestimated. Caused quite a stir. And it makes sense when you learn how
people count animals in aerial surveys - photographic interpretation is
_novel_ because most ecologists are not used to dealing with that level of
data, nor the complexity in designing the camera systems, and it was
impractical to do with film in the past. The gold standard is someone with a
voice recorder in a plane. When you actually go through aerial photographic
surveys, you spot all sorts of things that the observers missed, because
they're not superhuman. That's not to say there is no decline - poaching has
still decimated populations - but for some species it might not be as bad as
you think. In theory the methods (things like JOLLY2) are supposed to correct
for you missing a certain percentage, and distance to the animals etc, but
that relies on you knowing what those uncertainties are.

I don't know how insect surveys are performed, but you have to understand that
you're always trying to make sweeping assumption about "the whole of the US"
based on very sparse sampling. Not to mention controlling for different
environments. For example in the paper you cited, they try and control for a
ton of stuff like habitat. I'm not an entomologist so I won't comment on the
paper beyond that, but do be aware that "standard techniques" may well be
something that we've done since the 60s and nobody questions it.

~~~
Natsu
For insects, there are a lot of different traps based on the nature of the
insects being sought. There's a pretty good list here:

[https://en.wikipedia.org/wiki/Insect_trap](https://en.wikipedia.org/wiki/Insect_trap)

As I understand the sampling, you pretty much just put the traps out and count
up how many insects you get of each type.

Purely anecdotally, I feel like the number of butterflies is way down from the
level you'd see during, say, the 90s. It seems like I just don't see as many
different types any more and even the more common types feel vastly reduced in
number. I used to see monarchs and sulfers and painted ladies and red admirals
and cabbage butterflies all the time, now I barely see a few cabbage
butterflies or sulfers and occasionally a painted lady or two. I never get to
see the less common things like buckeyes any more, which is a pity given that
they're my favorite.

~~~
9nGQluzmnq3M
This is anecdotal, but during Singapore's lockdown, one of the many services
cut for about two months was curb maintenance. Being deep in the tropics, all
green spaces immediately turned into jungles of flowers and weeds, and the
butterfly population consequently _exploded_ :

[https://mothership.sg/2020/06/grass-cutting-
butterflies/](https://mothership.sg/2020/06/grass-cutting-butterflies/)

[https://www.bbc.com/news/world-asia-52960623](https://www.bbc.com/news/world-
asia-52960623)

On the other hand, mosquito populations also increased and there were lots of
people stuck at home as bait for them, contributing to Singapore's worst
dengue outbreak in years:

[https://www.tnp.sg/news/singapore/three-more-dengue-
deaths-s...](https://www.tnp.sg/news/singapore/three-more-dengue-deaths-
singapore-outbreak-worsens)

So at least one lesson here is that, if given an opportunity to bounce back,
many insect populations can and will.

~~~
refurb
Singapore is also going through a particularly bad Dengue fever season, so
there is a ton being done for mosquito control including spraying of
insecticides.

I have no idea how selective those insecticides are, but one could imagine an
impact on other insects.

~~~
CydeWeys
Insecticides in general are quite broad spectrum. You need to use different
tactics entirely if you only want to target mosquitoes.

------
eecc
Yes, less fireflies and ladybugs, yet plenty of bloody tiger mosquitoes... I’d
say is a typical case of “half chicken statistics”

~~~
MereInterest
I'm not familiar with the phrase "half chicken statistics", and a basic google
search was unhelpful. What does that generally refer to?

~~~
Recursing
It's a famous saying in in Italy on the problem of losing information when
averaging

"If one person eats a chicken and another person doesn't eat anything, on
average they both ate half a chicken"

Or in a similar way something like:

"If I eat two chickens and you eat none, statistically we both ate one"

~~~
skocznymroczny
In Poland we use "on average, me and my dog have three legs"

~~~
strbean
In Latvia, we say "on average, all have no potato." Then we are sad.

~~~
sulam
I dunno, I saw lots of potatoes in Riga!! :)

~~~
dllthomas
The saying dates back to before the discovery of the New World, when in fact
no one in Latvia had potatoes.

------
stx
This sounds pretty surprising to me since I thought I kept hearing that
insects were in decline globally. This made me curious.

One thing I often check is who the author(s) are and what their links to
industry might be. For example if the paper claims that "Smoking is good for
you in moderation" and then after googling the author I find they have ties to
Marlboro I start to doubt the authenticity of the research.

In this case the authors are mostly organizations that from what I can tell do
not have any affiliation with for example an insecticide company or even a
company. The only non organization author I see listed is Michael S. Crossley.
I googled him and did not find anything suspicious. He does not appear to have
a background in entomology or ecology. I am not really sure if that is reason
to be suspicious but just thought I would share.

Here is a link about one of the authors:
[http://www.bristol.ac.uk/education/people/michael-w-
crossley...](http://www.bristol.ac.uk/education/people/michael-w-
crossley/index.html)

~~~
AlotOfReading
You've linked Michael _W._ Crossley, the lead author is Michael _S._ Crossley.
The google scholar profile for the latter matches the contact email in the
paper and shows a history of related work.

[1]
[https://scholar.google.com/citations?user=X5W_3dYAAAAJ&hl=en...](https://scholar.google.com/citations?user=X5W_3dYAAAAJ&hl=en&oi=ao)

------
durbatuluk
This type of measurement using quantitative data should be interpreted with
care. At least here in Brazil most of places where some impact occur have an
increase in net diversity and abundance. Many new sp. invade the niche left
open by the former community and what you see is a shift of the entire
community.

~~~
ImaCake
Which, while terrible to see the loss, gives me some hope that we have less
power over nature than we think. A housing suburb is undeniably a less
wonderful place than the forest it replaced. But life will inevitably find a
way to colonise that suburb. Black birds and Camel crickets bring me hope. But
I wish we would stop burning down rainforests and building boring suburbs.

~~~
rcoveson
> A housing suburb is undeniably a less wonderful place than the forest it
> replaced.

Agreed, though with the notable exception of my own housing suburb, which I
prefer over whatever it may have replaced.

------
nkurz
Full article: [https://sci-hub.tw/10.1038/s41559-020-1269-4](https://sci-
hub.tw/10.1038/s41559-020-1269-4)

Fun sentence about the breadth of the data: "Types of arthropod data include
grasshoppers per sweep in Konza Prairie (Kansas), ground arthropods per
pitfall trap in Sevilleta desert/grassland (New Mexico), mosquito larvae per
ovi-trap in Baltimore (Maryland), pelagic macroinvertebrates per tow and
crayfish per fyke net in North Temperate Lakes (Wisconsin), aphids per suction
trap sample in the Midwestern United States, crab burrows per quadrat in
Georgia Coastal Ecosystems, ticks per person/hour in Harvard Forest
(Massachusetts), caterpillars per plot in Hubbard Brook (New Hampshire),
arthropods per pitfall trap and sweep net in Phoenix metro area (Arizona) and
stream insects per rock scrub in the Arctic (Alaska) (Table 1)."

The crayfish and crabs surprised me, considering the title mentions only
insect abundance.

~~~
throwaway5752
From the paper's abstract, _" The apparent robustness of US arthropod
populations [...]"_

------
sradman
> The US National Science Foundation initiated the establishment of a network
> of Long-Term Ecological Research (LTER) sites in 1980, and these now
> encompass a web of 25 monitoring locations across each of the country’s
> major ecoregions (Fig. 1).

The paper includes both source data and source code (R data analysis) [1].

[1]
[https://datadryad.org/stash/dataset/doi:10.5061/dryad.cc2fqz...](https://datadryad.org/stash/dataset/doi:10.5061/dryad.cc2fqz645)

------
giardini
The classic Predator-Prey Model demonstrates drastic swings in both predator
and prey populations:

[http://www.scholarpedia.org/article/Predator-
prey_model](http://www.scholarpedia.org/article/Predator-prey_model)

This model was one of my favorite revelations in high school.

------
lostmyoldone
Seems there is a fair bit of non-flying insects in the data, and seems also to
be only few sites, so might be hard to compare with European data?

European decline is afaik mostly related to flying insects.

Short on time, but it would be interesting to compare population densities, as
that's quite likely a major factor.

------
ball_of_lint
Good on these scientists to post a "No change" result, even if it is
surprising.

~~~
hn_throwaway_99
Well, in science you actually usually get bonus points for "surprising"
results, so while I'm glad they published it I think the same incentives that
encourage scientists to publish some findings and trash others are still at
play here.

~~~
ImaCake
I think the title of this paper does a real disservice to the much more
carefully written abstract. The abstract is very careful to point out the
limitations of this study and flesh out why the main conclusion should be
considered cautiously.

------
esarbe
This is such an amazing finding. The data from Europe is really scary, so
having such a positive finding from the USA is dearly needed, good news.

It's a shame that there seems to be some valid criticism with regards to the
paper, I'll have to dig in further.

I hope we get more data soon so we get a fuller picture of where we stand in
matters of insect population and diversity.

------
BurningFrog
One way we're all misinformed is because "things are pretty OK" studies like
this never go viral.

------
TheMagicHorsey
I know anecdote is not data, but I’ve been driving through rural California
for decades. I definitely noticed that in the last few years I have
significantly less insects caking my windshield after a long drive than I did
ten years ago. This could be explained by changes to windshield design,
changes to car lights, and changes to the land adjacent to highways.

~~~
throwaway0a5e
Denser bits of the air, like insects, will have a much harder time abruptly
changing direction so vehicles with worse aerodynamics tend to pick up insects
for the same reasons that water trap style air filters work.

While windshield angles haven't changed much over the years car front ends
tend to get much more aerodynamic treatment than even 20yr ago.

~~~
robocat
I’m not sure about windscreens, but research disagrees overall with your
point: “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.” From
[https://www.theguardian.com/environment/2020/feb/12/car-
spla...](https://www.theguardian.com/environment/2020/feb/12/car-splatometer-
tests-reveal-huge-decline-number-insects)

~~~
viraptor
This makes sense to me. A flat box design will push a thicker pillow of air in
front of it than an angled surface. I wouldn't expect it to matter for a
bumblebee for example, but would think the small mosquitoes get pushed away
more easily with airflow.

------
mfer
Some things to think about...

It's important to look at total diversity and changes within that total. They
don't need to happen together.

Noting differences between the US and other places like EU is useful. Might
there be something happening in one place that's not happening in another?
Identifying differences can provide insight.

------
belly_joe
Is there a way to check local insect levels without harming their populations?

A lot of comments in here have been anecdotal observations of pretty big
population swings and I too (in the northeast of the USA) have noticed the
insect populations have increased over the past two years after a nadir in
prior years, but I have no real way of determining what's going on
scientifically.

Wondering if anyone has experience doing something like this:
[https://rodaleinstitute.org/science/articles/how-to-
monitor-...](https://rodaleinstitute.org/science/articles/how-to-monitor-
insect-populations-on-your-farm/)

~~~
jimmaswell
I've heard the correlation of bug splatters on windshields a lot. Apparently
used to happen all the time, now more rare.

Looks like it has a wikipedia article:
[https://en.m.wikipedia.org/wiki/Windshield_phenomenon](https://en.m.wikipedia.org/wiki/Windshield_phenomenon)

~~~
rootusrootus
I got downvoted to oblivion a few months back for suggesting that maybe cars
were just getting more aerodynamic. I still wonder if anybody has really
considered that. I assume so, it seems like a plausible first guess.

~~~
nathanmcrae
Interestingly, this article [0] states that the opposite is true: "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."

[0]: [https://www.theguardian.com/environment/2020/feb/12/car-
spla...](https://www.theguardian.com/environment/2020/feb/12/car-splatometer-
tests-reveal-huge-decline-number-insects)

~~~
refurb
The UK study mounts a grid where the license plate goes which doesn’t
necessarily disprove a change in aerodynamics for bigs hitting the windshield.

------
sgt101
I have noticed a sharp upswing in insect life in the UK this year - but
perhaps because I was really thrown by the talk of decline last year so have
been looking hard since.

~~~
Loughla
I've noticed a sharp downturn in invasive species in my portion of the US this
year (Japanese Beetles and Asian "Lady" Beetles especially) with an upturn in
native species.

I attributed it to the really late frost. Maybe there's something else to
this? I don't know anymore, everything is upside down anyways.

~~~
sgt101
we had the opposite - an early and warm spring that didn't end with a sharp
surprise in April or May. Loads of butterflys and moths as a result.

------
partiallypro
Anecdotal, but I've seen so many insects this year in the US, more than other
years. It could be a factor of being home more and also a resurgence. I'm not
sure.

------
wozer
So maybe it's only in Europe.

Could there be some influence in Europe which is not observable in the US, not
even in the densely populated areas?

~~~
DoingIsLearning
Another aspect, beyond potential differences in pesticides or pesticide
application methods might be Air pollution.

Europe has very small footprint compared to the US but proportionally a very
high PM2.5 particle concentration and NO2 concentrations (specially Northern
Europe) in particular around major port trading hubs and petro-chemical
facilities, the market share of Diesel engines in Europe is also a major NO2
contributor.

The US is heavily industrialized but sites are actually much more spread out
and most of the pollution above recommended levels is concentrated on the East
coast of the US.

If the air pollution aspect is a factor in insect population than it would
follow that we would see huge insect population losses in large parts of China
and Southeast Asia but I don't have data that supports or denies this?

------
ur-whale
[https://sci-hub.tw/https://doi.org/10.1038/s41559-020-1269-4](https://sci-
hub.tw/https://doi.org/10.1038/s41559-020-1269-4)

------
mensetmanusman
I wonder if it is the dramatic difference in population density.

------
m4r35n357
Feed bees; grow Lavender!

~~~
angst_ridden
Our (non-native) fennel plants seem to be a significant attractor of bees and
other pollinators. They also serves as a host plant for Anise Swallowtail
butterflies. The bees also really like the citrus (oranges, lemons, citron,
grapefruit), cuphea, milkweed, buddleia, lavender, and lantana.

~~~
hinkley
On the fennel, or any umbel flower for that matter, you should also be seeing
adult ladybugs and lacewings (both eat aphids during part of their lifecycle)
as well as hoverflies and predatory wasps.

~~~
angst_ridden
Yup, we see all of those. As well as the occasional assassin bug.

------
marcus_holmes
Gotta love the way that good environmental news is greeted with caution and
skepticism, while bad news is greeted with immediate acceptance and
acclamation.

This is good news! Let's hear it for the bugs! woohoo!

~~~
veddox
The majority of data we've gathered so far (though mostly in Europe) points in
another direction. Therefore this study is unexpected and we're trying to
figure out what's going on - is America doing so much better than Europe seems
to be, or is the data in this study too patchy?

Actually, even before this study, there's been a lot of discussion among
ecologists about just how serious the insect decline actually is. My
impression of the recent literature is that while there's definitely a
worrisomely strong decline (certainly in Europe), talk of an "apocalypse" is
rather overdone. But of course, the wider media usually only pick up on the
dramatic results and leave out a lot of nuance.

~~~
marcus_holmes
Yeah, the media reporting is always sensationalised. But they need the clicks,
so it's kinda understandable. Annoying, but understandable.

I'm more fascinated by the set of people who refuse to accept that there can
be any good environmental news. There was a story a while back about the fact
that there are more trees in the world now that in the 70's, and that got
greeted with the same skepticism and argument.

I guess some people have a worldview that's locked into environmental
catastrophe and are unwilling to accept any evidence that contradicts that.

------
option
this is great news! Insects population decline would mean almost immediate
catastrophic consequences.

------
BiteCode_dev
How do they take into account the insects that were in areas turned into
fields, industries and cities ?

Are there traps there as well ?

------
afrcnc
Scientific research coming from the US, country of all climate-change deniers
and big corps.

Yeah, I'll pass.

~~~
lopmotr
You disregard all US science? Really? Good luck knowing anything about the
world at all.

------
mistrial9
.. did not read, serious BS radar alarms.. lifelong California resident and
this absolutely does not match my observed experience.. Particularly since the
Malathion spray event, which showed massive elimination of larger spiders and
colorful insects, by direct observation with my own eyes

[https://en.wikipedia.org/wiki/1989_California_medfly_attack](https://en.wikipedia.org/wiki/1989_California_medfly_attack)

~~~
lopmotr
It agrees with you - "Some taxa and sites showed decreases in abundance and
diversity"

But rejecting science in favor of personal anecdote is ridiculous bad thinking
when an anecdote doesn't disprove it.

~~~
mistrial9
yes agree, AND one paper is not big-S science

~~~
lopmotr
You'd better also reject any "one paper" that entirely agrees with your
personal experience too. You do that, right?

------
antisthenes
Certainly true for mosquitoes in the Northeast. Despite me improving drainage
on the property, there seems to be at least a dozen of them hovering near my
legs as soon as I go outside.

N=1, however.

~~~
mohaine
If you live near others, good luck. Too many people leave buckets other
containers out.

------
hguant
>Recent reports of dramatic declines in insect abundance suggest grave
consequences for global ecosystems and human society. Most evidence comes from
Europe, however, leaving uncertainty about insect population trends worldwide.

This makes me wonder how much of the decline in Europe is due to the
ecological side effects of two highly destructive world wars. Mechanized,
combined arms combat moves a lot of dirt around, via explosions, and tracked
vehicles ripping up the soil, which would kill or disrupt a lot of insect's
breeding/eggs. Large swaths of mainland Europe were carpet bombed, or subject
to intense artillery fire. Additionally, after the war, reconstruction efforts
would have disturbed even more soil and insect habit, coupled with the Green
Revolution's increase in fertilizers, pesticides, etc.

If the insect population in Europe was previously devastated, or diminished by
physical upheaval, then it wouldn't surprise me that the population as a whole
hasn't recovered from, and is still losing ground to, the more pervasive
insecticide and manufactured pollutants (ie all the plastic derivatives, BPAs,
etc) that have become part of our environment.

~~~
AMerrit
While the world wars certainly would have had some impact, most of the current
studies are comparing current populations to what was around in the 80's/90's.
This one for example covers 1989-2017:
[https://journals.plos.org/plosone/article?id=10.1371/journal...](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809)

