Insectageddon? Maybe not . . .


Guest Essay by Kip Hansen


featured_imageReading widely across the literature of many scientific fields broadens one’s view of the rate of scientific progress — both our increased knowledge and our “steps backwards”.  A recent piece in Nature Ecology & Evolution  represents both:  one of these advances and one of these “steps backwards”.

The article is a Brief Communication titled “Moth biomass increases and decreases over 50 years in Britain” by Callum J. Macgregor, Jonathan H. Williams, James R. Bell and Chris D. Thomas.   (a full .pdf is available via SciHub with doi: 10.1038/s41559-019-1028-6).  Here’s the abstract:

“Steep insect biomass declines (‘insectageddon’) have been widely reported, despite a lack of continuously collected biomass data from replicated long-term monitoring sites. Such severe declines are not supported by the world’s longest running insect population database: annual moth biomass estimates from British fixed monitoring sites revealed increasing biomass between 1967 and 1982, followed by gradual decline from 1982 to 2017, with a 2.2-fold net gain in mean biomass between the first (1967–1976) and last decades (2008–2017) of monitoring. High between-year variability and multi-year periodicity in biomass emphasize the need for long-term data to detect trends and identify their causes robustly.”

In surprisingly straightforward (and diplomatic) language, the authors start out with a clear explanation of the scientific problem:

Insufficient Comparable and Consistently Collected Long-term Data

  “Reports of declining insect biomass give credence to the notion that insects are at the forefront of a ‘sixth mass extinction’. However, some reports have received criticisms for poorly justified conclusions, potential biases and extrapolating beyond the data. Regional abundance and distribution declines have taken place in many individual species but populations of other species are stable or increasing, leaving uncertainty over the consequences for biomass change and associated ecosystem processes. Nearly all existing estimates of biomass change lack continuous, systematically controlled monitoring or sufficient survey sites. Hence, analyses of continuously collected data from multiple sites and environments are necessary to establish the robustness of the conclusion that insect biomass is declining.”  [footnote numbers removed — see original for these references — kh]


There is a Press Release related to the article here.

The authors point out:  “Contrary to previous reports of insect biomass change, moth biomass increased before it declined and remains higher than in the late 1960s (Fig. 1).”

Fig_1_800[click image or here for larger version]

There are several interesting things to notice in the graphs presented in Figure 1  but first and foremost, in my mind, is that in panel “a” we see that Total Moth Biomass varies on an annual basis as much as three orders of magnitude — from a low of 1,000 mg up to 1,000,000 mgs.  The Supplemental Information shows the mean varying from 8,000 mgs to 80,000 mgs.  That’s a lot of variation.

[This should not be a surprise to anyone familiar with Population Dynamics.   Even in very simple populations, one sees oscillations and deterministic chaos.]

The author’s main points are obvious in this one four-panel figure:  1)  Total moth biomass rose from the mid-1960s to about 1980.  2)  from 1980 to 2017, there is a declining trend, but totals remain above 1960s levels.  3)  There are “winners and losers” — Panel “b” —  the moth family Erebidae has been steadily increasing across the entire time period whereas Geometridae and Noctuidae show the rise-then-decline pattern.   and 3)  The changes do not seem to be due to land use changes, as the pattern is similar across all four land use categories —  arable land, woodland, urban and grassland.

This data supports their conclusions that “analyses of continuously collected data from multiple sites and environments are necessary to establish the robustness of the conclusion that insect biomass is declining”  and that “Such severe declines [“insectageddon”] are not supported by the world’s longest running insect population database”.    This paper represents a step forward in its own field, and points to other papers that, through their failures, have represented a step backwards.

Even more impressive is the amount of detailed Supplemental Information that is attached at the end of the full .pdf file for this study [use the doi and SciHub to obtain a copy].  There are charts by land use, charts of periodicities in the data and many more.

Callum J. Macgregor, Jonathan H. Williams, James R. Bell and Chris D. Thomas, our authors, are to be congratulated for their extremely well-done paper which is complete, transparent and supplies all the data (or links thereto).

This is Real Science.

And “Insectageddon” ?  — probably not.

# # # # #

I encourage readers to obtain a full copy of the .pdf  of this paper, for an entirely different reason.

At the end of the paper, after all the author’s work and supplemental information, there is a two-page section headed Reporting Summary:


The very existence of this section represents the hope and future of Science and of Science Journals.  The topics covered in the Reporting Summary include:


In this case that the authors followed all the statistical guidelines that applied to their study.


“Data collection:  No software was used in the data collection process (data were obtained from Rothamsted Research and other sources as described in the Methods section). Identical datasets can be obtained from these sources on request.”

Software and code:

“Data analysis:  All analyses were conducted in open-source software, R version 3.6.1, as stated in the manuscript. All R scripts, from initial processing of datasets to final analyses, are archived online at Zenodo (doi: 10.5281/zenodo.3356841).”

Field-specific reporting:

The authors report their study to be in “Ecological, evolutionary & environmental sciences”

Ecological, Evolutionary & environmental sciences study design:

In this section, the authors report their study design in detail:


[click image or here for larger version]

While these NatureResearch steps may not be everything that John P.A. Ioannidis and  others who are striving to reform research standards towards replicability and full-disclosure science reporting would demand, it is a beautiful thing to see.  Imagine if every published Climate Science paper came with a required, field-appropriate section like the above.  Or for that matter, if all science used by the E.P.A., the C.D.C. or the F.D.A. was published to these standards for explicit declaration of study design and  full data and code availability.

I had not realized that the Nature group had advanced so quickly, and admirably, on this topic.  They have my congratulations and thanks.  

# # # # #

  Author’s Comment:

 On a personal note, I have been away sailing, serving  under my youngest son, now a Captain and Master in his own right — from the mid-Hudson Valley of New York (on the Hudson River) to Elizabeth City, N.C.   Wonderful trip with three young men, all ranked as Captains.   

Insects are a “subject of interest” for me — and I have hundreds of pictures of different “shield spider” species that live in the Dominican Republic — thus my first interest in the paper highlighted above.

In the end though, I found the NatureResearch’s Reporting Summary more significant.

Glad to read your comments on either topic.

# # # # #

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November 30, 2019 10:03 pm

It’s all progress, forward,backward, a monotonic [unqualified] process.

Bryan A
Reply to  n.n
December 1, 2019 8:19 am

If they really think insectageddon is possible, just wait till the GND removes Beef from the equation and requires the consumption of insects for protein. On average per person more than 42kg of Animal Based Protein annually. How will bugs fill that need for 7b people without Insectageddon?

Jay Willis
Reply to  Bryan A
December 1, 2019 9:00 am

People eating cows didn’t end too badly for the cow population.

Reply to  Bryan A
December 1, 2019 10:43 am

Bryan ==> You won’t be eating wild bugs, but domesticated bugs. they’ll be bigger and fatter and have more protein than ever.

Bryan A
Reply to  Kip Hansen
December 2, 2019 2:19 pm

All thanks to Plant Matter (food) sourced by increasing CO2.
OOH Grub Ranches as far as the minds eye can see.
Bound to bring out the Grub Rustlers
At least Russel Upsomegrub will have a job

November 30, 2019 10:07 pm

Biomass increasing — horses getting fatter — what’s not to like about a warmer climate?

November 30, 2019 10:23 pm

While these NatureResearch steps may not be everything that John P.A. Ioannidis and others who are striving to reform research standards towards replicability and full-disclosure science reporting would demand, it is a beautiful thing to see.

Ioannidis points out that the majority of published research findings are wrong. It’s called the replication crisis and scientists are taking it seriously.

The one field where replication is routinely attempted is biomedical research. Drug companies scan the literature looking for findings that can be used to produce new drugs. The first thing they do is attempt to replicate the results.

… biotechnology firm Amgen tried to reproduce 53 “landmark” cancer studies and managed to confirm only six … link

In a discouraging number of cases scientists couldn’t even reproduce their own experimental results.

Scientists know that science is no longer trustworthy. The public at large doesn’t yet.

Reply to  commieBob
December 1, 2019 6:56 am

Commie ==> Good science, done well is trustworthy and a joy to see.

There are myriad reasons why this is so . . . But journals requiring reporting like this example from NatureReseach is encouraging.

Reply to  KipHansen
December 1, 2019 8:37 am

You’re right.

Bad science is a result of perverse incentives. link

Over the last 50 years, we argue that incentives for academic scientists have become increasingly perverse in terms of competition for research funding, development of quantitative metrics to measure performance, and a changing business model for higher education itself. Furthermore, decreased discretionary funding at the federal and state level is creating a hypercompetitive environment between government agencies (e.g., EPA, NIH, CDC), for scientists in these agencies, and for academics seeking funding from all sources—the combination of perverse incentives and decreased funding increases pressures that can lead to unethical behavior. If a critical mass of scientists become untrustworthy, a tipping point is possible in which the scientific enterprise itself becomes inherently corrupt and public trust is lost, risking a new dark age with devastating consequences to humanity. Academia and federal agencies should better support science as a public good, and incentivize altruistic and ethical outcomes, while de-emphasizing output.

– You won’t get a job at all and, if you do, you won’t get tenure if you don’t publish.
– The journal editors are the gatekeepers.
– Journal editors are looking for novel, interesting, results.
– There is no penalty if your results are wrong.

If you want a career in academia, you have to produce interesting results, as opposed to actual good science. As long as you don’t upset any apple carts, nobody is going to check your work. Peer review is a joke.

If you google on science perverse incentives you will get a bazillion hits and many of them will be in top line journals like Nature. This is well know in the scientific community. To repeat the above link:

… a tipping point is possible in which the scientific enterprise itself becomes inherently corrupt and public trust is lost …

It’s a big problem.

Reply to  commieBob
December 1, 2019 10:47 am

commie ==> Yes, it is a big problem. That’s why many of us write about junk and worthless science — call out bad studies. In some cases, such as this, it is a good to write about Good science, well done.

Steven Mosher
November 30, 2019 10:30 pm

” This paper represents a step forward in its own field, and points to other papers that, through their failures, have represented a step backwards.”

Imagine that. people can actually publish science that is critical of alarmism

lousy gatekepers failed?
Didnt these guys get the grooup think memo?

Hokey Schtick
Reply to  Steven Mosher
November 30, 2019 11:37 pm

Not even wrong

Clyde Spencer
Reply to  Hokey Schtick
December 1, 2019 12:37 pm

Hokey Schtick
Did I just hear an echo? 🙂

Patrick MJD
Reply to  Steven Mosher
November 30, 2019 11:51 pm

Did you see the BBC article about Victoria Falls in Zimbabwe/Zambia that promotes alarmism which is completely and utterly and provably wrong?

Scott W Bennett
Reply to  Steven Mosher
December 1, 2019 1:49 am

“one swallow doesn’t make a summer”

Unless of course, you’re Berkeley Earth and your BEST work is published in Volume 1, issue 1 of a previously non-existent journal!

Reply to  Scott W Bennett
December 1, 2019 3:07 am

Scott W Bennett

And who employ a salesman, and just hand him the title of scientist.

Reply to  Steven Mosher
December 1, 2019 6:43 am

1) Not a climate science paper.
2) Nobody ever claimed that the pal review blockade was perfect.
3) steve once again resorts to poorly written snark rather than actual think about the subject. (Apparently his paymasters don’t pay him to think, just to protect)

Reply to  Steven Mosher
December 1, 2019 7:02 am

Mosher ==> Just good honest science, well done. This type of work requires a bit of willingness to do the right thing even at the risk of offending colleagues. That`s why I label it Real Science.

Mickey Reno
Reply to  Steven Mosher
December 1, 2019 8:24 am

Mosher, while I confess the possibility of error on my own part, I suspect that your strange comment is meant as a clever way of calling many WUWT readers hypocrites. If that’s what you mean, would you please just say this with clarity, so that we can understand you?

And if so, because such an assertion is highly inflammatory and fraught, the burden to make your case is also higher, not lower. Such a contention and such passion requires a better case then some infernal or hidden implications of which only you know the exact meaning. A long chain of failure on this score makes me doubt that you can do it, but if you want to persuade people of something or other, I urge you to try the path of explicit clarity, honesty and logic.

Of course, if I’m misjudging you, and your real aim is to become the next Brad Keyes, then disguising your meaning in clever, sophistical deceptions to bring sarcasm and shame and parody and troll-ery to new heights of high humor, then, although you have failed to amuse in this instance, by all means, keep working at it. I’m sure that sooner or later you might say something amusing. As I often say to exhort people to do better, today is the first day of the rest of those days when you can start to get ready to commence to begin to endeavor to persevere.

Rich Davis
Reply to  Steven Mosher
December 1, 2019 10:00 am

Another drive-by shooting of a poor innocent strawman by mosh.

Bravo! Only a couple of typos and punctuation errors in your sentence fragments!

November 30, 2019 10:31 pm

If there are insect population decreases such as in Germany and Holland, they are due to pesticide drift from agriculture. Nothing to do with climate.

Reply to  Mike
December 1, 2019 12:25 am

Hi Mike, – German regulations set a minimum buffer of 3 meter width alongside pesticide sprayed areas. Obviously there are other factors relevant to drift & not just wind variables.

The German protocol accepts there is likely going to be 2.8% drift in the 1st meter out from sprayed terrain & 0.6% drift 5 meters out from sprayed cereals. For vineyards the drift is calculated to be 8% at 3 meters & decreases to 3.6 % drift at 5 meters, so ideally the vineyard buffer zone should to be 6 meters wide. In the case of orchards they recognize 2.8% drift likely getting up to 20 meters away from fruit trees being sprayed.

I am not sure what Holland has established to regulate pesticide drift.

Reply to  gringojay
December 1, 2019 3:56 am

drift or not the bugs themselves travel into and over crops n gound.
pesticides leach and travel far beyond paddock boundaries.

and theres the detail that some bugs work on long year cycles
first yr in this place we had massive golden beetle swarms ending in handsfulls in window ledges to be removed
as well as rutherglen bugs inside and ruining mulberry crops
then we had bogong moths the next yr

the golden beetles returned in far fewer numbers maybe 5 yrs later
rutherglen bugs are heat n moisture triggered and last yr they swarmed but the mulberry tree got a break as the fruit wasnt ripe yet;-)

and for most species no one really know what the hell their triggers or cycles ARE

Reply to  ozspeaksup
December 1, 2019 10:56 am

oz ==> Population Dynamics are prone to Deterministic Chaos. Robert May studied this back in 1976. See his major piece here or download the pdf here..

I gave some examples in my series on Chaos here at WUWT.

Rainer Bensch
Reply to  gringojay
December 2, 2019 4:19 am

They should regulate the insects from drifting into the sprayed areas.

Johann Wundersamer
Reply to  Rainer Bensch
December 5, 2019 9:01 am

“Kip Hansen December 2, 2019 at 7:47 am

Rainer Bensch ==> Perhaps the could post signs?

“Danger! Insecticide Treated Area. Insects Keep Clear.””

Kip, from kids we learn such advice could backfire.

Signs posting “Danger! Insecticide Treated Area. Kids Keep Clear.” draws on kids light moths under street lamps.

Krishna Gans
Reply to  Mike
December 1, 2019 2:41 am

How many tons of insects are drawn into windmills ?

A C Osborn
Reply to  Krishna Gans
December 1, 2019 3:55 am

1200 tonnes per year in Germany alone, or 12000 insects per day.

Bryan A
Reply to  A C Osborn
December 2, 2019 2:23 pm

Windmills??? Those are Automated Insect Processing Plants…
Yet another job created by the Green Economy.

Reply to  Krishna Gans
December 1, 2019 3:58 am

quite a lot I gather
someone here did post a great article on that recently in comments section

and add suburban lighting and even rural homes now using sensor lights that a moth sets off and then more moths come etc etc
once farmyards were dark.
my place is pitch black uless I turn a light on but most arent

Reply to  Mike
December 1, 2019 6:16 pm

My observations, and curiosity about them, began perhaps 10 years before I read anything on the subject of insect population changes. I moved to this area from a coastal one about 40 years ago (west coast of the US). There, in the general surroundings of the bay, most flying insects were scarce. Flies were hardly ever seen, mosquitoes may have been entirely absent. Also, spiders were present but not terribly abundant or at least obvious. A general belief among the inhabitants was that breezes off the ocean made conditions unsatisfactory for insects.

Traveling over the hills surrounding the bay, many flying insects were revealed through the collection that invariably appeared on the windshields. Also, while my backyard garden was generally quite successful, certain insects, particularly whiteflies, had to be battled every year, i.e. insects did exist. In general, however, insects were more notable by their absence, compared to various places I previously lived, than by any specific presence.

When we moved here from the bay area, the change was dramatic. The air seemed filled with buzzing and fluttering entities. Mosquitoes and mites were a constant annoyance, particularly in the evenings. Spiders abounded inside and outside; it seemed impossible to keep them outside. With my commute, the windshield had to be scrubbed almost every day just to assure safe travel. It seemed strange that pesticides should be necessary in the surrounding agriculture areas where highways and back roads were common. Could there really be enough insects that the unslaughtered population was still a problem?

Then, rather suddenly the spiders and flies seemed to virtually disappear. Previously, every spring, there seemed to be hundreds of spiders hatching inside the house and many flies mysteriously appearing inside regardless of efforts to deny them entry. Now there were almost none at all, most years none were observed. Bugs on the windshield also became uncommon. While hardly overwhelming evidence, other people I’ve talked to have also noticed the change, often only really becoming aware of it when I asked them.

In the last two years there has been a small increase, or at least an increase in intersections between my path and insect paths, but still nothing compare to what used to be. Climate never occurred to me as a factor. The general climate doesn’t seem different although a marked decrease in heavy night time fogs has been apparent in the last six or eight years. Coming home after dark, as I frequently did during the week, was often extremely tense during the foggy part of the year. Large scale multi-vehicle crashs were not uncommon. I have experienced few fogs of any quality in recent years. Are fogs relevant to insect lives, in general?

Joel O'Bryan
November 30, 2019 10:54 pm

Clearly the answer to this Moth Mystery lies in the Reagan Revolution that began in 1981.
(see Fig 1 above)

For more on the Reagan Revolution, listen here:

Moths, and insects in general, clearly love ineffective leaders like Jimmy Carter.
Lesson: Insects thrive under Democrats. People … not so much.

Reply to  Joel O'Bryan
November 30, 2019 11:44 pm

Yes, and priates caused global warming. link

November 30, 2019 11:32 pm

Hi Kip, – Lead author Macgregor in the related press release (“Down, but not out”) actually makes the point “… biggest declines were in woodland & grassland ….” Bear in mind also that the original post here is about moths (which are also what Macgregor was referring to in preceding quote) &, unless I am mistaken, you seems to infer these may be a proxy for insects in general.

Which brings me to Seibold’s team’s research entailing 3 German regions reviewing about 10 years of fairly recent data (2008-2017) using standardized sampling (>1million bugs consisting of 2,700 insect species) from 150 grassland sites & 149 forest sites. Their report states that in German grasslands insect biomass decreased 67% & in terms of those insects in those grasslands they were 78% less abundant. While in German forests insect biomass decreased by 41% &, to be precise for habitat comparison, that in those forests no change was seen in insect abundance. [Authors also report decreases in the more rare insect species populations in both habitats of over 30%.]

The above is as per (2019) “Arthropod decline in grasslands and forests is associated with landscape-level drivers”.

Reply to  gringojay
December 1, 2019 8:18 am

Gringo ==> This paper is about insects, particularly moths, in the UK. One of their points is that to really understand insect populations, longer consistent databases are needed. Ten years may not be enough. Population dynamics are complex and chaotic — and conclusions should not be drawn to quickly.

Reply to  KipHansen
December 1, 2019 8:57 am

Here is plot that illustrates how insect populations change on an annual basis,
Ten years is way too short a period:

Reply to  Chas
December 1, 2019 11:11 am

Chas ==> Great link. As we see, the forest population of that insect fluctuates wildly and selecting any ten-year period would give one an entirely false idea of the long-term situation.

These are early papers: “On the stabilization of animal numbers. Problems of testing
3. What do we conclude from significant test results?
” by Den Boer trying to puzzle out real population number results.

Robert May’s work did seem to make it into Den Boer’s sphere — but should have.

Reply to  Chas
December 1, 2019 11:41 am

Hi Chas, – The chart is of moth pupae, so is related to the original post insect.
If you have anything like this for grasshoppers them that would be more instructive for grasslands.

Reply to  gringojay
December 1, 2019 5:09 pm

Gringojay – I have had a look in some books and cant find anything Grasshopper ish , though on the internet there is an analysis of 1000+ years of (anecdotal) locust numbers from China :-0
Re. the basis of the moth data in the original post: The light traps are a standardised design which use(d?) an incandescent bulb and are run pretty continuously, the observers collect the catch out of the pot in the bottom, and as I understand it, generally identify and count the species.
So even though non-profesionals are involved, the method of trapping is standardised . It is more rigorous than someone popping out to a square twice a year and seeing what they can find ( how the UK common bird census works ) .
A decade or so ago I believe the network had collected and recorded ~8.5 million (macro?) moths, so I guess that they should be quite well past the ten million mark, by now.

Reply to  gringojay
December 1, 2019 8:02 pm

Hi Chas, – I did look for some comparable long input (1948 – 2014) for a grasshopper niche & posted some observations to the following in response to Rich Davis’ comment. I will preview it by saying that if my deduction from correlates I found has any validity then a wet spring has more impact on that grasshopper population than any slight summer temperature variation, or even average number arid days when lay eggs.

Whether the current trend to wetter spring weather is going to be a relatively consistent occurrence in (say) central Europe I have no opinion. I, like many, read that rising CO2 promotes wetter spring weather & the trend is there will be wet springs; personally I am not convinced about that theory.

Referenced region I nattered on about was much, much wetter in spring back in 1950 & 1951 than the wet springs since 2007 that I reproduced a grasshopper’s trends for. I haven’t the time to attempt any comparable compilation with long term moth data to see if moth population changes show more correlation with wet springs than they do with mid-season temperature or aridity.

Reply to  KipHansen
December 1, 2019 11:31 am

Hi Kip, – The German work was done after reflecting on existing 27 years of national insect data not being standardized. In other words that 27 years of data was not deemed rigorous enough, because in large part it’s source was amateurs’ input.

So I wonder if this O.P. England moth data collected over 5 decades is in some periods input from amateur naturalists & thus comparable to the almost 3 decades of German insect data Seibold’s team felt best not to rely on for a scientific insect evaluation.

On a another issue: I am surprised you promoted the use of SciHub in a WUWT forum. The intellectual rights of authors in regard to access is not respected using SciHub.

Reply to  Kip Hansen
December 1, 2019 6:31 pm

Hi Kip, – I don’t get the impression you 1st contacted any of the report’s team for an “Author’s Copy”. Sometimes someone other than the lead author has the free full text of the paper on the internet as well.

If you don’t already know it here’s how to look for reports without using SciHub. True, it isn’t always successful & takes effort/time on one’s part.

Find the different authors on-line (via a profile or academic association) & look for what articles they published. Sometimes you then can see if the one you like has any link taking you to a webpage more extensive than the abstract. True, this takes some personal time & not always comes through.

Another tactic is to use Yandex search engine for the article title instead of Bing/Google & see if they have a PDF link. I’ve found “Researchgate” PDFs via Yandex that the more popular GoogleScholar doesn’t give a link for free.

. Yandex is also quite good for searching out secondary authors’ by name who might have a free full text link on-line. This is often the way to get non-American authors’ from Universities that have published in English.

So far I have not found any free full texts from the Chinese research clearinghouse “CNKI”. Their English abstracts are quite intriguing, despite language mistakes.

I have a CNKI account but when went to pay for their content it would not process. My Beijing friend said I had to be in country & also that the CNKI abstracts on-line in English do not mean the report is translated into English.

Rich Davis
Reply to  gringojay
December 1, 2019 9:51 am

The hypothesis is what exactly? That a 40-80% decrease in insect biomass is the consequence of a 0.2C increase in average temperatures over a decade? Because correlation is causation? If the data are reliable, a huge “if”, what possible mechanism is supposed to be responsible?

Common sense would guide us to the fact that insect populations peak during the summer when temperatures are 35 degrees or more higher than in winter. But somehow we should believe that if temperature ranges go from (-5 to +30), where the insects thrive, to (-4.8 to +30.2), that’s going to be a decisive and catastrophic change? Are you serious?

Over the same period, how many new wind turbines were built in Germany?

If the data are accurate, it will surely not be the case that the decline is due to an almost imperceptible change in temperature.

Reply to  Rich Davis
December 1, 2019 11:17 am

Rich ==> I don’t believe there is any real scientific hypothesis behind “insectageddon” other than the general fear that mankind is “killing all the insects”. There are some studies that have found what appear to be shocking drops in local insect populations. What Macgregor and his co-authors are saying is that their long term data set for moths in the UK doesn’t show cause for concern and they suggest that maybe studies that do are using too short a data set of inconsistent-over-time measurements — inappropriate for a subject like insect populations.

Rich Davis
Reply to  Kip Hansen
December 1, 2019 11:56 am

Thanks for your response, Kip. I should have made clear that my comment was a response to gringojay and not to dispute anything from your article.

Just to be clear, we usually hear about this alleged unprecedented disaster in the context of “human-caused climate change”. As you’ve noted, a longer period of study calls into question any claim of lack of precedent.

I wanted to add that it makes no sense to correlate without even proposing a plausible mechanism. We might as reasonably correlate to the number of electric vehicles on the road. Maybe the bugs can’t hear them coming?

There may or may not be a real phenomenon where insect populations are unusually depressed and are fluctuating more than has been the case in prior periods. It might well be due to human actions. But to posit that it is caused by a very minor increase in average temperatures when insect populations are known to be positively correlated with temperature is illogical (or disingenuous).

Reply to  Rich Davis
December 1, 2019 2:50 pm

Rich ==> For insect populations, there may be many observable possible causes of insect declines — pesticides, land use changes, urbanization — but most of these studies are done “with intent to find” a particular result so as to justify blaming a predetermined cause.

The most likely cause — population dynamics — is almost never listed in the studies. Animal populations don’t necessarily need a smoking gun cause to change — or even fluctuate wildly up and down. Read Robert May.

Thanks for your participation -you make good, valuable points – and don’t worry — I don’t take differences of opinion personally and am fine with people disagreeing. I think disagreement adds to the conversation when done in a collegial manner.

Reply to  Rich Davis
December 1, 2019 5:53 pm

Hi Rich Davis, – I will give some data on a Rhine-Palatinate region ~509 meter elevation grasshopper. Please understand this is my estimates from graphs off my tablet size screen.

The weather goes back to 1948/1949 but only to 2014. So I can not bring it fully forward to Seibold’s 2017 data period & will start a year earlier under the assumption 2008 bugs are from 2007 bugs.

This grasshopper’s egg laying time is April to Nov. The rainfall in April was less than 5 mm in 2007, was 40 mm in 2008, was 30 mm in 2009, was 10 mm in 2010, was 20 mm in 2011, was 60 mm in 2012, was 60 mm in 2013 & was 20 mm in 2014.

The number of arid days during this grasshopper’s egg laying time of April to Nov. is as follows. The number of arid days then was 27 days in 2007, was 12 days in 2008, was 8 days in 2009, was 10 days in 2010, was 11 days in 2011, was 22 days in 2012, was 15 days in 2013 & was 10 day in 2014.

The average air temperature midway into this grasshoppers egg laying period for August is as follows. The avg. Celsius temp. was 21* in 2007, was 22* in 2008, was 25* in 2009, was 23* in 2010, was 24* in 2011, was 25* in 2012, was 24* in 2013 & was 21* in 2014.

Now this grasshopper responds to temperature gradients differently based on sex.
Mortality at 22*C for males is 12% & female mortality is 20%. Mortality at 27*C is lower, being 5% for males & 10% for females.

Size in mm length for this grasshopper is also temperature gradient responsive. Length at 22*C for males is 14 mm & for females 18 mm. Length at 27*C for males is 15 mm & for females 19 mm. Which I think we can safely say means larger bugs mean greater individual mass; bigger bugs weight more.

Yet temperature also impacts the sex ratios. For this grasshopper there are 7 males to10 females at 22*C. While there are only 6 of these males to 10 females at 27*C.

Now I have cribbed 1948/49 to 1955 comparative weather data (April rainfall, arid # days April – Nov, & avg. Aug. *C) to assess a historical pattern that could match original post’s lengthy moth record period. For brevity I am skipping this, but would report it for you if requested.

OK, so back to the specific grasshopper in it’s specific niche.

A count of this grasshopper’s density was made in the month of August 2010, which I will use as a reference. In 2010 there were few arid days during it’s egg laying time, it averaged 23*C in that month & their overwintering spring ground had not been notably sodden.

A comparable August 2011 count came up 54% lower in population than the year before. There had only been 1 more arid day during egg laying months, the Aug. temp. was only 1*C more; April spring rain did double, but nowhere near the 6 fold increase in moisture known to happen.

Come August 2012 the population was down 72% from 2011. There was a sodden April spring of 60 mm rain, with an extensive 22 days of aridity. Yet there was a higher Aug. temperature that reduced the rate of mortality, hastened development time & made bigger bugs.

Then come August 2013 the population was further reduced by 32%. This despite arid number of key days dropped to just 15 days & Aug. temp. was only 1*C less. But April spring rain was again quite sodden at 60 mm.

A wet spring seems to be a big player in this mid-season grasshopper population. I can’t say whether (my cited) Seibold’s standardized data of 2008 up to 2017 also shows wet springs as a factor in grassland bug loss.

In closing to be precise, I do not ascribe to rising CO2 causes insectageddon.

And, as original post alludes that long time frames need consideration, the same locale had quite a wet April in 1948 (55mm rain), a drier 1949 (25 mm), and then 2 saturated springs (1950 got 90 mm & 1951 got 85 mm rain in April) …. So, if my supposed proceeding correlation is relevant, that grasshopper population back then might have gone down significantly.

Reply to  gringojay
December 2, 2019 7:33 am

gringo ==> Very nice. One thing that comes through the data is that there are many factors that affect these grasshopper numbers — the factors themselves are not closely correlated (some can be up while others down, etc) — this causes an apparent chaotic population count – wildly swinging up and down without there being a single “smoking gun” cause. Predator/prey relationships have not even been factored in yet…..

30 years or more of careful consistently done counts might reveal the overall pattern and inform us if there is any reason to be concerned for the long-term survival of this species.

Reply to  Rich Davis
December 1, 2019 6:31 pm

World wide averages in temperature changes, accurate or not, most likely have zero relevance to changes in any particular place. Year to year differences in both high and low temperatures in my vicinity are many times greater than any averages calculated over a country wide area.

December 1, 2019 12:15 am

I seem to remember this was preceded by a big scare report about insect extinction which was widely reported. The contradiction will not make the headlines so people will be left believing the scare. That’s journalism for you: ‘if it bleeds, it leads.’

Reply to  Susan
December 1, 2019 11:23 am

Susan ==> You make a good point — if a study finds shocking bad news, it gets a lot of coverage. Unfortunately, those studies should have drawn a lot of critical attention (critical as in critical thinking).

Macgregor et al. show that even in the UK, where agriculture abounds and development is rampant, when one uses a long-term, consistent data set of carefully maintained long-term careful research, there is no evidence of a drastic reduction in insect numbers over the long term (in their case, moths, which are a pretty good proxy for insects in general).

December 1, 2019 3:43 am

Seems highly unlikely that the historical insect biomass data is complete —or accurate.

Anecdotally, the swarms of moths one sees around streetlights here in Central Texas are nowhere near as thick as they were 30+ years ago. This is not due to “climate change,” as the climate has not changed appreciably over this period. (If anything, slightly warmer winters should increase the insect population.)

But — as always WUWT— we love it when politics and natural science are conflated to produce political science.

Reply to  Richie
December 1, 2019 11:28 am

Richie ==> You make Macgregor’s point rather well — in you case, he would say that anecdotal observational data is not sufficient to determine long-term scientific views of insect populations. It may be, for instance, that there are far more streetlights for moths to flock to, thus density at each light appear far lower to the human eye.

December 1, 2019 4:13 am

My own non-scientific observations of dragonfly and non-domestic bees at/near a popular fishing lake north of me, over a period of 15 years, says that insect populations come and go with changes in available flora. Bees won’t both with places where they can’t get nectar. Dragonflies won’t bother with places where they can’t lay eggs int he water and ensure the survival of their offspring. Bugs are all over the place and they’ve survived on this planet for – how long now? over 300 million years, maybe more?

And spiders? They were there in the Carboniferous, too. Something like 40,000 to 45, 000 species have been identified so far, but there is no census count on those not identified as yet, which means there are likely thousands of other spider species we don’t know about.

Let’s do remember that the bug kingdom was here first and will probably survive any/all epoxyclypses, no matter what the Gloom & Doomers try to pretend. Ignoring the fact that bugs go where there’s shelter and food and lack of predators has something to do with it, too, but that’s what the Doomsayers don’t understand. Panic attack jargon is much more likely to draw an audience.

Insectageddon, my Fat Aunt Harriet!

Thanks for the article. Glad to see something done correctly.

Curious George
Reply to  Sara
December 1, 2019 8:44 am

Technically, spiders are not insects 🙂

Reply to  Curious George
December 1, 2019 12:48 pm

Very true (spiders are not insects)! My wife kills insects. I have to dispose of the spiders. Spiders seem much scarier to her. Even scarier than a Jerusalem cricket (which is not a cricket).

Rich Davis
Reply to  Curious George
December 1, 2019 5:20 pm

True but they’re all arthropods. My favorite bugs to eat are lobsters, shrimp, and crabs. Happy to eat more if that’s what it takes to save the planet.

Reply to  Sara
December 1, 2019 11:33 am

Sara ==> A nice long perspective — Macgregor would approve. And my best to your Aunt Harriet!

As for spiders…they may not be insects but they are BUGS1

My younger brother is still, in his late 60’s know to family as “Bug” — named so for his propensity, when 3 or so, of picking up bugs of all kinds (insects and spiders) and putting them in his bib-overall’s pockets.

December 1, 2019 6:17 am

“I had not realized that the Nature group had advanced so quickly, and admirably, on this topic. They have my congratulations and thanks.”

Agreed, Kip!

Now, we’ll see if the Nature Group holds all research to these standards…
I have my doubts.

Reply to  ATheoK
December 1, 2019 11:34 am

ATheoK ==> Time will tell, but it is encouraging. Maybe it will be enforced in other related fields of study — maybe not.

December 1, 2019 6:35 am

Just went into my back yard to take a survey and I found no insects whatsoever. It was 12F and the ground is covered with solid precipitation. I’ve seen insects when it was much warmer. Therefore, the evidence would suggest that fewer insects are a result of lower temperatures. On a universal scale, this would be called global cooling.

Reply to  Scissor
December 1, 2019 11:35 am

Scissor ==> Gee, we are getting that funny white stuff on our yard today too!

Bryan A
Reply to  Kip Hansen
December 2, 2019 2:28 pm

It’s Water Powder…
Or instant water. Just add liquid water and it will expand Contract

December 1, 2019 8:31 am

The hopeful aspect of this paper is that the resiliency of the moth population is much greater than one would have naively expected.
That said, here in the Northeastern US, the front of my car used to be covered with bugs after a vacation drive. Now, several decades later, there are only a handful after a similar trip.
Pretty much everyone in the US has seen similar changes, a huge drop in the number of insects. Widespread use of insecticides is the most broadly accepted factor behind this decline. It seems logical that the substantial (estimated 29%, or about 3 billion since 1970) decline in the number of North American birds recently reported reflects this decline in their food supply.
In contrast, I don’t think climate change is even remotely plausible as a factor, as the systemic changes are very small compared to the annual fluctuations.

Reply to  etudiant
December 1, 2019 9:37 am

Wind turbines, another contributing factor, kill birds, bats and yes even insects.

Reply to  Scissor
December 1, 2019 1:10 pm

And don’t forget the windtunnel-honed aerodynamics of modern vehicles. Every splat is a failure of streamlining.

Reply to  etudiant
December 1, 2019 11:48 am

etudiant ==> I seem to recall a European study based on windshield smears — but it may be a highly improper measure of insect populations. With millions (literally) more cars on the roads, there are fewer bugs per car as a natural consequence. Hiways have gotten broader and have their shoulders cut regularly now, instead of being narrow roads with tall weeds just a few feet away.

This idea of long-term, consistent and appropriate measurements is what Macgregor et al are saying. They have “perhaps the best insect population database available anywhere in the world” — the Rothamsted Insect Survey’s national network of light-traps — and using this databse, they conclude:

“Our study does not support the narrative that insects are vanishing en masse before our eyes, because there has been a net increase in biomass over the last 50 years. However, the clear decline we observed since the 1980s is still a cause for concern. Moths come in all shapes and sizes, so measuring their combined weight allowed us to analyse changes in their populations that are relevant to their predators and food plants.”

Reply to  Kip Hansen
December 1, 2019 1:49 pm

Every splat on a windshield is a failure of modern aerodynamics

Reply to  etudiant
December 3, 2019 4:26 am

Etudiant, yes, I too have driven through clouds of moths in the past. The question is really ‘does that constitute a trend’ (?).
I think that we can be thrown in our judgment partly becuase we have not been given the particular tool we need to understand what is going on:
We were told in school that many things (eg the height of adults) vary pretty much according to the normal distribtuion ie the bell shaped curve, a person is equally likely to be two inches taller as to be two inches shorter than the average , which in the case is also the commonest height and indeed the height about which half are below and half are above.
What they never told everyone about was that somethings dont vary this way.
Some things are equally likely to halve or double, this leads to a distribution known as the log-normal
Where rather than life events adding an inch to your height or taking an inch off it, they double it or halve it. This seems to be way the way of things with natural populations; when creatures mutliply-up, bad events might mean that only half their eggs survive .
The long and the short of this is that sometimes you can have ten times as many of one group of insects as usual, or one tenth – two orders of magnitiude change. If an insect population is on a lucky run with the weather (perhaps like the summer of 1976 here in the UK) then there can be big increase a year, and of course we remember it.
If human adult heights varied as natural populations do, there might be 5cm (2 inch) adult humans walking next to 5metre (15 feet) adults.
Lognormal behaviour can really throw us; the expectation from it is that a smaller proportion will do well (say a third) and some spectacularly well, whilst the larger proportion (the two thirds) will do badly.

(Irritatingly and counter intuitively, it not the logarithm of a normal distribution, but a distribution ‘that when logged’ is normal or bell shaped ) .
About as clear as mud, as ever 😉

December 1, 2019 10:05 am

Twice as many moths now as in the 1960s in the UK.

Populations of organisms such as insects oscillate chaotically especially when involved in predator-prey relationships.

In the contemporary mindset that any change in any natural parameter of any kind whatsoever is always sign of impending disaster and of the moral bankruptcy of right wing politics, the study of insects is an exceptionally rewarding field.

Maybe too many bats, who eat moths, are killed by wind turbines and that is causing moth numbers to increase?

Or maybe it’s all just stuff that happens.

In any case it’s worse than we thought and the only solution is a left-progressive one world government.

Reply to  Phil Salmon
December 6, 2019 2:31 pm

Phil ==> This is absolutely right “Populations of organisms such as insects oscillate chaotically especially when involved in predator-prey relationships.” but it doesn’t require predator/prey — just plain old Robert May population dynamics.

December 6, 2019 2:36 pm


This little essay isn’t meant to say that that aren’t some insect populations introuble — only that researchers need long-term consistently collected data to make such determinations.

That’s what these British researchers have shown — they do good science and aren’t afraid to imply that others have failed to use adequate data for the topic being studied.

As I and many readers have pointed out — population dynamics are chaotic and can fluctuate wildly on a year-to-year, season-to-season basis and can be cyclical for reasons that are not apparent and may only be due to the chaotic dynamics of populations.

Thanks for reading!

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