Insectageddon is a great story. But what are the facts?


Hype is an ineffective communication strategy, especially when based on limited facts. There are many elements to effective communication – simply raising awareness about a problem is not enough if audiences don’t engage with the facts and participate in developing solutions.

The latest instalment in the Insect Armageddon saga is out. I wasn’t going to write about it. After my previous posts, I didn’t want to sound like a stuck record. But I’ve had a few media requests, some from journalists who found my original blogs. Most journalists I spoke to have been great, and really understand the importance of getting the facts straight. But a few seemed confused when they realised I wasn’t agreeing with the apocalyptic narrative – ‘other scientists are confirming this, so why aren’t you?’

This latest review paper has limitations, just like the German and Puerto Rican studies that received similar hype over the last few years. This doesn’t make any of them ‘bad’ studies, because every single research paper has limitations. No single study can answer everything neatly. Science takes time.

This is why it’s so important to consider the results of a study relative to the methods and aims. Are the methods and analysis techniques appropriate? Do they actually answer the questions/aims the authors claim to answer?

In this particular review, the methods don’t match the aims, and they select for a particular type of research. The authors state that their aim is to “compil[e] all long-term insect surveys conducted over the past 40 years that are available through global peer-reviewed literature databases.”

The methods don’t achieve this aim:

  • The authors use a very limited and selective search string (insect* + decline* + survey). This is problematic for a few reasons: (i) it will mostly find papers showing declines, not population increases or stability; (ii) the term ‘insect’ is too broad and will likely miss many studies focused on particular taxonomic groups (e.g. bees) that don’t use the word insect; (iii) ‘survey’ is just one term that could pick up long-term studies. Ideally, you would also include other terms that might pick up long-term data, like “long-term” “monitoring” “historical records” “population dynamics” etc.
  • The authors only search one database. There are multiple databases of peer-reviewed literature. For a comprehensive review, and to ensure the widest coverage of literature, it’s good practice to search more than one database.
  • The authors only considered “surveys that reported changes in quantitative data over time, either species richness or abundance”. This means that any study showing stability (i.e. no change over time) would have been discarded.
  • The study is not systematic or a true meta-analysis, as claimed by the authors. This may be pedantic, but science is based on standards.

The results are equally limited – partly because of the limited search terms, and partly because of lack of existing knowledge. There are no data available from most countries, or for many insect taxa.

(Disclaimer: I have nothing against the authors of this paper, I am not funded by anybody who would benefit from insect decline denial, and I think this paper is a useful contribution to the literature. And kudos to the authors for acknowledging some of the limitations of their study.)

These are all important limitations – this study simply does not show evidence that global insect declines are happening, nor does it provide evidence that insects will be extinct in 100 years.

But, along with previous studies, it is a wake-up call. It provides a nice review of the drivers that we already know are having devastating impacts on wildlife and ecosystems. And it highlights the many, many knowledge gaps that we need to urgently address.

So why am I arguing about this? I’m an ecologist; I work on insects and sustainable agriculture; I care about the Earth my children will grow up in. Of course I’m concerned about insect declines. Insects are vital to our future – they keep our ecosystems functioning and contribute to multiple ecosystem services.

My issue is with the effects of miscommunication of research. Over-exaggerating the results of a single study does a disfavour to science. Science is not based on n = 1. This is why consensus, built from many years of different types of research in different parts of the planet, is so valuable and important.

Now more than ever we need to increase public trust and understanding of science. We desperately need everyone to understand that the value of scientific knowledge is built on time, details, and contexts; not broad generalisations.

So what are the Insectageddon facts?

  • Declines of some species or taxonomic groups (e.g. monarch butterflies, some groups of moths and butterflies, some types of bees and beetles) are confirmed in some parts of the world, predominantly in Western Europe, UK and North America.
  • Human activities are definitely impacting insect populations – and every other organism and ecosystem on Earth! The main drivers (in no particular order) are habitat loss, climate change, agricultural intensification, invasive species, and overuse of synthetic chemicals. We know this. We’ve known it for over 100 years, so why do we still need convincing to do something about it?

What don’t we know?

  • We don’t know anything about most insect species on Earth. Only about one-fifth of the estimated number of insect species are known to science. Of those that are described, comprehensive knowledge of ecology, life history, and distribution is only available for the most charismatic, economically-important, or visible species.
  • Most of the published long-term insect surveys are from the UK and Europe – there are very limited data from the rest of the world.
  • Most available data from these regions are for a few groups of species, mostly bees, butterflies, moths, and dung beetles. This is mostly because these groups are more charismatic or economically-important, so they have been studied more. There are no long-term data available for most other insect taxa. This is a problem because  all insects do not have the same ecology or life cycle – so we can’t assume that all insect species will react the same way to the same driver.
  • Why are some species declining and some increasing? e.g. this recent study from Spain showing increases in pollinator abundance over time. Why do declines/increases happen periodically? Why do some species decline from identified drivers, and then recover? How do invasive species impact native insects? If we want to save insects, we need to answer these questions.

How can we fix this?

  • More conservation actions. We already know what disrupts the balance of ‘good’ vs. ‘bad’ insects (in terms of human impacts): pesticides, habitat loss, pollution, land degradation, manicured lawns, too much waste, crop monocultures, invasive species etc. We can take action to minimise these effects now.
  • More research. We can’t identify what insects we’re saving if we don’t get to know them first.
  • More funding. Researchers can’t do research, people can’t act without funds and support. We need widespread public and political support for unbiased funding to fill knowledge gaps and make change to stop insect populations declining.

UPDATE: See my American Scientist article ‘No Simple Answers for Insect Conservation‘ based on this blog post.

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© Manu Saunders 2019

56 thoughts on “Insectageddon is a great story. But what are the facts?

  1. sleather2012 February 16, 2019 / 11:31 PM

    Nice article – what we need, as Stuart Reynolds says in the comments section of my article, is some joined together action from entomologists globally and locally. Ideally we need a few Gates type donors.

    Liked by 2 people

  2. Tony Mannetta February 17, 2019 / 5:54 AM

    Good article, but the Puerto Rican studies sounded very bad..by the researchers themselves. No hype, just sadly astounded by the lack of insects and birds in a preserve far from human activity. There wasn’t a small loss of insects, there were literally no insects to study. (98% decrease from the last study 35 year earlier by the same researcher?) He emphasized the need for more research before running to conclusions. But your points are well taken. (If you have additional info on Puerto Rico i’d like to hear about it, what i wrote was gleaned from the Guardian).

    Liked by 1 person

  3. Mike Lewinski February 17, 2019 / 9:32 AM

    Might this be a case of the Texas sharpshooter fallacy? I notice the lead author on the paper relates a windshield anecdote in The Guardian article. Is it possible that his observation of fewer insects on the windshield led to the original biased search terms?

    There’s at least one paper describing localized declines along busier roadways. It makes sense that day after day, year after year, road traffic will cause a lot of mortality.

    Martin, Amanda E., et al. “Flying insect abundance declines with increasing road traffic.” Insect Conservation and Diversity 11.6 (2018): 608-613.

    https://onlinelibrary.wiley.com/doi/abs/10.1111/icad.12300

    Liked by 2 people

    • Manu Saunders February 17, 2019 / 10:07 AM

      I’m not convinced about the ‘bugs on the windshield’ anecdotes, although they get a lot of traction – if you drive in rural/remote parts of Australia, you will often end up with plenty of bugs on the windshield! There are some studies showing declines on or near roads, but other studies show no effect, e.g. this study from Australia https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.4609

      I think the effect of traffic is definitely plausible, but as far as I know no one has addressed the many confounding factors around different kinds of roads, existing local insect communities, other effects not related to roads (eg pollution, habitat clearing etc), seasonal differences, distance from roads, how cars have changed over time (faster, different designs etc). etc. etc.

      Liked by 3 people

    • Jonathan Ratzlaff February 20, 2019 / 2:02 PM

      In 2008 I drove to Saskatchewan from BC. When we arrived, the front of the car was full of insects. In 2018, I did the same drive late August. Way less bugs. I never had to clean the windshield. Tells me there are less bugs around then there used to be.

      Given the amount of wind in the area, I would suggest that there was no local depletion of insects. It is too easy for the population to be replenished. Wishful thinking in the prairies.

      Liked by 1 person

  4. B manning February 19, 2019 / 12:35 AM

    Great comments — especially for general public who arnt scientists but have a genuine interest in the world around us.

    Liked by 1 person

  5. cinnabarreflections February 19, 2019 / 6:07 AM

    Another excellent blog, Manu. It is all too easy to get swept along in hysteria, but sometimes I wonder if we are not too honest about objectivity. I calmed down industry people who phoned me in a panic when mountain pine beetle started killing spruce. In retrospect I should have told them to invest in research to figure out what was going on, perhaps. In my mind, admittedly subjectively, it seems like some taxa are less prominent now than they were 35 years ago, but objectively, I agree with your statements 100%

    Liked by 2 people

  6. Bishop Hill (@aDissentient) February 19, 2019 / 9:13 AM

    The Puerto Rico paper used temperature data known to be unreliable for climate analyses to draw conclusions about the effect of climate on insects. I’m interested that you don’t think it a bad paper!

    Liked by 1 person

  7. cazuarina February 19, 2019 / 11:03 AM

    You have certainly been kind to the authors. I think they have been grandstanding. The insects on the windscreen is just too anecdotal for me.

    The guardian is too eager to buy into the agriculture is bad trope that has plagued issues like organics vs traditional ag and the use of roundup.

    Dr Karen Smith. Urban trees and soils.

    Liked by 1 person

  8. russ george (@russgeorge2) February 19, 2019 / 10:23 PM

    Blaming the insect apocalypse on the usual suspects of pesticides and agriculture is folly. The direct, though slow, lethal effects of high and rising CO2 on insects via induced oxidative mortality and CO2’s ATP inhibition mechanism just like neocorinoid and organophospate insecticides is a better suspect. Here’s a link to read more.. http://russgeorge.net/2019/02/18/insects-arthropods-and-their-entire-food-chain-collapses-in-pristine-rainforests/

    Liked by 1 person

  9. JonnyB February 19, 2019 / 11:06 PM

    Great article. I had a random thought about this the other day. Does anyone know what (if any) effect bird feeders are having on insect populations?
    My first (and probably naive) thought would be that they are causing an artificial rise in bird populations.

    Liked by 1 person

  10. Steve Humphries February 20, 2019 / 1:59 AM

    Many insect species are diminishing in my area due to an invasion of fire ants. The northern march of fire ants seem to be aligned with the disappearance for some of the original common hoards of the creepy crawly little pests. And there is no shortage of fire ants. Some people like the fire ants simply because of their insect control but I can’t go barefoot out in my yard anymore and I don’t like fire ants.

    Liked by 1 person

  11. aucklandecology February 20, 2019 / 8:17 AM

    Our study showed feeding birds in urban areas did change the bird community (Galbraith J.A., Beggs J.R., Jones D.N., Stanley M.C. 2015 Supplementary feeding restructures urban bird communities. PNAS 112 (20), E2648-E2657 https://www.pnas.org/content/112/20/E2648). However most people, in NZ anyway, provide bread or grain for birds, so it is generally granivorous birds that benefit from the feed and not the insectivores. So my guess is that feeding birds is not likely to increase the abundance of insectivorous birds at a landscape scale and is unlikely to be the main cause of any decline in insect abundance.

    Liked by 2 people

  12. tanya February 20, 2019 / 8:40 AM

    As an ecologist, have you looked into the likelihood that insects of all kinds are being affected adversely by the increasing EMF fields from our telecommunications systems? I believe that this is another major drivers in the decline of insects.

    Liked by 1 person

    • Lucia March 4, 2019 / 8:55 PM

      Yeah that’s the ignored elephant in the room. Lots of insects who are dependant on EMF-Fields to find their way around, are having a hard time with all our artificial EMF-Fields . Digital fields being broadcasted by air also have detrimental effects on life see;
      https://www.globalresearch.ca/adverse-health-effects-from-the-operation-of-digital-broadcast-television-stations-dvb-8208-t/12596
      Up till now very sloppy research has been done to measure the effects of artificial EMF-fields on humans and a few on animals. Scientist worldwide are calling for better research which not only takes a stance on the heat issue but also the overriding of our own weak emf-fields by the stronger artificial external fields issue. Bio physicists for instance are sounding the alarm over effects on our nervoussystem , DNA and Heart and brainfunction, they also plead for an investigation into the cumulative effects which people undergo in real life…. since the existing researches do not take that into account, The fact that it’s a booming money making business not only for companies but also for governments, selling out the frequencieranges does not make it easier to investigate… who protects humanity if and when the government and private companies are looking to the problem through the,” dollarsigns in the eye syndrome”.
      After all if it turns out to be a disaster they know we can just put some flowers on a stupid monument once a year and say sorry to those who lost familymembers… that’s how they manage to get away with it all the time.
      Another development in the last 10 years or so is, that insects have become part of our foodchain and also are being used in animalfood also as a cheap protein source , so in the light of above scenario what chance is there that this is merely a CO2 problem. REALITY is much more CONVOLUTED than the very meagre and simplistic idiotic models our contemporary shortsighted and over compartimentalized researchers are proclaiming and than i don’t even mention the fact, that the results of said researches are often a matter of what big parties in the game want and pay for them to be.With fundings for universities and investment in promising students being paid for by rich families, with ties to big pharma, big agro etc.how independent is research and the researcher……. funding for research is definately tied to interests !!!!

      Liked by 1 person

      • Lucia March 4, 2019 / 8:58 PM

        Great article by the way*****

        Like

  13. Marco Mello February 22, 2019 / 1:53 AM

    Excellent post! As scientists we need to exercise criticism in all instances, even regarding studies that confirm our most beloved hypotheses. Of course no ecologist denies the importance of conserving natural resources. However, conservation turned into an academic religion in the past decades. Full package (sensu Harari): Evangelion, dogmas, code of conduct, rites of passage, and ad hominem attacks on infidels. That is one reason why the public mistrusts scientists so strongly nowadays and prefer to listen to conspiracy theories. Did you see this opinion piece: https://doi.org/10.1073/pnas.1805868115?

    Liked by 1 person

  14. Jim February 22, 2019 / 5:31 AM

    A comment yesterday on an NPR report on insect decline said that modern car windshield design results in most insects encountered merely sailing over the automobile.

    Liked by 1 person

    • jim March 2, 2019 / 11:59 AM

      This makes sense for 3 reasons (I think): 1) car windshields are at a much lower angle to horizontal than in the past; 2) this design is being universally adopted because gov mandated fuel efficiency is forcing all vehicles toward the single optimal fuel efficient shape; 3) lower angle probably also reduces chip likelihood.

      Liked by 1 person

  15. Marc RobinsonRechavi (@marc_rr) March 6, 2019 / 11:22 PM

    Thank you for this very interesting post. I have two questions concerning your sentence “The main drivers (in no particular order) are habitat loss, climate change, agricultural intensification, invasive species, and overuse of synthetic chemicals.”

    For synthetic chemicals, do you have any references on larger impact of synthetic vs. non synthetic chemicals on insects, please? I was under the impression that toxicity was not related to the synthetic or not nature of the products.

    Second, intuitively (and from some of the literature), agricultural intensification would seem to be a positive relative to habitat loss, since the same amount of produce is obtained from less land. Do you have references on the impact of agricultural intensification please?

    Best regards
    Marc

    Liked by 1 person

  16. Matthew Vowels April 27, 2019 / 6:40 AM

    Classic peer review process in the soft sciences

    Liked by 1 person

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