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.
© Manu Saunders 2019