Do you remember seeing more flying insects in your childhood than you see today? If you have, you're not alone. There's a frightening trend worldwide. Research has found populations of flying insects have dropped dramatically - by as much as three quarters - over the past 30 years.
So, what is causing it? (Hint - it's more than you think.) What does it mean for ecosystems - and ourselves? And is there anything that we can do about it that goes beyond platitudes and that will make a meaningful difference? This post explains what's happening and the key reasons for it. My following blog episodes will explore how to effectively tackle each cause in turn.
When I was a kid, back in the UK in the 1970s and 80s, I remember heaps of bugs that got stuck on the headlights and windscreen after car trips. I used to get flies in my eyes when I went on bike rides (not fun), or accidentally get one stuck in my mouth while excitedly running about - the joys of childhood! Today, even with the ever present pesky mosquito on summer evenings, and the many blowflies that mysteriously appear inside our house every day, Canberra feels a lot less insect-y than my childhood did. Even since I arrived in Canberra in 2006, it seems like those pretty Christmas beetles have dwindled in recent years.
I thought I'd ask some locals to see if their experience matched mine. So, I put a question onto the Canberra Noticeboard Group on Facebook. Over the following day I got over 100 answers - clearly an engaging topic! Although more anecdotal rather than statistical, the replies are interesting in how much they mirror what scientists have found around the world. While a few people reported not seeing a difference, a large majority of respondents said they had noticed marked declines in Christmas beetles, coffee beetles, bogong moths, ladybugs, dragonflies, butterflies, cicadas, spit fires (saw fly larvae), and even large blowflies.
What is going on?
The Insect Apocalypse
In a 2017 study, flying insect populations in Germany were found to have declined by over 75% in just 27 years. Similar declines were then observed in other parts of the world. A 2019 synthesis study found that insect declines were very likely to be a worldwide trend, and suggested that if these trends continue, up to 40% of insect species may become extinct in coming decades. As I read over these points I've just written, I think it's worthwhile pausing for a moment. There's so much awful environmental news out there that I often read things like this in a state of grey numbness. Perhaps you do too? I feel my stomach tighten a little as I add this knowledge to the pile of grim statistics I already know, but I don't really feel it. Because, to be honest, I can't fully allow myself to feel the tragedy of what that means - it's too overwhelming. I know insects are only one part of the massive biodiversity losses we are facing - and that awful statistics like these can be told about a great many species, including those that are far cuddlier and cuter than insects. But I still want to pause, perhaps just long enough for us both to sit with this knowledge for a few more uncomfortable moments. Research tells us we are in danger of losing almost half of all flying insects in coming decades. What does that even mean? I find I can't quite get my head around that - it's both really easy - and really hard - to imagine. I'm not that old - I will probably still be alive to see if that prediction comes true. I hope it doesn't. I hope that what share in this series of blog posts can be my contribution - no matter how tiny - to that prediction not coming true.
When I sit in the garden and look at the bees and hoverflies on my spring blooms, it seems impossible that half of them could be gone in a few decades. And yet, somehow it also feels quieter than I would like. I can already feel that there is a lack, that perhaps there should be more variety, more species, more diversity. I can only see honeybees (from my neighbour's hives) and a few hoverflies. Oh and some blowflies. It's still early in the season, perhaps the others will join as the weather warms. I will keep watching, and hoping.
Birds in crisis
As flying insect populations decline, many insect-eating bird populations around the world are falling in tandem with the decline of their prey. A 2019 study in Science found that bird populations in North America had dropped by almost a third since 1970 - that is, there are approximately 3 billion fewer birds in North America than there were in 1970. Three billion. That's another of those mind-numbing statistics that's almost too crushing to imagine if you think about it for too long. I find myself able to consider the full implications of what I know about the silent retreat of the natural world for only a few seconds at a time. It's almost impossibly sad.
If the above two points weren't harrowing enough, I'm sorry to have to tell you that the decline of flying insects directly affects us too. We need flying insects to guarantee our own food supply.
What it will do to us
Many flying insects are pollinators. Everyone has heard of the valuable role of honey bees as pollinators, but actually all sorts of other bees are also vital, as well as wasps, butterflies, and moths. Even the humble blowfly does a bit of pollinating, though perhaps more by accident than design. Pollinators are essential for the plants they pollinate. Many fruits, vegetables, and nuts are insect-pollinated - about one-third of total global food production relies on insect pollination. That means, a decline in pollinators threatens our ability to grow food. In parts of China apple and pear crops have been hand pollinated since the 1980s because of pollinator declines, due to habitat loss and pesticide use. You probably won't be surprised to read that hand pollinating is labour-intensive and less efficient than insect pollination. It's not a great Plan B.
Why is it happening?
The reasons for the declines are numerous. While insecticides and habitat loss are well known causes, there are some other reasons that might surprise you. I know some of them surprised me. Below I briefly describe some of the key reasons for insect declines.
Note: because there is so much to know - and importantly, so much that we can do - I have decided to write a separate blog post for each of the issues below. My aim is to provide you with more detailed and strategic information on what we can do than the usual platitudes you see in gardening blogs. While pollinator-friendly gardens are a pleasant little step forward, we will need to be a lot more strategic and broad thinking, as individuals and societies, to reverse the insect apocalypse.
1. Pesticide use: Not surprisingly, the widespread use of pesticides is a major contributor. The term pesticide covers any chemical that kills anything deemed as a pest - that includes insects (insecticides), plants (herbicides), bacteria (bactericides), fungi (fungicides), even rodents (rodenticides). Basically, if there's a form of life that can be viewed as a pest, it seems that a chemist somewhere has invented a chemical form of death for them. I'm not sure how I feel about this. Is this really a mark of our progress as a species - that we are getting more and more efficient at stealth killing?
While there has been a fair amount of press on the role of certain insecticides - called neonics - in the collapse of bee populations, I was surprised to learn that other pesticides, even those not targeting insects, can also cause problems. In the post following this one, I will explain what pesticides are doing, and try to give you some bigger picture and meaningful ideas for approaching this issue, individually and collectively.
2. Habitat Loss: Habitat loss is caused by land clearing for both agriculture and urban expansion. Here's a sobering statistic - did you know that almost half of all habitable land on this planet is used for agriculture or urban areas? (In this context, habitable refers to land that isn't completely barren or covered in glaciers.) The remaining land includes previously cleared areas and plantations as well as virgin forests, so these are by no means untouched. In the words of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES - basically the biodiversity equivalent of the IPCC) about three quarters of the total land area of the planet has been significantly altered by humanity in some way.
It should not be surprising then to learn that insect declines have already been so large, when so much habitat has been disrupted. In my upcoming post on this issue I will go beyond generalist advice like 'plant a few more flowers and we'll do our bit for the bees.' Even at this level of individual action I think there are more strategic ways to do this, as well as some cultural questions to ask ourselves. In addition I will have some thoughts about how we might address things systemically.
3. Cars and roads: This one was quite surprising to me. I recently heard an interview with Paul Donald, the author of a very interesting new book called Traffication: How Cars Destroy Nature and What We Can Do About It. In the interview he pointed to a kind of collective blindness in our society where, because we all drive, we tend to overlook the obvious impacts of driving. I realised that I too have mostly overlooked this, having grown up around cars and seeing them as completely 'normal.'
While vehicles directly kill countless insects - as the bugs found on windscreens will attest - the building of roads also fragments and destroys their habitats. As such, it extends the issue of habitat destruction outlined above. Roads act as barriers, preventing insects from accessing essential breeding and foraging areas, and creating tiny islands of lower resilience habitat between them. If that wasn't bad enough, the ozone created from car exhausts in cities also happens to be an effective insecticide itself. No wonder dense cities aren't full of insects. In my upcoming post on this issue, I'll give you some understanding of why small islands of habitat are generally less resilient than larger ones, and give you a fun exercise to do with your kids (or anyone really) to explore your neigbourhood from the perspective of a small bee.
4. Light Pollution: Have you ever noticed moths and other bugs flocking to lights after dark, flying round and round and at the lights until they collapse from exhaustion? It stands to reason that the more light pollution there is, the more disruption to nocturnal insects. Light pollution from urban areas disrupts the natural behaviors of nocturnal insects, including their breeding, navigation, and foraging. This leads to decreased populations in well-lit regions and so, perhaps unsurprisingly, light pollution is a major issue for insects. It's also got quite a lot of solutions too, and so in my upcoming post on this I'll take you through some of the ways the situation for our poor nocturnal flying insects can be improved.
5. Climate Change: You knew I was going to have to mention it somewhere! But it's placed last for a couple of reasons. Firstly, climate change already gets a lot of press, so it probably doesn't need me to repeat a lot of it. Secondly, it can be tempting to blame everything on climate change, which is disempowering, because as you can see from the above points, there are many factors that are causing the decline in insect numbers. Even if there was no climate change insects would be in trouble. And we can do something about these, even as climate change relentlessly progresses and we pray that the world's leaders will get their acts together. That said, like my other posts, my intention is to explore what we can do both individually and collectively in relation to climate change and insect decline.
So - are you ready to embark on learning something about this frightening insect decline and what you can do about it? If so, I invite you to read my next blog about the role of pesticides and some thoughts from a systems perspective about what we can do about it, personally, culturally and societally.