In the largest-ever study of insect population changes around the globe to date, researchers have found that land-dwelling insects are in decline, while freshwater insect populations are increasing.
The study is the first to combine available data from 1,676 insect study sites around the world to paint a global picture of the state of the world’s insects.
“The amounts of data are so vast here, and so many people contributed to what we have amassed here, that it’s a bit humbling,” said lead author Roel van Klink, a postdoctoral researcher at the German Center for Integrative Biodiversity Research. “We knew this had to be done. We needed to bring [these datasets] into the conversation.”
Over the past several years, multiple studies have shown dramatic insect declines. The most prominent paper came out in 2017, and showed a 75 per cent decline of flying insects in West German nature reserves over a span of 27 years, sparking headlines referring to an ‘insect apocalypse.’ However, many of these studies only looked at regional differences, and van Klink felt a more global approach was necessary.
In his study, published in the journal Science, van Klink and his colleagues found that globally, populations of terrestrial insects, such as butterflies, ants and grasshoppers, have decreased 24 per cent over the past 30 years. These declines are likely due to a range of factors including climate change, pesticides and habitat loss
However, they also found that insects that live part of their lives underwater, such as dragonflies, midges and mosquitoes, have increased 38 per cent over 30 years.
Van Klink attributes these increases to water protection measures put in place over the past 50 years. “That is not to say that the water quality right now is so incredibly good. It is more to say that it used to be much much worse,” he said.
And even though the numbers don’t quite suggest we’re facing an imminent ‘insect apocalypse,’ van Klink still feels this is proof that protection measures work, so they should be applied to help protect terrestrial insects.
“We’re talking about a 25 percent decrease in 30 years. That is not 75 percent. It’s still a lot, and yes we should absolutely do something about that,” he said.
“The narrative has been very panicky, very apocalyptic, and not very scientific so far. And I definitely hope that we can bring a bit of nuance and actual science to the table to discuss what to actually do now.”
Saving the insects by showing them some respect
Aside from habitat protection and curbing pesticide use, one entomologist is suggesting a different approach to helping insects: just treating them with more respect. In a new book, John Hainze sets out to change how we feel about the insects around us, to help people realize that they’re not pesky bugs, they’re a part of nature, just like we are.
Hainze spoke with Quirks & Quarks host Bob McDonald about his book Nature Underfoot: Living with Beetles, Crabgrass, Fruit Flies, and Other Tiny Life Around Us.
This interview has been condensed and edited for clarity.
You write in your book that as humans we have a moral obligation to insects. What do you mean by that?
Well, by moral obligation I mean that we should be concerned about what’s right for those insects and other small living beings. And we should be concerned about the actions that we take that might inhibit their flourishing, inhibit their lives, inhibit the interests that they have.
How important are they to us that we should give them such respect?
Well insects are important to us in a number of ways. I mean pollination is getting a lot of play these days. Insects are important for their recycling capabilities. But I try to make the point that it’s not just about how important the insects are to us. They’re important in and of themselves. They have an inherent value, an inherent worth. There’s something about insects and other living beings that give them value despite what value or dis-value they might have to human beings. They have value on their own.
There are some insects that we’re sort of innately more afraid of, or grossed out by, than others, and we tend to call them pests. Where do you think this fear or disgust of insects comes from?
The two main theories that come back to why we feel the way we do about insects and their kin is related partly to socialization, and partly perhaps to evolved feelings. Spiders for example.
There was a study done a number of years ago where scientists put pictures of spiders in front of six month old infants and they noticed that the infants eyes dilated much more when shown a picture of a spider than shown a picture of a fish. And what they’re saying based on these results is that infants have some evolved propensity to be concerned about spiders.
In fact even entomologists, many entomologists list spiders as their greatest fear which seems kind of strange. In any case, spiders, in this study with college students, were much more greatly feared and provided more disgust relative to things like bees or wasps. And then at another level below the bees and wasps were things like beetles and below that were maybe butterflies.
Maybe the immediate reaction for many of us is to say, yuck, gross; but I’d like to shift that.– Dr. John Hainze
And so I think what you can see there in that progression of the strength of negative feelings about these insects is that there’s probably something to do there with the propensity to harm us.
We fear a spider bite and we fear a bee sting. Evolutionarily, you know that those sorts of things may have made us less fit, less able to go out and hunt or gather food. So going back in time maybe that was a useful adaptation to fear these kinds of organisms. Much less so today. I don’t think we need to have those same kinds of worries, and that’s kind of what I’m trying to get at in the book — trying to develop a more of an appreciation for these organisms.
What do you think people need to know about pesticides?
The first thing is it should not be the first thing that we turn to. There are other things we can do, in many cases, to manage insect issues, or even weed issues.
I think the second thing people should be aware of is, if you really need to use pesticides, if somehow the insects are causing suffering or will cause suffering or are threatening in some way be targeted, don’t use products that are sprayed all over the home. Learn what you can about how to best approach the problem and be very targeted.
The last thing I would say is be aware that many of these insecticides last for months and in fact the manufacturers on their labels will say quite proudly “kills insects for six months,” for nine months, for 12 months, and that’s not really a great thing. You’re leaving pesticide in different parts of your home. Aside from any human health effects that will continue to kill whatever crawls over them indiscriminately. So I think those are some important considerations when you’re contemplating using an pesticide product.
You suggest that one of the things we should be changing is our attitude, that if we see an insect in the home that we’re living with them and there’s no getting around that.
Yeah I think that really my goal in the book is: ‘What do you think, what do you feel when you encounter a pill bug or when you encounter a house centipede in your home? What’s your reaction?’
And I understand that maybe the immediate reaction for many of us is to say, yuck, gross, but I’d like to shift that. If you learn a little bit more about some of these animals that you’re living with, maybe your attitude will change a little bit, and recognizing that these are deeply ingrained attitudes, how we feel when we see an insect or a spider. But I think that rationally maybe we can overcome a little bit of that and treat these organisms with some respect and maybe even begin to feel OK about sharing our space with them.
Produced and written by Amanda Buckiewicz
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