We Need Insects More Than They Need Us

The interconnection of the world is a wonder. Consider the United States Declaration of Independence, says Anne Sverdrup-Thygeson, a conservation biologist. It was written with the help of a wasp.

In July, 1776, when Timothy Matlack, a clerk with stately penmanship, copied the bold resolution on parchment, he dipped his pen in ink derived from tannins inside galls, tiny pods or growths, formed on trees. Normally trees produce tannins, an astringent chemical, to help fight infection by invading bacteria. The sour tannins also discourage predators from eating a tree’s fruit. Opportunistic wasps land on trees and secrete chemicals that induce the tree to produce a gall. The wasps then use the galls to shelter their larvae until they hatch. Centuries ago, ingenious human chemists came along and discovered that tannins inside tree galls, mixed with iron sulfates and Arabic gum, produced an ink that penetrated paper and wasn’t easily washed away by moisture like previous inks derived from lamp soot.

The tale of gall wasps is one of the many splendors in Buzz, Sting, Bite: Why We Need Insects, a new book by Sverdrup-Thygeson, a professor of conservation biology at the Norwegian University of Life Sciences. It arrives at an auspicious time, as scientists and writers are increasingly drawing attention to the potential for a collapse of insect populations around the world. Sverdrup-Thygeson illuminates the ecological role of insects and challenges the common notion that some insects are useful and the rest are pests. She studied history before biology and brings a historian’s eye to her work.

“History is not so different from ecology because it’s all about seeing the system,” Sverdrup-Thygeson says. “Seeing the connections between the details, the small things, like the species in ecology or the single events in history; and the big picture—the web of life, or how history is developing across continents and across time.”

I recently caught up with Sverdrup-Thygeson over Skype. She was sitting in one of her daughters’ bedrooms. A Hunger Games T-shirt hung on the wall—appropriate décor for a conversation about the variety of adaptations insects use to compete and survive. Sverdrup-Thygeson listened to my questions with anticipation and eagerness, as if they were rocks on a loamy patch of ground, just begging to be turned over.

In Buzz, Sting, Bite you quote E.O. Wilson: “The truth is that we need invertebrates but they don’t need us. If human beings were to disappear tomorrow, the world would go on with little change… But if invertebrates were to disappear, I doubt that the human species could live more than a few months.” What did Wilson mean?

If all insects were to disappear from today to tomorrow, if they were all gone when you wake up tomorrow, we would all be in big trouble. But the good thing is that insects have been here for 479 million years. They predated the dinosaurs by a wide margin. They were the sole flying creatures for 150 million years. They have survived five mass extinctions already. It’s not like we were going to kill them off, anyway. It’s not like that is something that is at all realistic. Of course, if we blow the entire planet to pieces, they will go, but then we definitely will, too. So they will be here long after we are gone, I think.

The experiment showed females can control what sperm they will later use to fertilize their eggs.

The fact that insects may be going extinct has surfaced in the mainstream press. Not long ago, The New York Times Magazine did an ominous story on it. Does your research point to widespread insect extinction?

There are lots of studies from different places that show dramatic decline, like in Germany and Puerto Rico. We lack the global overview, though, because we only have point data from here and there, and we have very few data that is over time. But it’s pretty sure that they are declining.

I should add that less than 1 percent of the insects that we know have been evaluated for any red list, international or regional. Which means that we really have no idea. If you look at the national red lists, the proportion of threatened insects can be pretty high—30 percent, 40 percent in some cases. A global report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) that came out in May took a very conservative outlook and said at least 10 percent of insects are globally threatened. Well, that’s still more than half a million species!

Remind us why insect extinction is a problem.

When species go extinct, there are two arguments for why that’s a problem. One, of course, is the argument that all species should have a right to living out their strange life potentials, even if they do not have soft hair or big brown eyes or look anything familiar to us at all. I think we are so lucky to be in this one spot in the universe where we know there is life. I think that gives us some sort of responsibility for the other 10 million species remaining on this planet, to actually sort of step down a little so there will also be room for them. And this is, of course, all about ethics and morals, something that each person will have to decide for him or herself.

But then even if you don’t care about that argument, I think it is strange more people don’t care about insects. They are so common—there are between 1 and 10 trillion individuals out there—and they are  such an important part of all sorts of ecological processes that go on. A decline in insects that leads to a decline in birds, fish, small game, would certainly influence us. A paper from 2006—old now—estimated the annual value of the ecosystem services of recreation and wildlife watching, provided by primarily native insects in the United States, to be worth $50 billion. And there are other ecosystem services. According to the IPBES, the abundance and species diversity of wild pollinating species are declining, even as the cultivation of crops that require pollination has tripled in the last 40 years.

So if a lot of them disappear, if we have large changes in their population or their communities, it is pretty sure that that will have knock-on effects on larger species, including us.

You call insects “strange, beautiful, and bizarre.” Tell us about their beauty.

If you look at insects close up, they’re amazing. If you look at the scales on the wing of a butterfly, it’s just incredible. You have these tiny beetles or wasps that are really metallic, colorful, like little jewels. And these things fly around you! But there’s a lot of beauty in the way insects are built and the way they live their lives. A strange beauty. The fact that a fly can live for several days without its head. That’s sort of a brutal beauty, maybe, but it’s incredibly fascinating that they have tiny brains throughout their body, or in several parts of their body, so that several functions can work if they are beheaded. Insects have so many weird and wonderful ways to live: Ears on their legs, like the bush crickets; the fact that some butterflies, some moths, have ears in their mouths to better be able to detect bats. Once you get up close to all these strange adaptations, you will see a lot of beauty.

Do you focus on a specific species?

My pure research is with deadwood insects: Insects that live in dead trees and hollow trees. Right now we are looking into how fungi and insects cooperate in this sort of janitor work that they’re doing out in nature, decomposing deadwood. The fungi have spores that will be blown by the wind in all directions—they don’t have any sort of directional dispersal—so they gain a lot by hitchhiking with a beetle, getting stuck on their side or in the gut. The beetle flies to a new and recently dead tree, which is right where this fungi wants to be, too. And that’s actually an advantage to the beetle, also, to have fungi along, because the fungi can break down some of these compounds that the insects have a hard time breaking down themselves. It’s a win-win thing, is our hypothesis.

Why is decomposing deadwood significant?

Otherwise, all those nutrients would be locked up in that dead biomass, especially in a forest. With trees being big plants, they have a lot of nutrients locked in. That’s the reason why, at least in the forests over here in Norway—and it’s probably not that different in other places—you will find almost one-third of all the species that live in the forest in the deadwood. A bit more than 20,000 species, and 6,000 or 7,000 of them are associated with deadwood. That’s not just insects, that’s fungi as well. And the rest of them, pretty much, are in the soil. So that’s really where you find the diversity: In the brown food web, in the decomposing organic material.

Honeybees can recognize human faces, even though their brains are the size of a sesame seed.

This sounds like a remarkable example of cooperation in nature—survival of the cooperative. Can you give us another example of cooperation that involves insects and benefits an ecosystem?

Well, 5 percent of all plants on this planet have their seeds dispersed by insects. And it’s usually ants. But the coolest example would be this bush from the southern hemisphere, from the African continent. It produces seeds that both look like and smell like the dung of an antelope, one of these animals that live in the same area. That is sort of a strange thing, because normally you would think that smelly seeds are a bad idea. You don’t really want to advertise, “Here are my seeds!” So researchers studied this, and they figured it would be a rodent or something that would come for these seeds. But it actually turned out it was a dung beetle, one of these big beetles that you see rolling dung along. And the thing is, it seems like the dung beetles are actually fooled into believing the seeds are dung. So they come and start rolling the seeds away, just like they would with antelope dung. And they actually also start digging a hole in the ground and put the seed into it. If it was dung, they would then lay eggs into it. But researchers found they didn’t do that! So probably the beetle realizes that she has been fooled, so she doesn’t lay eggs on it and she doesn’t eat it. But the plant has achieved what it really wants, which is to get the seed carried away a certain distance from the mother plant—and even planted!

What experiment has struck you as particularly ingenious in helping us to understand insects?

There was an experiment done by a female entomologist to look into the fight between the sexes when it comes to who has the upper hand during mating. Males can have these really weird looking male organs that are sometimes meant to hurt the female so that she won’t be able to mate with more males; they often stay attached so that she can’t go off and mate with anyone else. And for a long time—and maybe because it was mostly males who were entomologists, as with all researchers—all this research into the sexual selection and reproduction in insects were focused on that perspective.

Then this female entomologist came along and designed this brutal but ingenious experiment with mealworms—males and females, two groups. She split both of those groups in two. Half of the males, she starved, so they would look like genetically bad individuals—not very attractive for having as a dad for your kids. And the others were normal. And then with the females, half she did nothing with, and the other half she killed. Then she put these males and the females together in equal ratios. The beetles mated in equal proportion—the males will mate with the dead females just as well as the living females.

You would expect that in the females, you would find equal amounts of sperm from strong and sexy males and from the weak, unwanted males, right? That’s what they found in the dead females. But in the living females, they found a much higher proportion of the sperm from the good fathers, the strong males. So in insects, the female actually keeps the sperm in an internal sperm bank for a while, and then uses it later to fertilize. And the experiment showed that females can actually control what sperm they will use later to fertilize their eggs! This is called “cryptic choice,” and for good reason—because it is cryptic.

The ecosystem services provided by insects in the United States alone is valued at $50 billion.

Many animals “play” in nature, for various evolutionary purposes. Do insects play?

There are some flies that will catch another insect and wrap it up and give it to the female. It’s really courtship behavior, but you could definitely anthropomorphize it into something playful, or romantic, even. Then you have lekking behavior: Males gather in a swarm, in the case of insects, and females come and choose which of the males she will mate with. That’s one of many ways you can have courtship behavior in insects, and there are definitely species that have elaborate rituals. If you look at it, we could interpret it as playful—but I don’t think it is play.

I think playing would demand a higher sort of consciousness than what we can say these creatures have. Although we might be wrong about that! But the life of an insect is pretty much governed by these basic things: eating, reproducing, and avoiding being eaten before you do the other two. So I don’t they would have time for play, just for fun. Everything pretty much has meaning.

The specter of extinction forms a shadow narrative to Buzz Sting Bite. You write about a slide toward “ecological homogeneity.” To be human-centered for a moment, how does that homogeneity affect us?

One example is a poisonous frog from Columbia that the medical industry was very interested in. It had painkiller potential that was really unheard of. Researchers realized when they removed the frog from its habitat that it stopped being poisonous because it was really poisonous because of its diet, because of these beetles that it ate. And this is a beetle and a frog living in the rainforest, and the rainforest is not doing that well in most parts of the world. This frog is pretty much almost extinct already. So we might be losing really interesting potential for medicine.

But sometimes we are so quick at separating species into those that are useful and those that we call pest species. Mealworms lived in my flour in my student flat! These are a really common species. And we call them pest species because we don’t like them. But then it turns out they can digest plastic, which we definitely like. So I think we shouldn’t be so quick to say that these species are useful and these are not. Because that all depends on the perspective. Take ants, for instance. Our agricultural revolution is 10,000 years old. They’ve been doing this for 50 to 100 million years!

How does ant agriculture work?

In different ways. And they do similar stuff—they protect their cows from predators. They’ll chase away ladybugs, because they’d eat the aphids, just like we would chase away the wolf from our sheep. Ants can actually bite off aphids’ wings so they can’t fly away, just like we would do with our geese. And there are even ants that will take the aphids into their anthills in winter to keep them safe through the cold period, take care of them, and then when spring comes they place them out again, on a nearby bush.

Then you have ants and termites that actually grow fungi where they live. You know the leaf-cutter ants? Those are the ones you always see in nature films, that carry little pieces of leaves back to where they live. They don’t eat those leaves. What they do is to chew them up and put them out in their fungal gardens, and then take small pieces of fungi from the old part of the garden to the new part, so that the fungi can grow on these leaves they’ve chewed up. Then the fungi sprouts these specific structures that look a little bit like yarn, and that is food for these leaf-cutter ants. That’s what the entire colony, with millions of individuals, lives from. And they protect this fungi. That’s why ants can be really interesting for us to look to for antibiotics: If another fungi comes in on the surface of an ant, that could easily spread through the entire colony, and it could kill their food fungi, which would be really bad.

So ants are doing amazing things within the agricultural business—things we can definitely learn from. They are able to grow these monocultures—this one fungi! This one species! And that works, and that’s worked for 50 million years! While we humans, we have a problem with our monocultural crops. It doesn’t work too good for us.

Right. Insects are able to do so much that we ourselves cannot. Which begs the question: How much remains unknown?

Oh, lots of things are unknown. This stuff with plastic-eating bugs is completely new. We’ve learned that honeybees can actually recognize human faces, even though their brains are the size of a sesame seed—neurobiologists thought that was impossible with that few cells, and that few synapses between the cells. We don’t really even understand how metamorphosis actually works. That is really quite a mystery. That this larvae changes, turns into this pupa or chrysalis, and then everything is just rebuilt inside there? It’s like if kids were playing with LEGO bricks, took those LEGO bricks and put them into the box, shook it, and then a completely new figure was inside when you opened it up.

Kevin Dupzyk is a writer and editor based in Brooklyn, New York.

Illustrations by Tuva Sverdrup-Thygeson

Lead image: MyStocks / Shutterstock

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