9 
9 What’s Next?
The extraordinary lives of insects are changing. The ecosystems on Earth have altered more rapidly in the past hundred years than at any previous time in human history. Well over half of the planet’s land area has been transformed through agriculture, livestock grazing, and construction. And the pace is increasing. This means that habitats are being lost and those that remain are being divided into small, isolated fragments. Dams and artificial irrigation are putting the planet’s freshwater resources under ever-increasing pressure. We have produced and thrown away so much plastic that we will be finding vestiges of it in the sediments in the form of microplastic for generations to come. Every year we produce substantial amounts of chemicals, including the pesticides we use to protect our crops, which kill insects. We displace species, both intentionally and unintentionally. We have doubled the amount of nitrogen and phosphorus in the soil through the use of artificial fertilizer, and carbon dioxide emissions are higher than they have been for tens of millions of years, contributing to climate change.
All of this affects insects. And anything that affects insects affects us. A decline in the number of insects and the extinction of species will spread through the ecosystem in a ripple effect with major consequences over time because of the impact on so many fundamental ecological functions.
Fortunately, we’ll never manage to wipe out all the bugs. But we would do well to take more care of our tiny six-legged winged friends, because despite their 479-million-year track record, they’re starting to struggle.
We know of only a tiny proportion of all the insect species in existence, and we have little solid monitoring data about those we do know of. Even so, one estimate indicates that one-quarter of all insects may be under threat of extinction.
One important point in this connection: it’s too late to worry when a species is on the brink of extinction. Species cease to function in the ecosystem long before the last individual dies out. That is why it is so vital not to focus exclusively on species extinction but to turn the spotlight on the decline in the number of individuals. And there is much to suggest that insects are becoming fewer. In Germany, the accumulated biomass of all insects trapped in more than sixty locations nationwide has plummeted by 75 percent in just thirty years. Global data suggest that while we humans have doubled our population in the past forty years, the number of insects has been reduced by almost half. These are dramatic figures.
Why are insect numbers falling? It isn’t easy to say, because there are probably many connected causes. Important factors include increasing land use, intensive farming and forestry practices, pesticides, and the decline in natural remnant habitats, as well as climate change.
What happens when our demands for constant growth in the use of land and resources cause insect populations to crash, species to disappear, and insect communities to change? Think of the world as a hammock made of woven fabric: all the species on the planet and their lives form part of the weaving, and all of them combined create the hammock we humans are resting in. Insects are so numerous that they account for a large share of the hammock’s fabric. If we reduce insect populations and wipe out insect species, it’s as if we are pulling threads out of the weave. That might be fine as long as there are only a few small holes and loose threads here and there. But if we pull out too many, the whole hammock will eventually unravel—and our welfare and well-being along with it.
Drastic changes in insect communities can have domino effects with consequences nobody can predict. Indeed, we do not know what their significance might be—only that things may become very different. We risk living in a world where we humans face a tougher existence because the challenges of ensuring clean water, sufficient food, and good health for all become even greater than they are today.
Let us look at a few challenges, some examples of the factors that threaten insect life, both locally and globally.
First: land use. This is undoubtedly the greatest threat. We are using land ever more intensively. That means fewer habitats, fewer intact rain forests in the tropics, and, back home, fewer flower meadows in agricultural land and densely built-up areas and fewer areas of natural forest, where old dead trees get to play out their role as homes for insect diversity. It also means more artificial light, which has an impact on many insects.
Second: climate change. Warmer, wetter, wilder—that’s the outlook. What do these changes mean for insect life?
Third: challenges related to the use of pesticides and new genetic manipulation techniques. This is a vast field that leaves us with more questions than we have answers for.
Fourth and finally: the introduction of nonnative species and their effect on bugs. What is the right way of dealing with “past sins” in this area? Is it possible to reverse them, and is this the correct prioritization? Because at the same time as we wipe out species, the changes we make create room on the planet for new species, brought to the fore by the thrust of evolution. How robust is nature, and how shall we weigh our concern for our own kind against our concern for millions of other species?
In the South American jungle lives a horribly poisonous frog with the appropriate Latin name of Phyllobates terribilis. In English it goes by the name golden poison frog. This isn’t a frog you’d want to kiss in the hope of finding a handsome prince. If you tried, you’d be dead within minutes—guaranteed. The poison in question is one of the most powerful nerve poisons known, batrachotoxin. An average frog contains roughly one milligram of the poison, which is about the same weight as a grain of salt. This alone is enough to kill ten grown men. And just so you know: there’s no antidote.
This little frog, no larger than a plum, used to be fairly common in the rain forest in parts of Colombia. The locals would carefully stroke their arrows along the frog’s back to ensure that their arrowheads were poisonous enough to kill anything they might encounter.
The pharmaceutical industry got wind of this shocking yellow poisonous sensation in the rain forest. Early tests indicated that the poison was an incredibly effective painkiller—in suitable doses. What’s more, because it affects the transport of sodium through cell membranes, it could also be significant for our understanding of numerous diseases where this is important, such as multiple sclerosis. A few specimens were fetched from the jungle for closer examination. But guess what happened to the catch when it arrived in the laboratory? The frog was no longer poisonous!
The fact is that nature is often craftier than we expect: the golden poison frog is not poisonous in itself. It produces the poison only while living in its natural habitat. Why? After much laborious detective work, we now know that the poison comes from a diet of beetles—yes, that’s right (this is a book about insects after all). A beetle from the soft-winged flower beetle family Melyridae, to be precise. So the frog is poisonous only when it eats the right kind of beetles in its natural forest habitat.
Thanks to rain forest logging, the golden poison frog is now listed as threatened with extinction. A desperate battle to rescue the species is under way, but there are few bright spots. Not only is the frog’s habitat vanishing, but the trade in frog legs has led to the spread of a fungal disease (popularly known as Bd) that is killing frogs, toads, and newts around the globe. A third of them are now on the point of vanishing for good. Soon there will no longer be any golden poison frogs and thus no opportunity to do further research into the active ingredients they produce.
If we want to preserve our chances of seeking out active medical ingredients, we need to take care of the habitats of these species. Conserving natural areas intact is one important means of securing habitats, both in the rain forest and in industrialized nations. Many specialized insects have such peculiar special needs when it comes to where they can live that they cannot survive in the totally transformed modern landscape. This means that nature reserves and other conservation areas are crucial if we are to safeguard unique species.
But it is also important to retain as much of the variation seen in the natural landscape in places outside the large conservation areas. In the forest, that may mean ensuring that there are enough old and dead trees—because dead wood plays a central role in a living forest (see page 112), housing a large share of forest species, including insects, which make themselves useful as decomposers, pollinators, dispersers of seeds, food for other animals, and pest controllers. And although many countries have recently launched initiatives to increase the amount of dead wood, the volumes are still low compared to natural conditions.
In our farmland and cities we can also achieve a great deal through simple measures that simultaneously serve to beautify the environment for us bipeds: a belt of trees and bushes alongside a stream in a residential area; green shoulders and hedges along roads, and a border of wildflower meadow along the edge of a field; a patch of uncultivated land in the middle of a field with old hollow oak trees. A varied landscape provides many more opportunities for complex insect life. Again, this benefits the pollination of both wildflowers and crop plants. Honeybees, wild bees, and bumblebees aren’t the only insects required for good and efficient pollination; this is high-level teamwork involving many players. It is often the case that flies, beetles, ants, wasps, and butterflies are less efficient pollinators per flower visit than bees and bumblebees. Yet this is often offset by the fact that they visit many more flowers overall because there are such a lot of them. Some of these “nonbees” may also have peculiar habits and adaptations that benefit pollination.
If we combine the data from a few dozen research projects from five continents about crops of, say, rapeseed, watermelon, mango, strawberries, and apples, we find that the plants produce better crops (an increased fruit set) when they receive visits from “nonbees” regardless of how many bees paid them a visit. It seems that these other insects contribute something unique, something that bees cannot deliver. There are also differences in how vulnerable the different insects are to changes in the landscape, which is an advantage for our food production. In sum, all these insects operate as a kind of pollinator insurance: if one species can’t get the job done, another one can step in.
We know that species diversity can make the ecosystem more effective when it comes to capturing resources, such as water and nutrients, and that this results in more biomass. That knowledge is key once we grasp that this biomass is precisely what serves as the basis of crops and the food that ends up on our dinner table. We also know that species diversity is central to breaking down the biomass once again and thereby ensuring that the nutrients are released, which enables new production.
What’s more, we are gaining increasing support for the notion that intact biological diversity can make ecosystems more stable over time than impoverished diversity does. There are many mechanisms in play, including the fact that different species have different strengths: one species grows best during cool summers, while another does so beneath a baking summer sun. When species decline or are wiped out, nature has fewer variants to play with and we are more poorly armed against both natural fluctuations and man-made changes—in the climate, for example.
It isn’t easy to put a price tag on the services insects provide, although that hasn’t stopped people from trying. For example, the annual global contribution of the many pollinating insects is estimated to be worth around $577 billion. Decomposition and soil formation are estimated to be worth four times as much as pollination in total. Although these figures vary depending on calculation methods and are pretty approximate, they still show that the contribution by insects is extremely valuable and that it makes good economic sense to encourage it.
The fact that we humans are spreading out over increasingly larger expanses of the planet also has some consequences we don’t think about on a day-to-day basis, such as light pollution, the sum of artificial outdoor light produced by streetlamps, houses, and industrial buildings. Light pollution is growing at a rate of 6 percent per year and is disturbing our ecosystems, including insects.
We all know that moths are attracted by light, although the exact cause is a matter of debate. According to the leading theory, they think the light is the moon and try to orient themselves by maintaining a fixed angle to it. While this works perfectly well with the moon, which is a long way off, the result in this case is that they spiral in toward the artificial light and generally end up getting fried.
Street lighting can alter the local species composition of bugs. When artificial light is reflected off shiny surfaces, this can confuse land-living insects that lay their eggs in water. Where we see a parked car beneath a streetlight, a dragonfly perceives the light as being reflected off the surface of a body of water and drops its entire life’s egg production in the wrong place.
What will happen to insects over the long term? Could light pollution cause urban insects to change their behavior and avoid light, for example? To test this, some Swiss scientists compared a thousand larvae of the spindle ermine moth species (Yponomeuta cagnagella), half of which came from the city and half from the countryside. All got to spend their childhood in similar lighting conditions in a laboratory. Right after hatching, as night fell, they were let out into a large net cage, with a light source placed on the opposite side. Then it was just a matter of waiting the whole night through. Would city moths and country moths be equally attracted to the light?
The result was clear: city moths were evidently much less attracted to the light, by an average of as much as 30 percent. This indicates that nocturnal moths that have spent generation after generation living in an artificially lit environment have undergone an evolutionary adaptation to artificial light. After all, it doesn’t make much sense for masses of them to fly round and round streetlamps getting burnt or eaten up by predators that have worked out where the buffet is being served. This could explain the emergence of selective pressure against attraction to light among urban moths.
On the one hand, this is fine, because it prevents them from dying like that. On the other, it can have far-reaching adverse consequences. Because there is a cost attached: the avoidance of light probably means that urban moths simply spend more time sitting still.
Consequently, the effect of artificial light in built-up areas alters the insects’ role in the ecosystem. For example, it is difficult for nocturnal insect eaters to catch an insect that is hidden and motionless. Nor is an insect that can’t be bothered to fly going to do much pollination among flowers that are adapted to nocturnally active pollinators. That is why it is important to restrict light pollution and, in particular, to try to keep artificial light away from natural areas that are not yet affected by it.
We know that we are heading toward a future in which the climate will be different. This will affect insects both directly and indirectly.
One challenge is that climate changes disturb the finely tuned synchronizations between different species. We see a shift in the timing of many processes, such as the return of migratory birds and foliation, or spring blossoming. The challenge is that different events do not necessarily shift in sync. If insect-eating birds produce their young too late or too early in relation to the period when there are the most insects, there may be too little food for the chicks in the nest. This can happen if some events are triggered by length of day (which is not affected by global warming) while others are triggered by mean temperature (which is), for instance. In the same way, plants that are reliant on particular insects for pollination may suffer from poor seed production if they flower at a point when these insects are no longer swarming.
The spring can be particularly challenging, especially a “false spring” that arrives far too early. When that happens, overwintering adult insects are tempted by the warmth to go out in search of food. When the frost returns, the insects will struggle to cope with the cold and with finding enough food because they have poor cold tolerance and few food reserves.
We see that many insects try to change in response to changes in the climate. Sometimes their entire distribution is shifted, but we often see that the species fail to keep up and the distribution shrinks instead. In the case of dragonflies and butterflies, it has been proven that many species have become less widespread and are shifting northward. Color charts of the different dragonfly species show that many butterflies and dragonflies, especially those with dark coloring, have vanished from southern Europe and sought refuge in the northeast, where the climate is cooler. Scenarios produced for bumblebees indicate that we may risk losing between a tenth and—in a worst-case scenario—half of our sixty-nine European varieties by 2100 owing to climate change.
In the north, climate change is increasing the distribution of leaf-eating caterpillars. This exacerbates the effects on the birch forests, which are being chewed bare. Over the course of a decade, outbreaks of autumnal moths and their relatives have caused considerable damage to the birch forests of Finnmark in northern Norway. The outbreaks have ripple effects on the entire system: food conditions, vegetation, and animal life are all changed.
Along with researchers in Tromsø and at the Norwegian University of Life Sciences outside Oslo, I have looked at how the autumnal moths’ depredations affect a different group of insects: the beetles that break down the dead birches, thereby ensuring that the nutrients are recycled. Our results show that the attack of the autumnal moths creates so many dead birch trees in such a short space of time that the wood-living beetles are simply unable to keep pace. They cannot respond to the increase in available food with an equivalent increase in the number of individuals. We do not know what effect this may have over the long term, and this illustrates a key point: we have no idea what sort of consequences continued temperature increases will have for the ecosystem in the north, but it is obvious that there will be dramatic changes.
Since one of my research fields is insects in large, ancient, hollow oak trees, I have been wondering how climate change will affect the beetles that inhabit them. A couple of years ago, my research group and some Swedish scientists compared a large data set that covered beetle communities associated with oak trees across the whole of southern Sweden and southern Norway. The oaks stood in places with differing climates, so that the range they spanned in terms of temperature and precipitation was roughly equivalent to the changes foreseen in climate scenarios. We looked at differences in the beetle communities in order to gain knowledge about how a warmer, wetter, and wilder climate might affect these different insect communities in the future.
In our study, we found that warmer climates were good for the most specialized and peculiar species. Unfortunately, though, these unique species reacted badly to increased precipitation. This means that climate change is hardly going to improve conditions for these particular insects. However, the more common species showed few reactions to climate differences.
This confirms a pattern that is common in our times, not just in relation to climate change but quite generally: locally unique, specially adapted species are the ones that suffer, whereas common species do fine. This means that many rare and unique species will go into decline, whereas relatively few species that are already common will become more common. This is known as ecological homogenization: the same species are found everywhere, and nature becomes more similar across different geographies.
Every year, we use massive amounts of chemicals quite intentionally to kill insects. After all, that’s the whole point of insecticides used in agriculture and private homes and gardens.
Many people think the intensive use of pesticides in agriculture is a price we have to pay to be able to feed a constantly increasing population through industrial agriculture. Others argue that we ought to take a more ecological approach and cooperate with nature in our agricultural practices, even if it might lead to lower crop yields.
Although we don’t have space to go into this discussion here, I must mention the large and growing documentation detailing the unwanted harmful effects of neonicotinoids, a widely used group of insecticides. These substances affect the navigation and immune defenses of honeybees and wild bees and may be among the reasons for the decline in these groups.
We humans have recently acquired a brand-new tool in our battle against insects that are harmful to us. I’m thinking of genetic manipulation, in particular what is somewhat cryptically known as the CRISPR/Cas9 method. This is like a pair of molecular scissors that can cut up genes and may be used to alter an organism’s DNA by removing or substituting certain genes. The method may be combined with something called a gene driver, which ensures that the genetic change rapidly spreads to pretty much all offspring.
Malaria is caused by a parasite that a mosquito carries from one infected person to another when it sucks their blood. Every year, around half a million people, most of whom are under five years of age, die of malaria. Even so, the numbers are much lower than they were just fifteen years ago, and much of this decrease is due to simple measures, such as the use of insect nets impregnated with insecticide. But now we also have a tool that could ultimately be used to wipe out the malaria mosquito once and for all. This can be achieved by making one of the sexes sterile or by ensuring that all the offspring are the same sex.
This has prompted a timely question from the Norwegian Biotechnology Advisory Board in several different forums: Dare we—and should we—use such tools in the natural world? We know little about their impact. One issue is that we don’t know what cascading effects doing so could have in the ecosystem. What if we eliminate one species and another simply steps in and takes over as a spreader of disease? For all we know, things could end up worse than they were to start off with.
Another question is whether the use of a tool like this could lead to undesirable mutations, with undreamed-of consequences. Terrifying scenarios, such as the spread of sterility to other organisms, lie in wait. Despite the need for haste, we must proceed with caution. Before we start to use the new gene technology tools to genetically alter or wipe out insects that spread serious diseases, we need to protect ourselves against undesirable consequences as best we can.
We humans have changed a lot of things on this planet. Some are things we cannot change—such as the fact that our forefathers wiped out most of the really big animals tens of thousands of years ago on continent after continent. Gone are the mammoth, the saber-toothed tiger, and the giant sloth. Along with them, a great many insects probably died out, too, insects associated with this megafauna in various ways, although we know even less about them.
Other changes are much more recent. Seagoing explorers took cats, rats, and other efficient predatory mammals to islands where life had gone its own way. Native species that hadn’t the wits to look after themselves, species that had developed in the absence of such enemies, were then often summarily dispatched.
We continue to displace species at a rapid pace, sometimes without meaning to and sometimes intentionally. One example is the import of buff-tailed bumblebees to South America, where they were supposed to improve pollination in fruit orchards and greenhouses. The buff-tailed bumblebee has spread rapidly and is crowding out the local giant bumblebee, Bombus dahlbomii, apparently because the buff-tailed bumblebee carries parasites that the giant bumblebee can’t cope with. The Bombus dahlbomii is the world’s biggest bumblebee, affectionately described by bumblebee expert Dave Goulson as “a monstrous fluffy ginger beast.” Soon it might be gone forever.
What are we to do with introduced species that threaten unique native species? This is a big, difficult, and important question that we need to debate more in society. In some cases the decision forces itself upon us, as in New Zealand. The government there has launched a plan to wipe out rats, opossums, and stoats. These alien species kill roughly 25 million birds every year.
Many other island nations suffer from the same problem. The challenge can be illustrated by a tale from Australia about a once extinct stick insect that was rediscovered and the living, but soon-to-be dead, black rats that ate it up.
On June 15, 1918, the steamship SS Makambo, packed to the gunwales with fruit and vegetables, ran around just off Lord Howe Island, a tropical island far out in the Pacific Ocean that was an easterly outpost of Australia. Its few inhabitants were separated from the mainland by more than 360 miles. The important point about this shipwreck is the creatures that managed to reach dry land: rats. In the nine days it took to repair the ship, an unknown number of black rats managed to reach the shore and establish a foothold on the island.
Lord Howe Island had lain isolated in the middle of the ocean for millions of years. Unique species had developed there that existed nowhere else on Earth. But the rats hadn’t come to chill on the beach. Remember the story of the very hungry caterpillar? The one that ate its way through an apple on Monday, two pears on Tuesday, and ended up plowing its way through oranges, sausages, ice cream, and chocolate cake before the weekend was over? That’s roughly what the rats did on Lord Howe, too, the only difference being that they ate up unique species one by one. In the early years alone, they finished off at least five species of birds and thirteen small animals that couldn’t be found anywhere else in the world.
One of these small creatures was a gigantic stick insect—you know, those thin pale brown insects that look like dried twigs. But this species wasn’t just any old stick insect. We’re talking about a quite special insect, the world’s heaviest stick insect: it was the size of a big barbecue sausage, dark, shiny, and wingless, and it aptly went by the nickname “tree lobster.” Its Latin name, should you wish to know it, was Dryococelus australis. It proved to be a delicious meal for hungry rats. As early as 1920, the species was already declared extinct—a kind of belated victim of the shipwreck two years earlier.
But this story takes an unexpected turn. Because the outpost has an outpost: 12 miles away from Lord Howe Island lies Ball’s Pyramid, a sheer narrow sea stack that is taller than the Empire State Building. For years, it attracted adventurous climbers, but since being awarded World Heritage status in 1982 (along with Lord Howe Island), only scientific expeditions have been allowed to visit. Around that time rumors also began to circulate that there were “tree lobsters” on the sea stack. Suddenly there was no end to the number of climbing expeditions with an inordinate interest in bugs that were applying for climbing permits to go looking for this rare stick insect. In the end, the man in charge got so sick of issuing climbing permits disguised as insect research that he decided to put an end to the rumors once and for all.
Thus it was that, in 2001, two scientists and two assistants traveled to the sea stack. They climbed up the sheer rock face without seeing a single tree lobster, but on their way down they discovered a little bush of the type eaten by the insect wedged into a crevice in the rock face. Below it lay some large droppings, which looked fresh. Hard as they searched, not a single living stick was to be seen.
So there was only one thing left to do: repeat the climbing expedition at night—because the world’s largest stick insect is known to be nocturnal. Equipped with headlamps and cameras, the climbers experienced something akin to a waking dream. Unbelievably, there in the middle of what was pretty much the sole bush on the entire stack sat twenty-four huge black stick insects staring at them.
Nobody knows how the insects made their way from Lord Howe Island to the sea stack some time before the extinction in 1920. If you can’t fly or swim, a 12-mile trip across the open sea is quite a challenge. The most likely explanation is that eggs or a pregnant female hitched a ride with a bird or on floating vegetation and then the stick insects managed to survive for at least eighty years on the inhospitable sea stack, which is almost bare of vegetation.
We will draw a veil of silence over the bureaucracy that ensued. After two years of paper shuffling, permission was finally obtained for two males and two females to be fetched from the sea stack to form the start of a breeding program. Two of them (christened Adam and Eve, of course) survived, and healthy stocks of stick insects can now be found in several zoos, including in Europe.
But then the question arose of returning the rest of them to Lord Howe Island, where the species actually belonged—because a sea stack with a single bush at the mercy of rock falls is hardly fit to be a permanent home for a viable population of stick insects living in the wild. But on Lord Howe, the black rats still prevail. Unless they are wiped out, there’s no point reintroducing the stick insects. And they aren’t the only animals that would be glad to see the rats killed off: thirteen bird species and two reptile species face extinction unless the rats are eliminated. So the authorities now plan to do away with the rats once and for all. This will require extreme measures: 42 metric tons of poisoned cereal will be scattered over the island from a helicopter.
Of course, the process won’t be entirely straightforward. First of all, animals other than the rats may die from eating the grain—including the birds people are trying to rescue. So the idea is to trap the most vulnerable bird species and keep them in a kind of temporary Noah’s Ark, then release them again after the poison rain. But what consequences will this have for the genetic diversity of the birds, for example—because it won’t be possible to capture all the individuals, will it?
And then some people are worried. There are only 350 human inhabitants on the island, but not all of them are keen on being showered with poisoned breakfast cereal, even though the authorities have assured them that no poison will be scattered near houses. Some probably also think that the big black stick insects are repulsive and no more deserving of protection than the black rats. Conservation biology is just as much about us humans and our thoughts and feelings as about the species we are trying to conserve.
In many ways nature is robust, and it is adapting all the time. New species emerge where we humans create new opportunities, such as deep below the ground in London, where the rough, damp tunnels of the Tube are home to a highly unusual mosquito. It belongs to the Culex pipiens species, the most common type of bloodsucking mosquito found in urban areas, but it has developed into a special genetic form (called molestus—“the troublesome one”), which is no longer capable of producing offspring with its mosquito relatives up in the light of day. What probably happened is that a couple of female mosquitoes found their way down into the depths at some point many years ago, perhaps when the Tube was being built in 1863. Since then, the London Underground mosquito has lived its own life down there, over thousands of mosquito generations.
The mosquito became notorious during the Second World War, when it was a source of great irritation to people seeking shelter in the Underground system during the Blitz. Today, hygienic standards are far better than in those days, and although roe deer, foxes, bats, woodpeckers, sparrow hawks, tortoises, and great crested newts have all been spotted in the tunnels, rats and mice are the main species that keep the few London Underground mosquitoes company.
Genetic analyses have shown that the mosquitoes’ DNA varies among lines and stations: the Piccadilly Line mosquito is different from the Central Line mosquito—although not different enough to prevent the different Underground mosquito varieties from mating with one another. The leading theory is therefore that all of them are descendants of the same bold forebears from 150 years ago.
If it is true that the mosquito has developed into a new genetic form in just 150 years, it is an example of how evolution can work quickly now and then—as when populations are living in total isolation. Charles Darwin theorized that new species needed tens of thousands, if not hundreds of thousands, of generations to come into being. It is odd to think that while he sat pondering this in his house on the outskirts of London—he had just published Origin of the Species in 1859—a process of lighting-fast evolution might have been starting right beneath his feet.
We will probably see more such examples of new and rapid species formation in the future as a result of our intentional and unintentional displacement of species. The North American fly Rhagoletis pomonella used to live contentedly on hawthorn trees until apples came to the United States from Europe. Now the fly has two different genetic forms: one that eats only hawthorn berries and another that eats only apples. In just a couple of hundred years, one species is well on its way to becoming two. Even the parasite that lives on this fly is in the process of splitting into two species, one for the hawthorn-eating and one for the apple-eating larvae.
When new insects appear and others die out, the effect will depend on which species change—because, as I have shown in this book, different insects perform different tasks in nature. What’s more, every insect is connected to other species through ingeniously adapted interactions, and this is the basis of all the goods and services nature offers us.
We humans have long taken the free services of insects for granted. Through intensive land use, climate change, insecticides, and the introduction of invasive species, we now risk altering conditions so quickly that insects will have difficulty delivering as they have done to date, despite nature’s adaptability. On egotistical grounds alone, we should therefore be concerned about the health and well-being of these little creatures. Taking care of them is a form of life insurance for our children and grandchildren.
If we could just stop navel gazing for a second, we would see that this is about more than mere utility value. As far as we know, our planet is the only place in the universe where there is life. Many would say that we humans have a moral duty to rein in our dominance of the earth and give our millions of fellow creatures a chance to live out their tiny, wonderful lives, too.