3589. Where Have All the Insects Gone?

By Elizabeth Kolber, The New Yorker, October 25, 2021

In the summer of 1942, Ed Wilson, age thirteen, decided that it was time to get serious about research. He had already determined that he wanted to be an entomologist, a choice made partly out of interest and partly out of injury. As a child, he’d been fascinated with marine life. One day, he jerked too hard on a fish he caught, and one of its needlelike spines lodged in his right eye. The lens had to be removed, and, following the surgery, to see something clearly he needed to hold it up near his face. Insects were just about the only animals that submitted to this treatment.

That summer, Wilson was living with his parents in Mobile, Alabama, in a run-down house that had been built by his great-grandfather. He resolved to survey every species of ant that lived in an overgrown lot next door. This proved to be quick work, as there were only four species. But one of them turned out to be, as Wilson put it nearly eighty years later, “the find of a lifetime—or at least of a boyhood.” It was a species that Wilson had never seen before; nor, it seems, had anyone else north of Brazil.

That species is now known formally as Solenopsis invicta and informally as the red imported fire ant. Native to South America, the creature has, from a human perspective, many undesirable characteristics. Its sting produces first a burning sensation—hence the name—and then a smallpox-like pustule. It has a voracious appetite and will consume anything from tree bark to termites to the seeds of crops like wheat and sorghum. Red imported fire ants have been known to kill fledgling birds, young sea turtles, and even, on occasion, baby deer. They construct rigid mounds that damage harvesting equipment. When a colony is disturbed, hundreds, even thousands of ants are dispatched, more or less instantaneously, to attack the intruder. Wilson once stuck his arm into one of these mounds and described the pain as “immediate and unbearable.” As he observed to his companions, “It was as though I had poured kerosene on my hand and lit it.”

Red imported fire ants were, almost certainly, introduced into the United States in cargo unloaded at the port of Mobile. When Wilson conducted his survey of the vacant lot, they had probably been in the city for several years but hadn’t ventured very far. This soon changed. The ants began to spread in a classic bull’s-eye pattern. In 1949, while Wilson was an undergraduate at the University of Alabama, he was hired by the state’s Department of Conservation to conduct a study of Solenopsis invicta. Since no one knew much about the species, the teen-age enthusiast counted as an expert. Wilson found that the ants had already pushed west into Mississippi and east into Florida. He was, he later recalled, “exhilarated” by his first professional gig, which gave him the self-confidence to pursue his insect-driven dreams.

By 1953, the red imported fire ant had spread as far north as Tennessee and as far west as Texas, and the so-called Fire Ant Wars had begun. In an early skirmish, the state of Mississippi provided farmers with chlordane, an indiscriminate, organochlorine pesticide long since banned. It made little difference. Next, the U.S. Department of Agriculture embarked on a campaign to spray heptachlor and dieldrin—two similar insecticides that are also now banned—over millions of acres of farmland. The campaign killed countless wild birds, along with vast numbers of fish, cows, cats, and dogs. The ants kept marching on. (“The research basis of this plan was minimal, to put it mildly,” Walter R. Tschinkel, an entomologist at Florida State University, has observed.) Undaunted, the U.S.D.A. launched itself into a new battle, this time claiming that it was going to eliminate the ants entirely, using Mirex, yet another since-banned organochlorine. In the late nineteen-sixties, more than fourteen million acres were sprayed with Mirex, which is a potent endocrine disrupter. The effort appears to have had the perverse effect of helping Solenopsis invicta spread, by exterminating any native ants that might have stood in its way.

As the U.S.D.A. was raining down destruction, Wilson’s career was taking off. He received a Ph.D. from Harvard and was offered a position on the university’s biology faculty. The job was supposed to be temporary, but by the time he was twenty-nine he had been granted tenure.

Wilson thought of himself as a naturalist in the venerable tradition of Joseph Banks, the English botanist who sailed with Captain Cook in 1768. Wilson loved to explore places no entomologist had surveyed before, and once spent ten months collecting ants from New Caledonia to Sri Lanka. But he was fated to follow a different path. Wilson became a professional biologist just as it was becoming clear that the biosphere was unravelling. Though he resisted the knowledge at first, later he would become perhaps the most important chronicler of this crisis—the nation’s first great post-naturalist.

Wilson is now ninety-two and lives in a retirement community in Lexington, Massachusetts. He’s the subject of a new biography, “Scientist: E. O. Wilson: A Life in Nature” (Doubleday), by the journalist Richard Rhodes. Rhodes, who’s the author of more than twenty books, including “The Making of the Atomic Bomb,” interviewed his subject several times before covid hit and they had to switch to the phone. During one of Rhodes’s visits, he ran into an old friend, Victor McElheny, a journalist who lives in the same retirement community and, as it happened, had written a biography of Wilson’s nemesis, James Watson. “Small world,” Rhodes observes.

Wilson’s dispute with Watson was an academic turf battle and, at the same time, something more than that. In 1953, Watson and his collaborator Francis Crick discovered the structure of DNA—the famous double helix. Three years later, Watson joined Harvard’s biology department. Though he was only twenty-eight when he arrived, he treated the two dozen other members of the department with an offhand contempt. Specimen collecting, he suggested, was for hobbyists. Henceforth, real scientists would study life by examining its molecular structure. The brilliance of Watson’s discovery, combined with his sublime self-assurance, intimidated many of his older colleagues. Wilson, who’d been hired at Harvard the same year, has described Watson as “the Caligula of biology.” When, owing to an offer from Stanford, Wilson received tenure ahead of Watson, the latter stomped through the halls of the Biological Laboratories declaiming, according to some sources, “Shit, shit, shit, shit!,” and to others, “Fuck, fuck, fuck, fuck!” Eventually, the differences between the traditionalists and the molecularists were judged insurmountable, and, in an intellectual version of speciation, Harvard’s biology department split in two.

Wilson continued to collect ants. He spent a sabbatical conducting field work on Trinidad and Tobago and in Suriname. But he was, by his own description, fiercely ambitious, and he yearned to make a bigger contribution to science—a contribution more like Watson’s. One of the obstacles, he decided, was math; he had never even taken an upper-level course in the subject. At the age of thirty-two, he enrolled in calculus and sat awkwardly in the lecture room with some of the same undergraduates he was teaching.

Around this time, Wilson began collaborating with a Princeton professor named Robert MacArthur, who possessed all the mathematical skills he lacked. In 1967, the two published “The Theory of Island Biogeography.” The book was an effort to explain how island ecosystems come into being, a puzzle that had fascinated both Charles Darwin and his rival, Alfred Russel Wallace. It combined field observations with a tangle of equations to account for why larger islands harbor more species than smaller ones, and also why distant islands host fewer species than similar-sized islands situated near a mainland. Wilson and MacArthur proposed that the keys to understanding island biogeography are the rate at which new species immigrate to an island (or evolve there) and the rate at which established species wink out. “There’s nothing more romantic than biogeography,” Wilson once told the author David Quammen.

Though Wilson and MacArthur boldly labelled their work on island biogeography the theory, it was still just a theory. Wilson, the field biologist, was eager to test it on the ground. The difficulty lay in finding the right islands; for a rigorous experiment, these would have to be empty. Wilson hit on the idea of using clumps of mangrove north of Key West. The cays were so small—about forty feet in diameter—that the only breeding animals on them were insects, spiders, and, occasionally, wood lice. Wilson persuaded the National Park Service to let him fumigate six of them. Then one of his graduate students, Daniel Simberloff, who’s now a professor at the University of Tennessee, spent a year monitoring the “defaunated” cays. It was painstaking, mud-splattered work, but, at least as far as Wilson was concerned, it paid off. Those cays closest to the shore were quickly recolonized. Species diversity rose, and then levelled off, just as Wilson and MacArthur’s theory had predicted. On the sixth, more distant islet, recolonization took longer, and the eventual number of resident species was lower—more confirmation. Though some of the details of “The Theory of Island Biogeography” have since been discarded, it’s still considered a classic. A paper that appeared on the occasion of its fiftieth anniversary noted that it remains one of the world’s “most influential texts on ecology and evolution.”

As many of Wilson’s colleagues soon realized, the significance of the theory extended well beyond actual islands. Through logging and mining and generalized sprawl, the world was increasingly being cut up into “islands” of habitat. The smaller and more isolated these islands, be they patches of forest or tundra or grassland, the fewer species they would ultimately contain. Wilson had moved on to new research questions, and initially didn’t concern himself much with the implications of his own work. When the first surveys of deforestation in the Amazon appeared, though, he was, in his words, “tipped into active engagement.” In an article in Scientific American, in 1989, he combined data on deforestation with the predictions of his and MacArthur’s theory to estimate that as many as six thousand species a year were being consigned to oblivion. “That in turn is on the order of 10,000 times greater than the naturally occurring background extinction rate that existed prior to the appearance of human beings,” he wrote.

The same year that Wilson published his article in Scientific American, a group of insect fanciers installed what are known as malaise traps in several nature reserves in Germany. Malaise traps look like tents that have blown over on their sides, and they’re designed to capture virtually anything that flies into them. The group, the Krefeld Entomological Society, was interested in how insects were faring in different types of parks and protected areas. Every summer from then on, society members set out new traps, usually in different preserves. In 2013, they resampled some of the sites they’d originally sampled back in 1989. The contents of the traps were a fraction of what they’d been the first time around.

Over the next three summers, the group members resampled more sites. The results were similar. In 2017, with the help of some outside experts, they published a paper documenting a seventy-five-per-cent decline in “total flying insect biomass” in the areas surveyed. These areas were exactly the sort of habitat fragments that, according to Wilson’s theory, were destined to lose species. Nevertheless, the findings were shocking. In 2019, a second group of researchers published a more rigorous and extensive study, and its findings were even more dire. In the course of just the previous decade, grasslands in Germany had, on average, lost a third of their arthropod species and two-thirds of their arthropod biomass. (Terrestrial arthropods include spiders and centipedes in addition to insects.) In woodlands, the number of arthropod species had dropped by more than a third, and biomass by forty per cent. “This is frightening” is how one of the paper’s authors, Wolfgang Weisser, a biologist at the Technical University of Munich, put it.

In the years since, many more papers have appeared with comparable findings. Significant drops have been found in mayfly populations in the American Midwest, butterfly numbers in the Sierra Nevadas, and caterpillar diversity in northern Costa Rica. While many species appear to be doing just fine—for instance, the spotted lanternfly, an invasive species from Asia, which was first detected in Pennsylvania around 2014, and has since spread to at least ten other states, including New York—there is, as was noted in the introduction to a recent special issue of the Proceedings of the National Academy of Sciences devoted to the state of the insect world, “ample cause for concern.”

Dave Goulson, an entomologist at the University of Sussex, is one of the experts the Krefeld group contacted to help make sense of its data. Like Wilson, Goulson could be described as a naturalist turned post-naturalist; he decided to study insects because he found them enthralling, and now he studies why they’re in trouble.

“I have watched clouds of birdwing butterflies sipping minerals from the muddy banks of a river in Borneo, and thousands of fireflies flashing their luminous bottoms in synchrony at night in the swamps of Thailand,” he writes in “Silent Earth: Averting the Insect Apocalypse” (Vintage). “I have had enormous fun. But I have been haunted by the knowledge that these creatures are in decline.”

Goulson bemoans the fact that many people consider insects to be pests. He wants readers to appreciate just how amazing they really are, and sets off his chapters with profiles of six-legged creatures. Males of many species of earwigs have two penises; if disturbed during mating, they snap off the one they’re using and beat a quick escape. Female jewel wasps sting their prey—large cockroaches—to induce a zombielike trance. Then they chew off the tips of the roaches’ antennae, use the stumps to guide the stupefied creatures back to their burrows, and lay their eggs inside them. Aging termites of the species Neocapritermes taracua develop pouches around their abdomens that are filled with copper-rich proteins. If an intruder is gaining the upper hand—or leg—in a fight, the elderly termites, in effect, blow themselves up to protect the colony, a practice known as suicidal altruism. The proteins react with chemicals stored in their salivary glands to become highly toxic compounds.

Insects are, of course, also vital. They’re by far the largest class of animals on Earth, with roughly a million named species and probably four times that many awaiting identification. (Robert May, an Australian scientist who helped develop the field of theoretical ecology, once noted, “To a first approximation, all species are insects.”) They support most terrestrial food chains, serve as the planet’s chief pollinators, and act as crucial decomposers. Goulson quotes Wilson’s observation: “If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed 10,000 years ago. If insects were to vanish, the environment would collapse into chaos.”

Like insects themselves, the threats to them are numerous and diverse. First, there’s habitat loss. Since Wilson’s article in Scientific American appeared, in 1989, South America has lost at least another three hundred million acres of tropical forest, and Southeast Asia has experienced similar losses. In places like the U.S. and Britain, which were deforested generations ago, the hedgerows and weedy patches that once provided refuge for insects are disappearing, owing to ever more intense agricultural practices. From an insect’s perspective, Goulson points out, even fertilizer use constitutes a form of habitat destruction. Fertilizer leaching out of fields fosters the growth of certain plants over others, and it’s these others that many insects depend on.

Climate change, light pollution, and introduced species present further dangers. The Varroa destructor mite evolved to live on (and consume the body fat of) Asian honeybees, which are smaller than their European counterparts. When European honeybees were imported to East Asia, the mites jumped hosts, and when European bees were taken to new places the mites hitched a ride. Varroa mites carry diseases like deformed-wing virus, and they’ve had a devastating effect on European honeybees, probably causing the loss of hundreds of thousands of colonies. In the U.S. (and in many other countries), European honeybees are treated as tiny livestock. They’re carted around to pollinate crops like apples and almonds, and their health is carefully monitored. But what’s been the impact of imported parasites and pathogens on other bees, not to mention ants, beetles, crickets, dragonflies, moths, thrips, and wasps? “For 99.9 per cent of insect species, we know simply nothing,” Goulson laments.

Then, there are pesticides. Since the Fire Ant Wars, which were prominently featured in Rachel Carson’s “Silent Spring,” a great many have been taken off the market. New ones, however, have replaced them. Goulson is particularly concerned about a class of chemicals known as neonicotinoids. Neonics, as they’re often called, are, in some respects, even more toxic than Mirex and chlordane. They were first marketed in the nineteen-nineties; by 2010, more than three million pounds a year were being applied to crops in the U.S., and almost two hundred thousand pounds to crops in Great Britain. Neonics are water-soluble, which means they can leak into soils and ponds and potentially be taken up by other plants. There’s a good deal of controversy over the dangers they pose to non-target insects, especially bees; in 2018, the European Union found the evidence of harm compelling enough to ban three key neonics from outdoor use. (The chemicals continue to be applied in many European countries under “emergency authorizations.”) Meanwhile, in the rest of the world, including the U.S., their use continues apace. “Carson may have won a battle, but not the war,” Goulson observes.

In the last chapter of “Silent Earth,” Goulson offers dozens of actions we can take to “change our relationship with the small creatures that live all around us.” Some involve tending one’s own garden—for instance, trying “to reimagine ‘weeds’ such as dandelion as ‘wildflowers.’ ” Others are regional or national in scope: “plant streets and parks with flowering, native trees” or “introduce pesticide and fertilizer taxes.” The list is long enough that nearly everyone who wants to can find some recommendation to follow, but it’s heavily tilted toward reducing the use of pesticides, which, as “Silent Earth” makes clear, is just one of the many hazards insects are facing.

Wilson, who’s been called the “father of biodiversity,” has a bigger idea. In “Half-Earth: Our Planet’s Fight for Life” (2016), he argues that the only way to preserve the world’s insects—and, for that matter, everything else—is to set aside fifty per cent of it in “inviolable reserves.” He arrived at the figure, he explains, using the principles of island biogeography; on fifty per cent of the globe, he calculates, roughly eighty-five per cent of the planet’s species could be saved. The task of preserving—or, in many places, restoring—half the world’s habitat is, he acknowledges, daunting. The alternative, though, is to grow dandelions while the world burns: “The only hope for the species still living is a human effort commensurate with the magnitude of the problem.” ♦

3379. America's Agriculture is 48 Times More Toxic Than 25 YearsAgo Due to Neonics Use

By Kendra Klein and Anna Lappé, The Guardian, August 7, 2019

More than 50 years ago, Rachel Carson warned of a “silent spring”, the songs of robins and wood thrush silenced by toxic pesticides such as DDT. Today, there is a new pesticide specter: a class of insecticides called neonicotinoids. For years, scientists have been raising the alarm about these bug killers, but a new study reveals a more complete picture of the threat they pose to insect life.

First commercialized in the 1990s, neonicotinoids, or neonics for short, are now the most widely used insecticides in the world. They’re used on over 140 crops, from apples and almonds to spinach and rice. Chemically similar to nicotine, they kill insects by attacking their nerve cells.

Neonics were pitched as an answer to pests’ increasing resistance to the reigning insecticides. But in an effort to more effectively kill pests, we created an explosion in the toxicity of agriculture not just for unwanted bugs but for the honeybees, ladybugs, beetles and the vast abundance of other insects that sustain life on Earth.

What we now know is that neonics are not only considerably more toxic to insects than other insecticides, they are far more persistent in the environment. While others break down within hours or days, neonics can remain in soils, plants and waterways for months to years, killing insects long after they’re applied and creating a compounding toxic burden.

The new study, published in the science journal PLOS ONE and co-authored by one of us, designed a way to quantify this persistence and combine it with data on the toxicity and total pounds used of neonics and other insecticides. For the first time, we have a time-lapse of impact: we can compare year-to-year changes in the toxicity of US agriculture for insects. The results? Since neonics were first introduced 25 years ago, US agriculture has become 48 times more toxic to insect life, and neonics are responsible for 92% of that surge in toxicity.

Looking at this toxic time-lapse, another interesting detail emerges: there’s a dramatic increase in the toxic burden of US agriculture for insects starting in the mid-2000s. That’s when beekeepers began reporting significant losses of their hives. It’s also when the pesticide companies that manufacture neonics, Bayer and Syngenta, found a lucrative new use for these chemicals: coating the seeds of crops like corn and soy that are grown on millions of acres across the country. These seed coatings now account for the vast majority of neonic use in the US.

Neonics are “systemic”, meaning they are water soluble and therefore taken up by the plant itself, making its nectar, pollen, and fruit – all of it – toxic. Only about 5% of a seed coating is absorbed by the plant, the remainder stays in the soil and can end up in rivers, lakes and drinking water with its runoff causing harm to wildlife and, as emerging evidence shows, to people.

This study comes on the heels of the first analysis of global insect populations, which found 40% of species face extinction, with near total insect loss possible by century’s end, driven in part by pesticides, with neonics a particular concern.

For all of this harm, farmers get few, if any, benefits from neonic seed coatings. According to the US Environmental Protection Agency, they provide “little or no overall benefits to soybean production”, though nearly half of soybean seeds in the US are treated. Similar analyses have found the same for corn, yet up to 100% of US corn seeds are treated.

All this risk without reward has led some regulators to take action. The European Union voted to ban the worst neonics in 2018. But the US government has so far failed to act. Chemical company lobbying can explain much of this inaction. Bayer, maker of the most widely used neonics, spent an estimated $4.3m lobbying in the US on behalf of its agricultural division in 2017.

Not only has the EPA stalled scientific review of neonics, last year, the Fish and Wildlife Service reversed an Obama-era ban on use of these dangerous insecticides in wildlife refuges. Congress could change this. Democratic representative Earl Blumenauer’s Saving America’s Pollinators Act would ban neonicotinoids and other systemic, pollinator-toxic insecticides. The bill has 56 co-sponsors, but faces a major hurdle clearing the House agriculture committee given that the chairman representative, Collin Peterson, a Democrat from Minnesota, counts Bayer and the pesticide industry’s trade association, Croplife America, among his top contributors.

Beyond a ban, we need a concerted effort to transition US agriculture away from dependence on pesticides and toward ecological methods of pest control. We already know how to do this. Research shows that organic farms support up to 50% more pollinating species and help other beneficial insects flourish. And by eliminating neonics and some 900 other active pesticide ingredients, they protect human health, too.

More than five decades ago, Rachel Carson warned that the war we are waging against nature with toxic pesticides is inevitably a war against ourselves. That is as true today as it was then. For the sake of the birds and bees – and all of us – this war must end.

• Kendra Klein, PhD, is senior staff scientist at Friends of the Earth US
• Anna Lappé is the co-founder of two national food and sustainability organizations and is working on a book on pesticides and our food

2859. Insect Decimation Upstages Global Warming

By Robert Hunziker, Counterpunch, March 27, 2018

Everybody’s heard about global warming. It is one of the most advertised existential events of all time. Who isn’t aware? However, there’s a new kid on the block. An alarming loss of insects will likely take down humanity before global warming hits maximum velocity.

For the immediate future, the Paris Accord is riding the wrong horse, as global warming is a long-term project compared to the insect catastrophe happening right now! Where else is found 40% to 90% species devastation?

The worldwide loss of insects is simply staggering with some reports of 75% up to 90%, happening much faster than the paleoclimate record rate of the past five major extinction events. It is possible that some insect species may already be close to total extinction!

It’s established that species evolve and then go extinct over thousands and millions of years as part of nature’s course, but the current rate of devastation is simply “off the charts, and downright scary.”

Without any doubt, it is difficult to imagine how humanity survives without insects, which are dropping dead in bunches right before our eyes. For proof, how many insect splats do people clean off windshields nowadays? Not many…. How many fireflies do children chase at night? Not many….

Several naturalists and environmental writers believe the massive loss of insects has everything to do with three generations of industrialized farming and the vast tide of poisons pouring over the landscape year-after-year, especially since the end of WWII. Ours is the first-ever pesticide-based agricultural society. Dreadfully, it’s an experiment that is going dead wrong… all of a sudden!

Insects are basic to thousands of food chains; for example, the disappearance of Britain’s farmland birds by over 50% in 40 years. Additionally, North America and Europe species of birds like larks, swallows, and swifts that feast on flying insects have plummeted.
But, these are only a few of many, many recorded examples of massive numbers of wildlife dropping dead right before our eyes.

Significantly, insects are the primary source for ecosystem creation and support. The world literally crumbles apart without mischievous burrowing, forming new soil, aerating soil, pollinating food crops, etc. Nutrition for humans happens because insects pollinate.

One of the world’s best and oldest entomological resources is Krefeld Entomological Society (est. 1905) tracking insect abundance at more than 100 nature reserves. They first noticed a significant drop off of insects in 2013 when the total mass of catch fell by 80%. Again, in 2014 the numbers were just as low. Subsequently, the society discovered huge declines in several observation sites throughout Western Europe.

For example, Krefeld data for hoverflies, a pollinator often mistaken for a bee, registered 17,291 hoverflies from 143 species trapped in a reserve in 1989. Whereas by 2014 at the same location, 2,737 individuals from 104 species, down 84%. (Source: Gretchen Vogel, Where Have All The Insects Gone? Science Magazine, May 10, 2017)

Down Under in Australia anecdotal evidence similarly shows an unusual falloff of insect populations. For example, Jack Hasenpusch, an entomologist and owner of the Australian Insect Farm collects swarms of wild insects but now says: “I’ve been wondering for the last few years why some of the insects have been dropping off … This year has really taken the cake with the lack of insects, it’s left me dumbfounded, I can’t figure out what’s going on.” (Source: Mark Rigby, Insect Population Decline Leaves Australian Scientists Scratching For Solutions, ABC Far North, Feb. 23, 2018)

Concerned, Mr. Hasenpusch talked to entomologists in Sydney, Brisbane, Perth, New Caledonia, and Italy. All of them related similar experiences.

According to entomologist Dr. Cameron Webb / University of Sydney, researchers around the world widely acknowledge the problem of insect decline but are at a loss to explain the causes.

Obviously, something dreadful is suddenly happening throughout the entire biosphere. The insect catastrophe is a relatively new phenomenon that has caught society unaware, blindsided. Interestingly, 97% of the Animal Kingdom consists of invertebrates such as insects, crabs, lobsters, clams, octopuses, jellyfish, and worms, etc.

Scientists have been noticing the problem for some time now, but widespread public knowledge is simply not there. Jürgen Deckert, insect custodian at the Berlin Natural History Museum is worried that “there’s a risk we will only really take notice once it is too late.” (Source: Christian Schwägerl, What’s Causing the Sharp Decline in Insects, and Why It Matters, YaleEnvironment360, July 6, 2012)

The Senckenberg Entomological Institute/Frankfurt recorded a 40% decline in butterfly and Burnet moth species over a period of decades.

A Stanford University global index developed by Rodlfo Dirzo showed a 45% decline for invertebrates over four decades. Of 3,623 terrestrial invertebrate species on the International Union for Conservation of Nature Red List, 42% are classified as threatened with extinction.

The Zoological Society of London in 2012 published a major survey concluding that many insect populations are in severe decline. And in both the U.S. and Europe researchers have recorded 40% declines in bee populations because of colony collapse disorder and sharp losses of monarch butterflies.

“Of particular concern is the widespread use of pesticides and their impact on non-target species. Many conservationists view a special class of pesticides called neonicotinoids — used over many years in Europe until a partial ban in 2013 — as the prime suspect for insect losses… “There are many indications that what we see is the result of a widespread poisoning of our landscape,” says Leif Miller, director general of the German chapter of Bird Life International,” Ibid.

Widespread poisoning of ecosystems is the norm in modern day society. “Ours is a poisoned planet, … This explosion in chemical use and release has all happened so rapidly that most people are blissfully unaware of its true magnitude and extent, or of the dangers it now poses to us all as well as to future generations for centuries to come.” (Source: Julian Cribb, Surviving the 21st Century, Springer Nature, Switzerland, 2017, page 104)

“Most people are blissfully unaware” may be a blessing in disguise as the angst, dread, and uneasiness that knowledge of this horrendous crisis brings is the root cause of severe bouts of sleeplessness along with difficult spells of deep depression.

2728. Where Have All the Insects Gone?

By Gretchen Vogel, Science Magazine, May 10, 2017

Entomologists call it the windshield phenomenon. "If you talk to people, they have a gut feeling. They remember how insects used to smash on your windscreen," says Wolfgang Wägele, director of the Leibniz Institute for Animal Biodiversity in Bonn, Germany. Today, drivers spend less time scraping and scrubbing. "I'm a very data-driven person," says Scott Black, executive director of the Xerces Society for Invertebrate Conservation in Portland, Oregon. "But it is a visceral reaction when you realize you don't see that mess anymore."

Some people argue that cars today are more aerodynamic and therefore less deadly to insects. But Black says his pride and joy as a teenager in Nebraska was his 1969 Ford Mustang Mach 1—with some pretty sleek lines. "I used to have to wash my car all the time. It was always covered with insects." Lately, Martin Sorg, an entomologist here, has seen the opposite: "I drive a Land Rover, with the aerodynamics of a refrigerator, and these days it stays clean."

Though observations about splattered bugs aren't scientific, few reliable data exist on the fate of important insect species. Scientists have tracked alarming declines in domesticated honey bees, monarch butterflies, and lightning bugs. But few have paid attention to the moths, hover flies, beetles, and countless other insects that buzz and flitter through the warm months. "We have a pretty good track record of ignoring most noncharismatic species," which most insects are, says Joe Nocera, an ecologist at the University of New Brunswick in Canada.

Of the scant records that do exist, many come from amateur naturalists, whether butterfly collectors or bird watchers. Now, a new set of long-term data is coming to light, this time from a dedicated group of mostly amateur entomologists who have tracked insect abundance at more than 100 nature reserves in western Europe since the 1980s.

Over that time the group, the Krefeld Entomological Society, has seen the yearly insect catches fluctuate, as expected. But in 2013 they spotted something alarming. When they returned to one of their earliest trapping sites from 1989, the total mass of their catch had fallen by nearly 80%. Perhaps it was a particularly bad year, they thought, so they set up the traps again in 2014. The numbers were just as low. Through more direct comparisons, the group—which had preserved thousands of samples over 3 decades—found dramatic declines across more than a dozen.

Such losses reverberate up the food chain. "If you're an insect-eating bird living in that area, four-fifths of your food is gone in the last quarter-century, which is staggering," says Dave Goulson, an ecologist at the University of Sussex in the United Kingdom, who is working with the Krefeld group to analyze and publish some of the data. "One almost hopes that it's not representative—that it's some strange artifact."

No one knows how broadly representative the data are of trends elsewhere. But the specificity of the observations offers a unique window into the state of some of the planet's less appreciated species. Germany's "Red List" of endangered insects doesn't look alarming at first glance, says Sorg, who curates the Krefeld society's extensive collection of insect specimens. Few species are listed as extinct because they are still found in one or two sites. But that obscures the fact that many have disappeared from large areas where they were once common. Across Germany, only three bumble bee species have vanished, but the Krefeld region has lost more than half the two dozen bumble bee species that society members documented early in the 20th century.

Members of the Krefeld society have been observing, recording, and collecting insects from the region—and around the world—since 1905. Some of the roughly 50 members—including teachers, telecommunication technicians, and a book publisher—have become world experts on their favorite insects. Siegfried Cymorek, for instance, who was active in the society from the 1950s through the 1980s, never completed high school. He was drafted into the army as a teenager, and after the war he worked in the wood-protection division at a local chemical plant. But because of his extensive knowledge of wood-boring beetles, the Swiss Federal Institute of Technology in Zurich awarded him an honorary doctorate in 1979. Over the years, members have written more than 2000 publications on insect taxonomy, ecology, and behavior.

The society's headquarters is a former school in the center of Krefeld, an industrial town on the banks of the Rhine that was once famous for producing silk. Disused classrooms store more than a million insect specimens individually pinned and named in display cases. Most were collected nearby, but some come from more exotic locales. Among them are those from the collection of a local priest, an active member in the 1940s and 1950s, who persuaded colleagues at mission stations around the world to send him specimens. (The society's collection and archive are under historical preservation protection.)

Weighty disappearances

The mass of insects collected by monitoring traps in the Orbroicher Bruch nature reserve in northwest Germany dropped by 78% in 24 years.

Tens of millions more insects float in carefully labeled bottles of alcohol—the yield from the society's monitoring projects in nature reserves around the region. The reserves, set aside for their local ecological value, are not pristine wilderness but "seminatural" habitats, such as former hay meadows, full of wildflowers, birds, small mammals—and insects. Some even include parts of agricultural fields, which farmers are free to farm with conventional methods. Heinz Schwan, a retired chemist and longtime society member who has weighed thousands of trap samples, says the society began collecting long-term records of insect abundance partly by chance. In the late 1970s and early 1980s, local authorities asked the group for help evaluating how different strategies for managing the reserves affected insect populations and diversity.

The members monitored each site only once every few years, but they set up identical insect traps in the same place each time to ensure clean comparisons. Because commercially available traps vary in ways that affect the catch, the group makes their own. Named for the Swedish entomologist René Malaise, who developed the basic design in the 1930s, each trap resembles a floating tent. Black mesh fabric forms the base, topped by a tent of white fabric and, at the summit, a collection container—a plastic jar with an opening into another jar of alcohol. Insects trapped in the fabric fly up to the jar, where the vapors gradually inebriate them and they fall into the alcohol. The traps collect mainly species that fly a meter or so above the ground. For people who worry that the traps themselves might deplete insect populations, Sorg notes that each trap catches just a few grams per day—equivalent to the daily diet of a shrew.

Sorg says society members saved all the samples because even in the 1980s they recognized that each represented a snapshot of potentially intriguing insect populations. "We found it fascinating—despite the fact that in 1982 the term ‘biodiversity' barely existed," he says. Many samples have not yet been sorted and cataloged—a painstaking labor of love done with tweezers and a microscope. Nor have the group's full findings been published. But some of the data are emerging piecemeal in talks by society members and at a hearing at the German Bundestag, the national parliament, and they are unsettling.

Beyond the striking drop in overall insect biomass, the data point to losses in overlooked groups for which almost no one has kept records. In the Krefeld data, hover flies—important pollinators often mistaken for bees—show a particularly steep decline. In 1989, the group's traps in one reserve collected 17,291 hover flies from 143 species. In 2014, at the same locations, they found only 2737 individuals from 104 species.

Since their initial findings in 2013, the group has installed more traps each year. Working with researchers at several universities, society members are looking for correlations with weather, changes in vegetation, and other factors. No simple cause has yet emerged. Even in reserves where plant diversity and abundance have improved, Sorg says, "the insect numbers still plunged."

Changes in land use surrounding the reserves are probably playing a role. "We've lost huge amounts of habitat, which has certainly contributed to all these declines," Goulson says. "If we turn all the seminatural habitats to wheat and cornfields, then there will be virtually no life in those fields." As fields expand and hedgerows disappear, the isolated islands of habitat left can support fewer species. Increased fertilizer on remaining grazing lands favors grasses over the diverse wildflowers that many insects prefer. And when development replaces countryside, streets and buildings generate light pollution that leads nocturnal insects astray and interrupts their mating.

Neonicotinoid pesticides, already implicated in the widespread crash of bee populations, are another prime suspect. Introduced in the 1980s, they are now the world's most popular insecticides, initially viewed as relatively benign because they are often applied directly to seeds rather than sprayed. But because they are water soluble, they don't stay put in the fields where they are used. Goulson and his colleagues reported in 2015 that nectar and pollen from wildflowers next to treated fields can have higher concentrations of neonicotinoids than the crop plants. Although initial safety studies showed that allowable levels of the compounds didn't kill honey bees directly, they do affect the insects' abilities to navigate and communicate, according to later research. Researchers found similar effects in wild solitary bees and bumble bees.

Less is known about how those chemicals affect other insects, but new studies of parasitoid wasps suggest those effects could be significant. Those solitary wasps play multiple roles in ecosystems—as pollinators, predators of other insects, and prey for larger animals. A team from the University of Regensburg in Germany reported in Scientific Reports in February that exposing the wasp Nasonia vitripennis to just 1 nanogram of one common neonicotinoid cut mating rates by more than half and decreased females' ability to find hosts. "It's as if the [exposed] insect is dead" from a population point of view because it can't produce offspring, says Lars Krogmann, an entomologist at the Stuttgart Natural History Museum in Germany.

No one can prove that the pesticides are to blame for the decline, however. "There is no data on insecticide levels, especially in nature reserves," Sorg says. The group has tried to find out what kinds of pesticides are used in fields near the reserves, but that has proved difficult, he says. "We simply don't know what the drivers are" in the Krefeld data, Goulson says. "It's not an experiment. It's an observation of this massive decline. The data themselves are strong. Understanding it and knowing what to do about it is difficult.”

The factors causing trouble for the hover flies, moths, and bumble bees in Germany are probably at work elsewhere, if clean windshields are any indication. Since 1968, scientists at Rothamsted Research, an agricultural research center in Harpenden, U.K., have operated a system of suction traps—12-meter-long suction tubes pointing skyward. Set up in fields to monitor agricultural pests, the traps capture all manner of insects that happen to fly over them; they are "effectively upside-down Hoovers running 24/7, continually sampling the air for migrating insects," says James Bell, who heads the Rothamsted Insect Survey.

Between 1970 and 2002, the biomass caught in the traps in southern England did not decline significantly. Catches in southern Scotland, however, declined by more than two-thirds during the same period. Bell notes that overall numbers in Scotland were much higher at the start of the study. "It might be that much of the [insect] abundance in southern England had already been lost" by 1970, he says, after the dramatic postwar changes in agriculture and land use.

The stable catches in southern England are in part due to constant levels of pests such as aphids, which can thrive when their insect predators are removed. Such species can take advantage of a variety of environments, move large distances, and reproduce multiple times per year. Some can even benefit from pesticides because they reproduce quickly enough to develop resistance, whereas their predators decline. "So lots of insects will do great, but the insects that we love may not," Black says.

Other, more visible creatures may be feeling the effects of the insect losses. Across North America and Europe, species of birds that eat flying insects, such as larks, swallows, and swifts, are in steep decline. Habitat loss certainly plays a role, Nocera says, "but the obvious factor that ties them all together is their diet."

Some intriguing, although indirect, clues come from a rare ecological treasure: decades' worth of stratified bird droppings. Nocera and his colleagues have been probing disused chimneys across Canada in which chimney swifts have built their nests for generations. From the droppings, he and his colleagues can reconstruct the diets of the birds, which eat almost exclusively insects caught on the wing.

The layers revealed a striking change in the birds' diets in the 1940s, around the time DDT was introduced. The proportion of beetle remains dropped off, suggesting the birds were eating smaller insects—and getting fewer calories per catch. The proportion of beetle parts increased slightly again after DDT was banned in the 1970s but never reached its earlier levels. The lack of direct data on insect populations is frustrating, Nocera says. "It's all correlative. We know that insect populations could have changed to create the population decline we have now. But we don't have the data, and we never will, because we can't go back in time."

Sorg and Wägele agree. "We deeply regret that we did not set up more traps 20 or 30 years ago," Sorg says. He and other Krefeld society members are now working with Wägele's group to develop what they wish they had had earlier: a system of automated monitoring stations they hope will combine audio recordings, camera traps, pollen and spore filters, and automated insect traps into a "biodiversity weather station". Instead of tedious manual analysis, they hope to use automated sequencing and genetic barcoding to analyze the insect samples. Such data could help pinpoint what is causing the decline—and where efforts to reverse it might work best.

Paying attention to what E. O. Wilson calls "the little things that run the world" is worthwhile, Sorg says. "We won't exterminate all insects. That's nonsense. Vertebrates would die out first. But we can cause massive damage to biodiversity—damage that harms us."