|Photo by Tibor Nagy 2014|
This little guy in the upper lefthand corner is a Pisaurina mira nursery web spider. As you know, spiders prey on insects for their food and grasshoppers are part of that diet. Given their choice of various plants for food, grasshoppers will preferentially feed on some plants more than others. These researchers found that grasshoppers prefer to eat grasses, but when these nursery web spiders are present, they will switch to another field and change their diet to other plants like Goldenrods. The Goldenrod often dominate an area where they grow, but in the presence of invading hungry grasshoppers who start munching on these plants, they chew holes and open up their monoculture canopy, which allows other plants an opportunity to thrive there as well. So apparently spiders do play an important role in the biodiversity of many plant ecosystems. An article on this was published by the In Defense of Plants journal below.
"How Spiders Increase Plant Diversity"
|Image - InDefenseofPlants.com|
"It's the shift in diet itself that has ramifications throughout the entire ecosystem in question. Many goldenrod species are highly competitive when left to their own devices. If left untouched, abandoned fields can quickly become a monoculture of goldenrod. That is where the spiders come in. By causing a behavioral shift in their grasshopper prey, the spiders are having indirect effects on plant diversity in these habitats. Because grasshoppers spend more time feeding on goldenrods in the presence of spiders, they knock back some of the competitive advantages of these plants.
The researchers found that when spiders were present, overall plant diversity increased. This is not because the spiders ate more grasshoppers. Instead, it's because the grasshoppers shifted to a diet of goldenrod, which knocked the goldenrod back just enough to allow other plants to establish. It's not just plant diversity that changed either. Spiders also caused an increase in both solar radiation and nitrogen reaching the soils!
In knocking back the goldenrod, the habitat became slightly more open and patchy as various plant species of different shapes and sizes gradually established. This allowed more light to reach the soil, thus changing the environment for new seeds to germinate. Also, because goldenrod leaves tend to break down more slowly, they can have significant influences on nutrient cycles within the soil. As a more diverse set of plants establish in these field habitats, the type of leaf litter that falls to the ground changes as well. This resulted in an overall increase in the nitrogen supply to the soil, which also influences plant diversity.
In total, the mere presence of spiders was enough to set in motion these top-down ecosystem effects. It's not that spiders eat more grasshoppers, it's that they are changing the behavior of grasshoppers in a way that results in a more diverse plant community overall. This is a radically different narrative than what has been observed with examples such as the reintroduction of wolves to the greater Yellowstone ecosystem yet the conclusions are very much the same. Predators have innumerable ecosystem benefits that we simply can't afford to ignore."
Great News for Biodiversity right ? 😍 Well not so fast! 😬Three days later after I read that wonderful article from the folks at "In Defense of Plants," who wrote about how these fascinating insect mechanism interactions which set off change reactions of events which leads to healthier biodiversity within plant community ecosystems, "Science Magazine," then comes out three days later with an article I had seen elsewhere about insect numbers disappearing. Now pay close attention, this was not about extinction, but population numbers dropping dramatically. This is something I've seriously wondered about with regards not only insects, but many lifeforms and even touched on this very subject once before in this post here where I noticed insect disappearances in my mother's yard where we do not used ANY harsh chemical pesticdes of any kind, including synthetic fertilizers. One outstanding strange thing that is now obvious is the total absence of the native red harvester ants in her backyard which is a third of an acre. Since I can remember as a kid since 1961, we always had 15 or 20 red harvester ant colonies for which my folks always tried to spray and eradicate with never any success. Prior to leaving the USA and moving here to Sweden in May 2006, there were only two actual colonies that I knew of. It caught my attention then and I went around and counted. Now there are none. There are also none across the street where there has always been a very wide dirt strip. Even up on Rattlesnake mountain at the end of the street I found none, only black harvester ants. But I also notived that the sow or pill bugs were very limited and even earwigs were gone. Again, we never spray with the synthetics:
There are also other loss of living lifeforms I've wondered about over the last few years like mycorrhizal fungi. Many would think the microbiological world is safely tucked away in a hidden darkness and in numbers so incomprehensible that it would make it impossible for the microbiome to be harmed. Really ??? I also wrote another piece about the disappearance of a certain specific mycorrhizal fungi truffles I use to collect in and around Anza California where I use to live. For two decades every Spring & Summer (after the first arrival of monsonnal thunderstorms) I would collect mature truffles for their spores to inoculate plants I grew on my acreage and restoration projects I involved myself with locally. Suddenly in 2001 I could no longer find them. I had also previously begun to notice pine and oak trees dying off in the same location before the fungi truffle disappearance. Now large numbers of those pines are gone except for a few and the oaks that still remain are sickly or dead, even Scrub Oaks. So I wrote about that experience as well:
The article below is a bit more spooky. This has happened over time, but so slowly that most people "take no note." Wow, where have we heard that before ? This scenario reminds me of the story about the frog put in a pan of water where a low fire is slowly heating up the water. By the time the frog realizes what has happened it's too late. His goose is cooked. That's about where we are now and that is what the researchers are finding in the article below. It's not so much lack of biodiversity or extinction, but a huge loss of bioabundance.
|PAUL VAN HOOF/MINDEN PICTURES|
|JEF MEUL/NIS/MINDEN Pictures/National Geographic Creative|
Where Have All the Insects Gone ?
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 other sites.
Many 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.)
The mass of insects collected by monitoring traps in the Orbroicher Bruch nature reserve in northwest Germany dropped by 78% in 24 years.
|(GRAPHIC) G. GRULLÓN/SCIENCE; (DATA) M. SORG ET AL., |
MITTEILUNGEN AUS DEM ENTOMOLOGISCHEN VEREIN KREFELD
1, 1–5 (2013) © 2013 ENTOMOLOGISCHER VEREIN KREFELD
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."
A Weather Station for Biodiversity
Researchers in Germany hope to develop a set of automated sensors that will monitor the abundance and diversity of plants, animals, and fungi with the help of pattern recognition and DNA and chemical analysis.
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."
|© ENTOMOLOGISCHER VEREIN KREFELD|
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."
Update May 20, 2017: Sithsoniaan Tropical Research Institute
|Credit: Chung Yun Tak|
|Credit: Saskya Van Nouhuys|
Predators are Real Lowlifes
Insects drove the trend, not mammals or birds. “As someone who has studied insect biodiversity in the tropics for most of my life, I wasn’t surprised that insects were responsible for most of the predation observed,” said Yves Basset, leader of the ForestGEO Arthropod Initiative at STRI.
The team put out almost 3,000 model caterpillars for four to 18 days at 31 different sites from Australia to Greenland at different altitudes, from zero to 2,100 meters above sea level. Based on characteristic marks left by predators in the clay, they could tell whether the models were attacked by birds, mammals or insects.This should be a wake up call, but most likely it will generally fall on deaf ears. Mere handfulls of interested ones will click "Like" on some Enviro-Facebook page, but mostly it will go unnoticed. The average human being hates bugs and buys into the industrial science marketing of "An only good Bug is a dead Bug." Think back on those RAID commercials. Synthetic Pesticides are incapable of differienting between and good and bad insect. Most don't care. They want bugs gone. Seriously, walk down any Home Depot, Lowes, Hornbach, Bau Haus or other local hardware store and the only viable healthy garden solution they offer is a science-based synthetic toxic option. No instruction or education of ever building a biodiverse system in your garden thru biomimicry. There was a reference to E.O. Wilson at the end of the article. These days everyone seems to want to worship the ground that E.O. Wilson walks on as something hallowed. The 80+ E.O. Wilson, is a Harvard professor of evolutionary biology who made his celebrity claim to fame back in the 1970s with his study of social species in two books, The Insect Societies and Sociobiology. He is internationally acknowledged as "the father of sociobiology" and is the world's leading authority on ants. Hence I can understand why Gretchen Vogel who wrote the article referenced him in the last paragraph where she quotes him as saying "we must pay attention to the little things that run the world." Sure enough in his book, Diversity of Life, E.O. Wilson stated:
“Most life on land depends ultimately on one relationship: the mycorrhiza, the intimate and mutually dependent coexistence of fungi and the roots systems of plants.”His point of course was that the importance of these beneficial fungi should not be underestimated. So okay, he has some good points on why our understanding of Nature's micro-world should be better. I totally agree. But then at other times he does an about face and turns right around and out of the other corner of his mouth tells the world that Industrial Agriculture's Biotech World is the only thing that can save Nature. In 2011 in an interview in "EarthSky Journal," E.O. Wilson said:
"And within science, this is going to be a century of biology. We are entering an age of synthesis. So many discoveries have been made in biology in the cell, at the molecular level, and on up to the development of organisms."
Clearly the very thing Wilson here is advocating is the very thing that is killing biodiversity and bioabundance. E.O. Wilson like Bill Nye will never admit that because supporting biotech world is paramont in keeping hold of their science celebrity darling icon status. Bill Nye was once opposed to GMOs, but then one day Monsanto showed him the light. More than likely he was ushered into a back room and explained the facts of life by the good'ol boys club about what he should do to keep that status quo as a celebrity icon if he knew what was healthy for him. Both Wilson and Nye are also staunch advocates of the "Agrument from Poor Design" religious dogma. I use the term religious here because there is nothing scientific about it. It's done more harm to the natural world and held back real world sustainable eco-green technological innovation more than anything else. Both men are also part of the new secular attitude espoused earlier by Edward Abbey who believed mankind is worthless and desperately needs culling if not outright removal. Although both men do not see either of themselves as part of that problem. Nobody questions these science celebrity icons and they should. Unfortunately, E.O. Wilson's and Bill Nye’s intolerant worldview seems to be rubbing off and infecting many of today's Gen-X and Millennials (think of turmoil & uncertainty) which might explain some of the insane chaos which is a common component of today's world.
"And we need all the biology and all the advances we can find in agriculture, especially. We’re going to have to switch worldwide to dry land agriculture. We don’t have enough water in enough countries to feed all those people and to restore soil to arable condition. So this means that we have to have genetically modified organisms. I’d take that as a given. Some people don’t like the idea. But that’s one of those necessities brought about by the human condition."
Well, getting back to insects and the two artcles. A couple years ago Germany (one of the biggest users of palm oil) expressed self-righteous indignation towards Indonesia for cutting down their country's rainforests and replacing them with palm oil plantations. The Indonesian leader also fired back exposing Germany for destroying 70% of Germany's original forests. Sure enough that is true. What forests that do exist have become industrial forestry plantations, with only those few scattered nature reserves which we spoke of earlier. This is also true of most of industrial Europe including Sweden. This may well account for the drop in not only insects, but also other wildlife. So blame cannot be put squarely on the shoulders of industrial science, but also these science celebrity icons whom they go to bed with figuratively speaking to promote their technology. For all the public shouting and fingerpointing these celebrities do at the average human being for not being eco-green, they themseves are the blind leading the blind. These icons need to be exposed for what they really are. As for the average person, follow the lead recommended by the first article from the "In Defense of Plants" people. Learn how nature works and biomimic that in your own landscape or garden. As far as the bigger picture, this world's leadership (irrespecitive of the ideological worldview) needs to be completely eradicated soon. If that doesn't happen, then nothing will be saved.
Now relax to eleven minutes of Insects and Birds in a Field on a Summer Day (Natural sound meditation)