Pages tagged "Pollinators"
‘Hyperalarming’ study shows massive insect loss
Insects around the world are in a crisis, according to a small but growing number of long-term studies showing dramatic declines in invertebrate populations. A new report suggests that the problem is more widespread than scientists realized. Huge numbers of bugs have been lost in a pristine national forest in Puerto Rico, the study found, and the forest’s insect-eating animals have gone missing, too.
In 2014, an international team of biologists estimated that, in the past 35 years, the abundance of invertebrates such as beetles and bees had decreased by 45 percent. In places where long-term insect data are available, mainly in Europe, insect numbers are plummeting. A study last year showed a 76 percent decrease in flying insects in the past few decades in German nature preserves.
The latest report, published Monday in the Proceedings of the National Academy of Sciences, shows that this startling loss of insect abundance extends to the Americas. The study’s authors implicate climate change in the loss of tropical invertebrates.
“This study in PNAS is a real wake-up call — a clarion call — that the phenomenon could be much, much bigger, and across many more ecosystems,” said David Wagner, an expert in invertebrate conservation at the University of Connecticut who was not involved with this research. He added: “This is one of the most disturbing articles I have ever read.”
Bradford Lister, a biologist at Rensselaer Polytechnic Institute in New York, has been studying rain forest insects in Puerto Rico since the 1970s. If Puerto Rico is the island of enchantment — “la isla del encanto” — then its rain forest is “the enchanted forest on the enchanted isle,” he said. Birds and coqui frogs trill beneath a 50-foot-tall emerald canopy. The forest, named El Yunque, is well-protected. Spanish King Alfonso XII claimed the jungle as a 19th-century royal preserve. Decades later, Theodore Roosevelt made it a national reserve, and El Yunque remains the only tropical rain forest in the National Forest system.
“We went down in ’76, ’77 expressly to measure the resources: the insects and the insectivores in the rain forest, the birds, the frogs, the lizards,” Lister said.
He came back nearly 40 years later, with his colleague Andrés García, an ecologist at the National Autonomous University of Mexico. What the scientists did not see on their return troubled them. “Boy, it was immediately obvious when we went into that forest,” Lister said. Fewer birds flitted overhead. The butterflies, once abundant, had all but vanished.
García and Lister once again measured the forest’s insects and other invertebrates, a group called arthropods that includes spiders and centipedes. The researchers trapped arthropods on the ground in plates covered in a sticky glue, and raised several more plates about three feet into the canopy. The researchers also swept nets over the brush hundreds of times, collecting the critters that crawled through the vegetation.
Each technique revealed the biomass (the dry weight of all the captured invertebrates) had significantly decreased from 1976 to the present day. The sweep sample biomass decreased to a fourth or an eighth of what it had been. Between January 1977 and January 2013, the catch rate in the sticky ground traps fell 60-fold.
“Everything is dropping,” Lister said. The most common invertebrates in the rain forest — the moths, the butterflies, the grasshoppers, the spiders and others — are all far less abundant.
Photo from Pixabay.
Glyphosate harms honeybees, research finds
The world’s most used weedkiller damages the beneficial bacteria in the guts of honeybees and makes them more prone to deadly infections, new research has found.
Previous studies have shown that pesticides such as neonicotinoids cause harm to bees, whose pollination is vital to about three-quarters of all food crops. Glyphosate, manufactured by Monsanto, targets an enzyme only found in plants and bacteria.
However, the new study shows that glyphosate damages the microbiota that honeybees need to grow and to fight off pathogens. The findings show glyphosate, the most used agricultural chemical ever, may be contributing to the global decline in bees, along with the loss of habitat.
“We demonstrated that the abundances of dominant gut microbiota species are decreased in bees exposed to glyphosate at concentrations documented in the environment,” said Erick Motta and colleagues from University of Texas at Austin in their new paper. They found that young worker bees exposed to glyphosate exposure died more often when later exposed to a common bacterium.
Other research, from China and published in July, showed that honeybee larvae grew more slowly and died more often when exposed to glyphosate. An earlier study, in 2015, showed the exposure of adult bees to the herbicide at levels found in fields “impairs the cognitive capacities needed for a successful return to the hive”.
“The biggest impact of glyphosate on bees is the destruction of the wildflowers on which they depend,” said Matt Sharlow, at conservation group Buglife. “Evidence to date suggests direct toxicity to bees is fairly low, however the new study clearly demonstrates that pesticide use can have significant unintended consequences.”
Prof Dave Goulson, at the University of Sussex, said: “It now seems that we have to add glyphosate to the list of problems that bees face. This study is also further evidence that the landscape-scale application of large quantities of pesticides has negative consequences that are often hard to predict.”
Photo from Pexels.
UK Supports Ban on Neonicotinoids
The UK will back a total ban on insect-harming pesticides in fields across Europe, the environment secretary, Michael Gove, has revealed.
The decision reverses the government’s previous position and is justified by recent new evidence showing neonicotinoids have contaminated the whole landscape and cause damage to colonies of bees. It also follows the revelation that 75% of all flying insects have disappeared in Germany and probably much further afield, a discovery Gove said had shocked him.
Neonicotinoids are the world’s most widely used insecticide but in 2013 the European Union banned their use on flowering crops, although the UK was among the nations opposing the ban. The European commission now wants a total ban on their use outside of greenhouses, with a vote expected in December, and the UK’s new position makes it very likely to pass.
“The weight of evidence now shows the risks neonicotinoids pose to our environment, particularly to the bees and other pollinators which play such a key part in our £100bn food industry, is greater than previously understood,” said Gove. “I believe this justifies further restrictions on their use. We cannot afford to put our pollinator populations at risk.”
Rep. Earl Blumenauer (D-Ore.) wants to include a ban on pesticides linked to declining bee health in next year’s farm bill
Rep. Earl Blumenauer (D-Ore.) wants to include a ban on pesticides linked to declining bee health in next year’s farm bill, one of several initiatives he is pushing in the legislation to reauthorize agriculture and nutrition programs.
Thirty-one Democrats are backing a bill—the Saving America’s Pollinators Act of 2017 ( H.R. 3040)—that would suspend the approval of neonicotinoid pesticides, common insect-killers that are said to harm honeybees, aquatic insects, birds, and other insects and animals. H.R. 3040 would ban imidacloprid, clothianidin, thiamethoxam, dinotefuran, and any other neonicotinoids until the Environmental Protection Agency can determine that the pesticides won’t harm pollinators, based on peer-reviewed studies.
Blumenauer, one of the bill’s sponsors, told Bloomberg BNA he hopes the bill “will be folded into part of a larger initiative” like the next farm bill. Blumenauer is set to release a report next week outlining several measures to support small farmers, local food systems, and sustainability.
Where have all the insects gone?
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 other sites.
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.