‘Hyperalarming’ study shows massive insect loss

The Washington Post reports:

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.” [Continue reading…]

Nanotubular highways between cells act as conduits for transferring all kinds of cargo

Viviane Callier writes:

When the physician and scientist Emil Lou was an oncology fellow at Memorial Sloan Kettering Cancer Center about a decade ago, he was regularly troubled by the sight of something small but unidentifiable in his cancer-cell cultures. Looking through the microscope, he said, he “kept finding these long, thin translucent lines,” about 50 nanometers wide and 150 to 200 microns long, extending between cells in the culture. He called on the world-class cell biologists in his building to explain these observations, but nobody was sure what they were looking at. Finally, after delving into the literature, Lou realized that the lines matched what Hans-Hermann Gerdes’ group at the University of Heidelberg had described as “nanotubular highways” or “tunneling nanotubes” (TNTs) in a 2004 paper in Science.

Lou worried that the lines he’d noticed might be illusory, so he checked the archive of tumor specimens from patients at the cancer center. Lo and behold, the same long cellular processes were present in the tumors, too, so he set out to investigate their relevance. Since then, as a faculty member at the University of Minnesota, he’s found evidence that tumor cells use these TNTs to share molecular messages in the form of short regulatory snippets of RNA called microRNA, enabling cancer cells resistant to chemotherapy drugs to confer the same resistance on their neighbors.

How did the tunneling nanotubes go unnoticed for such a long time? Lou notes that in the last couple of decades, cancer research has centered primarily on detecting and therapeutically targeting mutations in cancer cells — and not the structures between them. “It’s right in front of our face, but if that’s not what people are focusing on, they’re going to miss it,” he said.

That’s changing now. In the last few years, the number of researchers working on TNTs and figuring out what they do has risen steeply. Research teams have discovered that TNTs transfer all kinds of cargo beyond microRNAs, including messenger RNAs, proteins, viruses and even whole organelles, such as lysosomes and mitochondria. [Continue reading…]

The hidden intelligence of plants

Rachel Ehrenberg writes:

More than 200 years ago, French botanist René Desfontaines instructed a student to monitor the behavior of Mimosa pudica plants as he drove them around Paris in a carriage. Mimosa pudica quickly closes its leaves when touched — presumably as a defense mechanism. Desfontaines was interested in the plants’ response to the continuous vibrations of the ride. Initially, the leaves closed, but after a time, they reopened, despite the shaking. “The plants are getting used to it,” the student wrote in his notebook.

Stefano Mancuso recounts this tale in The Revolutionary Genius of Plants and reports on a modern follow-up: a repeat of the experiment (without the carriage) demonstrating that plants can indeed learn that an external provocation is harmless and remember what they’ve learned for weeks.

Learning is impossible without memory, and both are hallmarks of intelligence, argues Mancuso, who leads the International Laboratory of Plant Neurobiology at the University of Florence in Italy. But our animal-centric view of neuroscience makes us loathe to employ terms like “memory” and “intelligence” when talking about organisms without a brain. With infectious passion, Mancuso sets out to convince us that the plant way of doing things not only deserves our respect, but also may help us solve greater societal woes. [Continue reading…]

Scientists fear that insects upon which humans depend are declining

The Associated Press reports:

A staple of summer — swarms of bugs — seems to be a thing of the past. And that’s got scientists worried.

Pesky mosquitoes, disease-carrying ticks, crop-munching aphids and cockroaches are doing just fine. But the more beneficial flying insects of summer — native bees, moths, butterflies, ladybugs, lovebugs, mayflies and fireflies — appear to be less abundant.

Scientists think something is amiss, but they can’t be certain: In the past, they didn’t systematically count the population of flying insects, so they can’t make a proper comparison to today. Nevertheless, they’re pretty sure across the globe there are fewer insects that are crucial to as much as 80 percent of what we eat.

Yes, some insects are pests. But they also pollinate plants, are a key link in the food chain and help decompose life.

“You have total ecosystem collapse if you lose your insects. How much worse can it get than that?” said University of Delaware entomologist Doug Tallamy. If they disappeared, “the world would start to rot.”

He noted Harvard biologist E.O. Wilson once called bugs: “The little things that run the world.” [Continue reading…]

A good place to start raising awareness about the importance of insects for humanity would be to stop calling them “bugs” — and likewise stop calling the soil in which so many of them live, “dirt.”

Octopuses on ecstasy reveal genetic link to evolution of social behaviors in humans

Johns Hopkins University School of Medicine:

By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or “ecstasy,” scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.

A summary of the experiments is published Sept. 20 in Current Biology, and if the findings are validated, the researchers say, they may open opportunities for accurately studying the impact of psychiatric drug therapies in many animals distantly related to people.

“The brains of octopuses are more similar to those of snails than humans, but our studies add to evidence that they can exhibit some of the same behaviors that we can,” says Gül Dölen, M.D., Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments. “What our studies suggest is that certain brain chemicals, or neurotransmitters, that send signals between neurons required for these social behaviors are evolutionarily conserved.”

Octopuses, says Dölen, are well-known to be clever creatures. They can trick prey to come into their clutches, and Dölen says there is some evidence they also learn by observation and have episodic memory. The gelatinous invertebrates (animals without backbones) are further notorious for escaping from their tank, eating other animals’ food, eluding caretakers and sneaking around.

But most octopuses are asocial animals and avoid others, including other octopuses. But because of some of their behaviors, Dölen still thought there may be a link between the genetics that guide social behavior in them and humans. One place to look was in the genomics that guide neurotransmitters, the signals that neurons pass between each other to communicate. [Continue reading…]

The first animal genus defined purely by genetic characters represents a new era for classifying animals

Charlie Wood writes:

The world’s simplest known animal is so poorly understood that it doesn’t even have a common name. Formally called Trichoplax adhaerens for the way it adheres to glassware, the amorphous blob isn’t much to look at. At just a few millimeters across, the creature resembles a squashed sandwich in which the top layer protects, the bottom layer crawls, and the slimy stuffing sticks it all together. With no organs and just a handful of cell types, the most interesting thing about T. adhaerens might just be how stunningly boring it is.

“I was fascinated when I first heard about this thing because it has no real defined body,” said Michael Eitel, an evolutionary biologist at the Ludwig Maximilian University in Germany. “There’s no mouth, there’s no back, no nerve cells, nothing.”

But after spending four years painstakingly reconstructing the blob’s genome, Eitel might know more about the organism than anyone else on the planet. In particular, he has looked closely enough at its genetic code to learn what visual inspections failed to reveal. The variety of creature that biologists have long called T. adhaerens is really at least two, and perhaps as many as a dozen, anatomically identical but genetically distinct “cryptic species” of animals. The discovery sets a precedent for taxonomy, the science of naming organisms, as the first time a new animal genus has been defined not by appearance, but by pure genetics.

The modern taxonomic system, little changed since Carl Linnaeus laid it out in the 1750s, attempts to chop the sprawling tree of life into seven tidy levels that grant every species a unique label. The two-part scientific name (such as Homo sapiens) represents the tail end of a branching path through this tree, starting from the thickest limbs, the kingdoms, and ending at the finest twigs, the genus (Homo) and then the species (sapiens). The path tells you everything there is to know about the organism’s relationship to other groups of creatures, at least in theory. [Continue reading…]

Seeking human generosity’s origins in an ape’s gift to another ape

Carl Zimmer writes:

How generous is an ape? It’s a hard question for scientists to tackle, but the answer could tell us a lot about ourselves.

People in every culture can be generous, whether they’re loaning a cellphone to an office mate or sharing an antelope haunch with a hungry family.

While it’s easy to dwell on our capacity for war and violence, scientists see our generosity as a remarkable feature of our species. “One of the things that stands out about humans is how helpful we are,” said Christopher Krupenye, a primate behavior researcher at the University of St. Andrews in Scotland.

This generosity may have been crucial to the survival of our early ancestors who lived in small bands of hunter-gatherers.

“When our own attempts to find food are unsuccessful, we rely on others to share food with us — otherwise we starve,” said Jan Engelmann, a researcher at Göttingen University.

To understand the origin of this impulse — known as prosociality — a number of researchers have turned to our closest living relatives. [Continue reading…]

Time-restricted eating can overcome the bad effects of faulty genes and unhealthy diet

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By Satchin Panda, University of California San Diego

Timing our meals can fend off diseases caused by bad genes or bad diet. Everything in our body is programmed to run on a 24-hour or circadian time table that repeats every day. Nearly a dozen different genes work together to produce this 24-hour circadian cycle. These clocks are present in all of our organs, tissues and even in every cell. These internal clocks tell us when to sleep, eat, be physically active and fight diseases. As long as this internal timing system work well and we obey them, we stay healthy.

But what happens when our clocks are broken or begin to malfunction?

Mice that lack critical clock genes are clueless about when to do their daily tasks; they eat randomly during day and night and succumb to obesity, metabolic disease, chronic inflammation and many more diseases.

Even in humans, genetic studies point to several gene mutations that compromise our circadian clocks and make us prone to an array of diseases from obesity to cancer. When these faulty clock genes are combined with an unhealthy diet, the risks and severity of these diseases skyrocket.

My lab studies how circadian clocks work and how they readjust when we fly from one time zone to another or when we switch between day and night shift. We knew that the first meal of the day synchronizes our circadian clock to our daily routine. So, we wanted to learn more about timing of meals and the implications for health.

[Read more…]

The microbiologist who fundamentally changed the way we think about evolution and the origins of life

David Quammen writes:

On Nov. 3, 1977, a new scientific revolution was heralded to the world — but it came cryptically, in slightly confused form. The front page of that day’s New York Times carried a headline: “Scientists Discover a Form of Life That Predates Higher Organisms.” A photograph showed a man named Carl R. Woese, a microbiologist at the University of Illinois in Urbana, with his feet up on his office desk. He was 50ish, with unruly hair, wearing a sport shirt and Adidas sneakers. Behind him was a blackboard, on which was scrawled a simple treelike figure in chalk. The article, by a veteran Times reporter named Richard D. Lyons, began:

Scientists studying the evolution of primitive organisms reported today the existence of a separate form of life that is hard to find in nature. They described it as a “third kingdom” of living material, composed of ancestral cells that abhor oxygen, digest carbon dioxide and produce methane.

This “separate form of life” would become known as the archaea, reflecting the impression that these organisms were primitive, primordial, especially old. They were single-celled creatures, simple in structure, with no cell nucleus. Through a microscope, they looked like bacteria, and they had been mistaken for bacteria by all earlier microbiologists. They lived in extreme environments, at least some of them — hot springs, salty lakes, sewage — and some had unusual metabolic habits, such as metabolizing without oxygen and, as the Times account said, producing methane.

But these archaea, these whatevers, were drastically unlike bacteria if you looked at their DNA, which is what (indirectly) Woese had done. They lacked certain bits that characterized all bacteria, and they contained other bits that shouldn’t have been present. They constituted a “third kingdom” of living creatures because they fit within neither of the existing two, the bacterial kingdom (bacteria) and the kingdom of everything else (eukarya), including animals and plants, amoebas and fungi, you and me.

Charles Darwin himself suggested (first in an early notebook, later in “On the Origin of Species”) that the history of life could be drawn as a tree — all creatures originating in a single trunk, then diverging into different lineages like major limbs, branches and twigs, with leaves of the canopy representing the multiplicity of living species. But if that simile was valid, then the prevailing tree of 1977, the orthodox image of life’s history, was wrong. It showed two major limbs arising from the trunk. According to what Woese had just announced to the world, it ought to show three.

Woese was a rebel researcher, obscure but ingenious, crotchety, driven. He had his Warholian 15 minutes of fame on the front page of The Times, and then disappeared back into his lab in Urbana, scarcely touched by popular limelight throughout the remaining 35 years of his career. But he is the most important biologist of the 20th century that you’ve never heard of. He asked profound questions that few other scientists had asked. He created a method — clumsy and dangerous, but effective — for answering those questions. And in the process, he effectively founded a new branch of science.

It began with a casual suggestion made to Woese by Francis Crick, the co-discoverer of DNA’s structure, who mentioned passingly in a scientific paper that certain long molecules in living creatures, because they are built of multiple small units, coded in sequences that change gradually over time, could serve as signatures of the relatedness between one form of life and another. The more similar the sequence, the closer the relative. In other words, comparing such molecules could reveal phylogeny. The new branch of science is called molecular phylogenetics. Wrinkle your nose at that fancy phrase, if you will, and I’ll wrinkle with you, but in fact what it means is fairly simple: reading the ancient history of life from the different sequences built into such molecules. The molecules mainly in question were DNA, RNA and a few select proteins. Carried far beyond Woese and his lab, these efforts have brought unexpected and unimaginable discoveries, fundamentally reshaping what we think we know about life’s history, the process of evolution and the functional parts of living beings, including ourselves.

Woese vanished into his lab, but his insights and methods, and his successors in applying them, have produced in particular one cardinal revelation: The tree of life is not a tree. That old metaphor is obsolete. Life’s history has been far more tangled. [Continue reading…]

The nastiest feud in science

Bianca Bosker writes:

While the majority of her peers embraced the Chicxulub asteroid as the cause of the [dinosaurs’] extinction, [Gerta] Keller [a 73-year-old paleontology and geology professor at Princeton] remained a maligned and, until recently, lonely voice contesting it. She argues that the mass extinction was caused not by a wrong-place-wrong-time asteroid collision but by a series of colossal volcanic eruptions in a part of western India known as the Deccan Traps—a theory that was first proposed in 1978 and then abandoned by all but a small number of scientists. Her research, undertaken with specialists around the world and featured in leading scientific journals, has forced other scientists to take a second look at their data. “Gerta uncovered many things through the years that just don’t sit with the nice, simple impact story that Alvarez put together,” Andrew Kerr, a geochemist at Cardiff University, told me. “She’s made people think about a previously near-uniformly accepted model.”

Keller’s resistance has put her at the core of one of the most rancorous and longest-running controversies in science. “It’s like the Thirty Years’ War,” says Kirk Johnson, the director of the Smithsonian’s National Museum of Natural History. Impacters’ case-closed confidence belies decades of vicious infighting, with the two sides trading accusations of slander, sabotage, threats, discrimination, spurious data, and attempts to torpedo careers. “I’ve never come across anything that’s been so acrimonious,” Kerr says. “I’m almost speechless because of it.” Keller keeps a running list of insults that other scientists have hurled at her, either behind her back or to her face. She says she’s been called a “bitch” and “the most dangerous woman in the world,” who “should be stoned and burned at the stake.”

Understanding the cause of the mass extinction is not an esoteric academic endeavor. Dinosaurs are what paleontologists call “charismatic megafauna”: sexy, sympathetic beasts whose obliteration transfixes pretty much anyone with a pulse. The nature of their downfall, after 135 million years of good living, might offer clues for how we can prevent, or at least delay, our own end. “Without meaning to sound pessimistic,” the geophysicist Vincent Courtillot writes in his book Evolutionary Catastrophes, “I believe the ancient catastrophes whose traces geologists are now exhuming are worthy of our attention, not just for the sake of our culture or our understanding of the zigzaggy path that led to the emergence of our own species, but quite practically to understand how to keep from becoming extinct ourselves.” [Continue reading…]