Light-colored butterflies and dragonflies thriving as European climate warms

Butterflies and dragonflies with lighter colours are out-competing darker-coloured insects in the face of climate change.

In a new study published in Nature Communications, scientists from Imperial College London, Philipps-University Marburg and University of Copenhagen have shown that as the climate warms across Europe, communities of butterflies and dragonflies consist of more lighter coloured species. Darker coloured species are retreating northwards to cooler areas, but lighter coloured species are also moving their geographical range north as Europe gets warmer.

For example, several Mediterranean dragonfly species have expanded their northern range and immigrated to Germany, such as the Southern Migrant Hawker (Aeshna affinis), the Scarlet Darter (Crocothemis erythraea) and the Dainty Damselfly (Coenagrion scitulum). In 2010, the Dainty Damselfly was also sighted in England for the first time in over 50 years. Butterfly species that thrive in warm climates, like the Southern Small White (Pieris mannii), have dispersed to Germany during the last ten years and are still continuing their northward shift.

As with lizards and snakes, the colour of an insect's body plays a key role in how they absorb energy from the sun, and is crucial in fuelling their flight as well as regulating their body temperature.

Dark-coloured insects are able to absorb more sunlight than light-coloured insects, in order to increase their body temperature, and are more likely to be found in cooler climates. In contrast, insects in hotter climates need to protect themselves against overheating. Light-coloured insects are more likely to be found in hotter climates as they can reflect the light to prevent overheating their body and be active for longer periods of time.

Carsten Rahbek, from the Department of Life Sciences at Imperial College London said: "For two of the major groups of insects, we have now demonstrated a direct link between climate and insect colour, which impact their geographical distribution."

"We now know that lighter-coloured butterflies and dragonflies are doing better in a warmer world, and we have also demonstrated that the effects of climate change on where species live are not something of the future, but that nature and its ecosystems are changing as we speak," concluded Professor Rahbek, who is also Director of the Center for Macroecology, Evolution and Climate at the University of Copenhagen. To identify whether colour lightness was correlated to temperature, the scientists combined digital image analysis, which scanned and measured colour values of butterfly and dragonfly wings and bodies, with distributional data which mapped where in Europe the species are found.

They looked at 366 butterfly species and 107 dragonfly species across Europe, and showed a clear pattern of light-coloured insects dominating the warmer south of Europe and darker insects dominating the cooler north.

To test whether a warming climate had caused any shifts, they looked at changes in species distributions over an 18-year period from 1988-2006. Results showed that on average insects were becoming lighter in colour, and that darker-coloured insects were shifting towards the cooler areas in Western margins of Europe, the Alps and the Balkans.

Read more at Science Daily

Biologists Find New Rules for Life at the Edge of Chaos

Detail from a computationally-modeled critical genetic network.

In the space between order and chaos, a zone usually described with the mathematics of impending avalanches and crystallizing liquids, scientists are finding new rules for life.

They’re researching the dynamics of criticality, where one system transforms rapidly into another. Scientists have studied such behavior in physical systems for decades; some have theorized that it might be found in living systems too, perhaps underlying some of biology’s fundamental and largely unexplained phenomena: how a few interacting genes shape an organism’s development, and how networked neurons give rise to complex cognitive functions.

Such speculation has been intriguing, but also difficult to study. Only now, with the advent of exquisitely sensitive biological probes and high-powered data analysis, have experiments started catching up to theory.

“In the past, there has been a lot of discussion about the potential benefits of biological systems poised at criticality,” said theoretical biophysicist Dmitry Krotov of Princeton University, co-author of a Feb. 10 Proceedings of the National Academy of Sciences paper on criticality in genetic networks. “Now high-quality experimental data are appearing, and we are able to quantitatively test these ideas.”

In the new study, Krotov and co-author William Bialek, also a biophysicist at Princeton, measured protein-coding activity in a genetic network crucial to the development of fruit fly embryos. Expressed in mathematical terms, the activity contained the signatures — relationships between gene activity, patterns of correlation at far-flung locations in embryos — characteristic of criticality.

The study is just one data point, a bit of extra weight on the evidentiary scale. But other researchers have made similar findings, observing apparently critical patterns in the genetic networks of single-celled and also multicellular organisms. Criticality seems to be an integral part of life.

Presence alone doesn’t signify importance, but the essential properties of critical networks should make them useful to biological systems, said physicist Maximino Aldana of the National Autonomous University of Mexico. His work suggests criticality could be an optimal evolutionary solution for systems that need to balance resilience with adaptability.

Another key feature of critical networks is the speed at which information passes through them. Though easier to describe in the rarefied language of statistical biophysics than in conversational terms, a tangible example comes from Bialek’s work on flocks of starlings, which fly in critically networked formations. Within them, thousands of birds move with uncanny coordination, with individual movements rippling almost instantaneously across the entire group.

Another instructive analogy, said biophysicist John Beggs of Indiana University, is of sand grains dropped one-by-one from a single point. For a long time, nothing much happens: a conical pile slowly accumulates. Eventually, however, it becomes so steep that the addition of just one more grain can trigger a miniature avalanche, though not in a predictable way. Avalanches can be small or large, and sometimes they don’t happen at all.

Just before the pile enters its avalanche-prone state, said Beggs, it’s poised at criticality. From a biological perspective, the trick is to harness the capacity for small perturbations — such as a protein’s presence or a neuron’s firing — to produce large effects without entirely entering that avalanche-prone state, in which perturbations would soon become overwhelming. Researchers studying such behaviors sometimes refer to this as the “edge of chaos.”

“You’ve got randomness, and you’ve got order. And right between them, you’ve got the phase transition,” Beggs said. “The idea is, you want to get as close as possible to chaos, but you don’t want to go into the chaos. You want to be on the edge, on the safe side.”

Beggs’ own research involves these avalanche behaviors in networks of neurons. These have been documented at small scales encompassing a few hundred or thousand cells, and also in large-scale, across-the-brain activity in organisms as disparate as roundworms and humans.

It’s been proposed that these criticalities may underlie cognition — the extraordinary dynamics of memory formation and sensory integration and on-the-fly processing — and even be involved in cognitive disorders, though these remain open and largely untested questions.

“It’s not clear how critical this phenomenon is to biology,” cautioned Krotov. He characterized the present state of research as one in which scientists, flush with results from early rounds of experiments, can now refine and update their models of criticality, and use those to inform new investigations.

One important insight, said Krotov, is that criticality in biology won’t precisely resemble what’s seen in the classical, physical systems where criticality was first studied. In the latter — the aforementioned pile of sand, or magnets losing their magnetization at high temperatures — criticality is a global property, the same at every point in a system. Biology could involve many critical networks, nestled together in hierarchies that generate ever more complex phenomena.

Another open question is whether criticality is found at even higher scales. Apart from group dynamics — in addition to starlings, crowds of people sometimes seem to be poised at the edge of chaos — criticality may even operate at ecological levels. This has primarily been studied in a catastrophic context, as when a diseased coral reef turns into an underwater desert, but it’s possible that communities of plants and animals also function as information-processing networks, exhibiting what one speculative early paper described as “coevolution to the edge of chaos.”

“Maximum information at a state of criticality in biodiversity has not been explored so much,” said ecologist Marten Scheffer of Wageningen University, who specializes in ecological tipping-point dynamics. “It’s a potentially interesting area.”

Read more at Wired Science

How a Swinging Pendulum Proves the Earth Rotates

Once upon a time, you were probably on an elementary school field trip at a science museum or an observatory. Just before lunch, your teacher had the class stand in a circle around an enormous weight suspended on a string, and watch it swing back and forth, back and forth.

The teacher (or maybe a tour guide) explained that if you watched the pendulum for long enough, it would seem to alter its course, swinging in a slightly different direction. And that this somehow proved the Earth was rotating beneath your feet. You probably nodded and watched the weight swing for a while. And even though you didn’t see anything really change, you thought, “Sure,” and then went to trade your friend an Oreo cookie for half of their Hi-C Ecto Cooler.

Now that you’re older, you’ll occasionally think back on that pendulum and wonder how it could have proved anything. After all, the demonstration was in a building on the Earth, so if the Earth was rotating, shouldn’t the pendulum be rotating with it?

This famous experiment, now found in museums around the world, was first demonstrated in 1851. French physicist Leon Foucault suspended a 61-pound weight from a 200-foot-long wire at the Pantheon in Paris and set it swinging. He needed the bob to be so heavy and the wire so long to ensure that the pendulum would be able to swing for a long time, at least an hour. A pin on the bottom of the weight drew a line in a circle of wet sand set underneath the experiment.

After an hour, the line the pin drew in the sand intersected with the first line at an angle of roughly 11.25 degrees, which is exactly what Foucault had predicted. The demonstration was an international sensation and was quickly repeated to crowds across Europe and North America. By this point, everyone knew that the Earth rotated but this was the first experiment to measure the speed at which it did so. Foucault got eternal fame by having a pendulum named after him, which later became the title of a mind-bending book by Umberto Eco you probably tried to read in college before turning to the much easier candy of Dan Brown novels.

So how does this all work? To explain, we’re going to have to do a little thought experiment.

Let’s say that one day you and a friend decide to play a game of catch at the North Pole (your friend is an eccentric billionaire in this story). You stand on one side of the pole and toss the ball directly over the pole to your friend, who is standing opposite you. Try to think about things from the ball’s perspective. At the moment it’s released from your hand, its path is set. It will travel in a straight line toward the point that you threw it. But in the time it takes the ball to travel, the Earth has rotated just a tiny bit. Your friend has moved ever so slightly to the right. This movement is so minute that it’s hardly going to affect your game of catch. But if you were on a planet with a very fast rotation rate, your friend would have moved much more in the time it takes the ball to travel. The ball could entirely miss your friend, going straight past her left arm.

As it goes through its swing, the pendulum acts like this ball. Once the pendulum reaches the top of its arc, its path is set. It will head to the opposite end of its swing without deviation. Essentially, it will continue swinging back and forth in the same exact plane. Imagine you’ve suspended the pendulum over the North Pole. You glue a pin to its bottom and send it swinging, drawing a line in the snow. But in the time it takes to go from one top of an arc to the next, the Earth underneath the experiment has rotated. And each time the pendulum swings; the Earth rotates a little more. If you kept the pendulum swinging for six hours, one-quarter of a day, the line it now traced in the snow would intersect the first line at 90 degrees. (Note: Some truly awesome and dedicated physicists did this in 2001 at the South Pole.)

Those of you checking my math will probably now interject something like this: “But you said that Foucault’s pendulum in Paris moved 11.25 degrees in one hour, which means it would have only changed by 67.5 degrees in six hours, not 90 degrees.” Well congratulations, you’ve shown that the thought experiment we did above only works at either the North or South Pole. And also, that you are a nerd.

Imagine the same setup at the equator. You start the pendulum swinging in a perfect east-west direction. The Earth still rotates each time the weight goes through an arc, but now it’s moving in exactly the same direction as the pendulum. There’s no relative motion. Think about this carefully. I can set the pendulum swinging north-south and the Earth’s rotation still won’t affect the plane it moves in. That’s because the Earth can’t twist underneath the setup; it’s always headed in the same direction.

Read more at Wired Science

Peat Bog the Size of England Discovered in Congo

A massive peat bog covering some 40,000 to 80,000 square miles has been discovered in the central African nation of the Democratic Republic of the Congo, reported the BBC.

After satellite images suggested what could be a huge tropical peatland -- about the size of England, according to the BBC -- in a remote area of Congo-Brazzaville, a research team from the University of Leeds, the Wildlife Conservation Society-Congo, and Congo-Brazzaville's Marien Ngouabi University ventured into the soggy area and confirmed its presence.

Peat is formed when plant matter does not fully decompose and sinks over time into the soil. The peat-layer in the enormous bog reaches nearly 23 feet beneath the ground and contains billions of tonnes of ancient, partially decayed vegetation, researchers said.

"Peatlands, generally, have been a big carbon sink over the past 10,000 years," the University of Leeds' Dr. Simon Lewis told BBC News. With so much organic matter caught so deep in the carbon-packed soil, the team hopes peat samples taken from the area will help shed more light on Earth's distant-past climate.

Besides its sheer size, another thing that makes the peat bog discovery amazing is its location in a tropical climate, Lewis said. Peatlands generally need colder areas that will slow vegetation decomposition. "It's rare to find them in the wet and warm tropics, so that makes this an unusual discovery," he said.

The peat samples taken from the expedition have been sent to the United Kingdom for analysis.

From Discovery News

Molecules do the triple twist

An international research team led by Academy Professor Kari Rissanen of the University of Jyväskylä (Finland) and Professor Rainer Herges of the University of Kiel (Germany) has managed to make a triple-Möbius annulene, the most twisted fully conjugated molecule to date, as reported in Nature Chemistry.

An everyday analogue of a single twisted Möbius molecule is a Möbius strip. It can be made easily by twisting one end of a paper strip by 180 degrees and then joining the two ends. A triple twisted Möbius molecule is more difficult to visualize, but its graphical representation resembles the well-known recycling logo, this time with three twisted corners.

However, it has turned out to be extremely difficult to twist molecules to a Möbius surface that has only one side. Up to now, only the simplest Möbius molecules have been prepared. Now Dr. Gaston Schaller and Professor Rainer Herges from the University of Kiel and M.Sc. Filip Topić and Academy Professor Kari Rissanen from the University of Jyväskylä, together with Professor Yoshio Okamoto (Osaka, Japan) and Jun Shen (Harbin, China), have succeeded in preparing and characterizing a triple twisted annulene -- a more complex Möbius molecule which has three twists but only one surface.

Currently these chiral one-sided compounds are merely scientifically intriguing topological objects and far from practical application, but they exhibit a high potential in future applications in molecular electronics and optoelectronics.

From Science Daily

Insights into genetics of cleft lip

Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, have identified how a specific stretch of DNA controls far-off genes to influence the formation of the face. The study, published today in Nature Genetics, helps understand the genetic causes of cleft lip and cleft palate, which are among the most common congenital malformations in humans.

"This genomic region ultimately controls genes which determine how to build a face and genes which produce the basic materials needed to execute this plan," says François Spitz from EMBL, who led the work. "We think that this dual action explains why this region is linked to susceptibility to cleft lip or palate in humans."

Previous studies had shown that variations in a large stretch of DNA are more frequent in people with cleft lip or cleft palate. But there are no genes in or around this DNA stretch, so it was unclear what its role might be. To answer this question, Spitz and colleagues genetically engineered mice to lack that stretch of DNA, as the mouse and human versions are very similar, and are therefore likely to have the same role in both species. They found that these genetically engineered mice had slight changes to the face -- such as a shorter snout -- and a few had cleft lips. The scientists also used this mouse model to look at what happened during embryonic development to lead to those changes.

"We found that this stretch of DNA contains regulatory elements that control the activity of a gene called Myc, which sits far away on the same chromosome," Spitz explains, "and it exerts that control specifically in the cells that will form the upper lip."

The researchers discovered that, in the face of mouse embryos that lack this stretch of DNA, Myc becomes largely inactive. This in turn affects two groups of genes: genes directly involved in building the face, and genes that make ribosomes, the cell's protein-producing factories. The latter effect could make the developing upper lip more sensitive to other genetic conditions and to environmental factors -- like smoking or drinking during pregnancy -- that can influence cell growth. This is because making the face in general, and the upper lip in particular, are very complex processes, requiring different groups of cells in the embryo to grow and fuse with each other at the right time. If the cells involved have their protein production impaired -- due to reduced Myc activity -- any additional burden could disrupt that growth, increasing the likelihood of a malformation like cleft palate. This increased susceptibility to a wide range of factors -- both genetic and environmental -- could the link between variations in this stretch of DNA and the incidence of cleft lip.

Read more at Science Daily

Sound and vision: Visual cortex processes auditory information, too

Scientists studying brain process involved in sight have found the visual cortex also uses information gleaned from the ears as well as the eyes when viewing the world.

They suggest this auditory input enables the visual system to predict incoming information and could confer a survival advantage.

Professor Lars Muckli, of the Institute of Neuroscience and Psychology at the University of Glasgow, who led the research, said: "Sounds create visual imagery, mental images, and automatic projections.

"So, for example, if you are in a street and you hear the sound of an approaching motorbike, you expect to see a motorbike coming around the corner. If it turned out to be a horse, you'd be very surprised."

The study, published in the journal Current Biology, involved conducting five different experiments using functional Magnetic Resonance Imaging (fMRI) to examine the activity in the early visual cortex in 10 volunteer subjects.

In one experiment they asked the blindfolded volunteers to listen to three different natural sounds -- birdsong, traffic noise and a talking crowd.

Using a special algorithm that can identify unique patterns in brain activity, the researchers were able to discriminate between the different sounds being processed in early visual cortex activity.

A second experiment revealed even imagined images, in the absence of both sight and sound, evoked activity in the early visual cortex.

Lars Muckli said: "This research enhances our basic understanding of how interconnected different regions of the brain are. The early visual cortex hasn't previously been known to process auditory information, and while there is some anatomical evidence of interconnectedness in monkeys, our study is the first to clearly show a relationship in humans.

"In future we will test how this auditory information supports visual processing, but the assumption is it provides predictions to help the visual system to focus on surprising events which would confer a survival advantage.

Read more at Science Daily

Buried fossil soils found to be awash in carbon

Soils that formed on Earth's surface thousands of years ago and that are now deeply buried features of vanished landscapes have been found to be rich in carbon, adding a new dimension to our planet's carbon cycle.

The finding, reported in the journal Nature Geoscience, is significant as it suggests that deep soils can contain long-buried stocks of organic carbon which could, through erosion, agriculture, deforestation, mining and other human activities, contribute to global climate change.

"There is a lot of carbon at depths where nobody is measuring," says Erika Marin-Spiotta, a University of Wisconsin-Madison assistant professor of geography and the lead author of the new study. "It was assumed that there was little carbon in deeper soils. Most studies are done in only the top 30 centimeters. Our study is showing that we are potentially grossly underestimating carbon in soils."

The soil studied by Marin-Spiotta and her colleagues, known as the Brady soil, formed between 15,000 and 13,500 years ago in what is now Nebraska, Kansas and other parts of the Great Plains. It lies up to six-and-a- half meters below the present-day surface and was buried by a vast accumulation of windborne dust known as loess beginning about 10,000 years ago, when the glaciers that covered much of North America began to retreat.

The region where the Brady soil formed was not glaciated, but underwent radical change as the Northern Hemisphere's retreating glaciers sparked an abrupt shift in climate, including changes in vegetation and a regime of wildfire that contributed to carbon sequestration as the soil was rapidly buried by accumulating loess.

"Most of the carbon (in the Brady soil) was fire derived or black carbon," notes Marin-Spiotta, whose team employed an array of new analytical methods, including spectroscopic and isotopic analyses, to parse the soil and its chemistry. "It looks like there was an incredible amount of fire."

The team led by Marin-Spiotta also found organic matter from ancient plants that, thanks to the thick blanket of loess, had not fully decomposed. Rapid burial helped isolate the soil from biological processes that would ordinarily break down carbon in the soil.

Such buried soils, according to UW-Madison geography Professor and study co-author Joseph Mason, are not unique to the Great Plains and occur worldwide.

The work suggests that fossil organic carbon in buried soils is widespread and, as humans increasingly disturb landscapes through a variety of activities, a potential contributor to climate change as carbon that had been locked away for thousands of years in arid and semiarid environments is reintroduced to the environment.

The element carbon comes in many forms and cycles through the environment -- land, sea and atmosphere -- just as water in various forms cycles through the ground, oceans and the air. Scientists have long known about the carbon storage capacity of soils, the potential for carbon sequestration, and that carbon in soil can be released to the atmosphere through microbial decomposition.

Read more at Science Daily

Untangling whole genomes of individual species from a microbial mix

A new approach to studying microbes in the wild will allow scientists to sequence the genomes of individual species from complex mixtures. It marks a big advance for understanding the enormous diversity of microbial communities -- including the human microbiome. The work is described in an article published May 22 in Early Online form in the journal G3: Genes|Genomes|Genetics, published by the Genetics Society of America.

"This new method will allow us to discover many currently unknown microbial species that can't be grown in the lab, while simultaneously assembling their genome sequences," says co-author Maitreya Dunham, a biologist at the University of Washington's Department of Genome Sciences.

Microbial communities, whether sampled from the ocean floor or a human mouth, are made up of many different species living together. Standard methods for sequencing these communities combine the information from all the different types of microbes in the sample. The result is a hodgepodge of genes that is challenging to analyze, and unknown species in the sample are difficult to discover.

"Our approach tells us which sequence fragments in a mixed sample came from the same genome, allowing us to construct whole genome sequences for individual species in the mix," says co-author Jay Shendure, also of the University of Washington's Department of Genome Sciences.

The key advance was to combine standard approaches with a method that maps out which fragments of sequence were once near each other inside a cell. The cells in the sample are first treated with a chemical that links together DNA strands that are in close proximity. Only strands that are inside the same cell will be close enough to link. The DNA is then chopped into bits, and the linked portions are isolated and sequenced.

Read more at Science Daily

Tiny muscles help bats fine-tune flight, stiffen wing skin

Bats appear to use a network of hair-thin muscles in their wing skin to control the stiffness and shape of their wings as they fly, according to a new study. The finding provides new insight about the aerodynamic fine-tuning of membrane wings, both natural and human-made.

A new study of bats reveals a capability within their wondrous wings that may help them fine-tune their flight.

Bats employ a network of nearly hair-thin muscles embedded in the membrane of their inherently floppy wing skin to adjust the wings' stiffness and curvature while they fly, Brown University researchers report. Birds and insects have stiff wings, but the new evidence suggests bats have evolved this muscular means of preserving or adjusting wing shape.

"Aerodynamic performance depends upon wing shape," said Brown biology graduate student Jorn Cheney, lead author of the newly published paper in Bioinspiration and Biomimetics. "The shape of a membrane wing might initially begin flat but as soon as it starts producing lift it's not going to remain flat because it has to deform in response to that aerodynamic load.

"The shape it adopts could be a terrible one -- it could make the animal crash -- or it could be beneficial," Cheney said. "But they are not locked into that shape. Because bats have these muscles in their wings, and also bones that can control the general shape as well, they can adopt any number of profiles."

Membrane muscle measurements

Cheney wasn't sure what to make of the tiny muscles, called plagiopatagiales, heading into the experiments reported in the paper. They have been known for more than a century but their function has never been demonstrated.

When Cheney considered the muscle function, he estimated that each individual muscle would be too weak to reshape the wing. That led him to form two competing hypotheses: either that the muscles would activate together to enhance force or that these oddly shaped, weak muscles might exist solely as sensors of stretch.

Only experiments could settle the question, so Cheney attached electrode sensors to a few muscles on the wings of a few Jamaican fruit bats and filmed them as they flew in the lab's wind tunnel.

Three key findings emerged from the data. They all point to the plagiopatagiales modulating skin stiffness.

One result was that the muscle activation and relaxation follows a distinct pattern during flight: They tense on the downstroke and relax on the upstroke.

"This is the first study showing that bats turn these muscles on and off during a typical wingbeat cycle," said co-author Sharon Swartz, professor of biology at Brown.

.Another finding was that the muscles don't act individually. Instead they exert their force in synchrony, providing enough collective strength to stiffen the wing.

Finally, Cheney found, the muscles appeared to activate with different timing at different flight speeds. As the bats flew faster, they tensed the muscles sooner in the upstroke-downstroke cycle.

In other words, the data suggested that the muscles do not behave passively but actively and collectively in keeping with conditions of flight.

None of the data, however, preclude the muscles from serving a sensory function as well.

Technological insight, too

Cheney's findings fit into a larger program of research at Brown between the labs of biologist Swartz and co-author Kenneth Breuer, professor of engineering, in which, as Breuer puts it, they are "using biology to inspire engineering and using engineering to inspire biology."

In parallel with studies of real bats, the team has also built a robotic bat wing that incorporates their biological observations. Then they use the wing to generate data from experiments that they could never do with living creatures, such as precisely varying kinematic parameters like wingbeat frequency and amplitude, or the degree of wing folding during flapping.

In a separate paper in the same edition of Bioinspiration and Biomimetics, Swartz, Breuer, and former student Joe Bahlman report on how energy costs and aerodynamic forces changed as they varied several kinematic parameters in the robotic bat wing. They found that to generate a given force, such as lift, each of several parameters requires about the same amount of energy, but that the timing and extent of wing folding varies the ratio between lift and power significantly.

Read more at Science Daily