It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, July 15, 2021
When fawns perceive constant danger from many sources, they almost seem to relax
Researchers use trail cameras to study animals' interaction, behavior in human-dominated landscapes
IMAGE: THESE FAWNS ARE SHOWING VIGILANCE. BUT WHEN YOUNG WHITE-TAILED DEER PERCEIVE THAT THERE IS SO MUCH DANGER COMING FROM SO MANY SOURCES, THEIR BEHAVIOR SEEMED LIKE THEY JUST RELAXED, ACCORDING... view more
CREDIT: ASIA MURPHY/PENN STATE
Burnout. It is a syndrome that is said to afflict humans who feel chronic stress. But after conducting a novel study using trail cameras showing the interactions between white-tailed deer fawns and predators, a Penn State researcher suggests that prey animals feel it, too.
"And you can understand why they do," said Asia Murphy, who recently graduated with a doctorate from Penn State's Intercollege Graduate Degree Program in Ecology. "Less than half of whitetail fawns live to see their first birthday, and many are killed by predators, such as coyotes, black bears and bobcats. Fawns instinctively 'know' they are in constant danger."
Ironically, the presence of humans -- who mean the fawns no harm and likely would protect them if they could -- only ratchets up the stress the young animals experience, Murphy added. Even if it's just people hiking on a trail in a state park, it is a disturbance to be avoided by fawns, leaving less landscape and less time for them to feed and evade predators.
"The presence of people creates an environment where the danger seems so high that the animals basically stop having vigilance behaviors," she said. "That was the surprising thing about my research -- when fawns perceive that there is so much danger coming from so many sources, their behavior seemed like they just relaxed, like there's no point in being ready to hide or flee. I saw that in older deer, too."
In areas where there are many predators and people present, fawns seem to relax instead of acting hypervigilant, she noted.
"Like so much constant stress leaves them burned out," she said.
CAPTION
This "camera trap" photo says it all: Less than half of whitetail fawns live to see their first birthday, and many are killed by predators, such as black bears, bobcats, and coyotes like the one shown here carrying the head of a fawn.
CREDIT
Asia Murphy/Penn State
The goal of the study was to examine how human-dominated landscapes influence the timing, frequency and physical spacing and locations of interactions between humans, black bears, coyotes, bobcats and fawns, as well as to contrast deer vigilance behavior at each location. The researchers compared "camera trap" data from six surveys in and around three central Pennsylvania public forest sites with different surroundings -- forest, agriculture and development.
The Bald Eagle and Rothrock State Forest sites were surrounded by agriculture and low-density housing, whereas the Susquehannock State Forest site was surrounded by largely unbroken forest. Analyzing more than 10,000 photos, researchers observed markedly different behavior of fawns, adult deer and predators at the three locations, dictated, they suggest, by the presence of humans and their changes to the landscape.
Camera trap surveys began in mid- to late-May, which coincided with the start of the period when fawns are born and are most vulnerable to predation, and ended in mid-September, before the hunting season. Researchers randomly established 18 camera locations at each of the three study sites, spaced a minimum of a half mile apart within an area of about 100 square miles.
At least one camera was placed at each location and typically remained there for an average of 47 days before being moved to a new location. Cameras were set to take three pictures when triggered by an animal with a one-minute rest period. Each location was baited with a combination of bobcat urine, a skunk-based scent attractant and a fatty acid tablet.
In findings recently published in the Journal of Animal Ecology, the researchers reported that bears, bobcats, coyotes, fawns and adult deer all had more frequent timing overlaps in the agriculture and development sites compared to the mostly unbroken forest site. In addition, factors that influenced deer vigilance, such as distance to forest edge and predator abundance in the agriculture and development sites, were not factors in the mostly unbroken forest site.
"By taking into account the different antipredator behaviors that can be detected and the different scales at which these behaviors might occur, we were able to gain a more comprehensive picture of how humans reduce available niche space for wildlife," Murphy said. "It was clear that disturbed landscapes -- agriculture and development -- create more time and space overlap between predators and fawns."
This research is important because it is among the first to document that human land disturbance influences the dynamics of predator-prey interactions, according to Murphy's adviser, Duane Diefenbach, adjunct professor of wildlife ecology in the College of Agricultural Sciences. Wildlife biologists suspected human interference enhances opportunities for predators, but they had not seen proof.
"This study shows that antipredator behavior by fawns varies across space, time and predator species," said Diefenbach, who is leader of the U.S. Geological Survey's Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State. "When multiple predator species co-occur but vary in their use of space, time of activity and hunting mode, it creates a complex landscape for prey trying to avoid predation. Human presence has the potential to shift interactions among predators and prey and where and when encounters occur."
CAPTION
When multiple predator species such as this bobcat co-occur but vary in their use of space, time of activity and hunting mode, researchers say, it creates a complex landscape for prey like fawns trying to avoid predation.
CREDIT
Asia Murphy/Penn State
Also involved in the research was David Miller, associate professor of wildlife population ecology, Penn State, and Pennsylvania Game Commission biologists Mark Ternent and Matt Lovallo.
The Pennsylvania Game Commission funded and supported this research.
University of Minnesota develops new tool to help farmers make crop input decisions
Understanding the cost and social benefits of using less nitrogen across the US corn belt
Reducing greenhouse gas emissions (GHGs) and nitrogen water pollution from agriculture are top environmental priorities in the United States. Key to achieving climate goals is helping producers navigate carbon markets, while also helping the environment and improving farm income.
A new tool developed by a University of Minnesota research team allows farmers to create a budget balance sheet of any nitrogen reduction plans and see the economic and environmental cost, return and margins, all customized to fields under their management.
Previous tools did not allow for customized predictions for every field in the U.S. corn belt, as the computational and storage costs of running these crop models at large scale would be very expensive.
As outlined in an article published in IOPscience, the research team built a series of machine-learning-based metamodels that can almost perfectly mimic a well-tested crop model at much faster speeds. Using the metamodels, they generated millions of scenario simulations and investigated two fundamental sustainability questions -- where are the mitigation hotspots, and how much mitigation can be expected under different management scenarios.
"We synthesized four simulated indicators of agroecosystem sustainability -- yield, N2O emissions, nitrogen leaching, and changes in soil organic carbon -- into economic net societal benefits as the basis for identifying hotspots and infeasible land for mitigation," said Taegon Kim, CFANS research associate in the BBE department. The societal benefits include cost savings from GHG mitigation, as well as improved water and air quality.
"By providing key sustainability indicators related to upstream crop production, our metamodels can be a useful tool for food companies to quantify the emissions in their supply chain and distinguish mitigation options for setting sustainability goals," said Timothy Smith, professor of Sustainable Systems Management and International Business Management in CFANS's BBE department.
The study, conducted in the U.S. Midwest corn belt, found that:
Reducing nitrogen fertilizer by 10% leads to 9.8% less N2O emissions and 9.6% less nitrogen leaching, at the cost of 4.9% more soil organic carbon depletion, but only a 0.6% yield reduction over the study region.
The estimated net total annual social benefits are worth $395 million (uncertainty ranges from $114 million to nearly $1.3 billion), including a savings of $334 million by avoiding GHG emissions and water pollution, $100 million using less fertilizer, and a negative $40 million due to yield losses.
More than 50% of the net social benefits come from 20% of the study areas, thus can be viewed as hot spots where actions should be prioritized.
"Our analysis revealed hot spots where excessive nitrogen fertilizer can be cut without yield penalty," said Jin. "We noticed in some places that reducing nitrogen-related pollution comes at a cost of depleting organic carbon in soil, suggesting that other regenerative practices, such as cover cropping, need to be bundled with nitrogen management."
In the future, the team will expand the framework presented in this study and develop more advanced and accurate carbon qualification models through a combination of process-based models, artificial intelligence and remote sensing.
###
This research was funded by the University of Minnesota AGREETT program, the National Science Foundation and the U.S. Department of Energy Advanced Research Projects Agency-Energy (ARPA-E).
International team of scientists turns methane into methanol at room temperature
IMAGE: BENJAMIN SNYDER (RIGHT) AND HIS FORMER PHD ADVISER, EDWARD SOLOMON, A PROFESSOR OF CHEMISTRY AT STANFORD AND OF PHOTON SCIENCE AT SLAC. view more
CREDIT: LINDA A. CICERO
A team of researchers from Stanford University and the University of Leuven in Belgium has further elucidated an intriguing process that could be an important step toward a methanol fuel economy with abundant methane as the feedstock, an advance that could fundamentally change how the world uses natural gas.
Methanol - the simplest alcohol - is used to make various products, like paints and plastics, and as an additive to gasoline. Rich in hydrogen, methanol can drive new-age fuel cells that could yield significant environmental benefits.
If natural gas, of which methane is the primary component, could be converted economically into methanol, the resulting liquid fuel would be much more easily stored and transported than natural gas and pure hydrogen. That also would greatly reduce the emissions of methane from natural gas processing plants and pipelines. Today, escaped methane, a greenhouse gas many times more potent than carbon dioxide, nearly negates the environmental advantages of natural gas over oil and coal. The team's new study in the current edition of Science is their latest to advance a low-energy way to produce methanol from methane.
"This process uses common crystals known as iron zeolites that are known to convert natural gas to methanol at room temperature," explains Benjamin Snyder, who earned his doctorate at Stanford studying catalysts to address key facets of this challenge. "But, this is extremely challenging chemistry to achieve on a practical level, as methane is stubbornly chemically inert."
When methane is infused into porous iron zeolites, methanol is rapidly produced at room temperature with no additional heat or energy required. By comparison, the conventional industrial process for making methanol from methane requires temperatures of 1000°C (1832°F) and extreme high pressure.
"That's an economically tantalizing process, but it's not that easy. Significant barriers prevent scaling up this process to industrial levels," said Edward Solomon, Stanford professor of chemistry and of photon science at SLAC National Accelerator Laboratory. Solomon is the senior author of the new study.
Keeping the zeolites on
Unfortunately, most iron zeolites deactivate quickly. Unable to process more methane, the process peters out. Scientists have been keen to study ways to improve iron zeolite performance. The new study, co-authored by Hannah Rhoda, a Stanford doctoral candidate in inorganic chemistry, uses advanced spectroscopy to explore the physical structure of the most promising zeolites for methane-to-methanol production.
"A key question here is how to get the methanol out without destroying the catalyst," Rhoda said.
Choosing two attractive iron zeolites, the team studied the physical structure of the lattices around the iron. They discovered that the reactivity varies dramatically according to the size of the pores in the surrounding crystal structure. The team refers to it as the "cage effect," as encapsulating lattice resembles a cage.
If the pores in the cages are too big, the active site deactivates after just one reaction cycle and never reactivates again. When the pore apertures are smaller, however, they coordinate a precise molecular dance between the reactants and the iron active sites - one that directly produces methanol and regenerates the active site. Leveraging this so-called 'cage effect,' the team was able to reactivate 40 percent of the deactivated sites repeatedly - a significant conceptual advance toward an industrial-scale catalytic process.
CAPTION
An illustration of the cage structures of two iron-based zeolites used in the study. The red and gold spheres (representing oxygen and iron, respectively) make up the active site. The cage structure, in gray, is formed of silicon, aluminum and oxygen. The blue sphere quantifies the size of the largest molecule that can diffuse freely in and out of the active site cage (the diameter of methane is ~4.2 Å).
CREDIT
Benjamin Snyder
"Catalytic cycling - the continual reactivation of regenerated sites - could someday lead to continual, economical methanol production from natural gas," said Snyder, now a postdoctoral fellow at UC-Berkeley in the Department of Chemistry under Jeffrey R. Long.
This fundamental step forward in basic science will help elucidate for chemists and chemical engineers the process iron zeolites use to produce methanol at room temperature, but much work remains before such a process might be industrialized.
Next up on Snyder's list: tackling achieving the process not only at room temperature but using ambient air rather than some other source of oxygen, such as the nitrous oxide used in these experiments. Dealing with a powerful oxidizing agent like oxygen, which is notoriously hard to control in chemical reactions, will be another considerable hurdle along the path.
For now, Snyder was both pleased and amazed by the illustrative powers of the sophisticated spectroscopic instrumentation in the Solomon labs that were leveraged for this study. These were invaluable to his understanding of the chemistry and the chemical structures involved in the methane-to-methanol process.
"It's cool how you can get some very powerful atomic-level insight, like the cage effect, from these tools that weren't available to previous generations of chemists," Snyder said.
University of Leuven researchers on this study were Max Bols, Dieter Plessers, Robert Schoonheydt and, Bert F. Sels.
GUNS IN AMERICA
Self-inflicted firearm injuries three times more common in rural youth
Targeted interventions needed in rural areas to prevent self-harm among youth
ANN & ROBERT H. LURIE CHILDREN'S HOSPITAL OF CHICAGO
A national study published in the Journal of Pediatrics found that Emergency Department (ED) visits by youth for self-harm were nearly 40 percent higher in rural areas compared to urban settings. Strikingly, ED visits by youth for self-inflicted firearm injuries were three times more common in rural areas. Youth from rural areas presenting to the ED for suicidal ideation or self-harm also were more likely to need to be transferred to another hospital for care, which underscores the insufficient mental health resources in rural hospitals.
"Our study used pre-pandemic data, and we know that increased attention to youth mental health is even more pressing now everywhere, but especially in rural settings to prevent self-harm in youth," said lead author Jennifer Hoffmann, MD, pediatric emergency medicine physician at Ann & Robert H. Lurie Children's Hospital of Chicago and Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine. "We need universal screening for suicidal ideation for all children and adolescents age 10 and up who present in the ED to identify youth at risk and intervene before tragedy occurs."
The study used national data on suicidal ideation or self-harm in youth (ages 5-19 years) from a sample of EDs across the country, including those in general hospitals and children's hospitals. Dr. Hoffmann and colleagues extrapolated the results to reach national estimates.
Dr. Hoffmann explains that a number of factors contribute to higher suicide rates and self-harm in rural youth. Access to mental healthcare is a huge challenge, she says. Shortages of pediatric mental health professionals in rural areas play a significant role, requiring patients to travel long distances for help, which is a barrier for many. Also, lower family income and higher unemployment rates in rural areas may result in poor insurance coverage, especially for mental health. In small towns, there are also concerns with anonymity, which may cause delays in seeking care until a crisis brings the child to the ED. Rural families are also more likely to own firearms, so increased access to firearms may account for the high degree of disparity in self-inflicted firearm injuries.
"We need to improve mental health training for ED providers, allocate more resources and implement policies in rural hospitals on managing young patients who present with suicidal ideation or self-harm," said Dr. Hoffmann. "More widespread use of tele-psychiatry also might help prevent unnecessary transfers to other hospitals. But even more importantly, we need to train primary care providers to help diagnose and treat mental health issues earlier, so we can prevent self-inflicted injuries and death."
###
Research at Ann & Robert H. Lurie Children's Hospital of Chicago is conducted through the Stanley Manne Children's Research Institute. The Manne Research Institute is focused on improving child health, transforming pediatric medicine and ensuring healthier futures through the relentless pursuit of knowledge. Lurie Children's is ranked as one of the nation's top children's hospitals by U.S. News & World Report. It is the pediatric training ground for Northwestern University Feinberg School of Medicine. Last year, the hospital served more than 220,000 children from 48 states and 49 countries.
Disclaimer: AAAS and EurekAlert! are not responsible for
Food insufficiency linked to lack of mental health services during pandemic
Americans experiencing food insufficiency more likely to use antidepressant medications
A new national study published in Public Health Nutrition on July 15 found that Americans experiencing food insufficiency were three times as likely to lack mental health support during the COVID-19 pandemic than those not experiencing food insufficiency.
The most extreme form of food insecurity, food insufficiency occurs when families do not have enough eat. Among a nationally representative sample of 68,611 adults who participated in the US Census Household Pulse Survey in October 2020, 11% reported food insufficiency. Of those, 24% also reported an unmet mental health need compared to 9% of food-sufficient adults.
"Hunger, exhaustion, and stress related to not getting enough food to eat may lead to depression and anxiety," says lead author, Jason Nagata, MD, assistant professor of pediatrics at the University of California, San Francisco.
"The experience of food insecurity could lead affected people to prioritize food over other needs such as seeking health care, using up considerable time and energy to navigate food pantries and free meal services, or locate and visit affordable food stores."
Food insufficiency was also associated with higher use of psychiatric medications: 27% of food-insufficient adults reported psychiatric medication use compared to 19% of food-sufficient adults.
"To better address these problems, medical professionals, social workers, and clinicians can screen patients for both symptoms of anxiety and depression to ensure they have sufficient access to food," says co-author Kyle T. Ganson, PhD, assistant professor at the University of Toronto's Factor-Inwentash Faculty of Social Work.
The researchers argue that clinicians should assess for food insecurity and provide referrals to food assistance programs.
"Policymakers should focus on increasing funding for food assistance and mental health services as part of pandemic relief legislation," says Nagata. "Expanding access to supplemental food programs may help to mitigate the need for more mental health services during the pandemic."
###
Media contacts:
How spiders distinguish living from non-living using motion-based visual cues
Ability to identify other animals from relative positioning of the joints not unique to vertebrates
IMAGE: UNKNOWN JUMPING SPIDER, AUGUST 2012, BELTSVILLE, MARYLAND, BENJAMIN A COULTER HELPED NARROW THIS DOWN TO PERHAPS AN IMMATURE THIODINA SYLVANA view more
CREDIT: SAM DROEGE, USGS BEE INVENTORY AND MONITORING LAB, FLICKR
Jumping spiders can distinguish living from non-living objects in their peripheral vision using the same cues used by humans and other vertebrate animals, according to a study publishing 15th July 2021 in the open-access journal PLOS Biology by Massimo De Agrò of Harvard University in the United States.
The ability to detect other living creatures in your surroundings is a key skill for any animal - it is crucial for finding mates, avoiding predators, and catching prey. The movements of vertebrates and invertebrates are distinct from inanimate objects because their rigid, jointed bones and exoskeletons constrain the relative positioning of certain body parts. Most vertebrates can recognize this biological pattern of movement from very limited visual information, such as a point-light display, which shows dots representing the positions of the main joints.
To investigate this phenomenon in invertebrates for the first time, researchers partially restrained 60 wild-caught jumping spiders (Menemerus semilimbatus) on a spherical treadmill and used a computer screen to show point-light displays on each side of their peripheral vision (only visible to their lateral eyes). They found that spiders were more likely to try to turn and face displays that showed random movements, compared to those that moved in a more biological way, with the distances between joints constrained.
The result seems contrary to the expectation that spiders should focus their attention on objects in their surroundings that appear to be living - potential prey, mate or predator. However, the authors suggest that this behavior may allow the spiders to focus their forward-facing primary eyes on unidentifiable objects to get a better look. Complex vision evolved independently in vertebrates and arthropods and so the ability to distinguish living from non-living motion using the relative positioning of the joints has most likely arisen convergently in the two groups of animals.
"Jumping spiders' secondary eyes confirm themselves to be a marvelous tool," the researchers add. "In this experiment, we observed how they alone can tell apart living from non-living organisms, using the semi-rigid pattern of motion that characterize the formers and without the aid of any shape cue. Finding the presence of this skill, previously known only in vertebrates, opens up new and exciting perspectives on the evolution of visual perception. My co-authors and I can't wait to see what other visual cues can be perceived and understood by these tiny creatures."
Citation: De Agrò M, Rößler DC, Kim K, Shamble PS (2021) Perception of biological motion by jumping spiders. PLoS Biol 19(7): e3001172. https://doi.org/10.1371/journal.pbio.3001172
Funding: PSS was supported by the John Harvard Distinguished Science Fellows Program within the FAS Division of Science, Harvard University. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist
A new spidey sense
Harvard study shows jumping spiders can distinguish living objects from non-living objects based on their movement
Add this to the list of real-life spidey senses: Harvard researchers have shown that jumping spiders are able to tell the difference between animate objects and inanimate objects -- an ability previously known only in vertebrates, including humans.
Using a specialized treadmill system and a point-light display animation, the team of scientists found that these spiders are able to recognize biological motion. This type of motion refers to the visual movements that come from living organisms when they are moving. The visual cue is how people, even babies, can tell someone is another person just by the way their bodies move. Many animals can do this, too.
The ability, which is critical for survival, is evolutionarily ancient since it is so widespread across vertebrates. The study from the Harvard team is believed to be the first demonstration of biological motion recognition in an invertebrate. The findings pose crucial questions about the evolutionary history of the ability and complex visual processing in non-vertebrates.
"[It] opens the possibility that such mechanisms might be widespread across the animal kingdom and not necessarily related to sociality," the researchers wrote in the paper, which published in PLOS Biology on Thursday.
The study was authored by a team of researchers who were John Harvard Distinguished Science Fellows during the time of the study or are current fellows. Massimo De Agrò, now a researcher at an animal comparative economics lab in Regensburg, Germany, led the work. Paul Shamble, a current fellow, and Daniela C. Rößler, and Kris Kim, former fellows, co-authored the study.
The researchers chose jumping spiders to test biological motion cues because the animals are among the most visually adept of all arthropods. With eight eyes, for example, vision plays a central role in a wide range of behaviors.
They placed the jumping spiders, a species called Menemerus semilimbatus, into a forced choice experiment. They suspended the spiders above a spherical treadmill so their legs could make contact with it. The spiders were kept in a fixed position so only its legs could move, transferring its intended direction to the sphere which spun freely because of a constant stream of compressed air shooting up below it.
(Friendly disclaimer: No spiders were harmed during the experiment and all were freed in the same place they were captured afterwards.)
Once in position, the spiders were presented two animations as stimuli. The animations were called point-light displays, each consisting of a dozen or so small lights (or points) that were attached to key joints of another spider so they could record its movements. The body itself is not visible, but the digital points give a body-plan outline and impression of a living organism. In humans, for example, it only takes about eleven dots on the main joints of the body for observers to correctly identify it as another person.
For the spiders, the displays followed the motion of another spider walking. Most of the displays gave the impression of seeing a living animal. Some of the displays were less real than others and one, called a random display, did not give the impression it was living.
The researchers then observed how the spiders reacted and which light display they turned toward on the treadmill. They found the spiders reacted to the different point-light displays by pivoting and facing them directly, which indicated that the spiders were able to recognize biological motion.
Curiously, the team found the spiders preferred rotating towards the more artificial displays and always toward the random one when it was part of the choice. They initially thought they would turn more toward the displays simulating another spider and possible danger, but the behavior made sense in the context of jumping spiders and how their secondary set of eyes work to decode information.
"The secondary eyes are looking at this point-light display of biological motion and it can already understand it, whereas the other random motion is weird and they don't understand what's there," De Agrò said.
The researchers hope to look into biological motion recognition in other invertebrates such as other insects or mollusks. The findings could lead to greater understanding of how these creatures perceive the world, De Agrò said.
###
Arrival of land plants changed Earth's climate control system
The arrival of plants on land about 400 million years ago may have changed the way the Earth naturally regulates its own climate, according to a new study led by researchers at UCL (University College London) and Yale.
IMAGE: WATER COLLECTS ON MOSSES. THE FIRST LAND PLANTS WERE THOUGHT TO BE NON-VASCULAR, LIKE MOSSES. view more
CREDIT: KATMAI PRESERVE NPS PHOTO/RUSS TAYLOR
The arrival of plants on land about 400 million years ago may have changed the way the Earth naturally regulates its own climate, according to a new study led by researchers at UCL and Yale.
The carbon cycle, the process through which carbon moves between rocks, oceans, living organisms and the atmosphere, acts as Earth's natural thermostat, regulating its temperature over long time periods.
In a new study, published in the journal Nature, researchers looked at samples from rocks spanning the last three billion years and found evidence of a dramatic change in how this cycle functioned about 400 million years ago, when plants started to colonise land.
Specifically, the researchers noted a change in the chemistry of seawater recorded in the rock that indicates a major shift in the global formation of clay - the "clay mineral factory" - from the oceans to the land.
Since clay forming in the ocean (reverse weathering) leads to carbon dioxide being released into the atmosphere, while clay on land is a byproduct of chemical weathering that removes carbon dioxide from the air, this reduced the amount of carbon in the atmosphere, leading to a cooler planet and a seesawing climate, with alternating ice ages and warmer periods.
The researchers suggested the switch was caused by the spread of land plants keeping soils and clays on land, stopping carbon from being washed into the ocean, and by the growth in marine life using silicon for their skeletons and cell walls, such as sponges, single-celled algae and radiolarians (a group of protozoa), leading to a drop in silicon in the seawater required for clay formation.
Senior author Dr Philip Pogge von Strandmann (UCL Earth Sciences) said: "Our study suggests that the carbon cycle operated in a fundamentally different way for most of Earth's history compared to the present day.
"The shift, which occurred gradually between 400 to 500 million years ago, appears to be linked to two major biological innovations at the time: the spread of plants on land and the growth of marine organisms that extract silicon from water to create their skeletons and cells walls.
"Before this change, atmospheric carbon dioxide remained high, leading to a stable, greenhouse climate. Since then, our climate has bounced back and forth between ice ages and warmer periods. This kind of change promotes evolution and during this period the evolution of complex life accelerated, with land-based animals forming for the first time.
"A less carbon-rich atmosphere is also more sensitive to change, allowing humans to influence the climate more easily through the burning of fossil fuels."
First author Boriana Kalderon-Asael, a PhD student at Yale University, said: "By measuring lithium isotopes in rocks spanning most of Earth's history, we aimed to investigate if anything had changed in the functioning of the carbon cycle over a large time scale. We found that it had, and this change appears to be linked to the growth of plant life on land and silicon-using animal life in the sea."
In the study, researchers measured lithium isotopes in 600 samples of rock taken from many different locations around the world. Lithium has two naturally occurring stable isotopes - one with three protons and three neutrons, and one with three protons and four neutrons.
When clay forms slowly on land, it strongly favours lithium-6, leaving surrounding water enriched with the other, heavier isotope, lithium-7. Analysing their samples using mass spectrometry, the researchers found a rise in the levels of lithium isotope-7 in seawater recorded in the rock occurring between 400 and 500 million years ago, suggesting a major shift in Earth's clay production coinciding with the spread of plants on land and emergence of silicon-using marine life.
Clay forms on land as a residue of chemical weathering, the primary long-term process through which carbon dioxide is removed from the atmosphere. This occurs when atmospheric carbon combines with water to form a weak acid, carbonic acid, which falls to the ground as rain and dissolves rocks, releasing ions including calcium ions that flow into the ocean. Eventually, the carbon is locked up in rocks on the ocean floor. In contrast, carbon drawdown by plant photosynthesis is negated once the plants decay, and rarely affects carbon dioxide levels on timescales longer than a few hundred years.
When clay forms in the ocean, carbon stays in the water and is eventually released into the air as part of the continual exchange of carbon that occurs when air meets water.
###
The study received support from the European Research Council and NASA.
High-ranking hyena mothers pass their social networks to their cubs
Using 27 years of detailed data on hyena social interactions, a team led by Penn biologists nailed down a pattern of social network inheritance and its implications for social structure, rank, and survival
IMAGE: USING 27 YEARS OF DETAILED DATA ON HYENA SOCIAL INTERACTIONS, A TEAM LED BY PENN BIOLOGISTS NAILED DOWN A PATTERN OF SOCIAL NETWORK INHERITANCE AND ITS IMPLICATIONS FOR SOCIAL STRUCTURE,... view more
CREDIT: KATE SHAW YOSHIDA
Hyenas are a highly social species, living in groups that can number more than 100. But within their clans, there is order: A specific matrilineal hierarchy governs societies in this species where females are dominant to males.
While researchers have intensively studied the social structure of hyenas and other animals, it's only recently that scientists have begun to investigate how this structure arises. A new study led by Penn biologists, which relies upon 27 years of detailed observations of hyena social behavior collected by researchers at Michigan State University, pulls back the curtain on how social order comes to be.
Their findings show that hyenas inherit their mother's social networks, so their social connections resemble their mother's. However, offspring of higher-ranking individuals more faithfully replicate their mother's interactions, winding up with social networks that more closely resemble their mother's than do offspring of females that rank lower on the clan's social ladder. The team reported their findings in the journal Science.
"We knew that the social structure of hyenas is based in part on one's rank in the agonistic hierarchy, which we know is inherited from mothers" says Erol Akçay, a study coauthor and associate professor in Penn's School of Arts & Sciences. "But what we found, that affiliative, or friendly interactions, are also inherited, hadn't been shown."
"This is a very simple process of social inheritance that we show works very, very well," says Amiyaal Ilany, a senior lecturer at Israel's Bar-Ilan University. "Individuals that were born to higher rank are more accurate in their inheritance, and they have good reason to do so. It fits well with what is already known about inheritance of rank. There are very strict rules about what place you sit in the hierarchy if you are a hyena."
The work builds on a theoretical model of social network inheritance Akçay and Ilany developed in 2016. According to that simple framework, animals establish their networks by "social inheritance," or copying their mother's behaviors. The model fit well with snapshots of real-world social networks from not only hyenas but also three other social species: bottle-nosed dolphins, rock hyrax, and sleepy lizards.
In the new work, the team aimed to refine their model to better understand the intricacies of social inheritance in hyenas. They were fortunate to have a robust dataset collected by Akçay and Ilany's coauthor, zoologist Kay Holekamp of Michigan State University, consisting of 27 years of detailed accounting of a clan's social interactions.
"We realized we could use that dataset to directly test our model, to see if social ties are inherited or not," Akçay says.
Field biologists from Holekamp's research group had meticulously tracked how hyenas in a clan interacted, including who spent time with whom as well as the social rank of each member. To do so, researchers spent months getting to know each member of the clan by sight.
"They are there year-round, every day, identifying individuals by their specific spot patterns and other characteristics," Ilany says.
These observations allowed Akçay, Ilany, and Holekamp to map out hyenas' social networks based on which individuals spent time close together.
"This use of proximity to track social networks isn't possible with humans, as two strangers might randomly get into an elevator together," Ilany says. "But with hyenas, if one individual gets within a few meters of another, that suggests that they have a social connection."
With this picture of each individual's social affiliations in hand, the researchers compared the social networks of mothers to their offspring. "We developed a new metric to measure social inheritance, to track how faithfully an offspring's network reproduces its mother's network," Akçay says.
Hyena cubs stick close to their mothers for the first couple years of life, so the networks of mothers and their offsprings were quite similar to start. However, the researchers noticed that even as the young stopped spending so much time in close proximity to their mothers they still sustained quite similar networks, particularly for female offspring, who generally remain members of the clan for life. "We have data in some cases showing that the network similarity between mothers and offspring, especially female offspring, was still very high after six or so years," says Ilany. "You may not be seeing your mother as often, or she even may have died, but you still have similar friends."
This pattern was especially strong for the higher-ranking mothers, for whom social inheritance was the strongest in the group.
"That is kind of intuitive because things like that happen in human society as well," Akçay says. "It happens so much we take it for granted. We inherit social connections, and there's a lot of social science research that shows that this has a huge influence on people's life trajectory."
Offspring of lower-ranking mothers were less likely to reproduce their mother's social networks, perhaps trying to compensate for their more lowly origins by associating with a greater variety of individuals.
There is no genetic inheritance of rank or close associates in this species, so in Holekamp's opinion one of the most remarkable things about the phenomenon documented here is that the youngsters' relationships with their mothers' close associates are all learned very early in life. One explanation for why inheritance of social networks works better for high- than for low-ranking hyenas may be that low-ranking females tend to go off on their own more often to avoid competition with higher-ranking hyenas, so their cubs have fewer learning opportunities than cubs of high-ranking females.
Mother-offspring pairs with more similar social networks also lived longer, the team found. This effect on survivorship may owe to the fact that offspring who spend more time with their mothers and thus replicate their social networks benefit from the increased care.
Social rank also had an effect on survivorship and reproductive success.
"Rank is super important," says Akçay. "If you're born to a lower-ranked mother, you are less likely to survive and to reproduce."
The researchers note that social network inheritance likely contributes to a group's stability and also has implications for how behaviors are learned and spread through groups.
The study also underscores how factors other than genetics hold sway in key evolutionary outcomes, including reproductive success and overall survival. "A lot of things that are considered by default to be genetically determined may depend on environmental and social processes," says Ilany.
###
Erol Akçay is an associate professor of biology in the School of Arts & Sciences at the University of Pennsylvania.
Amiyaal Ilany is a senior lecturer at the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University and completed a postdoctoral fellowship working with Akçay at Penn.
Kay Holekamp is a professor of zoology at Michigan State University.
The research was supported by the Israel Science Foundation (grants 244/19 and 245/19), U.S. Army Research Office (Grant W911NF-17-1-0017), Israel-U.S. Binational Science Foundation (grants 2015088 and 2019156), and National Science Foundation (grants 185
Inherited social networks shape spotted hyena society and survival
AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
In spotted hyena societies, inherited social networks - passed from mothers to offspring - are essential to hyena life and survival, according to a new study. While the structure of animal social networks plays an important role in all social processes as well as health, survival and reproductive success, the general mechanisms that determine social structure in the wild remain unknown. One proposed model, termed social inheritance, suggests that an offspring's social affiliations tend to resemble those of their parents, particularly those of the mother. Previous research has indicated that these inherited social networks may influence social structure across generations in multiple species. Here, Amiyaal Ilany and colleagues evaluate the role of social inheritance in spotted hyena society, which is female-dominated and highly structured. Combining social network analysis and a transgenerational dataset comprised of 73,767 social observations among a population of wild hyenas collected over 27 years, Ilany et al. found that that the social relationships of juvenile hyenas are similar to those of their mothers and that the degree of similarity increases with the mother's social rank. What's more, the results show that the strength of the maternal relationship affects social inheritance and is also positively correlated with the long-term survival for both mother and offspring. According to the authors, the findings suggest that selection for social inheritance might play an essential role in shaping hyena social behavior and the fitness of individual hyenas. "Future work should seek to examine how widely specific social relationships are inherited in a range of population structures and what implications this has for the rate of evolution of the many processes that depend on social network structure," write Josh Firth and Ben Sheldon in a related Perspective.
###
Disclaimer:AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.3934 and 1755089).
CAPTION
A massive study of data collected over 27 years, published today in the journal Science, sheds new light on social networks, rank and survival of spotted hyenas.
Dr. Amiyaal Ilany, a biologist at Bar-Ilan University in Israel, integrates behavioral ecology, network science, and social science, to study broad aspects of social behavior in the wild. As a postdoctoral researcher at the University of Pennsylvania, he developed, together with Dr. Erol Akçay, a theoretical model suggesting that social inheritance - in which offspring inherit their social bonds from their parents, either passively or by copying them - could explain the social networks of multiple species. To test their model Ilany and Akçay forged a partnership with Dr. Kay Holekamp, of Michigan State University. Holekamp had spent the previous 27 years observing wild spotted hyenas in Kenya. Poring over Holekamp's data, which included nearly 74,000 social interactions among the spotted creatures, they were able to show, for the first time on such a large scale, that their model correctly hypothesized that a process of social inheritance determines how offspring relationships are formed and maintained. Their study also elucidates the major role that social rank plays in structuring the spotted hyena clan, and how this affects survival.
CREDIT
Lily Johnson-Ulrich
Among spotted hyenas, social ties are inherited
Massive study of data collected over 27 years sheds light on social networks, rank, and survival of this African species
IMAGE: A MASSIVE STUDY OF DATA COLLECTED OVER 27 YEARS, PUBLISHED TODAY IN THE JOURNAL SCIENCE, SHEDS NEW LIGHT ON SOCIAL NETWORKS, RANK AND SURVIVAL OF SPOTTED HYENAS. DR. AMIYAAL ILANY, A... view more
CREDIT: KATE SHAW YOSHIDA
Social networks among animals are critical to various aspects of their lives, including reproductive success and survival, and could even teach us more about human relationships.
Dr. Amiyaal Ilany, a biologist at the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University in Israel, integrates behavioral ecology, network science, and social science, to study broad aspects of social behavior in the wild. As a postdoctoral researcher at the University of Pennsylvania, he developed, together with Dr. Erol Akçay, a theoretical model suggesting that social inheritance - in which offspring inherit their social bonds from their parents, either passively or by copying them - could explain the social networks of multiple species.
In a study published today in the journal Science, the researchers show, for the first time on such a large scale, that their model correctly hypothesized that a process of social inheritance determines how offspring relationships are formed and maintained. Their study also elucidates the major role that social rank plays in structuring the spotted hyena clan, and how this affects survival.
To test their model Ilany and Akçay forged a partnership with Dr. Kay Holekamp, of Michigan State University. Holekamp had spent the previous 27 years observing wild spotted hyenas in Kenya. The researchers pored over Holekamp's data, which included nearly 74,000 social interactions among the spotted creatures.
"Social affiliations are, indeed, inherited within clusters of hyenas. The plethora of data on spotted hyenas that was collected by Kay Holecamp provided us with a golden opportunity to test the model we developed several years ago," says Dr. Ilany, the lead author of the study. "We found overwhelming evidence that social connections of offspring are similar to those of the mother. A mother who has social affiliations with another hyena can connect her offspring to that hyena and the two, in turn, will form a social bond. Even after the mother-offspring bond itself weakens dramatically, the offspring still remain connected to their mother's friends."
Spotted hyenas live in clans, the size of which depends on the abundance of prey and may vary from only a few individuals to more than a hundred. Life in the clan can be difficult for lower-ranked individuals. They may be excluded and may not get access to food.
"Rank is super important," says Dr. Akçay, who co-authored the study. "Spotted hyena live in a matriarchal society. Those born to a lower-ranked mother are less likely to survive and to reproduce." Descendants of high-class individuals face fewer constraints than descendants of lower-class individuals in choosing their social partners. The researchers found that offspring born to high-ranked mothers copied their mother's bonds more accurately than those born to low-ranked mothers.
Social inheritance plays an important role in survival, and the researchers discovered an association between the two in both mothers and female offspring. There was a positive relationship between offspring survival and social associations that were similar to their mothers, but only in offspring of high-ranked mothers. Mothers of offspring who were more similar to them in social association were more likely to survive to the following year, possibly reflecting a change in maternal relationships as they get older.
The results of this study suggest that social inheritance plays an important role in building the social networks of hyenas and further supports Ilany's and Akçay's hypothesis that in species with stable social groups, the inheritance of social connections from parents is the cornerstone of social structure. In several species successful social integration is associated with higher survival and reproductive success. The results add to this by showing that social inheritance is also associated with both offspring and mother survival.
The researchers note that social network inheritance likely contributes to a group's stability, and also has implications for how behaviors are learned and spread through groups. The study also underscores how factors other than genetics hold sway in key evolutionary outcomes, including reproductive success and overall survival. "A lot of things that are considered by default to be genetically determined may depend on environmental and social processes," concludes Ilany.
CAPTION
A massive study of data collected over 27 years, published today in the journal Science, sheds new light on social networks, rank and survival of spotted hyenas.
Dr. Amiyaal Ilany, a biologist at Bar-Ilan University in Israel, integrates behavioral ecology, network science, and social science, to study broad aspects of social behavior in the wild. As a postdoctoral researcher at the University of Pennsylvania, he developed, together with Dr. Erol Akçay, a theoretical model suggesting that social inheritance - in which offspring inherit their social bonds from their parents, either passively or by copying them - could explain the social networks of multiple species. To test their model Ilany and Akçay forged a partnership with Dr. Kay Holekamp, of Michigan State University. Holekamp had spent the previous 27 years observing wild spotted hyenas in Kenya.
Poring over Holekamp's data, which included nearly 74,000 social interactions among the spotted creatures, they were able to show, for the first time on such a large scale, that their model correctly hypothesized that a process of social inheritance determines how offspring relationships are formed and maintained. Their study also elucidates the major role that social rank plays in structuring the spotted hyena clan, and how this affects survival.
