Woodrats’ dietary choices driven by constraints

A woodrat munches on a juniper berry.
Photo Credit: Sara Weinstein/USU

It’s not easy eating green, as most plants have chemical defenses to deter would-be grazers. Getting enough to eat, while minimizing exposure to toxins, is a persistent challenge that shapes an herbivore’s foraging choices. Do they boost their survival by eating a bit of everything, bypass biological booby traps by specializing on one plant or adapt their strategy as environmental conditions change?

The diversity of an animal’s diet—known as dietary niche breadth—is critical to a species’ resilience, yet it remains poorly understood in mammalian herbivores. In a new study, researchers report findings from an eight-year, large-scale survey exploring the dietary choices of a model herbivore, the woodrat (genus: Neotoma). By analyzing plant DNA in the rodents’ droppings, the scientists compared dietary breadth between individuals, within populations and across species of woodrats throughout North America.

Woodrats exhibited a wide spectrum of diet diversity that included both generalists and specialists. Species-level specialists stuck to narrow food niches, with little difference between individual diets. In contrast, generalist populations contained individuals with more varied diets. Even these individuals appeared to forage on a consistent subset of plants, which likely helps them to manage the risks of consuming potentially poisonous food.

Women of Science: A Legacy of Achievement

Future generations to pursue their passions and break down barriers in the pursuit of knowledge.
Image Credit: Scientific Frontline stock image

Throughout history, women have made groundbreaking contributions to science, despite facing significant societal barriers and a lack of recognition. Their relentless pursuit of knowledge and innovation has shaped our understanding of the world and paved the way for future generations of scientists. This article celebrates the achievements of some of these remarkable women, highlighting their struggles and the impact of their work.

The women featured in this article, along with countless others throughout history, have made invaluable contributions to the advancement of science. Their achievements, often accomplished in the face of adversity and societal barriers, have shaped our understanding of the world and paved the way for future generations of scientists. These women demonstrate the power of perseverance, the importance of challenging established norms, and the profound impact that individual dedication can have on scientific progress. By recognizing and celebrating their legacies, we not only honor their contributions but also inspire future generations to pursue their passions and break down barriers in the pursuit of knowledge.

Life cycles of some insects adapt well to a changing climate. Others, not so much.

A grasshopper, Melanoplus boulderensis, typical of the Colorado Rocky Mountains.
Photo Credit: ©Thomas Naef, 2022

As insect populations decrease worldwide in what some have called an “insect apocalypse,” biologists are desperate to determine how the six-legged creatures are responding to a warming world and to predict the long-term winners and losers.

A new study of Colorado grasshoppers shows that, while the answers are complicated, biologists have much of the knowledge they need to make these predictions and prepare for the consequences.

The findings, published in the journal PLOS Biology, come thanks to the serendipitous discovery of 13,000 grasshoppers collected from the same Colorado mountain site between 1958 and 1960 by a biologist at the University of Colorado Boulder (CU Boulder). After that scientist’s untimely death in 1973, the collection was rescued by his son and donated to the CU Museum, where it languished until 2005, when César Nufio, then a postdoctoral fellow, rediscovered it. Nufio set about curating the collection and initiated a resurvey of the same sites to collect more grasshoppers.

Blood-powered toes give salamanders an arboreal edge

Wandering salamanders are known for gliding high through the canopies of coastal redwood forests, but how the small amphibians stick their landing and take-off with ease remains something of a mystery.

A new study in the Journal of Morphology reveals the answer may have a lot to do with a surprising mechanism: blood-powered toes. The Washington State University-led research team discovered that wandering salamanders (Aneides vagrans) can rapidly fill, trap, and drain the blood in their toe tips to optimize attachment, detachment and general locomotion through their arboreal environment.

The research not only uncovers a previously unknown physiological mechanism in salamanders but also has implications for bioinspired design. Insights into salamander toe mechanics could ultimately inform the development of adhesives, prosthetics, and even robotic appendages.

“Gecko-inspired adhesives already allow surfaces to be reused without losing stickiness,” said Christian Brown, lead author of the study and an integrative physiology and neuroscience postdoctoral researcher at WSU. “Understanding salamander toes could lead to similar breakthroughs in attachment technologies.”

How mites have survived for millions of years

oribatid mite Platynothrus peltifer
Image Credit: Gemini (AI)

An international research team has discovered various mechanisms in asexual mites that generate genetic diversity and thus ensure survival

In collaboration with colleagues from international partner institutions, researchers at the University of Cologne have investigated the asexual reproduction of oribatid mites using genome sequencing techniques. They show that the key to evolution without sex in oribatid mites may lie in the independent evolution of their two chromosome copies – a phenomenon known as the ‘Meselson effect’. The research team identified various mechanisms that may contribute to the genetic diversity of the chromosome sets, potentially enabling the long-term persistence of the mite.

Like humans, oribatid mites possess two sets of chromosomes. However, the asexual oribatid mite Platynothrus peltifer reproduces parthenogenetically: Mothers produce daughters from unfertilized eggs, resulting in a population consisting entirely of females. Using single-individual sequencing, the researchers analysed the accumulated differences between the chromosome copies for the first time and evaluated their significance for the mite’s survival. The study titled ‘Chromosome-scale genome dynamics reveal signatures of independent haplotype evolution in the ancient asexual mite Platynothrus peltifer’, funded by the German Research Foundation (DFG), was published in Science Advances.

Peeing with your peers

 

Male chimps socializing
Photo Credit: Kyoto University, Kumamoto Sanctuary

In Italy, it has been said, there is a proverb for everything.

Chi non piscia in compagnia o è un ladro o è una spia -- "Whoever doesn't pee in the company of others is either a thief or a spy" -- goes one such saying, describing a communal act that in Japanese is known as tsuré-shon.

Social urination can be found represented in artwork across the centuries and around the world, and even today continues to be represented in cultural tropes. Now, researchers in Japan -- observing chimpanzees -- are suggesting that this phenomenon has evolutionary roots even deeper than previously expected.

Despite decades of research into other contagious behaviors such as yawning, contagious urination has never been studied scientifically in any species. To tackle this, a team at Kyoto University conducted 604 hours of direct observation at the University's Kumamoto Sanctuary, documenting 1,328 urination events. The researchers analyzed whether these were aligned in time, triggered by nearby individuals, or influenced by social relationships.

Polygamy is (not) for the birds

Rafael S. Marcondes, a faculty fellow in ecology and evolutionary biology at Rice
Photo Credit: Alex Becker/Rice University

Researchers at Rice University have uncovered new insights into the evolution of bird behavior, revealing why certain mating systems persist while others disappear over time. In a recent paper published in the journal Evolution, Rafael S. Marcondes and Nicolette Douvas reveal that lekking — a mating system where males display for females without forming lasting bonds — is an evolutionarily stable strategy. In contrast, resource-defense polygamy, where one sex — usually but not always the male — guards territories to attract mates, is highly unstable and often reverts to monogamy.

“This research not only examines how mating behaviors influence species survival but also sheds light on larger evolutionary questions,” said Marcondes, the corresponding author and a faculty fellow in ecology and evolutionary biology at Rice. “By studying birds, we’re uncovering principles that may resonate across other species too.”

The study analyzed data from more than 60% of the world’s bird species — approximately 6,620 species — making it one of the most comprehensive analyses of its kind.

Shy sea anemones are more likely to survive heatwaves

Photo Credit: Praveen Kenderla

Even in nature, pride can prevail. A study with researchers from the University of Gothenburg shows that sea anemones that react more slowly to change can survive a heatwave better than individuals that change their behavior quickly.

Along the Atlantic coasts of Europe, many species are exposed to abrupt shifts in habitat. Tides, storms and rapid temperature changes are commonplace for the marine species that live there. With climate change, heatwaves are expected to become more frequent, and researchers wanted to find out how coastal marine species cope with extreme water temperatures. They chose to study the sea anemone species Actinia equina, a species that exhibits individual behaviors.

Bold or shy

“We call them animal personalities. They are different behavioral life strategies found in the same species. The anemones we studied have two personality traits, bold and shy, and in extreme heat waves the shy anemones do better,” says Lynne Sneddon, a zoophysiologist at the University of Gothenburg and co-author of the study published in the Journal of Experimental Biology.

Discovery could end global amphibian pandemic

Panamanian golden frog
Photo Credit: Brian Gratwicke/U.S. Fish & Wildlife Service

A fungus devastating frogs and toads on nearly every continent may have an Achilles heel. Scientists have discovered a virus that infects the fungus, and that could be engineered to save the amphibians.

The fungus, Batrachochytrium dendrobatidis or Bd, ravages the skin of frogs and toads, and eventually causes heart failure. To date it has contributed to the decline of over 500 amphibian species, and 90 possible extinctions including yellow-legged mountain frogs in the Sierras and the Panamanian golden frog. 

A new paper in the journal Current Biology documents the discovery of a virus that infects Bd, and which could be engineered to control the fungal disease.

The UC Riverside researchers who found the virus are excited about the implications of their discovery. In addition to helping them learn about how fungal pathogens rise and spread, it offers the hope of ending what they call a global amphibian pandemic. 

“Frogs control bad insects, crop pests, and mosquitoes. If their populations all over the world collapse, it could be devastating,” said UCR microbiology doctoral student and paper author Mark Yacoub. 

“They’re also the canary in the coal mine of climate change. As temperatures get warmer, UV light gets stronger, and water quality gets worse, frogs respond to that. If they get wiped out, we lose an important environmental signal,” Yacoub said. 

Behavior of ant queens is shaped by their social environment

A black garden ant queen caring for her brood
Photo Credit: © Romain Libbrecht)

The queens in colonies of social insects, such as ants, bees, and wasps, are considered the veritable embodiment of specialization in the animal kingdom. The common perception is that the queen's only task is to lay eggs – and that this attribute is an inherent trait, not influenced by external factors. In contrast, recent research undertaken at Johannes Gutenberg University Mainz (JGU) has demonstrated that in certain ant colonies the social environment can play a crucial role in shaping the behavioral specialization of the queens. "With regard to the ant species we studied, it is social factors that control whether queens become specialized or not. Our findings challenge the widely accepted notion of social insect queens as inherently specialized egg-laying machines," stated Dr. Romain Libbrecht.

The research was conducted by the Reproduction, Nutrition, and Behavior in Insect Societies group at JGU under the supervision of Dr. Romain Libbrecht, an evolutionary biologist. The corresponding paper has recently been published in Functional Ecology. Dr. Romain Libbrecht currently works at the Centre National de la Recherche Scientifique (CNRS) in the Insect Biology Research Institute of the University of Tours.

Honey bees at risk for colony collapse from longer, warmer fall seasons

WSU researchers and students collect samples and perform honey bee colony health assessments in orchards near Modesto, CA.
Photo Credit: Brandon Hopkins

The famous work ethic of honey bees might spell disaster for these busy crop pollinators as the climate warms, new research indicates.

Flying shortens the lives of bees, and worker honey bees will fly to find flowers whenever the weather is right, regardless of how much honey is already in the hive. Using climate and bee population models, researchers found that increasingly long autumns with good flying weather for bees raises the likelihood of colony collapse in the spring.

The study, published in the journal Scientific Reports, focused on the Pacific Northwest but holds implications for hives across the U.S. The researchers also modeled a promising mitigation: putting colonies into indoor cold storage, so honey bees will cluster in their hive before too many workers wear out.

“This is a case where a small amount of warming, even in the near future, will make a big impact on honey bees,” said lead author Kirti Rajagopalan, a Washington State University climate researcher. “It’s not like this is something that can be expected 80 years from now. It is a more immediate impact that needs to be planned for.”

Bees master complex tasks through social interaction

Bees can learn complex, multi-step tasks through social interaction, even if they cannot figure them out on their own.
Photo Credit: Michael Hodgins

In a groundbreaking discovery, bumblebees have been shown to possess a previously unseen level of cognitive sophistication.

 A new study, published in Nature, reveals that these bees can learn complex, multi-step tasks through social interaction, even if they cannot figure them out on their own. This challenges the long-held belief that such advanced social learning is unique to humans, and hints at the presence of key elements of cumulative culture in these insects.

Led by Dr Alice Bridges, postdoctoral researcher at the University of Sheffield, the research team designed a two-step puzzle box requiring bumblebees to perform two distinct actions in sequence to access a sweet reward at the end. The temporary reward was eventually taken away, and bees subsequently had to open the whole box before getting the treat. 

While individual bees struggled to solve the puzzle when starting from scratch, those allowed to observe a trained "demonstrator" bee readily learned the entire sequence – even the first step – while only getting a reward at the end.

What Makes Birds So Smart?

The avian brain is smaller than that of many mammals, but just as capable.
Photo Credit: Kevin Mueller

Researchers at Ruhr University Bochum explain how it is possible for the small brains of pigeons, parrots and corvids to perform equally well as those of mammals, despite their significant differences.

Since the late 19th century, it has been a common belief among researchers that high intelligence requires the high computing capacity of large brains. They also discovered that the cerebral cortex as typical of mammals, is necessary to analyze and link information in great detail. Avian brains, by contrast, are very small and lack any structure resembling a cortex. Nevertheless, scientists showed that parrots and corvids are capable of planning for the future, forging social strategies, recognizing themselves in the mirror and building tools. These and similar aptitudes put them on a par with chimpanzees. Even less gifted birds, such as pigeons, learn orthographic rules that enable them to recognize typos in short words or classify pictures according to categories such as “impressionism”, “water” or “man-made”. How do they do it with such small brains and without a cortex? With their article in Trends in Cognitive Science, Professor Onur Güntürkün, Dr. Roland Pusch and Professor Jonas Rose from Ruhr University Bochum come closer to solving this more than one hundred-year-old puzzle.

Reptile roadkill reveals new threat to endangered lizard species

The western spiny-tailed skink.
Photo Credit: Dr. Holly Bradley

The chance sighting of a dead snake beside a sandy track in remote Western Australia, and the investigation of its stomach contents, has led Curtin University researchers to record the first known instance of a spotted mulga snake consuming a pygmy spiny-tailed skink, raising concerns for a similar-looking, endangered lizard species.

Lead researcher Dr Holly Bradley from Curtin’s School of Molecular and Life Sciences said the discovery of the partially digested pygmy spiny-tailed skink within the snake had implications for the vulnerable western spiny-tailed skink species.

“Found about 300km east of Geraldton and likely killed by a vehicle, the snake’s consumption of the pygmy spiny-tailed skink raises concerns about the susceptibility of similar-sized juvenile western spiny-tailed skinks, which also inhabit the Mid-West region and are classified as endangered,” Dr Bradley said.

“Pygmy spiny-tailed skinks look and act a lot like babies of the endangered western spiny-tailed skink, which live in the same area, so if these snakes are preying on one of them, they are likely also preying on the other.

Study of slowly evolving ‘living fossils’ reveals key genetic insights

The alligator gar, and other gar species, are “living fossils” that it shows little species diversity or physical differences from ancestors that lived tens of millions of years ago.
Photo Credit: David Solomon

In 1859, Charles Darwin coined the term “living fossils” to describe organisms that show little species diversity or physical differences from their ancestors in the fossil record. In a new study, Yale researchers provide the first evidence of a biological mechanism that explains how living fossils occur in nature.

The study, published in the journal Evolution, shows that gars — an ancient group of ray-finned fishes that fit the definition of a living fossil — have the slowest rate of molecular evolution among all jawed vertebrates, meaning their genome changes more slowly than those of other animals.

By linking this finding to the process of hybridization — when two different species produce viable offspring — of gar species in the wild that last shared common ancestry during the age of the dinosaurs, the researchers demonstrate that slow evolution rate of their genome drives their low species diversity.

“We show that gars’ slow rate of molecular evolution has stymied their rate of speciation,” said Thomas J. Near, professor of Ecology and Evolutionary Biology in Yale’s Faculty of Arts and Sciences and the paper’s senior author. “Fundamentally, this is the first instance where science is showing that a lineage, through an intrinsic aspect of its biology, fits the criteria of living fossils.” 

Oregon State University researchers are first to see at-risk bat flying over open ocean

Hoary bat at sea.
Photo Credit: Courtesy of Will Kennerley / the MOSAIC Project.

On a research cruise focused on marine mammals and seabirds, Oregon State University scientists earned an unexpected bonus: The first-ever documented sighting of a hoary bat flying over the open ocean.

The bat was seen in the Humboldt Wind Energy Area about 30 miles off the northern California coast; the Humboldt area has been leased for potential offshore energy development, and the hoary bat is the species of bat most frequently found dead at wind power facilities on land.

OSU faculty research assistant Will Kennerley, the first to see the bat, and colleagues documented the sighting with a paper in the Journal of North American Bat Research. The bat was spotted just after 1 p.m. on Oct. 3, 2022, in observing conditions rated as excellent.

“I have spent a lot of time at sea in all oceans of the world, and I’ve seen a lot of amazing things,” said Lisa Ballance, director of OSU’s Marine Mammal Institute. “A hoary bat was a first for all of us. It’s a reminder of the wonder of nature, and of its vulnerability.”

New Fish Species Discovered at Remote Islands Off Mexico’s Pacific Coast

Two females of the newly discovered species, Halichoeres sanchezi or the tailspot wrasse. The males are larger and have different coloration.
Photo Credit: Allison & Carlos Estape

A team of scientists including Ben Frable of UC San Diego’s Scripps Institution of Oceanography have discovered a new species of tropical fish during an expedition to the remote islands of the Revillagigedo Archipelago off Mexico’s Pacific coast. The fish is likely endemic to these islands, meaning it is found no place else on Earth. The Revillagigedos are sometimes called the “Mexican Galapagos” for their trove of marine biodiversity and rugged beauty. 

The researchers describe the new species, dubbed Halichoeres sanchezi or the tailspot wrasse, in a paper published Feb. 28 in the journal PeerJ. Halichoeres sanchezi was named in honor of marine scientist Carlos Armando Sánchez Ortíz of the Universidad Autónoma de Baja California Sur (UABCS) who collected the first specimen and who organized the 2022 expedition that led to the fish’s discovery.

The eight specimens of the new species collected by the team range in size from around an inch long to nearly six inches. The smaller females of the species are mostly white with reddish horizontal stripes along their top half and black patches on their dorsal fin, behind their gills, and just ahead of their tail fin. Frable described the males as “orangy red up top fading to a yellow belly with a dark band at the base of the tail.” 

Halichoeres sanchezi is a member of the wrasse family, a highly diverse and colorful group of more than 600 species. Most wrasse are less than seven inches long, such as the bluestreak cleaner wrasse (Labroides dimidiatus), but some get much larger like the California sheephead (Semicossyphus pulcher) or the massive humphead wrasse (Cheilinus undulatus), which can reach seven feet in length.

Researchers encountered the new wrasse species inhabiting an underwater field of volcanic rubble at a depth of around 70 feet near San Benedicto Island.

Scientists assemble a richer picture of the plight and resilience of the foothill yellow-legged frog

Foothill yellow-legged frogs live in the flowing water of rivers and streams, so are especially vulnerable when these shrink to isolated pools.
Photo Credit: Brome McCreary / USGS

Up to only a few inches in length, with a lemon-hued belly, the foothill yellow-legged frog may seem unassuming. But its range once stretched from central Oregon to Baja California. In 2023, it was listed under the federal Endangered Species Act. Its rapidly decreasing range is due in part to a fungal pathogen called Batrachochytrium dendrobatidis, or Bd, that has devastated amphibians around the world.

A team of researchers, including UC Santa Barbara’s Andrea Adams, has conducted the most comprehensive study to date of disease dynamics in foothill yellow-legged frogs. The team’s data — sourced from both wild frogs and specimens in museum collections — enabled them to track patterns of infection across a large geographic range. In a study published in Royal Society Open Science, the researchers reveal that drought, rising temperatures and the increasing conversion of land for agriculture appear to be the largest factors driving Bd infection in this species.

The researchers aimed to assemble as much data as they could, both in space and time. They surveyed in the creeks and rivers of California and Oregon, where they swabbed wild yellow-legged frogs for the presence of Bd. It also led them into fluorescent-lit museum collections to sample specimens from as far back as the 1890s.

Study provides rare glimpse of the ringtail, an important but poorly understood predator

Ringtail
Photo Credit: Jonathan Armstrong, Oregon State University

Secretive species can pose special conservation challenges simply because they are so skilled at staying under the radar that researchers have uncovered comparatively little about their basic needs.

One such species is the ringtail, a relative of the raccoon that has cultural significance to many Indigenous peoples in North America.

A collaboration among scientists from Oregon State University, the Hoopa Valley Tribe, Penn State and Cal Poly Humboldt has shed new light on the cat-like animal known for its large eyes and fluffy, striped tail.

The nocturnal carnivore, known scientifically as Bassariscus astutus, usually weighs between 1 and 2 pounds and is around 24 inches long including its tail.

Ringtails use the cavities of living trees or standing dead ones, called snags, to rest, sleep, avoid bad weather, hide from predators and make dens to raise their young.

The research, conducted on the Hoopa Valley Reservation northeast of Eureka, California, found ringtails selected tree cavities in mature and older forests, as well as in younger forests with some older trees still present, rather than oak woodlands or other more open areas.

Snakes do it faster, better

An Australian “snake-lizard” (Lialis burtonis).This species shares numerous similarities with snakes, including loss of limbs and highly flexible skull. But it is an entirely different type of reptile. It is, in fact, a gecko, and is only distantly related to snakes. The snake-lizard is a specialized predator of other lizards and thus has a diet that is also more similar to snakes than it is to other lizards. With just two known species, the snake-lizard has undergone very little evolutionary diversification. Snakes, in contrast, have diversified into many hundreds of species in Australia alone.
Photo Credit: Pascal Title, University of Michigan/Stony Brook University.

More than 100 million years ago, the ancestors of the first snakes were small lizards that lived alongside other small, nondescript lizards in the shadow of the dinosaurs.

Then, in a burst of innovation in form and function, the ancestors of snakes evolved legless bodies that could slither across the ground, highly sophisticated chemical detection systems to find and track prey, and flexible skulls that enabled them to swallow large animals.

Those changes set the stage for the spectacular diversification of snakes over the past 66 million years, allowing them to quickly exploit new opportunities that emerged after an asteroid impact wiped out roughly three-quarters of the planet’s plant and animal species.