Caring glass frog fathers have smaller testes

Males of the glassfrog species Hyalinobatrachium valerioi are very dedicated fathers.
Photo Credit: © Francesca Angiolani

An international team of researchers including the University of Bern shows in a new study that male glass frogs that care for their offspring have smaller testes than males of species that do not provide any brood care. This indicates an evolutionary trade-off between sperm production and parenting.

Living in the tropical rainforests of Central and South America, frogs of the glass frog family are fascinating because of their transparent skin on their belly, which reveals their internal organs. However, it is not only the appearance of these amphibians that is remarkable, but also their social behavior. In many - but not all - glass frog species, the males remain with the clutch after mating and guard and care for their offspring. In a new study, an international team, including researchers from the Institute of Ecology and Evolution at the University of Bern, shows that there is a link between this paternal care and the testes size of glass frogs. The results were recently published in the journal Proceedings of the Royal Society B.

Physically impaired primates find ways to modify their behaviors to compensate for their disabilities

Infant macaque at the Awajishima Monkey Center.
Photo Credit: Sarah Turner

Primates show a remarkable ability to modify their behaviors to accommodate their physical disabilities and impairments according to a new literature review by Concordia researchers.

Whether the disabilities are the result of congenital malformations or injuries, many primate species exhibited behavioral flexibility and innovation to compensate for their disabilities. They also benefitted from flexible and innovative behavior by their mothers early in life and from their peers within their population group as they aged.

Researchers at the Primatology and Interdisciplinary Environmental Studies (PIES) Lab looked at 114 studies and published their findings in the American Journal of Primatology.

The survey also revealed something the researchers had not anticipated.

“Brogan Stewart, a PhD candidate and the paper’s lead author, noticed that a high proportion of the papers mentioned a connection to human activity as a potential or actual cause of impairment,” says co-corresponding author Sarah Turner, an associate professor in the Department of Geography, Planning and Environment in the Faculty of Arts and Science.

“The disabilities may be the result of primates being caught in snares intended for other animals, or farmers trying to deter crop foraging. Perhaps they are the result of vehicle collision, or sometimes there are links between a small population’s genetics and the impairments, or diseases transmitted from people or contaminants in the environment.”

Birds have been adapting to human activity for millennia

Coot nesting on bike on a lake in Copenhagen. Birds and humans also co-inhabited specific environments in our prehistory, new research shows.
Photo Credit: Lisa Yeomans

Roughly 14,500 to 10,500 years ago, in the transition from the last glacial period, humans harvesting vegetation from the wetlands of eastern Jordan created a habitat for birds that would otherwise have migrated, a new study reveals. It shows that human activity is not necessarily detrimental to biodiversity but may allow for species to co-inhabit specific environments, the researchers suggest.

The presence of humans is usually associated with negative effects on flora and fauna, and our species has demonstrably influenced biodiversity negatively in the course of history.

But in a new study published in the Journal of Archaeological Method and Theory, a team of researchers from the University of Copenhagen and the University of Turin have discovered that some human activities may have had an encouraging effect on biodiversity through modification of specific ecosystems.

Scientists are unraveling the secrets of red and grey squirrel competition

Image Credit: Gemini Advance AI

In a first of its kind study, researchers have identified significant differences between the diversity of gut bacteria in grey squirrels compared to red squirrels which could hold the key to further understanding the ability of grey squirrels to outcompete red squirrels in the UK. 

New research, published in the Journal of Medical Microbiology, looked to understand more about the mechanisms by which grey squirrels are able to gain an advantage over red squirrels. Chris Nichols, Conservation Evidence Manager at the Woodland Trust, and co-author of the study, said:

“The more we know about grey squirrels, the more equipped we’re going to be in the future to tackle the threats they pose to red squirrels and our native trees, which is one of the biggest problems for forest conservation in the UK.”

Grey squirrels are an invasive, non-native species introduced from North America to sites in Great Britain and Ireland between 1876 to 1929. They out-compete the native red squirrels and multiply thanks to various traits including their ability to access a broader range of food sources including the bark of UK broadleaved trees. This causes significant damage to the trees, and is a behavior that, prior to this research, was not completely understood. 

Desert Ants: The Magnetic Field Calibrates the Navigation System

The desert ant Cataglyphis nodus at its nest entrance - an inconspicuous hole in the ground that cannot be seen from the ant's perspective. To find its way back there, the ant uses the earth's magnetic field during its learning walks.
Photo Credit: Robin Grob

Desert ants find their way during an early learning phase with the help of the Earth's magnetic field. The associated learning process leaves clear traces in their nervous system. This is shown in a new study by a Würzburg research team.

They are only a few centimeters tall and their brains have a comparatively simple structure with less than one million neurons. Nevertheless, desert ants of the Cataglyphis genus possess abilities that distinguish them from many other creatures: The animals are able to orient themselves to the Earth's magnetic field.

Visible Changes in the Nervous System

A research team from Julius-Maximilians-Universität Würzburg (JMU) discovered this a few years ago. However, it was previously unknown where in the ants' brains the magnetic information is processed. This has now changed: In a new study published in the journal PNAS - Proceedings of the National Academy of Sciences, the team shows that information about the Earth's magnetic field is primarily processed in the ants' internal compass, the so-called central complex, and in the mushroom bodies, the animals' learning and memory centers.

Genetic analysis and archaeological insight combine to reveal the ancient origins of the fallow deer

Fallow deer
Photo Credit: Nick Fewings

Modern populations of fallow deer possess hidden cultural histories dating back to the Roman Empire which ought to be factored into decisions around their management and conservation.

New research, bringing together DNA analysis with archaeological insights, has revealed how fallow deer have been repeatedly moved to new territories by humans, often as a symbol of colonial power or because of ancient cultures and religions.

The results show that the animal was first introduced into Britain by the Romans and not the Normans, as previously believed. They also reveal how British colonial links during the 17th-19th centuries played a key role in spreading the deer around the world, including the Caribbean island of Barbuda, where it is the national animal.

The research, conducted jointly by the University of Exeter and Durham University, compares contemporary fallow deer records with zooarchaeological samples dating back 10,000 years.

Funded by the Arts and Humanities Research Council, the work has been published in two new studies, simultaneously. The 10,000-year biocultural history of fallow deer and its implications for conservation policy is featured in the latest edition of PNAS, while Ancient and modern DNA tracks temporal and spatial population dynamics in the European fallow deer since the Eemian interglacial is published in Scientific Reports.

Ants Recognize Infected Wounds and Treat Them

A Matabele ant tends to the wound of a fellow ant whose legs were bitten off in a fight with termites.
 Photo Credit: Erik Frank / Universität Würzburg

The African Matabele ants are often injured in fights with termites. Their conspecifics recognize when the wounds become infected and initiate antibiotic treatment.

The Matabele ants (Megaponera analis), which are widespread south of the Sahara, have a narrow diet: They only eat termites. Their hunting expeditions are dangerous because termite soldiers defend their conspecifics – and use their powerful mandibles to do so. It is therefore common for ants to be injured while hunting.

If the wounds become infected, there is a significant survival risk. However, Matabele ants have developed a sophisticated healthcare system: they can distinguish between non-infected and infected wounds and treat the latter efficiently with antibiotics they produce themselves. This is reported by a team led by Dr Erik Frank from Julius-Maximilians-Universität (JMU) Würzburg and Professor Laurent Keller from the University of Lausanne in the journal Nature Communications.

Human-driven extinction of birds much greater than previously known

The dodo was endemic to the island of Mauritius. It could not fly and was exterminated by man during the 17th century.
Image Credit: German Rojas

On many of the world's islands, bird species began to become extinct with the arrival of humans. In a new study involving researchers from the University of Gothenburg and Uppsala University, it is estimated that humans have contributed to the extinction of around 1,400 bird species – twice as high as previously thought.

Because the lightweight bones of birds break down quickly, few fossils are formed. In the past, when scientists had to rely on observations and fossils, it was estimated that 640 species of birds had become extinct during the lifetime of modern humans, 90 percent of them on islands inhabited by humans. Classic examples are the dodo on Mauritius and the great auk in the North Atlantic, which, like penguins, could not fly.

However, by using statistical modeling, scientists now dare to estimate that around 1,400 bird species have become extinct.

“This is twice as many species as those that have left fossils as evidence of their existence. “Virtually all of these species were wiped out directly or indirectly due to human activity,” says Søren Faurby, a researcher in Zoology at the University of Gothenburg and co-author of the study published in Nature Communications.

Insects already had a variety of defense strategies in the Cretaceous

Larva of a wedge-shaped beetle in amber, which could have lived inside other insects like its modern counterparts. 
Image Credit: © Carolin Haug

Analyses of amber show that insect larvae were already using a wide variety of tactics to protect themselves from predators 100 million years ago.

Early life stages of insects fulfill important functions in our ecosystems. They decompose dead bodies and wood, forming soil and returning various elements into material cycles. Not least, they are a major food source for many larger animals such as birds and mammals. This has led to many insect larvae developing structures and strategies for reducing the danger of being eaten. These include features like spines and hairs, but also camouflage and concealment. Over millions of years, a wide variety of such adaptation strategies have developed.

Researchers at LMU and the universities of Greifswald and Rostock have studied particularly well-preserved fossils from Burmese amber and have been able to demonstrate that such anti-predator mechanisms had already evolved very diverse forms in insect larvae during the Cretaceous period 100 million years ago. This includes well-known strategies such as that employed by lacewing larvae, which carry various plant and animal materials on their back to give them camouflage, or the ploy of mimicking the appearance of certain plant parts.

Scientists collect aardvark poop to understand how the species is impacted by climate in Africa

Aardvark.
Photo Credit: Peter Buss

In a first-of-its-kind study of aardvarks, Oregon State University researchers spent months in sub-Saharan Africa collecting poop from the animal and concluded that aridification of the landscape is isolating them, which they say could have implications for their long-term survival.

“Everyone had heard of aardvarks and they are considered very ecologically important but there has been little study of them,” said Clint Epps, a wildlife biologist at Oregon State. “We wanted to see if we could collect enough data to begin to understand them.”

In a just-published paper in Diversity and Distribution, the researchers used genetic information gleaned from 104 aardvark poop samples to begin to understand the range of where they live.

“During times of rapid environmental change, evaluating and describing changes in the landscape where a species lives is important for informed conservation and management decisions,” said Rachel Crowhurst, a wildlife geneticist who works with Epps and co-authored the paper.

Deadly chicken disease: ancient DNA reveals evolution of virulence

With the increase in poultry farming, Marek's disease virus evolved
Photo Credit: Heidi-Ann Fourkiller

Using genetic analyses, an international team led by LMU paleogeneticist Laurent Frantz has revealed the evolutionary history of the pathogen of a fatal disease in chickens.

A notifiable animal disease in Germany, Marek’s disease is caused by the globally distributed Marek’s disease virus (MDV). Over the past century, the virus, which causes tumors in chickens and has a high mortality rate, has become increasingly aggressive. Combating the disease costs the poultry industry over a billion dollars every year. With the help of ancient DNA, an international team of scientists led by LMU paleogenomicist Professor Laurent Frantz and Professor Greger Larson and Professor Adrian Smith from the University of Oxford has now decoded the evolution of MDV and shed light on what is behind the growing virulence.

The international team from the fields of paleogenetics, archeology, and biology isolated viral genomes from chicken bones up to 1,000 years old from 140 archeological sites in Europe and the Near East. “Our data shows that the virus was already widely distributed at least 1,000 years before the first description of the disease in 1907,” says Frantz. When the disease was first described, it was said to produce only mild symptoms in older chickens. With the dramatic increase in poultry farming in the 1950s and 1960s, the virus evolved and has become increasingly virulent despite the development of several vaccines.

Camera traps uncover mysterious lesula monkey’s ‘business’

Camera traps equipped with infrared sensors automatically and non-invasively captured videos of Africa’s lesula monkey in the central Congo Basin in the Democratic Republic of the Congo without any disturbance to their social groups.

Video Credit: Florida Atlantic University

Strategically placed camera traps have uncovered the mysterious behavior of an elusive species of African monkey – Cercopithecus lomamiensis, commonly known as the “lesula.”

In much the same way that Ring home security cameras capture both mundane and extraordinary events, strategically placed camera traps have uncovered the mysterious behavior of an elusive species of African monkey – Cercopithecus lomamiensis, commonly known as the “lesula.” With its large human-like eyes, golden mane and pink face, this cryptic species was discovered in 2012 in the central Congo Basin in the Democratic Republic of the Congo.

Because of the lesula’s mysterious behavior, traditional observational methods in the field are challenging. To date, no behavioral study has been done to evaluate this species’ degree of terrestriality.

To address a lack of comprehensive ecological knowledge on this lineage, Florida Atlantic University researchers were the first to design and employ an intensive camera trap study to document the lesula’s terrestrial movement, daytime activity pattern, birth seasonality, group size and social organization.

Camera traps, equipped with infrared sensors to automatically and non-invasively capture videos, provided the researchers with the best approach to estimate group counts from non-habituated lesula individuals without any disturbance to their social groups.

Bats declined as Britain felled trees for colonial shipbuilding

A western barbastelle.
Photo Credit: Antton Alberdi

Bat numbers declined as Britain’s trees were felled for shipbuilding in the early colonial period, new research shows.

The study, by the University of Exeter and the Bat Conservation Trust (BCT), found Britain’s Western barbastelle bat populations have dropped by 99% over several hundred years.

Animals’ DNA can be analyzed to discover a “signature” of the past, including periods when populations declined, leading to more inbreeding and less genetic diversity.

Scientists used this method to discover the historic decline of Western barbastelles in Britain – and also analyzed modern landscapes to see what helps and harms bats.

They found more genetic diversity among bats in areas rich in broadleaf woodland and diverse habitats.

Artificial light reduced connectivity between populations, probably because bats avoid areas with bright lighting, while rivers and woodlands increased connectivity.

“These bats usually roost in mature oak and beech trees, and move around every few nights – so they benefit from areas with substantial woodland cover,” said Dr Orly Razgour, from the University of Exeter.

Poison dart frogs: Personality determines reproductive strategies

The Allobates femoralis species of poison dart frogs follows different strategies during reproduction according to their behavioral type.
Photo Credit: Eva Ringler

Poison frogs of the species Allobates femoralis are common in the rainforests in South America. Their highly poisonous relatives, such as frogs of the genus Phyllobates, were frequently used by indigenous people of Colombia to extract toxins by rubbing the skin onto arrowheads for the purposes of hunting and fighting. Allobates femoralis frogs are not poisonous. Like many other animal species, however, they have distinct personality traits. Both the males and females, for example, may be particularly bold, aggressive, or eager to explore. Poison frogs mate with several partners over the course of a reproductive period and their character traits have a considerable influence on the reproductive strategies employed by individual animals. 

Most of the previous studies in other animal taxa have examined the effect of personality traits on a single measure of reproductive success. In two recently published studies, researchers in the Institute of Ecology and Evolution at the University of Bern have presented new results on the effects of different combinations of personality traits in both males and females on different components of reproductive success. They examined the influence of personality on mating success, the number of clutches produced, as well as the numbers of offspring that survive into adulthood. The researchers were able to show that certain personality traits are already present in poison dart frogs at tadpole stage and that they also persist after the subsequent metamorphosis. 

Why are songbirds larger in colder climates?

A song-sparrow
Photo Credit: Anish Lakkapragada

Scientists have unlocked the genetic basis underlying the remarkable variation in body size observed in song sparrows, one of North America’s most familiar and beloved songbirds. This discovery also provides insights into this species’ capacity to adapt to the challenges of climate change.

The study, published today in Nature Communications, used genomic sequencing to successfully pinpoint eight genetic variants, or DNA mutations, largely responsible for the nearly threefold difference in body size observed across the song sparrow range from Mexico to Alaska. For instance, song sparrows that live year-round in the Aleutian Islands can be up to three times larger than their counterparts in the coastal marshes of California.

Katherine Carbeck, the study’s first author and a PhD candidate in the faculty of forestry, University of British Columbia, explains that body size varies predictably in many species that inhabit vastly different climatic conditions, aligning with “Bergmann’s rule” which states that organisms in cooler climates tend to be larger as an adaptation to regulate body temperature.

European wildcats avoided introduced domestic cats for 2000 years

A wildcat which is part of the Saving Wildcats conservation breeding for release program which conducted the first release of wildcats to the Cairngorms National Park, Scotland in 2023
Photo Credit: Saving Wildcats

Domestic cats introduced from the Near East and wildcats native to Europe did not mix until the 1960s, despite being exposed to each other for two thousand years.

Two studies published today in Current Biology involving new archaeological and genetic evidence rewrites the history of cats in Europe.

The international team of researchers sequenced and analyzed both wildcats and domestic cats including 48 modern individuals and 258 ancient samples excavated from 85 archaeological sites over the last 8,500 years. They then assessed the patterns of hybridization (or interbreeding) after domestic cats were introduced to Europe over 2,000 years ago, and came into contact with native European wildcats.

The results of the studies demonstrate that, since their introduction, domestic cats and European wildcats generally avoided mating with each other. About 50 years ago in Scotland, however, that all changed and rates of interbreeding between wildcats and domestic cats rose rapidly. This may have happened as a result of dwindling wildcat populations and a lack of opportunity to mate with other wildcats.

Study reveals location of starfish’s head

Postdoctoral scholar Laurent Formery (left) and biology Professor Christopher Lowe with starfish on the shore of Stanford’s Hopkins Marine Station, in Monterey, California.
Photo Credit: LiPo Ching / Stanford University

A new study that combines genetic and molecular techniques helps solve the riddle of starfish body plans, and how starfish start life with bilateral body symmetry – just like humans – but grow up to be adults with fivefold “pentaradial” symmetry.

If you put a hat on a starfish, where would you put it? On the center of the starfish? Or on the point of an arm and, if so, which one? The question is silly, but it gets at serious questions in the fields of zoology and developmental biology that have perplexed veteran scientists and schoolchildren in introductory biology classes alike: Where is the head on a starfish? And how does their body layout relate to ours?

Now, a new Stanford study that used genetic and molecular tools to map out the body regions of starfish – by creating a 3D atlas of their gene expression – helps answer this longstanding mystery. The “head” of a starfish, the researchers found, is not in any one place. Instead, the headlike regions are distributed with some in the center of the sea star as well as in the center of each limb of its body.

Researchers observe wolves hunting and killing sea otters and harbor seals on Alaska’s Katmai coast

Wolf with a sea otter on Alaska's Katmai coast.
Photo Credit: Kelsey Griffin

Firsthand observations of a wolf hunting and killing a harbor seal and a group of wolves hunting and consuming a sea otter on Alaska’s Katmai coast have led scientists to reconsider assumptions about wolf hunting behavior.

Wolves have previously been observed consuming sea otter carcasses, but how they obtain these and the frequency of scavenging versus hunting marine prey is largely unknown. Scientists at Oregon State University, the National Park Service and Alaska Department of Fish and Game are beginning to change that with a paper just published in Ecology.

In the paper, they describe several incidents they observed involving wolves and marine mammals in Katmai National Park that they believe haven’t been previously documented:

Humans have substantially altered the relationship between wolves and deer

A breeding female wolf traveling on a logging road carrying a deer fawn back to her pups in June 2023.
 Photo Credit: Voyageurs Wolf Project

New research from the University of Minnesota’s Voyageurs Wolf Project found that human activities in northern Minnesota — logging, road and trail creation, and infrastructure development — have profoundly impacted where wolves hunt and kill deer fawns. By altering forest ecosystems, humans have created an environment that possibly favors predators. 

This research, recently published in Ecological Applications, is a collaboration between the University of Minnesota, Northern Michigan University, the University of Manitoba, Voyageurs National Park, and the Voyageurs Wolf Project. The Voyageurs Wolf Project is funded, in part, by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). 

“The premise is really quite simple: human activities change where deer are on the landscape, and wolves go where the deer are,” said co-lead author Thomas Gable, a postdoctoral researcher at the University of Minnesota and project lead for the Voyageurs Wolf Project. 

Fruit, nectar, bugs and blood: How bat teeth and jaws evolved for a diverse dinnertime

A side-view image of the skull of a greater spear-nosed bat, Phyllostomus hastatus, a noctilionoid species with an omnivorous diet.
Photo Credit: Sharlene Santana/University of Washington

They don’t know it, but Darwin’s finches changed the world. These closely related species — native to the Galapagos Islands — each sport a uniquely shaped beak that matches their preferred diet. Studying these birds helped Charles Darwin develop the theory of evolution by natural selection.

A group of bats has a similar — and more expansive — evolutionary story to tell. There are more than 200 species of noctilionoid bats, mostly in the American tropics. And despite being close relatives, their jaws evolved in wildly divergent shapes and sizes to exploit different food sources. A paper published in Nature Communications shows those adaptations include dramatic, but also consistent, modifications to tooth number, size, shape and position. For example, bats with short snouts lack certain teeth, presumably due to a lack of space. Species with longer jaws have room for more teeth — and, like humans, their total tooth complement is closer to what the ancestor of placental mammals had.