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.

On the trail of a great mystery; how did the baboons get to ancient Egypt?

The first sequenced mitogenome of a mummified non-human primate connects an Egyptian ba-boon dated to ca. 800-540 BCE to modern baboon populations in Eritrea, Ethiopia and eastern Su-dan, providing evidence for Egyptian-Adulite trade centuries earlier than current archaeological evidence.
 Illustration Credit: © 2023 by Mike Costelloe
(CC BY-NC-ND 4.0.)

An interdisciplinary project led by primatologist Gisela Kopp is using genetic analysis to determine the geographic origin of mummified baboons found in ancient Egypt. The team finds evidence that the two legendary trading regions of Punt and Adulis may have been the same place separated by a thousand years of history.

In ancient Egypt, various deities were portrayed as animals. Thoth, the god of learning and wisdom was represented by a hamadryas baboon. Baboons, probably held in captivity in Egypt, were mummified as votive offerings after their deaths. Today, no wild baboons live in Egypt, and there is no evidence to suggest that these primates did so in the past. In an interdisciplinary project involving biologists, Egyptologists and anthropologists, Gisela Kopp, a biologist from Konstanz who conducts research on non-human primates, pursued the question of how and from where baboons came to Egypt. The results have been published in the current issue of the journal eLife.

Research reveals three new marsupial species – though all likely extinct

A Crest-Tail Mulgara.
Photo Credit: Bobby Tamayo, Simpson Desert, QLD

The exciting discovery of three new species of a small Australian marsupial has been tempered by the sad fact that each of the newly identified species of mulgara is likely already extinct.

The Curtin University-led study has identified three new species of mulgaras, which are small carnivorous marsupials related to the Tasmanian Devil and quoll and that are important to the arid and semi-arid regions they inhabit in South Australia, Western Australia, the Northern Territory and Queensland.

Led by Curtin PhD student Jake Newman-Martin, a collaboration with Dr Kenny Travouillon from the Western Australian Museum, Associate Professor Natalie Warburton from Murdoch University and Associate Professor Milo Barham and Dr Alison Blyth both from Curtin analyzed preserved specimens of mulgaras from museums across the country, including bones found in caves which had previously not been identifiable.

Mr. Newman-Martin said the research had identified six species of mulgaras, as opposed to the previously accepted two and it also concluded that a third previously named mulgara was indeed a valid species. However, four of the proposed species appeared to be already extinct.

Scientists uncover cause of mysterious deaths of elephants in Zimbabwe

Photo Credit: Charl Durand

During this unique study, scientists from the Victoria Falls Wildlife Trust, the Animal and Plant Health Agency UK, the University of Surrey and laboratories in South Africa investigated the mysterious deaths of 35 elephants mostly between August and September 2020, in a 40 x 25 km radius of North-Western Zimbabwe. This incident followed the death of approximately 350 elephants in neighboring northern Botswana from May to June 2020, which triggered much international concern. 

African savanna elephants are an endangered species with only 350,000 remaining in the wild and ongoing losses estimated at eight percent annually. This finding is very worrying since elephants are on the International Union for Conservation of Nature red list already. Investigating the deaths of these elephants is crucial to sustaining the future of this majestic species. 

New insights into the genetics of the common octopus: genome at the chromosome level decoded

Octopus vulgaris
Photo Credit: ©Antonio, Valerio Cirillo (BEOM SZN), 2023

Octopuses are fascinating animals – and serve as important model organisms in neuroscience, cognition research and developmental biology. To gain a deeper understanding of their biology and evolutionary history, validated data on the composition of their genome is needed, which has been lacking until now. Scientists from the University of Vienna together with an international research team have now been able to close this gap and, in a study, determined impressive figures: 2.8 billion base pairs - organized in 30 chromosomes. What sounds so simple is the result of complex, computer-assisted genome analyses and comparisons with the genomes of other cephalopod species. This groundbreaking research has just been published in the renowned journal G3: Genes / Genomes / Genetics.

Octopuses, together with squid and cuttlefish, belong to a group of coleoid cephalopods consisting of several hundreds of species that are characterized by highly diversified lifestyles, body structure and adaptations to their environment. The study of these animals looks back on a long tradition, especially since the neuronal plasticity of the octopus brain – meaning the brain's ability to change and adapt as you learn and experience new things – provides evidence for the existence of functionally analogous structures to the brains of mammals. This is making them a comparative model group for neurophysiological studies. Also, their ability to regenerate parts of their bodies as well as the rapid changes of their body patterns, which are important for camouflage and communication, make octopuses a popular research subject for studying how these innovative traits arose – and how they have changed – during evolution.

Marine mammals in zoos and aquariums now live 2-3 times longer than in the wild

Photo Credit: Los Muertos Crew

A new study provides compelling evidence that animal care and management practices at zoos and aquariums have significantly improved over time. The study, led by Species360 and University of Southern Denmark Research Scientist Dr. Morgane Tidière in collaboration with 41 co-authors from academic, governmental, and zoological institutions around the world, is the first to examine life expectancy and lifespan equality together as a proxy of population welfare in marine mammal species.

The study also found that marine mammal species live longer in zoological institutions than in the wild as a result of advances in animal care practices centered on animal welfare. The results have been published in Proceedings of the Royal Society B: Biological Sciences.

From SDU the following researchers contributed: Fernando Colchero, Johanna Staerk, Ditte H. Andersen, Kirstin Anderson Hansen and Dalia A. Conde.

The animals in the study
The four species in this study (harbor seal, sea lion, polar bear and bottlenose dolphin) were selected because they represent 63,4% of all marine mammals, registered in the global Species360 Zoological Information Management System (ZIMS).

Critical step made for managing brushtail possums

Researchers say mapping the genetic code of the brushtail possum will benefit those working to both conserve and control the animal.

In a five-year long study, just published in Nature Communications, an international group of researchers led by the University of Otago, has assembled the entire genetic code of the marsupial mammal.

The work also uncovered where and when their genes are expressed, and revealed surprising details about their population diversity, reproduction, and origins.

Study lead Associate Professor Tim Hore, of Otago’s Department of Anatomy, describes possums as “a fascinating animal that is loved in one country and a cause of concern in another”.

“They are hunted in Aotearoa New Zealand for their fur, and controlled for conservation, but treasured and protected in Australia. Having their full genetic code is important for both countries as efforts to manage their respective populations are being held back by the lack of this knowledge,” he says.

AI Models Identify Biodiversity in Tropical Rainforests

The Banded Ground Cocoo (Neomorphus radiolosus, left) and the Purple Chested Hummingbird (Polyerata rosenbergi) are among the birds recorded in tropical reforestation plots in Ecuador.
Photo Credits: John Rogers / Martin Schaefer)

Animal sounds are a very good indicator of biodiversity in tropical reforestation areas. Researchers led by Würzburg Professor Jörg Müller demonstrate this by using sound recordings and AI models.

Tropical forests are among the most important habitats on our planet. They are characterized by extremely high species diversity and play an eminent role in the global carbon cycle and the world climate. However, many tropical forest areas have been deforested and overexploitation continues day by day.

Reforested areas in the tropics are therefore becoming increasingly important for the climate and biodiversity. How well biodiversity develops on such areas can be monitored very well with an automated analysis of animal sounds. This was reported by researchers in the journal Nature Communications.

Genomic analysis in snakes shows link between neutral, functional genetic diversity

Eastern massasauga rattlesnake.
Photo Credit: Scott Martin

In the world of threatened and endangered species conservation, the genomic revolution has raised some complicated questions: How can scientists justify assessing species genetic diversity without consulting entire genomes now that they can be sequenced? But then again, how can scientists justify the time and expense of genome sequencing when age-old measures of neutral genetic diversity are much cheaper and easier to obtain?

A new study suggests making a transition from “old school” genetics to “new school” genomics for species conservation purposes probably isn’t necessary in all cases.

Researchers found the functional genetic diversity they detected by analyzing gene variations in fully sequenced genomes of 90 Eastern massasauga rattlesnakes correlated nicely with the neutral genetic diversity seen across broad sections of those same genomes containing no protein-coding genes – similar to the type of genetic material historically used to assess genetic diversity. 

“If we’re worried about the genetic health of populations, neutral diversity can give us a pretty good answer, as has long been argued. We have directly tested that for this species,” said H. Lisle Gibbs, professor of evolution, ecology and organismal biology at The Ohio State University and senior author of the study. 

Space weather disrupts nocturnal bird migration

A Baltimore oriole in flight. Orioles are nocturnal migratory birds.
Photo Credit: Andrew Dreelin

It’s well-known that birds and other animals rely on Earth’s magnetic field for long-distance navigation during seasonal migrations.

But how do periodic disruptions of the planet’s magnetic field, caused by solar flares and other energetic outbursts, affect the reliability of those biological navigation systems?

University of Michigan researchers and their colleagues used massive, long-term datasets from networks of U.S. Doppler weather radar stations and ground-based magnetometers—devices that measure the intensity of local magnetic fields—to test for a possible link between geomagnetic disturbances and disruptions to nocturnal bird migration.

They found a 9%-17% reduction in the number of migrating birds, in both spring and fall, during severe space weather events. And the birds that chose to migrate during such events seemed to experience more difficulty navigating, especially under overcast conditions in autumn.

The new findings, published online Oct. 9 in Proceedings of the National Academy of Sciences, provide correlational evidence for previously unknown relationships between nocturnal bird migration dynamics and geomagnetic disturbances, according to the researchers.

Feather-tailed possums in New Guinea were originally Aussies: fossil study

The New Guinean feather-tailed possum, Distoechurus pennatus, never developed gliding.
Photo Credit: UNSW Sydney

Scientists have long known that the miniature feather-tailed possums in Australia and the island of New Guinea – members of the marsupial family Acrobatidae – were evolutionary cousins, but where they started their long evolutionary journey has been a bit of a mystery – until now.

According to recently published research in Alcheringa: An Australasian Journal of Paleontology, paleontologists from UNSW Sydney say the modern-day animals on either side of the Torres Strait came from common ancestors in Australia before diverging into their living gliding and non-gliding descendants, known as Acrobates pygmaeus in Australia and Distoechurus pennatus in New Guinea.

Professor Mike Archer from UNSW’s School of Biological Earth and Environmental Sciences says that in an analysis of extinct species found at Riversleigh World Heritage Area fossil deposits in north-western Queensland revealed that ancestors of both groups of possums were present in Australia by at least 25 million years ago.

“As Riversleigh started revealing its prehistoric treasures, we discovered four different species of feathertail possums, the first ‘deep-time’ fossil record known for the whole family,” he says.

Curtin study suggests rare echidna noises could be the ‘language of love’

Echidnas, sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae
Photo Credit: Emmanuel Higgins

Curtin University researchers have captured rare recordings of echidnas cooing, grunting and making a range of other sounds, but only during the breeding season.

Lead author Dr Christine Cooper, from Curtin’s School of Molecular and Life Sciences, said there had been ongoing scientific debate around the ability of echidnas to vocalize as a way of communicating or if the sounds they make are simply sniffing noises related to breathing.

“We observed wild short-beaked echidnas at Dryandra National Park, near Narrogin, Western Australia, making cooing and grunting sounds, in addition to the wheezing and exhalation noises that the animals are known to make,” Dr Cooper said.

“Our team managed to capture some of these sounds with hand-held microphones as well as a camera and microphone left unattended at the entrance to a cave popular with echidnas.

Study shows birds that have evolved greater complexity are less biodiverse

Songbirds have less complex skeletons and are species rich
Photo Credit: cocoparisienne

A new study of the evolution of birds shows that as their skeletons become more complex, they also decrease in diversity, with fewer species as they become more specialized in their niches. The findings, published in Nature Communications, show a correlation between skeleton complexity and bird diversity for the first time, and help biologists better understand why biodiversity varies across the birds.

Researchers at the Milner Centre for Evolution at the University of Bath looked at 983 species across all major groups of living birds and measured the complexity of their skeletons by comparing the bones in their fore limbs (wings) and hind limbs (legs).

They found that less complex birds - those with a smaller difference between their fore and hind limbs - had more species diversity than those with higher complexity and a larger difference between their limbs.

For example, birds such as pigeons, gulls and songbirds (passerines) have low skeletal complexity but a high diversity of species living in varied habitats across the world.