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. 

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:

Stunting in infancy linked to differences in cognitive and brain function

Photo Credit: bethL

Children who are too short for their age can suffer reduced cognitive ability arising from differences in brain function as early as six months of age, according to new research.

Researchers from the University of Nottingham were part of a team led by the University of East Anglia who compared the ‘visual working memory’ – the memory capacity that holds visual cues for processing – in children who had stunted growth with those having typical growth.

Published today in the journal Nature Human Behavior, the study found that the visual working memory of infants with poor physical growth was disrupted, making them more easily distracted and setting the stage for poorer cognitive ability one year later.

Stunted growth had previously been linked with poor cognitive outcomes later in life, but this is the first time that this association has been found in infancy. It is also the first time stunted growth has been linked to functional differences in how the brain works in early development.

Bumblebees drop to shake off Asian hornets

Asian hornet
Photo Credit: Public Domain 

Bumblebees have a remarkably successful method for fighting off Asian hornets, new research shows.

When attacked, buff-tailed bumblebees drop to the ground – taking the hornets down with them. This either causes the hornet to lose its grip, or the bee raises its sting and tussles until the hornet gives up.

University of Exeter scientists witnessed over 120 such attacks, and were stunned to find that bumblebees fought off the hornets every time.

Despite this, they found bumblebee colonies had reduced growth rates in areas with high numbers of Asian hornets – suggesting the hornets still had a negative impact, even if their attacks at colony entrances usually failed.

Asian hornets (also known as yellow-legged hornets) have already invaded much of mainland Europe and parts of east Asia, and have recently been reported in the US for the first time.

Sightings in the UK and continental Europe are at record levels this year – raising fears for pollinators and prompting substantial control efforts.

Why Are Killer Whales Harassing and Killing Porpoises Without Eating Them

A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists. A study from Wild Orca and UC Davis’ SeaDoc Society investigates what may be behind it.
 Photo Credit: Courtesy Wild Orca

For decades, fish-eating killer whales in the Pacific Northwest have been observed harassing and even killing porpoises without consuming them — a perplexing behavior that has long intrigued scientists.

A study published today in Marine Mammal Science, co-led by Deborah Giles of Wild Orca and Sarah Teman of the SeaDoc Society, a program of the UC Davis School of Veterinary Medicine, looked at more than 60 years of recorded interactions between Southern Resident killer whales and porpoises in the Salish Sea to better understand why they exhibit this behavior.

Southern Resident killer whales are an endangered population, numbering only 75 individuals. Their survival is intimately tied to the fortunes of chinook salmon — also an endangered species. Without enough chinook salmon, these whales are in danger of extinction.

“I am frequently asked, why don’t the Southern Residents just eat seals or porpoises instead?” said Giles. “It's because fish-eating killer whales have a completely different ecology and culture from orcas that eat marine mammals — even though the two populations live in the same waters. So we must conclude that their interactions with porpoises serve a different purpose, but this purpose has only been speculation until now.”

New insights into the origin of food sharing among humans

Chimpanzees Gremlin and son Grendel, begging for food, at Gombe National Park, Tanzania.
Photo Credit: Courtesy of University of Minnesota

As humans evolved to hunt, gather and share food, cooperation provided a key to our success as a species. While chimpanzees and other primates sometimes share food, humans stand out. As hunter-gatherers — the subsistence strategy that all humans followed until the invention of agriculture — our survival depended on daily sharing of food between unrelated adult males and females. 

While hunter-gatherers today depend heavily on hunting and cooking, long before these activities became important for our ancestors, species such as Australopithecus extracted foods such as roots, tubers and nuts. Since hunter-gatherers and nonhuman primates tend to share foods that are large, valuable and divisible, these nutrient-dense foods are likely candidates for sharing, and may have been susceptible to theft by hungry group members. 

In new research published in the Proceedings of the National Academy of Sciences (PNAS), a team led by College of Biological Sciences Professor Michael Wilson developed a conceptual and mathematical model of the evolution of food production and sharing in early human ancestors. The interdisciplinary team included an economist, a theoretical biologist, an anthropologist and a primatologist. 

Reindeer can show great performance at following human-given indications

Photo Credit: Courtesy of University of Turku

An international team of researchers from the University of Turku, Finland, and the INRAE of Nouzilly, France, explored the ability of sledging reindeer to follow directional indications from humans. Their results highlight that reindeer, which are well habituated to humans, can make use of gestural cues very well with minimal training.

Working animals, such as equines, shepherd dogs, and logging elephants, spend a significant amount of time interacting closely with humans to fulfil specific tasks. Effective communication plays a crucial role in their working relationship. Animals' understanding of human cues, particularly manual pointing gestures, is an important aspect of this communication. 

The use of pointing gestures to communicate with others and to show them where to look or to go is very natural for humans. For other animals that do not use this means of communication, the gesture may not always be easy to understand. For this reason, the pointing gesture is often used in experiments to see if animals can understand cues that are specific to humans. 

“Many species, such as dogs, primates, horses, goats or elephants, have already shown great potential at following human gestures, but this has never been investigated in any deer species. “, says the lead author of the study, Doctoral Researcher Océane Liehrmann from the Department of Biology at the University of Turku, Finland. 

Our visual perception is more rational than we think

Our visual perception adapts flexibly and unconsciously to the decision context when it’s to our advantage.
Photo Credit: Colin Lloyd

Our visual perception depends more strongly on the utility of information than previously thought. This has been demonstrated in a series of experiments conducted by researchers at the Neuroscience Center Zurich. Cognitive biases can begin at the retina.

Are our senses there to provide us with the most complete representation of the world, or do they serve our survival? For a long time, the former was the dominant view in neuroscience. “Was” is the operative word here. In the last 50 years, psychologists such as Nobel Prize winners Daniel Kahnemann and Amos Tversky have shown that human perception is often anything but complete and instead is highly selective.

Experiments have now verified that there is a whole list of examples of cognitive biases. One of the most important is confirmation bias: we often process new information in a way that confirms our beliefs and expectations.

But up until now, researchers haven’t been able to fully explain under what conditions these distortions come into play and when exactly in the perceptual process they begin. A study by researchers led by University of Zurich Professor Todd Hare and ETH Professor Rafael Polania, recently published in the journal Nature Human Behavior, now shows that the brain already adjusts the visual perception of things on the retina when it is in our interest to do so. Or, to put it another way, we unconsciously see things distorted when it comes to our survival, well-being, or other interests.

Researchers warn of future ‘fish wars’ as consequence of climate change

Photo Credit: Sabrina Eickhoff

How climate change could give rise to “fish wars” between nations is the subject of a new research project awarded a £1.1m grant by the US Department of Defense.

The project, entitled “Future Fish Wars: Chasing Ocean Ecosystem Wealth”, is one of 11 to receive a total funding of $18m as part of the US Department of Defense's Minerva Research Initiative, which supports research in social and behavioral sciences on topics relevant to US national security.

The researchers aim to develop new economic theory and approaches to measure the economic value of fisheries in the context of climate change and growing geopolitical ocean conflict.

They say illegal fishing, contested claims to fishing rights and future conflicts are likely outcomes as fish swim for the poles as a result of climate change warming the oceans. 

Over three years, the research team will develop new economic theory for valuing multiple stocks of marine resources, which they will use alongside novel data on conflict and cooperative events to achieve a deeper understanding of future fisheries conflict.

Is “second-guessing” a hard-wired behavior? Mouse study offers clues

U of U Health scientists have found that genes bias decision-making, even decisions that seem irrational.
Illustration Credit: Cornelia Stacher-Hörndli, PhD.

Have you ever made a decision that, in hindsight, seemed irrational? A new study with mice, which could have implications for people, suggests that some decisions are, to a certain extent, beyond their control. Rather, the mice are hard-wired to make them.

“This research is telling us that animals are constrained in the decisions they make,” said Christopher Gregg, PhD, a neurobiologist at University of Utah Health and senior author of the study that was recently published in iScience. “Their genetics push them down one path or another.”

Gregg and his research team started investigating decision-making after noticing mice repeatedly making what appeared to be an irrational decision. After finding a stash of hidden seeds, rather than staying put to eat them, mice kept returning to a location that had food in it the day before. Only on this day, the original location was empty.

“It was as if the mice were second-guessing whether the first location really had no food,” Gregg said. “Like they thought they had missed something.”

Computational model mimics humans’ ability to predict emotions

While a great deal of research has gone into training computer models to infer someone’s emotional state based on their facial expression, that is not the most important aspect of human emotional intelligence, says MIT Professor Rebecca Saxe. Much more important is the ability to predict someone’s emotional response to events before they occur.
Image Credit: Christine Daniloff, MIT
(CC BY-NC-ND 3.0)

When interacting with another person, you likely spend part of your time trying to anticipate how they will feel about what you’re saying or doing. This task requires a cognitive skill called theory of mind, which helps us to infer other people’s beliefs, desires, intentions, and emotions.

MIT neuroscientists have now designed a computational model that can predict other people’s emotions — including joy, gratitude, confusion, regret, and embarrassment — approximating human observers’ social intelligence. The model was designed to predict the emotions of people involved in a situation based on the prisoner’s dilemma, a classic game theory scenario in which two people must decide whether to cooperate with their partner or betray them. 

To build the model, the researchers incorporated several factors that have been hypothesized to influence people’s emotional reactions, including that person’s desires, their expectations in a particular situation, and whether anyone was watching their actions.

“These are very common, basic intuitions, and what we said is, we can take that very basic grammar and make a model that will learn to predict emotions from those features,” says Rebecca Saxe, the John W. Jarve Professor of Brain and Cognitive Sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study.

Adult Friendships Can Triumph Over Childhood Trauma, Even in Baboons

Members of a baboon group in Amboseli, Kenya, relax and groom together, a baboon's way of social bonding.
Photo Credit: Susan C. Alberts, Duke University

Decades of research show that experiencing traumatic things as a child -- such as having an alcoholic parent or growing up in a tumultuous home -- puts you at risk for poorer health and survival later in life.

But mounting evidence suggests that forging strong social relationships can help mitigate these effects. And not just for people, but for our primate cousins, too.

Drawing on 36 years of data, a new study of nearly 200 baboons in southern Kenya finds that adversity early in life can take years off their lifespan, but strong social bonds with other baboons in adulthood can help get them back.

“It’s like the saying from the King James Apocrypha, ‘a faithful friend is the medicine of life,’” said senior author Susan Alberts, professor of biology and evolutionary anthropology at Duke University.

Baboons who had challenging childhoods were able to reclaim two years of life expectancy by forming strong friendships.

The findings were published May 17 in the journal Science Advances.

Most species, including humans, who experience early life adversity suffer as adults. How are gorillas different?

Experienced the loss of her mother and father and the disintegration of her family group before the age of 5. Now 20, she has become a successful mother, raising three offspring.
Photo Credit: Dian Fossey Gorilla Fund

There’s something most species—from baboons to humans to horses—have in common: When they suffer serious adversity early in life, they’re more likely to experience hardship later on in life.

When researchers from the Dian Fossey Gorilla Fund and the University of Michigan decided to look at this question in gorillas, they weren’t sure what they would find.

Previous studies by the Fossey Fund revealed that young gorillas are surprisingly resilient to losing their mothers, in contrast to what has been found in many other species. But losing your mother is only one of many potential bad things that can happen to young animals.

“Assuming that you survive something that we consider early life adversity, it’s often still the case that you will be less healthy or you will have fewer kids or your lifespan will be shorter—no matter what species you are,” said Stacy Rosenbaum, U-M assistant professor of anthropology and senior author of the study. “There’s this whole range of things that happens to you that seems to just make your life worse in adulthood.”

Singing humpback whales respond to wind noise, but not boats

UQ researchers recorded humpback whales off the Queensland coast for the study.
Photo Credit: Mike Doherty

A University of Queensland study has found humpback whales sing louder when the wind is noisy, but don’t have the same reaction to boat engines.

Research lead Dr Elisa Girola from UQ’s Faculty of Science said this quirk of whale evolution could have consequences for breeding and behavior.

“Humpback whales evolved over millions of years with noise from natural sources but noise from man-made vessels is foreign to their instincts,” Dr Girola said.

“It’s a surprising finding given engine noise has a similar frequency range to the wind.

“It’s possible the whales are picking out other differences such as wind noise being broadband and the same over large areas, while vessel noise is generated by a single-point source with specific peaks in frequency.

“We don’t know yet if this lack of response to boat noise is making whales communicate less effectively or making breeding practices more difficult.

The evolution of honey bee brains

European honey bee worker. The researchers studied honey bees exhibiting different behaviors: foragers, nurse bees, and queens. Honey bees in general have been a key insect model for better understanding learning and memory for more than 100 years.
Photo Credit: ©2023 Hiroki Kohno

Researchers have proposed a new model for the evolution of higher brain functions and behaviors in the Hymenoptera order of insects. The team compared the Kenyon cells, a type of neuronal cell, in the mushroom bodies (a part of the insect brain involved in learning, memory and sensory integration) of “primitive” sawflies and sophisticated honey bees. They found that three diverse, specialized Kenyon cell subtypes in honey bee brains appear to have evolved from a single, multifunctional Kenyon cell-subtype ancestor. In the future, this research could help us better understand the evolution of some of our own higher brain functions and behaviors.

Are you “busy as a bee,” a “social butterfly” or a “fly on the wall”? There are many ways we compare our behavior to that of insects, and as it turns out there may be more to it than just fun idioms. Studying insects could help us understand not only how their behavior has evolved, but also the behavior of highly evolved animals, including ourselves. Mammalian brains are big and complex, so it is difficult to identify which behaviors and neural and genetic changes have co-developed over time. By comparison, insect brains are much smaller and simpler, making them useful models for study.

Horses living in groups are better at following human indications than horses living in individual paddocks

An illustration and photo of the research situation.
Photo Credit: Océane Liehrmann

Wild horses live in complex social groups and can move an average distance of 9–16 kilometers in a day, and cover areas up to 40 km2 in one summer. In contrast, domestic horses are kept in enclosures and groups varying in size and even in individual stalls or small paddocks.

Horses living in bigger fields or pastures are more active – they are free to move according to their needs and, for example, to look for shade or shelter against wind and rain. When living in a group, horses can fulfil their social needs, interact in complex ways with many individuals, and have enough space to avoid unwanted interactions.

“It has been observed in earlier studies that horses with access to a pasture with other horses showed better learning performance and were less aggressive towards humans than horses kept in individual stables. Therefore, we wanted to explore whether horses’ social and physical environment affect their responsiveness to human indications,” says the lead author of the study, Doctoral Researcher Océane Liehrmann from the Department of Biology at the University of Turku, Finland.

Study shows how machine learning can identify social grooming behavior from acceleration signals in wild baboons

Photo Credit: Charl Durand

Scientists from Swansea University and the University of Cape Town have tracked social grooming behavior in wild baboons using collar-mounted accelerometers.

The study, published in the journal Royal Society Open Science, is the first to successfully calculate grooming budgets using this method, which opens a whole avenue of future research directions.

Using collars containing accelerometers built at Swansea University, the team recorded the activities of baboons in Cape Town, South Africa, identifying and quantifying general activities such as resting, walking, foraging and running, and also the giving and receiving of grooming.

A supervised machine learning algorithm was trained on acceleration data matched to baboon video recordings and successfully recognized the giving and receiving grooming with high overall accuracy.

The team then applied their machine learning model to acceleration data collected from 12 baboons to quantify grooming and other behaviors continuously throughout the day and night-time.

Wild animals stop the spread of socially transmitted misinformation

For wild animals, false alarms are the most widespread form of misinformation.
Photo Credit: Kaylee Rose Fahimipour

Despite the benefits of learning about the world through social ties, social connections also provide a conduit for misinformation that impedes effective decision-making.

For wild animals, false alarms are the most widespread form of misinformation. For example, when an individual animal in a group makes the decision to produce an alarm signal or initiate an escape maneuver in the absence of a real threat. This initial action produces sensory stimuli that can be perceived by others in the group as an indication of danger, resulting in a cascade of erroneous escape responses that can spread contagiously.

Behavioral and neurophysiological studies suggest that relatively simple behavioral strategies control decision-making in many of these settings. Yet, it is unknown whether these strategies somehow account for the possibility of exposure to misinformation.

Social bird species may be less competitive

Northern mockingbird
Photo Credit: Brian E. Kushner/Cornell Lab of Ornithology 

Using Cornell Lab of Ornithology data, a new study finds that birds that have evolved to be more social are less likely to kick other birds off a bird feeder or a perch.

Spend any time watching backyard bird feeders and it becomes clear that some species are more “dominant” than others. They evict other birds from a feeder or perch, usually based on their body size. Scientists wanted to learn if birds that have evolved to be more social have also evolved to be less aggressive.

Their findings published March 1 in the Proceedings of the Royal Society B, “The Effect of Sociality on Competitive Interactions Among Birds.”

“We found that species’ sociality was inversely related to dominance,” said lead author Ilias Berberi from Carleton University in Ottawa, Canada. “Using data collected from thousands of birdwatching volunteers, we measured the sociality of different species based on their typical group size when seen at bird feeders. Though some species are often found in groups, other tend to be loners. When we examined their dominance interactions, we found that more social species are weaker competitors. Overall, the more social bird species are less likely to evict competing species from the feeders.”

Flamingos form cliques with like-minded pals

The partner of one Caribbean flamingo helps it out in an argument with another pair.
Photo Credit Paul Rose

Flamingos form cliques of like-minded individuals within their flocks, new research shows.

Scientists analyzed the personalities and social behavior of Caribbean and Chilean flamingos.

Birds of both species tended to spend time with others whose personality was similar to their own.  

The study, by the University of Exeter and the Wildfowl & Wetlands Trust (WWT), reveals the complex nature of flamingo societies and could help in the management of captive flocks.

“Our previous research has shown that individual flamingos have particular ‘friends’ within the flock,” said Dr Paul Rose, from WWT and Exeter’s Centre for Research in Animal Behavior.

“In this study, we wanted to find out whether individual character traits explain why these friendships form.

“The answer is yes – birds of a feather flock together.