LEOPARD'S VS HYENAS

Spotted apex predator being pressured by spotted pack hunters – and it's our fault

UNIVERSITY OF COPENHAGEN - FACULTY OF SCIENCE

 

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IMAGES FROM CAMERA TRAPS IN UDZUNGWA. FROM THE LEFT: FEMALE LEOPARD, HYENA, MALE LEOPARD

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CREDIT: RASMUS W. HAVMØLLER

Who’s stronger? A solitary leopard or cackle of hyenas? And which is best at getting along with humans?

University of Copenhagen researchers closely studied this in a large East African natural area surrounded by rural settlements. The study demonstrates that the presence of humans has a direct impact on the competitive relationship between the two large predator species: leopards (Panthera pardus) – the iconic spotted feline and the spotted hyena (Crocuta crocuta) – a kleptoparasite and pack hunter known for its comical appearance and characteristic 'laugh'.

"We humans continue eating our way into the little bit of wilderness left in the world. As we do, we impact wildlife. This study demonstrates that human disturbance upsets the balance between competing species and that this advantages hyenas," says Rasmus W. Havmøller, the study’s first author and a postdoc at the University of Copenhagen’s Natural History Museum of Denmark.

For months, Havmøller have been using camera traps to observe the dynamics between hyenas and leopards living in Tanzania’s Udzungwa Mountains – an approximately 2,000 km2 national park that is completely surrounded by agricultural and populated areas. The study is the first to combine camera observations of large predators over both time and space in a single analysis.

While the hyena as a species seems to be increasing in numbers, the population of leopards has been in significant decline for decades, both in Africa and worldwide. Since hyenas are the leopards' only competitor in this particular natural area, the ability of the two species to coexist is important for their survival. And here, the local population is an important factor:

"As the local people definitely don’t' like leopards, the leopards retreat as far away from humans as possible. Hyenas, on the other hand, benefit from the fact that humans don’t feel threatened by or pursue them. Consequently, hyenas live in close to human populations and may even exploit humans as shields against the leopards," says Havmøller.

"But the areas nearest to humans are also the areas with the most prey. And as hyenas assert dominance over these areas, it increases their ability to outcompete leopards and potentially threaten the leopard's adaptability," adds Havmøller.

Size matters

The researchers' observations confirm that size matters. While male leopards, which are larger, retain their dominance over hyenas, the situation is different for female leopards, which are smaller.

"Even though the male leopards are the ones in charge, the hyenas aren’t exactly scared off by them. They simply hang out in the background – probably to follow the leopards and steal their prey. But the physical inferiority of the hyenas seems to be compensated for in the areas closest to humans, because male leopards pull out," says Rasmus W. Havmøller, who continues:

"Female leopards, on the other hand, completely change their behavior when hyenas are in the area. They become diurnal, whereas hyenas are primarily nocturnal. This is probably because female leopards are smaller than hyenas, and that they will likely lose in any fight over prey."

Overall, the study shows that the hyenas benefit from living near humans.

"This suggests that the hyena's ability to adapt to areas of human activity may strengthen their overall success as a species and their competitive advantage over other large predators as we humans disturb more and more nature," says Havmøller.

When leopards are pressured, cascade effects may follow

According to the researcher, the shift in female leopard hunting patterns may have negative consequences:

"If you open up for more tourism and build more roads in the national park, the female leopards will be pressured immediately. They aren’t able to differentiate between safari tourists – who are most active during the day – and poachers. In time, they will probably learn that safari guests aren’t dangerous. But if there is a large and rapid influx into the area, you will probably see a decline in their population," says Rasmus W. Havmøller.

If leopards are seriously pressured out of the food chain, one should expect the emergence of what are known as cascade effects in the ecosystem:

"Plucking a large predator like leopards out of a food chain, which can be the ultimate consequence of human disturbances, may have very violent effects. Populations of other species, such as certain monkeys, whose populations are kept in check by leopards, will suddenly become too large and change the balance of the entire ecosystem," says the researcher.

As such, Havmøller hopes that the study will serve to encourage restraint when it comes to managing wilderness areas.

"Our results clearly indicate that human disturbances can change the competitive relationship between important predators. So, I hope that considerations will be made when expanding activities in wilderness areas, so as to roll them out slowly and give animals a chance to adapt. Furthermore, it would be good if the effects of human disturbances were monitored in more places using camera traps," concludes Rasmus W. Havmøller.

 

 

HYENAS VS. LEOPARDS 

• Leopards are unpopular among local people in many places because they may hunt livestock and attack humans. Hyenas, on the other hand, "clean up" by eating sick or dead livestock and don’t pose a problem for humans.
• Female leopards (approx. 20-43 kg.) are about half the size of male leopards (approx. 51-72 kg). Hyenas are in the middle in terms of weight (approx. 48-56 kg).
• Leopards are solitary hunters, whereas hyenas hunt in large cackles (clans), which can be an advantage for hyenas in confrontations with leopards.
• Hyenas are kleptoparasites that regularly steal the prey of other carnivores – including leopards.
• Leopards on the other hand, are masterful tree-climbers, which allows them to protect their prey from hyenas.

 

ABOUT THE STUDY

• The researchers behind the study are: Rasmus W. Havmøller and Linnea W. Havmøller from the Natural History Museum of Denmark, University of Copenhagen; Arielle W. Parsons from Lincoln Park Zoo, USA and Roland Kays from North Carolina State University, USA.
• The study has been published in the scientific journal Ecosphere.
• The research is supported by the ERC under the EU’s Horizon 2020 programme.

  

Map of Udzungwa Mountains, Tanzania

CREDIT

(map from the scientific article)

JOURNAL

Ecosphere

DOI

10.1002/ecs2.4913 

ARTICLE TITLE

Sex and size matter: Intricate dominance relationships in an East African large carnivore guild

ALGAE HAVE EARS

Study illuminates cues algae use to ‘listen’ to their environment

BIGELOW LABORATORY FOR OCEAN SCIENCES

 

IMAGE: 

A SCANNING ELECTRON MICROSCOPE IMAGE OF C. PARADOXA, THE SPECIES OF GLAUCOPHYTE THE STUDY’S AUTHORS EXAMINED (COURTESY OF JOHN BURNS).

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CREDIT: JOHN BURNS, BIGELOW LABORATORY FOR OCEAN SCIENCES

Plants have long been known to release chemicals to respond to stress and relay information to their neighbors. A team of scientists from Bigelow Laboratory have shown that glaucophytes, a small group of single-celled algae distantly related to plants, appear to have the same penchant for chemical communication. This suggests that the ability to use chemical cues in this way may not be unique to complex life as once thought, but rather evolved further back on the tree of life.

“We’re looking at this organism that shares ancestry with plants, and uses a communication process that people once thought only plants used,” said Senior Research Scientist John Burns, a co-author on the study. “It’s possible that many branches of life  started with similar tools for communication but then diverged in the particular genetic way they do it.”

Discovering how cell communication works in new lineages helps scientists understand how these abilities emerged and have changed over time. Microalgae, like glaucophytes, are also essential to biogeochemical cycling in aquatic systems so understanding them is essential for predicting how the larger ecosystem functions, especially in stressful situations.

“The underlying communication process used by plants and glaucophytes is similar, and they’re based on the same basic components of life,” said Baptiste Genot, a former postdoctoral researcher at Bigelow Laboratory and the study’s lead author. “But going beyond plants to understand how single cells like these algae carry these processes out is really paving a new trail.” 

Their results were recently published in The Journal of Eukaryotic Microbiology.

Scientists have long understood that plants emit informational molecules, like hormones and other organic compounds, as a way to communicate information and adapt to stressful situations like changes in temperature or exposure to toxins. But there’s far less information on the strategies used by microalgae, despite them being the most abundant primary producers in aquatic systems.

That includes glaucophytes, one of the three main lineages in what’s called the Archaeplastida. Organisms in this group, including plants, as well as green and red algae, are known to have a common ancestor over a billion years ago. Understanding commonalities between the complex communication strategies used by these different organisms can help scientists map the timeline of when lineages branched off from each other. It can also help them better understand how the tools used for photosynthesis evolved.

“Glaucophytes are this other branch of life that developed chloroplasts at the same time as plant ancestors did, but ran with it in a whole different evolutionary direction,” Burns said. “So, you can use these comparisons to answer really basic questions about photosynthesis across all branches of life.”

The researchers focused on one species of glaucophyte, called Cyanophora paradoxa. They found that, in response to external stressors like changing light, C. paradoxa produces potent hormones like ethylene, which plays a key role in fruit ripening and is known to be released by plants in response to stress. When the team supplied the algae with a chemical that’s a precursor to ethylene, they found that the glaucophytes produced large quantities of the hormone, and slowed down their growth rate in response.

“If you looked at the genes plants have, you would never think that glaucophytes could use these same signaling pathways, because they just don’t have the same ‘parts,’” Burns said. “We often use plants as our baseline for photosynthetic life, but, in this story, they’re the ‘weirdos’ who took off in a different evolutionary direction. Glaucophytes may have more in common with other algae than plants do when it comes to these behaviors.”

This study provides the first evidence of glaucophytes releasing hormones as a stress response, but questions remain about how these organisms change their actual behaviors, like how they swim or develop, in response to these hormones. Burns and Genot are also interested in how other organisms in the ecosystem respond to these chemical shifts, and whether other algae species use these same hormonal cues for communication.

Beyond communication, though, the study also highlights the value of glaucophytes more broadly. Because of their unique place in the tree of life, how stable they are in the lab, as well as how fast they grow — Burns likens them to “weeds” — they’re a valuable tool for answering questions about evolutionary history and even developing algae-based products like plastic alternatives.

“The knowledge gap between what we know about these unicellular, photosynthetic eukaryotes and cultivated plants is still huge,” Genot said. “It’s challenging but exciting because we have so much more to learn about these little cells living all around us!”

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JOURNAL

Journal of Eukaryotic Microbiology

DOI

10.1111/jeu.13041 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Functional stress responses in Glaucophyta: Evidence of ethylene and abscisic acid functions in Cyanophora paradoxa

ARTICLE PUBLICATION DATE

1-Jul-2024

 

Unlocking iron homeostasis: apple plants reveal key mechanism

NANJING AGRICULTURAL UNIVERSITY THE ACADEMY OF SCIENCE

 

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A MODEL OF FE HOMEOSTASIS REGULATION BY MDCML15–MDBT2–MDBHLH104–MDAHA8 IN APPLE TREES. WHEN APPLE ROOTS ARE EXPOSED TO FE-SUFFICIENT CONDITIONS, MDCML15 IS INDUCED TO INTERACT WITH MDBT2 IN THE NUCLEUS TO ACCELERATE MDBT2-MEDIATED UBIQUITINATION AND DEGRADATION OF MDBHLH104, RELIEVE TRANSCRIPTIONAL ACTIVATION OF MDAHA8, REDUCE H+ EFFLUX, AND THEREBY INHIBIT FE ABSORPTION AND PREVENT FE TOXICITY.

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CREDIT: HORTICULTURE RESEARCH

A pivotal study has uncovered the intricate dance between calcium signaling and iron regulation in apple plants. The research reveals how the calmodulin-like protein MdCML15 and the BTB domain protein MdBT2 interact to control iron homeostasis, offering new strategies for improving crop nutrition and yields. This discovery could transform agricultural practices by addressing the widespread issue of iron deficiency in crops, which significantly impacts both plant health and food production.

Iron is a vital micronutrient for plants, essential for photosynthesis, respiration, and various metabolic processes. Despite its abundance in the soil, iron often exists in insoluble forms, particularly in calcareous soils, making it difficult for plants to absorb. This limited availability can severely impact crop yields and plant health. Addressing these challenges requires a deeper understanding of iron uptake and regulation mechanisms in plants, which can lead to improved agricultural practices and the development of crops better suited to iron-deficient conditions.

Researchers from Nanjing Agricultural University have made significant strides in this field, with their findings (DOI: 10.1093/hr/uhae081) published in the Horticulture Research journal on March 25, 2024. The study explores the interaction between a calmodulin-like protein and an apple-specific BTB domain protein, key to iron homeostasis.

The study demonstrated that MdCML15 functions as an upstream regulator of MdBT2, which is involved in the ubiquitination and degradation of MdbHLH104. This process results in the reduced expression of MdAHA8, a plasma membrane H+-ATPase crucial for iron uptake. Consequently, the interaction between MdCML15 and MdBT2 negatively affects the plant's ability to acidify the rhizosphere and absorb iron. Transgenic apple plants overexpressing MdCML15 showed decreased iron uptake and severe chlorosis under iron-deficient conditions compared to wild-type plants. Conversely, plants with suppressed MdCML15 expression exhibited enhanced iron uptake and improved growth under the same conditions. These findings provide new insights into the regulatory network of iron absorption in apple trees and highlight the potential of targeting MdCML15 to improve iron uptake in crops.

Dr. Chun-Xiang You, one of the corresponding authors, stated, "Our findings highlight the intricate regulatory mechanisms plants use to balance nutrient uptake and avoid toxicity. Understanding the role of proteins like MdCML15 in these processes opens new avenues for developing crop varieties with improved nutrient efficiency."

This research provides valuable insights into the molecular mechanisms of iron regulation in apple trees. By manipulating the expression of MdCML15, it may be possible to enhance iron uptake in crops, leading to improved growth and yield, particularly in iron-deficient soils. This knowledge can inform breeding programs and biotechnological approaches aimed at developing nutrient-efficient crop varieties.

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References

DOI

10.1093/hr/uhae081

Original Source URL

https://doi.org/10.1093/hr/uhae081

Funding information

This work was supported by grants from National Key Research and Development Program (2022YFD1201701), the National Natural Science Foundation of China (32001336 and 32272683), the China Agriculture Research System of MOF and MARA (CARS-27), and the Natural Science Foundation of Shandong Province (ZR2022QC093).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.

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JOURNAL

Horticulture Research

DOI

10.1093/hr/uhae081 

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Calmodulin-like protein MdCML15 interacts with MdBT2 to modulate iron homeostasis in apple

 

USDA, university researchers develop near chromosome-level genome for the Mojave poppy bee

US DEPARTMENT OF AGRICULTURE - AGRICULTURAL RESEARCH SERVICE

 

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A MOJAVE POPPY BEE FEMALE PINNED SPECIMEN.

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CREDIT: MICHAEL BRANSTETTER, USDA AGRICULTURAL RESEARCH SERVICE

LOGAN, Utah, July 1, 2024 – Scientists at the United States Department of Agriculture (USDA)’s Agricultural Research Service (ARS) and university research partners developed a near chromosome-level genome for the Mojave poppy bee, a specialist pollinator of conservation concern, according to a recent Journal of Heredity paper.

Putting together the Mojave poppy bee genome is part of the Beenome100 project, a first-of-its-kind effort to create a library of high-quality, highly detailed genome maps of 100 or more diverse bee species found in the United States. Beenome100 is a collaborative undertaking led by ARS and the University of Illinois, with collaboration of researchers across ARS and universities in the United States and Canada. The expectation is that these genomes will help researchers answer the big questions about bees, such as what genetic differences make a bee species more vulnerable to climate change or whether a bee species is likely to be more susceptible to a pesticide.

Restricted to the eastern Mojave Desert, the Mojave poppy bee (Perdita meconis) is a solitary, mining bee of the Andrenidae family that specializes in pollinating the Las Vegas bearpoppy (Arctomecon californica) and the dwarf bearpoppy (Arctomecon humilis) -- the latter being protected under the U.S. Endangered Species Act as of 1979. The poppies are found primarily in gypsum soil deposits, which are rare and scattered throughout the region.

The Mojave poppy bee and Las Vegas bearpoppy are also being considered for listing under the Endangered Species Act. Both species will be evaluated for potential declining populations and vulnerability to extinction due to climate change and to habitat loss from urban development and mining in their native region.

Researchers assembled the genome or genetic map that will help further to understand the Mojave poppy bee’s biological traits.

“The genome, with additional genetic sampling of individuals, will also potentially give us insights into the genetic basis for host-plant specialization, susceptibility to pesticides, and susceptibility to drought and climate tolerance,” said Rena Schweizer, a research entomologist at the ARS Pollinating Insect-Biology, Management, Systematics Research Unit in Logan, Utah.

In particular, the Mojave poppy bee is capable of weathering drought years by remaining in the ground in stasis -- a phenomenon called diapause. The trait is not well understood by researchers and, by having its genome sequenced, they may be able to learn about the genes and regulatory pathways that make the adaptation possible.

They will also use the genome to assess the species’ genetic health, find insights into how bees can be specialists or generalists, and look what the tradeoffs are in terms of a bee’s long-term fitness.

“It could also lead to us finding genetic signatures of decline,” said Schweizer. “By studying this one bee’s genome, we might be able to help conserve the bee better and identify other species that are in decline using genetic information.”

To develop the genome of the small and mighty bee, researchers isolated DNA from a single, small male specimen.

This genome assembly, according to Schweizer, is impressive given that the bee is tiny (a male bee averages five to seven millimeters in length). Researchers collected the specimen in the field in a remote wilderness location.  

“What is also remarkable about this research is that the specimen used for the genome was collected in non-ideal preservation methods,” said Schweizer. “We still obtained high-quality DNA from a field-collected specimen due to technological advancements in sequencing technology and learned more about this unique bee. We hope that our research will set the groundwork for developing genomes of other bee species.”

The detailed, high-resolution map of the reference genome is available in the National Center for Biotechnology Information’s database.

The research was done in collaboration with the University of Montana, Utah State University, and the ARS Tropical Pest Genetics and Molecular Biology Research Unit in Hilo, Hawaii.

The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.

A Mojave poppy bee male next to dime.

CREDIT

Chelsea Ritner, USDA Agricultural Research Service

JOURNAL

Journal of Heredity

DOI

10.1093/jhered/esad076/7471740 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Reference genome for the Mojave poppy bee (Perdita meconis), a specialist pollinator of conservation concern

 

Unlocking the grape's secret: how wounding boosts anthocyanin defenses

NANJING AGRICULTURAL UNIVERSITY THE ACADEMY OF SCIENCE

 

IMAGE: 

THE IMPACTS OF EXOGENOUS MEJA TREATMENT ON GRAPE ANTHOCYANIN SYNTHESIS. A, B PHENOTYPES (A) AND TOTAL ANTHOCYANIN CONTENT (B) OF ‘RED GLOBE’ GRAPE FRUITS TREATED WITH 100 ΜM MEJA FOR 7 DAYS. CONTROL, GRAPE FRUITS WITHOUT MEJA TREATMENT. SCALE BAR, 1 CM. C, D PHENOTYPES (C) AND TOTAL ANTHOCYANIN CONTENT (D) OF ‘GAMAY’ GRAPE CALLI CULTURED ON A B5 MEDIA CONTAINING 100 ΜM MEJA. CONTROL, GRAPE CALLI WITHOUT MEJA TREATMENT. SCALE BAR, 1 CM. E EXPRESSIONS OF JA SYNTHESIS GENES IN VVWRKY5-OE GRAPE CALLI. DATA ARE MEANS ± SDS OF THREE SEPARATE EXPERIMENTS. STATISTICAL SIGNIFICANCE AT P < 0.01 (**) WAS DETECTED USING TUKEY’S TEST.

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CREDIT: HORTICULTURE RESEARCH

A recent study sheds light on the biochemical response of grapevines to wounding stress. It reveals that the transcription factor VvWRKY5 is a key regulator that enhances anthocyanin production, which serves as a protective mechanism for the plant. This discovery provides insights into the genetic control of the plant's defense system and could lead to the development of more resilient and nutritious crops.

Anthocyanins are vital for plant defense, coloration, and attracting pollinators. They play a significant role in protecting plants from environmental stresses such as temperature fluctuations, drought, and pathogen attacks. Despite their importance, the molecular mechanisms underlying stress-induced anthocyanin production remain unclear. Based on these challenges, there is a pressing need to conduct in-depth research on the factors that enhance anthocyanin biosynthesis, particularly under stress conditions, to improve crop quality and resilience.

A study conducted by researchers from the College of Horticulture at Shenyang Agricultural University and the National & Local Joint Engineering Research Center of Northern Horticultural Facilities Design and Application Technology in China, published (DOI: 10.1093/hr/uhae083) on March 25, 2024, in Horticulture Research, reveals the molecular mechanisms of wounding-induced anthocyanin accumulation in grapes. The research focuses on the transcription factor VvWRKY5 and its interaction with VvMYBA1 and jasmonic acid (JA)biosynthesis.

The study identified VvWRKY5 as a crucial regulator in the enhancement of anthocyanin production in grapes under wounding stress. Upon wounding, the expression of VvWRKY5 significantly increased, leading to higher anthocyanin levels around the wound sites. VvWRKY5 interacts with VvMYBA1, a well-known regulator of anthocyanin biosynthesis, enhancing VvMYBA1’s ability to activate target genes involved in this pathway. Additionally, VvWRKY5 promotes the biosynthesis of JA, a phytohormone that further stimulates anthocyanin accumulation. The combined action of VvWRKY5 and VvMYBA1 amplifies the grape’s response to wounding, resulting in robust anthocyanin production. These findings demonstrate the dual role of VvWRKY5 in both direct gene regulation and hormone-mediated pathways, providing a comprehensive understanding of the molecular mechanisms behind stress-induced anthocyanin biosynthesis in grapes.

Dr. Yinshan Guo, a corresponding author of the study, states, "Our findings shed light on the intricate regulatory mechanisms of anthocyanin biosynthesis in response to wounding stress. Understanding these processes opens up new avenues for enhancing the stress resilience and quality of grape crops through targeted genetic and agronomic interventions."

The insights gained from this study can be applied to improve grape cultivation practices, enhancing the quality and stress resistance of grape varieties. By leveraging the regulatory roles of VvWRKY5 and VvMYBA1, breeders and farmers can develop strategies to boost anthocyanin content, leading to better fruit coloration and increased market value. Additionally, this research provides a foundation for exploring similar mechanisms in other crops, potentially benefiting a wide range of horticultural practices.

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References

DOI

10.1093/hr/uhae083

Original Source URL

https://doi.org/10.1093/hr/uhae083

Funding information

The work was funded by the China Agriculture Research System (CARS-29-yc-6), the National Natural Science Foundation of China (31972368), the Major Agricultural Science Projects of Liaoning Province (2023JH1/10200004), and the Science and Technology Program of Shenyang (23-410-2-03).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.

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JOURNAL

Horticulture Research

DOI

10.1093/hr/uhae083 

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

VvWRKY5 positively regulates wounding-induced anthocyanin accumulation in grape by interplaying with VvMYBA1 and promoting jasmonic acid biosynthesis

 

Watching others’ biased behavior unconsciously creates prejudice

Peer-Reviewed Publication

UNIVERSITEIT VAN AMSTERDAM

We unconsciously form prejudice toward groups when we see biased people interact with members of a group. That is according to new research by psychologists of the University of Amsterdam (UvA), who show for the first time that observational learning is an important mechanism of prejudice formation. Their results were published today in Science Advances.

David Amodio (UvA): ‘What we found in our research is that prejudice can form by merely observing other people’s social interactions. When an observer views a prejudiced person’s interaction with a group member, they unconsciously form the same prejudice. Moreover, because observers are unaware that they picked up this bias, they go on to act with prejudice in their own behavior.'

This mechanism helps to explain how societal prejudices spread so easily, for example, through the viewing of TV programmes, YouTube or other social media where biased interactions with a certain groups takes place. By merely observing those interactions, vicariously and with no direct contact, people may take on the same prejudices.

Experiment

During the experiments, a research participant viewed interactions between an actor and members of two different groups. Across participants, the actor varied in prejudice, but the behavior of group members was always identical. When observers later interacted with the same group members, observers showed a preference in line with the actor’s prejudice. Moreover, observers were unaware that they were influenced by the prejudiced actor; instead, they misperceived worse behavior from group members who interacted with a prejudiced actor, when in fact, members of both groups acted the same.

Bad behaviour

Amodio: 'A troubling implication is that, because the observer believes that their preference is based on objective evidence, they have no reason to question it or control it.'

Publication details

David T. Schultner (UvA), Björn R. Lindström (Karolinska Institutet, Sweden), Mina Cikara (Harvard University, USA), David M. Amodio (UvA). Transmission of social bias through observational learning. Science Advances (28 June 2024).  DOI: 10.1126/sciadv.adk2030

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JOURNAL

Science Advances

DOI

10.1126/sciadv.adk20 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Transmission of social bias through observational learning

 

Evidently efficient: Self-organization of informal bus lines in the Global South

SELF ORGANIZATION IS @

TECHNISCHE UNIVERSITÄT DRESDEN

Public transport systems vary widely around the world. Developed countries in the Global North usually have centrally-planned public transport systems with fixed routes and timetables. In contrast, in the developing countries of the Global South, making up more than 80 % of the world's population, public transportation is mostly provided by informal transport services featuring ad hoc routes, e.g. in the form of privately organized minibus services. Due to their seemingly chaotic operation, such informal transport services are often considered as inefficient from an outside perspective. Due to a lack of data a systematic comparison was not possible so far. 

In a new scientific paper recently published in Nature Communications, Kush Mohan Mittal, Marc Timme and Malte Schröder from the Chair of Network Dynamics at TU Dresden analyze and compare the structural efficiency of more than 7,000 formal and informal bus lines across 36 cities and 22 countries. One of the central, surprising findings is that the routes of informal transport self-organize in a way that reaches or even exceeds the efficiency level of centralized services.  

Following on from the group's previous research on on-demand ridepooling, i.e. demand-driven shared taxi services, the research group has greatly expanded the scope for the current study and attempted to evaluate an immensely large sample that includes data from very different places around the world.  

In the countries of the Global South in particular, informal transport systems often cover areas where publicly organized transport does not offer services or is not affordable for a large proportion of users. In some cases, such services are organized by non-governmental organizations (NGOs), but often by private, commercially motivated actors. "Our central question in the study was: How are the routes organized in the various systems? How efficient are they? Can we identify specific patterns, which similarities and differences do we see?" explains Malte Schröder. The study was based on freely available GPS route data for over 7,000 bus routes from the OpenStreetMap provider. In the case of informal transport services, this data is usually only available if it is collected by local volunteers. Using this data, the researchers analyzed how the routes are aligned with local population densities and the extent of detours being included into the routes.  

The findings call into question the general perception of informal transport as an 'inferior alternative' to centrally-organized services. Here too, more or less fixed routes, lines or travel corridors emerge. The typical routes are fairly straight in the central area of the routes, with more detours at the ends in order to cover larger areas. This pattern can be found in both centrally-organized and informal transport, and arises regardless of the different geography of the cities. "Informal transport, however, has fewer detours and more uniform routes than centrally-planned services, so the routes are efficient - and profitable even without the extensive subsidies that are common in the Global North," emphasizes Kush Mohan Mittal. Other factors that go beyond the examined structure of the routes could not be included in the analysis due to the still limited availability of data for informal transport. However, aspects such as wage levels, vehicle safety, driver training, predictability and reliability of services, etc., of course, play just as an important role in an efficient and sustainable public transport system as routing. 

Nevertheless, the findings of the study already show that existing informal systems should not simply be replaced by formal, centrally-planned routes. Instead, operators can build on the efficient self-organization and improve the services by increasing the frequency and reliability of informal transport. Public, centrally-organized services may also be able to learn from the routing of informal systems. This comprehensive analysis of informal transport systems underlines the potential benefits and calls for a paradigm shift in the way they are perceived and integrated into urban transport planning.

Paper title: Efficient self-organization of informal public transport networks
DOI: 10.1038/s41467-024-49193-1
Authors: Kush Mohan Mittal, Marc Timme, Malte Schröder
Published: Nature Communications, 8 June 2024
Download: http://doi.org/10.1038/s41467-024-49193-1  

Blogpost on ‘Springer Nature Research Communities’:
https://communities.springernature.com/posts/informal-transport-a-symphony-in-chaos

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JOURNAL

Nature Communications

DOI

10.1038/s41467-024-49193-1 

ARTICLE TITLE

Efficient self-organization of informal public transport networks

 

Prosocial influencers can promote societal cooperation

@ IN @CTION

PNAS NEXUS

A modeling study suggests that influential neighbors can be as effective as despotic leaders at promoting social cooperation. Prosocial behaviors can be difficult to sustain in large societies over the long term, as people give into the temptation to defect to strategies that prioritize the wellbeing of themselves and their immediate family. Stefani Crabtree and colleagues constructed a general theoretical framework to explore how cooperation could arise and be maintained in a large society. The authors explore three possible mechanisms for encouraging prosocial actions: neighbors that monitor one another for defection, despotic leaders who monitors and punishes at the whole-society level, and influencers that convince neighbors to cooperate. The authors built mathematical models and simulated individuals playing a common-pool resource game. The simulated society was made up of many types of agents; some agents always cooperated; some always defected; some cooperated and monitored their neighbors for cooperation; and some cooperated only after being caught defecting and punished. In some cases, the authors included influencers, who recruited neighbors to behave prosocially if the influencer found that cooperation resulted in higher individual gains for themselves than defection did. This strategy produced similar results in terms of average agent wealth as the strategies of having a strong leader that prevents detected defectors from ever defecting again. Both influencing and despotic leadership performed much better than monitoring by neighbors. The size of the fine for defecting influenced which strategy was most lucrative, with steep fines promoting cooperation. According to the authors, prosociality can be achieved via a multitude of methods, although punishment of defection is always required. 

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JOURNAL

PNAS Nexus

ARTICLE TITLE

Influential individuals can promote prosocial practices in heterogeneous societies: a mathematical and agent-based model

ARTICLE PUBLICATION DATE

2-Jul-2024