Dolphins learn in similar ways to great apes

UNIVERSITY OF ZURICH

DOLPHIN'S PROVE ADVANCED COGNITIVE TOOL MAKING, TOOL USING, FOR THOSE WITHOUT HANDS (NOT A DISABILITY A DIFFERENT ABILITY)  AND TEACHING ABILITIES TO OTHERS, TRANSFER  OF KNOWLEDGE, EPISTEMOLOGY BY ANY OTHER NAME 

ANOTHER THINKING MAMMAL WHERE HAVE WE HEARD OF THEM BEFORE

The Part Played by Labor in the Transition From Ape to Man

http://www.rawillumination.net/2018/07/intelligent-dolphins-and-illuminatus.html

     

Howard | The Illuminatus! Trilogy Wiki | Fandom

https://illuminatus.fandom.com › wiki › Howard

Howard is a dolphin,and one of the earliest allies of Hagbard Celine to appear in the trilogy...

https://www.media.uzh.ch/dam/jcr:bdc17949-71e7-447f-bec3-46435d800a1b/Delfin_Shelling_EN.mp4

VIDEO: DURING SHELLING, DOLPHINS TRAP FISHES INSIDE LARGE EMPTY GASTROPOD SHELLS. THEY ARE THEN BROUGHT TO THE SURFACE AND VIGOROUSLY SHAKEN SO THE FISH FALLS INTO THEIR OPEN MOUTH. view more 

CREDIT: SONJA WILD, DOLPHIN INNOVATION PROJECT

Dolphins use unusual techniques to obtain food: One of them, called "shelling", is used by the dolphins in Shark Bay in Western Australia. Dolphins in this population trap fishes inside large empty gastropod shells. The shells are then brought to the surface and vigorously shaken so that the water drains out and the fish falls into their open mouth. Using the empty shell in this manner is comparable to tool use in humans.

Dolphins learn directly from their peers

It was previously thought the only way dolphins could learn new foraging methods while with their mother, a process known as vertical social transmission. However, a study initiated by Michael Krützen, director of the Department of Anthropology at the University of Zurich (UZH), has now shown that "shelling" is mainly passed on between peers rather than across generations - that is, via horizontal transmission. "Our results provide the first evidence that dolphins are also capable of learning from their peers as adults," says Krützen. The analysis of extensive behavioral, genetic and environmental data spanning more than a decade led to these findings.

Cultural behavior similar to that of great apes

"This is an important milestone. It shows that cultural behavior of dolphins and other toothed whales is much more similar to the behavior of great apes, including humans, than was previously thought," says Krützen. Gorillas and chimpanzees also learn new foraging techniques through both vertical and horizontal transmission. Although their evolutionary history and their environments are very different, there are striking similarities between cetaceans and great apes, according to Krützen: "Both are long-lived mammals with large brains that are capable of innovation and of passing on cultural behaviors."

Behavioral observation over more than 10 years

The researchers made their discovery between 2007 and 2018 in the Western Gulf Zone of Shark Bay, where they observed Indo-Pacific bottlenose dolphins (Tursiops aduncus) and documented how the shelling behavior was spread within the population. During this time, they identified more than 1,000 individuals from around 5,300 encounters with dolphin groups. "In total we documented 42 individual uses of shelling by 19 different dolphins," says study leader Sonja Wild, who completed her PhD at the University of Leeds, and is now a postdoc at the University of Konstanz.

Quicker adaptation to changing environments

This discovery that wild dolphins can learn new foraging techniques outside of the mother-calf bond significantly widens our understanding of how they can adapt to fluctuating environmental conditions through behavioral changes. "Learning from others allows for a rapid spread of novel behaviors across populations," says Wild.

For example, an unprecedented marine heatwave in 2011 was responsible for wiping out a large number of fish and invertebrates in Shark Bay, including the gastropods inhabiting the shells. "While we can only speculate as to whether the heatwave and subsequent prey depletion gave the dolphins a boost to adopt new foraging behavior from their associates, it seems quite possible that an abundance of dead shells may have increased learning opportunities for shelling behavior," says Sonja Wild.

Uganda's Ik are not unbelievably selfish and mean

Small ethnic group is cooperative and generous, contrary to 1972 book portrayal

RUTGERS UNIVERSITY

IMAGE: IK WOMEN SHARING A MEAL. view more 

CREDIT: CATHRYN TOWNSEND

The Ik, a small ethnic group in Uganda, are not incredibly selfish and mean as portrayed in a 1972 book by a prominent anthropologist, according to a Rutgers-led study.

Instead, the Ik are quite cooperative and generous with one another, and their culture features many traits that encourage generosity, according to the study in the journal Evolutionary Human Sciences.

"The Mountain People," an ethnography by anthropologist Colin M. Turnbull, made a big splash for an academic work. The New York Times and Time magazine reviewed the book, which inspired a stage play, and physician Lewis Thomas included an essay about the Ik in his bestselling book "The Lives of a Cell: Notes of a Biology Watcher."

The Ik live in the far northeast corner of Uganda, near its borders with Kenya and South Sudan. A Rutgers-led team of scientists studied them as part of The Human Generosity Project, a transdisciplinary effort to better understand generosity and other forms of cooperation among people around the world.

The scientists included the Ik in their project because of Turnbull's claim that, far from being generous, the Ik were extraordinarily selfish and mean. He attributed the selfish behaviors he witnessed to a culture of selfishness.

Lead author Cathryn Townsend, a former Rutgers post-doctoral scientist and faculty member now at Baylor University, spent 2016 with the Ik and returned briefly in 2017 and 2018. She discovered that their culture includes many traits that encourage generosity. For example, a favorite Ik saying is tomora marang, which means "it's good to share," and many Ik believe that Earth spirits called kijawika monitor people's behavior, punish those who fail to share and reward the very generous.

Townsend also documented Ik generosity quantitatively using an experimental game, finding they're no less generous, on average, than any of the hundreds of other groups of people in the world who have played the same game.

Why, then, did Turnbull observe so much selfishness among the Ik? Although Turnbull was aware that they experienced a severe famine while he was there, he failed to appreciate the impact starvation has on human behavior. Instead, he followed a common tendency among cultural anthropologists to attribute all human behavior to culture.

"One implication of Townsend's work is that we must always consider the possibility that factors other than culture, including but not limited to starvation, can also shape human behavior," said senior author Lee Cronk, a professor in the Department of Anthropology in the School of Arts and Sciences at Rutgers University-New Brunswick. "Another implication is that we can no longer use the Ik as an example of a society that has embraced selfishness. Far from being an exception, the Ik are just as cooperative and generous as other people around the world. They do not deserve the reputation they have been given by Turnbull's book."

Townsend plans to return to the Ik to continue her studies of how they cooperate. She will be looking in particular at how they are interdependent with one another.

###

Coauthors include Athena Aktipis at Arizona State University and Daniel Balliet at Vrije Universiteit Amsterdam.

CHILE
Papers concludes that incentives to afforestation can be harmful to the environment

UNIVERSIDAD DE CONCEPCIÓN

IMAGE: SATELLITE IMAGE OF THE BIOBIO AND ARAUCANÍA COAST view more 

CREDIT: CRISTIAN ECHEVERRÍA

"Through a counterfactual analysis, we showed that between 1986 and 2011 the incentives to afforestation in Chile caused an increase in forest plantations, but reduced the extent of native forests", explains the academic from the Faculty of Forest Sciences at the Universidad de Concepción, UdeC, Dr. Cristian Echeverría, about the main conclusions of the paper Impacts of Chilean forest subsidies on forest cover, carbon and biodiversity, published by the journal Nature Sustainability, co-written with academicians Robert Heilmayr from the U. of California, and Eric F. Lambin of Stanford University, both from the United States.

For the UdeC researcher, this international collaboration was of the "highest scientific standard, with great strictness and close cooperation in the stages of formulation of the idea, preparation of the manuscript and data analysis", he sustains and explains that the idea of the study emerged "about seven years ago, when the other authors got interested in my research related to deforestation in Chile. After publishing a joint paper about land use changes in Chile, we decided to continue the collaboration between the Landscape Ecology Laboratory, LEP, and U. Stanford to answer new scientific questions"

In the same way, the study -which aims to assess the impacts of an incentive to afforestation on carbon sequestration, forest cover and biodiversity- was possible thanks to various sources of financing and information, given that "having classified maps of satellite images was an immense task of the three universities", says Echeverría, adding that they had "financing from various Fondecyt projects and from the LEP's own resources and other funds obtained by the leading author, Robert Heilmayr, during his PhD studies", he details.

Regarding the main scientific conclusions of the recent study, Echeverría details that the increasing establishment of exotic plantations caused "small negative impacts on the total carbon stored in the above-ground biomass. Additionally, the policy produced the substitution of native forests for plantation which resulted in a significant decrease in the richness of species of flora and fauna".

In the researcher's opinion, based on the results of this study, it is possible to "strengthen research in the evaluation of the impact of environmental policies on other components, such as, for example, ecosystem services; evaluating current policies on native forests and other environmental matters; identifying the most critical areas of biodiversity loss for the design of restoration plans. In addition, contributing with new evidence on the future impacts that the NdC (Nationally Determined Contributions) of Chile would have on the design of mitigation measures and adaptation to climate change".

"The reforestation and restoration policies that the country is currently pursuing need to be carefully designed and firmly applied to ensure the protection of natural ecosystems. Such safeguards can improve the benefits of a policy, as well as its impacts on carbon sequestration and biodiversity conservation", states the UdeC academician.

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Researchers identify N95 respirator decontamination method using microwave-generated steam

AMERICAN SOCIETY FOR MICROBIOLOGY

 

Washington, DC - June 25, 2020 - Due to the rapid spread of COVID-19, there is an increasing shortage of personal protective equipment (PPE) crucial to protecting health care workers from infection. N95 respirators are recommended by the CDC as the ideal protection method from COVID-19 and, although traditionally single-use, PPE shortages have necessitated the need for reuse. New research published this week in mBio an open-access journal of the American Society for Microbiology, describes an effective, standardized method of decontamination for hospitals and health care centers facing N95 respirator shortages.

The researchers, from Beth Israel Deaconess Medical Center, Harvard University and Massachusetts General Hospital, have detailed a reproducible decontamination approach that all health care workers would be able to utilize. "We identified an effective method of N95 decontamination by microwave-generated steam utilizing universally accessible materials. Our method resulted in almost complete sterilization after only 3 min of treatment and did not appear to affect the integrity of N95 filtration or fit with repeated treatment," the researchers write.

###

Please email communications@asmusa.org for a copy of the study or to arrange an interview with the researchers.

The American Society for Microbiology is one of the largest professional societies dedicated to the life sciences and is composed of 30,000 scientists and health practitioners. ASM's mission is to promote and advance the microbial sciences.

ASM advances the microbial sciences through conferences, publications, certifications and educational opportunities. It enhances laboratory capacity around the globe through training and resources. It provides a network for scientists in academia, industry and clinical settings. Additionally, ASM promotes a deeper understanding of the microbial sciences to diverse audiences.

KUNG-FU FIGHTING

Tiny brains, big surprise: Eavesdropping wasps gain insights about fighting abilities of potential rivals

UNIVERSITY OF MICHIGAN

Paper wasps eavesdrop on fighting rivals to rapidly assess potential opponents without personal risk. This new finding adds to mounting evidence that even mini-brained insects have an impressive capacity to learn, remember and make social deductions about others.

Many vertebrate animals--including some birds and fish and numerous primates--minimize the costs of conflict by using "social eavesdropping" to learn about the fighting ability of potential rivals before interacting with them personally.

Keeping track of a network of individually differentiated social relationships is thought to be cognitively challenging and, until recently, was considered to be beyond the reach of lowly insects like paper wasps, which have brains a million times smaller than the human brain.

But a growing body of evidence suggests that the miniature nervous systems of insects do not limit sophisticated behaviors. The capacity for complex insect behavior may be shaped more by social environment than brain size, according to University of Michigan biologist Elizabeth Tibbetts, senior author of a paper scheduled for publication June 25 in the journal Current Biology.

"It is surprising that wasps can observe and remember a complex network of social interactions between individuals without directly interacting with them," said Tibbetts, a professor in the U-M Department of Ecology and Evolutionary Biology. "Complex social relationships are thought to favor the evolution of large brains and increased social intelligence, but paper wasp brains are relatively small."

In the study, Tibbetts and her students collected female Polistes fuscatus paper wasps from sites around Ann Arbor, Michigan, in the early spring.

Unlike a honeybee colony--which has a single queen and multiple equally ranked female workers--paper wasp colonies contain several reproductive females called foundresses. These females battle their rivals and form complex, linear dominance hierarchies based on the outcomes of those fights. A wasp's rank in the hierarchy determines its share of reproduction, work and food.

In the laboratory, the researchers used enamel to mark all foundresses with unique color patterns on the thorax. Then, two at a time, "fighter" wasps were placed in a small container known as the fighting arena while two "bystander" wasps observed the pair through clear plastic partitions.

All trials were videotaped, and a research assistant assigned scores to each fighter using an aggression index that awards points for behaviors like biting, mounting, grappling and stinging. Dominance rank was determined using the number of mounts--a dominance behavior in which the dominant wasp drums her antennae on the subordinate while the subordinate crouches and lowers her antennae--during a fight.

Later, bystander wasps were paired in the fighting arena either with a wasp they had observed (experimental trial) or a fighter they had never seen before (control trial). Tibbetts and her students compared the behaviors in the experimental and control trials to determine the role of social eavesdropping.

They found that bystander wasps were more aggressive when paired with an individual that was the victim of lots of aggression in a previous bout, as well as individuals who initiated very little aggression in the previous fight.

By comparing experimental and control trials, the researchers were also able to reject non-eavesdropping explanations for the observations, including phenomena called priming and winner/loser effects.

"The results show that P. fuscatus wasps use social eavesdropping," Tibbetts said. "Bystanders observe other individuals fight, and they use information about the fight to modulate subsequent behavior."

In previous studies over more than a decade, Tibbetts and her colleagues showed that paper wasps recognize individuals of their species by variations in their facial markings, and they behave more aggressively toward wasps with unfamiliar faces.

They also demonstrated that paper wasps have surprisingly long memories and base their behavior on what they remember of previous social interactions.

But the previous work focused on how wasps use individual recognition during direct interactions and did not test--as this new study did--whether wasps learn about other individuals via observation alone.

###

In addition to Tibbetts, the authors of the Current Biology paper are Ellery Wong and Sarah Bonello of the U-M Department of Ecology and Evolutionary Biology. The work was funded in part by the National Science Foundation.

Elizabeth Tibbetts

Images: https://drive.google.com/drive/folders/16Mnm_5tFd9nanRwkt3KD4WM2nI3DgMij

Video: https://drive.google.com/file/d/1b-JEtsLyxfYHJDv8tF-CESMGb5Rk1AbO/view

Women underrepresented in academic hospital medicine leadership roles, study finds

JOHNS HOPKINS MEDICINE

 

IMAGE: A NEW STUDY BY JOHNS HOPKINS MEDICINE RESEARCHERS SHOWS THAT WOMEN ARE UNDERREPRESENTED AS DIRECTORS AND FULL PROFESSORS IN ACADEMIC HOSPITAL MEDICAL PROGRAMS ACROSS THE NATION. view more 

CREDIT: M.E. NEWMAN, JOHNS HOPKINS MEDICINE

In recent years, the number of women who entered U.S. medical school surpassed the number of men. But gender inequities still exist in many areas of medicine. Of academic hospital medicine programs, 79% are run by men, Johns Hopkins researchers report in a new paper published March 3 in the Journal of General Internal Medicine, and male hospitalist leaders are more likely to have attained the rank of full professor than women leaders.

"Despite making a number of strides in medicine when it comes to gender bias, this is an area where we still haven't reached full equality," says Carrie Herzke, M.D., assistant professor of medicine and associate vice chair for clinical affairs in the Department of Medicine at the Johns Hopkins University School of Medicine.

Previous studies found that, in academic medicine, women comprise only 39% of full-time faculty and 22% of full-time professors. They are also significantly underrepresented in hospital leadership positions, and there are gender disparities regarding career advancement and compensation.

Hospital medicine as a dedicated medical specialty is a relatively young field. "Hospitalists" who are trained in internal medicine and focus their work on hospitalized patients rather than outpatient settings have only existed for about two decades. Due to how new the field is, some speculate it may have fewer gender imbalances than more established fields of medicine.

In collaboration with the Society of Hospital Medicine, Herzke and her colleagues conducted a survey of all U.S. academic hospital programs associated with the Association of American Medical Colleges. After identifying 135 programs, surveys were sent electronically to academic hospitalist leaders of each program. Participants were asked about the gender of the hospitalist program leader, the program's size and organization, faculty characteristics, and perceptions about promotion and faculty development.

"We had a sense that there were some gender issues when people had looked at these areas before," says Herzke. "Obviously, our hope was that we would see fewer inequities in our data."

Of the 135 programs, 80 responded to the survey, and responding programs did not differ significantly from nonresponding programs in terms of funding, region, age or type of institution. While programs reported approximately equal numbers of male and female faculty members, 79% of program directors were male. Moreover, 37% of male hospitalist leaders were full professors while no female hospitalist leaders held that rank.

"Even in this new specialty, we don't have gender parity," says Herzke. "There have been numerous studies suggesting that programs, and society in general, do better when we have more diverse teams and diverse leadership."

###

Herzke and her colleagues plan more studies to look at promotion and faculty development in academic hospital medicine. Also, they plan similar studies to understand if there are issues with racial inequity in leadership in academic hospital medicine. This topic in particular, says Herzke, is incredibly important to evaluate and, if inequality exists, address.

In addition to Carrie Herzke, authors of the Journal of General Internal Medicine paper are Amanda Bertram, Hsin-Chieh Yeh, Ariella Apfel and Joseph Cofrancesco Jr. of Johns Hopkins and Joanna Bonsall of Emory University.

The authors received no financial support for the research

Superbug impact on the gut

MONASH UNIVERSITY

 

IMAGE: E CADHERIN AND BETA CATENIN STAINED INFECTED MOUSE COLONIC TISSUE. view more 

CREDIT: (C) MONASH BDI

Monash University researchers have discovered that the devastating bacterial superbug Clostridioides difficile hijacks the human wound healing system in order to cause serious and persistent disease, opening up the development of new therapies to treat the disease.

Clostridioides difficile is the most common hospital-acquired disease and causes persistent and life-threatening gut infections - particularly in elderly and immunocompromised patients.

The infection is very difficult to treat, and often repeatedly reoccurs in patients even after they have been given powerful and debilitating antibiotics for many months. C. difficile is also highly resistant to antibiotics, which greatly complicates treatment.

A team based in the Monash Biomedicine Discovery Institute (BDI) found that C. difficile massively activates a human enzyme called plasminogen in order to destroy gut tissue and to help spread the infection throughout the patient. Ordinarily, plasminogen, and its active form plasmin, is deployed in a highly controlled fashion to break down scar tissue and help wounds heal.

"The results were a huge surprise, and revealed that the severe damage caused to the gut by C. difficile was actually caused by a human enzyme rather than a bacterial toxin," said study co-leader and infectious disease expert Prof Dena Lyras.

Given their findings, the researchers decided to investigate whether potent antibodies developed by the team and that inhibited the plasminogen / plasmin system could be used to treat the disease.

"We found that an antibody that prevented plasminogen from being activated dramatically stalled the progress of infection and tissue damage," said first author Milena Awad.

The researchers now aim to commercialise their antibodies in order to treat a range of bacterial and inflammatory diseases.

An advantage of targeting a human protein in an infectious disease is that resistance to the therapy is far less likely to occur.

"The antibody could have broad utility, since the plasminogen / plasmin system is dysregulated in a range of different serious inflammatory and infectious diseases - for example, the plasminogen system most likely is a driver of the devastating lung damage seen in COVID-19," said study co-leader and structural biologist Prof James Whisstock.

###

The study, published in the leading US journal Gastroenterology today, was led by senior authors Professor Dena Lyras, Dr Ruby Law and Professor James Whisstock, in conjunction with joint-lead authors Dr Milena Awad, Dr Melanie Hutton, and Dr Adam Quek.

Read the abstract of the paper in Gastroenterology titled: Human Plasminogen Exacerbates Clostridioides difficile Enteric Disease and Alters the Spore Surface

About the Monash Biomedicine Discovery Institute at Monash University

Committed to making the discoveries that will relieve the future burden of disease, the newly established Monash Biomedicine Discovery Institute at Monash University brings together more than 120 internationally-renowned research teams. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.

ARACHNOPHOBIA TRIGGER 
TOO LATE 

Spider baby boom in a warmer Arctic 

Climate change leads to longer growing seasons in the Arctic. A new study shows that predators like wolf spiders respond to the changing conditions and have been able to produce two clutches of offspring during the short Arctic summer

AARHUS UNIVERSITY

 

IMAGE: THE SNOW DISAPPEARS EARLIER AND EARLIER FROM THE ARCTIC TUNDRA AND CLIMATE CHANGE THEREFORE ENTAILS A LONGER GROWTH SEASON FOR ARCTIC PLANTS AND ANIMALS. view more 

CREDIT: TOKE T. HØYE

Climate change leads to longer growing seasons in the Arctic. A new study, which has just been published in Proceedings of the Royal Society B, show that predators like wolf spiders respond to the changing conditions and have been able to produce two clutches of offspring during the short Arctic summer.

Arctic spiders are at the top of the food chain among invertebrates and are numerous on the Arctic tundra. They typically take several years to become adults, and only produce offspring .

But something is happening in the high north in these years. A lot, actually.

Climate change is more dramatic here than in no other place on Earth. The average temperature is increasing significantly and this affects the ecosystems.

Researchers have previously reported how plants bloom earlier and earlier in the season. There are also signs that species move farther north and up into the mountains.

A team of researchers led by senior researcher Toke T. Høye from the Arctic Research Centre and Department of Bioscience at Aarhus University has now shown that changes are also occurring in the reproduction of invertebrates.

For almost 20 years, researchers at the Zackenberg Research Station in north-eastern Greenland have caught wolf spiders as part of the monitoring programme Greenland Ecosystem Monitoring. The spiders were caught in small pitfall traps set up in different vegetation types.

Wolf spiders carry their eggs in a so-called egg sac. The researchers counted the number of eggs in the individual spider's egg sacs and compared this information with the time of the season that the animal was caught. By looking at the distribution of the number of eggs in the egg sacs throughout the season, it became clear that in some summers the spiders produced two egg sacs - a phenomenon that is known from warmer latitudes, but which has not previously been observed in the Arctic.

Arctic ecosystems are changing

"We now have the longest time series of spiders collected the Arctic. The large amount of data allows us to show how small animals in the Arctic change their life history in response to climate change," says Toke T. Høye.

The long time series tells the researchers that the earlier the snow disappears from the ground, the greater the proportion of spiders that can produce a second clutch of offspring.

"These changes in the life history have not been seen earlier and evidence suggests that the phenomenon plays an important role for Arctic insects and spiders," Toke T. Høye says.

The researchers see the spiders' response to climate change as an ability to adapt to the new conditions.

Wolf spiders feed on small organisms such as springtails in the soil. If there are more spiders - or insects - in the future Arctic, it can have an influence on the food chains on land.

The wolf spider Pardosa glacialis is extremely common in the Arctic tundra. If, in future, it produces two generations of offspring during a season, these may have a significant effect on the prey on which the spider lives.

"We can only speculate about how the ecosystems change, but we can now ascertain that changes in the reproduction of species are an important factor to include when we try to understand how Arctic ecosystems react to the rising temperatures on the planet," Toke T. Høye says.

###

Bugs resort to several colours to protect themselves from predators

Colourful bugs look very different as young and adults, but why?

UNIVERSITY OF MELBOURNE

 

IMAGE: FEMALE AND NYMPH OF THE COTTON HARLEQUIN BUG SHOW THE GLORIOUS COLOURS, THAT HELP KEEP THEM SAFE. view more 

CREDIT: ILIANA MEDINA

New research has revealed for the first time that shield bugs use a variety of colours throughout their lives to avoid predators.

Shield bugs are often bright, colourful insects that use colours to warn off their distastefulness to predators. The paper, published in Proceedings of the Royal Society B, found that it is impossible to predict how an adult bug will look like based on their colour when young.

"We found that in most species, the same individual bug will use different colour combinations as nymphs - young bugs - and adults, going for example from red and green to yellow and green," said lead author and ecologist, Dr Iliana Medina, from the University of Melbourne's School of Biosciences.

"This is significant because many of these species use colour to warn predators that they are distasteful, and for years it has been thought that animals living in the same environment - like nymphs and adults of the same species - should use similar warning colours, not different ones."

The joint research between scientists at the University of Melbourne and the Australian National University combined information on colour in young and adults for more than 100 species of shield bugs worldwide. They then used field work in Canberra, with white-winged choughs, to measure how likely these birds were to attack adult and nymphs of one Australian species of shield bug, the cotton harlequin bug.

Experiments were also conducted in the aviary, training two-week-old chicks to see how fast they learned to avoid nymphs and adults, then testing whether their previous experience with adults could reduce attack rates on nymphs.

"Our experiments with the cotton harlequin bug showed that predators could quickly learn to avoid both types of colour signals from nymphs and adults, but nymphs get a larger benefit," Dr Medina said.

"Although young and adult cotton harlequin bugs have different colours, previous experience with adults make chicks less likely to attack the nymphs. Also, chicks and wild predators that have never seen the insects before do not show much interest in eating them. The colours in these insects are a great strategy against predators."

Many animals such as frogs, insects and sea slugs use bright colourations to advertise toxicity or distastefulness. In theory, warning signals of prey that live in the same environment should be the same because predators can learn more effectively to avoid one type of pattern, instead of many different ones.

While this idea has been used to explain the great examples of mimicry in nature, and why distantly related species end up having the same warning colours, such as black and red, or black and yellow, researchers say there are multiple examples of variation in local warning signals and an overlooked type of variation is that across life stages.

"If predators were able to learn to avoid only one type of warning colour, we would expect nymphs and adults to look similar in many species," Dr Medina said. "What our findings show, however, is that the wide colour variation in shield bugs is probably the result of predators being able to learn to avoid different types of colourful signals."

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ANIMAL EXPERIMENTATION 

From Jekyll to Hyde: New study pinpoints mutation that makes E. coli deadlier

Scientists identify an important protein that increases "bacterial virulence," when mutated, changing harmless bacteria to harmful ones

OKAYAMA UNIVERSITY

IMAGE: SILKWORMS ARE USED IN INFECTION EXPERIMENTS TO PERFORM EXPERIMENTAL EVOLUTION OF PATHOGENIC BACTERIA. view more 

CREDIT: CHIKARA KAITO

As far as humans are concerned, bacteria can be classified as either harmful, pathogenic bacteria and harmless or beneficial non-pathogenic bacteria. To develop better treatments for diseases caused by pathogenic bacteria, we need to have a good grasp on the mechanisms that cause some bacteria to be virulent. Scientists have identified genes that cause virulence, or capability to cause disease, but they do not fully know how bacteria evolve to become pathogenic.

To find out, Professor Chikara Kaito and his team of scientists from Okayama University, Japan, used a process called experimental evolution to identify molecular mechanisms that cells develop to gain useful traits, and published their findings in PLoS Pathogens. "We're excited by this research because no one has ever looked at virulence evolution of bacteria in an animal; studies before us looked at the evolution in cells," said Prof Kaito.

The scientists decided to start with a non-pathogenic Escherichia coli (or E. coli for short) and repeatedly mutate it and use it to infect silkworms, an insect that is often used as a model for infectious diseases, and then test whether it will cause death in silkworms.

Through this experiment, the scientists created E. coli strains with a 500-fold increased virulence compared to the original bacterial strain and found that mutations in the gene that code for one specific protein, the "lipopolysaccharide transporter (LPS) transporter," was one of the reasons for the increased virulence. This protein forms a part of the bacterial cell membrane and protects the bacteria from harm. Because of this, the LPS transporter is necessary for E. coli to grow.

The mutations that increased bacterial deadliness appeared to give E. coli resistance against some antibiotics, as well as some antibacterial substances from the silkworms. The reason for this is likely a corresponding increase in the concentration of structures called outer membrane vesicles, which the bacteria release to absorb harmful compounds to prevent them from entering the bacteria and harming them.

Researchers also identified the characteristics of substances that pathogenic strains were resistant to, showing that they were "hydrophobic" (or water-repelling) and positively charged. This fit with the increased amount of outer membrane vesicles, which are hydrophobic and negatively charged, allowing them to hold onto those substances (because, of course, opposite forces attract). The scientists also showed that the mutations occurred in parts of LPS transporter that are directly on the outside of the bacterial membrane. The scientists suspect that this is because these areas are more exposed to the environment, thereby experience more natural selection, and are thereby more susceptible to mutation.

"What we've done here is identify several things about pathogenic bacteria," explains Prof Kaito. "We showed for the first time that mutations to LPS transporter can increase virulence, and we provided evidence for how that virulence actually happens--the mutant bacteria make more outer membrane vesicles." And that's not all, the team also pinpointed specific structural changes to mutated LPS transporter that could explain why virulence is different across bacteria--because each species might have a different structure.

When asked about how his work contributes to scientific understanding and to medicine, Prof Kaito elaborates, "Before our study, it wasn't very clear how bacteria actually evolved properties that made them more harmful, so our study helps clarify this. An understanding of this process means the possibility of creating drugs or other therapy that can keep bacteria from becoming pathogenic, especially if we find more proteins like LPS transporter, where mutations can have such a big effect."

Of course, further studies are needed to explore whether the mutations observed in this study will also increase virulence when the bacteria infect animals bigger than silkworms, like mammals. But this study is definitely the first step toward unraveling the mystery of differences between dangerous and harmless bacteria.

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