Bacterial competition in situations of food scarcity prevents survival of mutants

Study compares the phenomenon observed in the species E. coli to a "tragedy of the commons", in which individual interests take precedence over the collective good. It masks the emergence of variants and makes the colony's mutation rate seem lower.

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

Research News 

IMAGE: AT TIMES OF NUTRITIONAL SCARCITY, BACTERIA DON'T INTERACT FOR MUTUAL BENEFIT, TO ASSURE GROWTH OF THE COLONY. view more 

CREDIT: BENY SPIRA

A study conducted by researchers at the University of São Paulo in Brazil shows that competition for nutrients and lack of cooperation among bacteria of the species Escherichia coli in the same population and in situations of food scarcity prevent mutants that are better adapted to the environment from flourishing, except those that organize in small groups. The phenomenon masks the emergence of novel bacterial variants, making the mutation rate seem lower than it is in fact.

Mutants constantly emerge and accumulate from one generation to the next. Mutation frequency determines the evolution of a given species. Understanding the origin of mutations is also important to explain biological processes. In the case of bacteria, for example, it helps explain the potential evolutionary divergence of a pathogen in an epidemic or resistance to antibiotics.

In an article on the study published in the journal BMC Biology, the researchers compare what happens in colonies of E. coli with the "tragedy of the commons", a term used by economists as well as ecologists to refer to the problems that occur when individuals pursue personal gain to the detriment of their community, resulting in the destruction of public goods or natural resources.

"At times of nutritional scarcity, bacteria don't interact for mutual benefit, to assure growth of the colony. We found that even the emergence of a few individuals that can use the available food sources doesn't prevent this lack of cooperation from jeopardizing the entire population. Only a small number of mutants are able to multiply and form new colonies," said Beny Spira, a professor at the university's Biomedical Sciences Institute (ICB-USP) and last author of the article.

The finding explains the longstanding question of why the frequency of mutants capable of cleaving certain nutrients (breaking them down into molecules that can be metabolized) is always much lower in practice than in theory.

The research on mutant frequency masking is part of a project supported by São Paulo Research Foundation - FAPESP via a Research Regular Grant, a doctoral scholarship and a scientific initiation grant.

Tragedy of the commons

Unlike wild-type E. coli, bacteria with PHO-constitutive mutations overexpress the enzyme alkaline phosphatase and hence can cleave glycerol-2-phosphate (G2P) to release phosphate and glycerol, an important source of carbon, especially in situations of nutritional scarcity. PHO stands for phosphate. The "PHO regulon" helps plant cells survive and thrive despite nutrient scarcity and phosphate depletion in the environment.

The frequency of PHO-constitutive colonies on G2P selective plates (cell culture dishes) is exceptionally low. "When we measure actual mutant frequency, we find that in a population of 100 billion bacteria there are tens of thousands of PHO-constitutive mutants. Yet only 50 to 100 manage to multiply and produce new colonies with the mutation that confers the ability to cleave G2P," Spira told.

The mutant, he explained, is capable of expressing large amounts of alkaline phosphatase, which is compartmentalized in the cell periplasm (a region between the inner cytoplasmic and outer membranes). Thus when G2P is cleaved and glycerol produced, the nutrient can be stored by the bacterium or released into the external environment, where it will be promptly taken up by the many wild-type (non-mutant) bacteria in the vicinity.

However, the glycerol released by mutants is not sufficient for colonies of wild-type bacteria to grow. Some 20,000 bacteria can be found in the vicinity of every mutant. "The few mutants that succeed in multiplying are those that cooperate with each other to form clusters and swap glycerol. Otherwise, the nutrient becomes scarce, mutants are inhibited, and the population dies out," Spira said.

Wild-type and mutant bacteria normally compete for insufficient glycerol. "Mutants don't multiply owing to the scarcity of this nutrient, creating the impression that there are no mutations and drastically reducing the frequency of PHO-constitutive mutants in the population," he said.

Inhibition of PHO-constitutive mutants, therefore, is an example of mutation frequency masked by competition between mutants and their ancestral wild-type cells. "The example shows that cases similar to a 'tragedy of the commons' may occur in other settings and should be taken into consideration when mutation rates are estimated," he said.

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About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at http://www.fapesp.br/en and visit FAPESP news agency at http://www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

 

Pandemic-related anxiety in pregnancy

TOHOKU UNIVERSITY

Research News

 

IMAGE: RESULTS OF THE SURVEY view more 

CREDIT: TOHOKU UNIVERSITY

Pregnant women in Japan who responded to an online survey early in the COVID-19 pandemic demonstrated higher levels of anxiety compared to women undergoing fertility treatments and to pregnant women in Iran.

The findings were published in the Journal of Affective Disorders Reports.

"The pandemic has changed the social environments of pregnant women and fertility patients," says Tohoku University clinical psychologist Koubon Wakashima.

For example, restrictions in Japan meant that pregnant women have been unable to participate in group parenting classes or travel to their parents' homes to receive traditional childbirth assistance. Medical institutions in the country reported fewer women accessing infertility treatments.

Wakashima and colleagues at Tohoku University, Hokkaido University and the National Foundation of Brief Therapy posted a survey on several pregnancy and fertility websites towards the end of May and the beginning of June 2020. Almost 300 pregnant women and 13 women undergoing fertility treatment responded to a Japanese version of the Fear of COVID-19 Scale, originally developed by Iranian researchers.

Analyses of the surveys revealed that pregnant women in Japan had higher levels of anxiety compared to fertility patients. Their anxiety levels were associated with increased stockpiling and monitoring their own health. Pregnant women who considered social networking services an important information source expressed lower levels of anxiety compared to those who preferred newspapers and TV. Finally, the researchers compared the results of their survey to a similar one done in Iran and found that pregnant Japanese women demonstrated higher levels of anxiety compared to pregnant Iranian women.

The scientists acknowledge that their study has several limitations regarding, for example, the ability to assess strict causal relationships between anxiety and various coping behaviours, and a lack of detailed information on the media content the women were accessing.

Nevertheless, they suggest the results indicate the importance of improving communications that can help pregnant women cope with feelings of anxiety in addition to relaying information on infection prevention.

The team next aims to analyse how fear of COVID-19 varies by occupation and by time of year. They also plan to investigate how one person's fears impact other family members.

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Tracing and controlling High Pathogenicity Avian Influenza

HOKKAIDO UNIVERSITY

Research News

IMAGE: THE NORTHERN PINTAIL, A MIGRATORY DUCK, ONE OF WHICH CARRIED THE HIGH PATHOGENICITY AVIAN INFLUENZA VIRUS H5N8 TO JAPAN (PHOTO: KOHEI OGASAWARA). view more 

CREDIT: KOHEI OGASAWARA

Scientists have discovered a route of introduction for High Pathogenicity Avian Influenza Virus (HPAIV) H5N8 into Japan and, in parallel, have investigated the potential of two human anti-influenza drugs for the control of HPAI in birds.

Since October 30, 2020, there have been over 30 recorded outbreaks of High Pathogenicity Avian Influenza (HPAI) in domestic poultry and wild fowl in Japan. This outbreak was caused by the influenza A virus H5N8, a known High Pathogenicity Avian Influenza Virus (HPAIV). In such a scenario, identification of the source of the virus and its transmission route is important to control its spread.

A team of scientists led by Professor Yoshihiro Sakoda of Hokkaido University have recently found the probable route of introduction of the current HPAIV into Japan -- by migratory birds from Europe. Separately, they showed that anti-influenza drugs used for humans can potentially be used to treat HPAI in poultry and wild fowl, providing an alternative to culling infected birds. Their findings were published within a week of each other in the journal Viruses.

HPAI is a devastating disease in poultry, leading to large losses both economically and materially. Once present in domesticated poultry, the primary means of controlling HPAI is by culling all infected populations. There is no approved drug for the treatment of HPAI. In addition, it can infect captive wild birds, such as those in zoos and sanctuaries, which has major implications for the protection and conservation of endangered species.

In addition, HPAI is closely related to influenza in humans; certain strains of HPAIV have jumped to humans in the past, most recently in mid February 2021, in Russia. For prevention and control, it is vital to track the spread of this disease.

The scientists collected migratory duck feces samples from the lakeside of Lake Komuke, eastern Hokkaido in October 2020. After a number of tests, they confirmed the presence of H5N8 virus in one of the samples. Further, their genetic analysis showed that the H5N8 virus was closely related to the variants that caused outbreaks in Europe from late 2019 to early 2020 and the variants found in Korea and southern Japan from October to November 2020, rather than from the H5N8 viruses in East Asia from 2018-2019. This suggested that the H5N8 virus transmitted with migratory birds from Europe to Eastern Asia within 10 months. In addition, the team found that it is a different H5N8 variant that is causing current outbreaks in Europe, raising the alarm that the northern biosphere is becoming a reservoir of HPAIV.

The scientists also investigated two antivirals, baloxavir marboxil (BXM) and peramivir (PR), used for the treatment of influenza in humans for their potential to treat HPAI in poultry. In their experiments, both drugs improved the survival rate of infected chickens and reduced viral amounts in their organs and feces, with BXM showing higher efficacy. Further work on BXM suggested that an early single-administration of BXM at doses of 2.5 mg/kg or higher would be most effective for the treatment of HPAI in real-life settings.

"Based on our findings, the government authorities warned poultries in Japan in November last year, which helped local businesses take measures to prevent potential outbreaks. As in the past years, we will continue to monitor HPAIV in migratory birds visiting Hokkaido as well as researching possible treatments of the disease," said Sakoda.

The next steps would be to confirm if the strain of H5N8 detected by the scientists is responsible for the ongoing HPAI outbreak in Japan, and to verify if BXM is capable of treating HPAI in rare wild birds and poultry farms.

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References

1. Augustin Twabela, et al. Evaluation of Baloxavir Marboxil and Peramivir for the Treatment of High Pathogenicity Avian Influenza in Chickens. Viruses. December 8, 2020. (https://doi.org/10.3390/v12121407)

2. Norikazu Isoda, et al. Re-Invasion of H5N8 High Pathogenicity Avian Influenza Virus Clade 2.3.4.4b in Hokkaido, Japan, 2020. Viruses. December 14, 2020. (https://doi.org/10.3390/v12121439) The key paper is the second paper (Norikazu Isoda, et al).

The full funding information for the papers is as follows:

1. Augustin Twabela, et al.: Environment Research and Technology Development (JPMEERF18S20103), Japan Agency for Medical Research and Development ( JP18Fm0108008), Japan International Cooperation Agency (JP20jm0110019).

2. Norikazu Isoda, et al.: Environment Research and Technology Development (JPMEERF18S20103), Japan Agency for Medical Research and Development (JP20jm0210054h0004), Japan International Cooperation Agency (JP20jm0110019).

CAPTION

Northern Pintails on Lake Komuke, eastern Hokkaido, the site where the infected feces sample was collected (Photo: Kohei Ogasawara).

CREDIT

Kohei Ogasawara

Climate change damaging North America's largest temperate rainforest, harming salmon

CU Denver's Brian Buma joined researchers to evaluate the region's ecosystem of 200-foot trees and deep soils

UNIVERSITY OF COLORADO DENVER

Research News

 

New research released in Bioscience found that a remote region of North America's largest temperate rainforest is experiencing changes to its ecosystem due to climate change. Brian Buma, a researcher and professor of integrated biology at University of Colorado Denver, co-leads the research network that outlined the changes in a new paper.

North America's largest remaining temperate rainforest, located in Southeast Alaska, is one of the most pristine and intact ecosystems. The entire ecosystem stretches well over 2,000 km from north to south and stores more carbon in its forests than any other.

The region can store more than 1,000 tons per hectare of carbon in biomass and soil. Although the area is extremely remote, researchers say it is not immune from the negative impacts of climate change. Glaciers are disappearing faster than most other places on Earth and winter snows are turning into winter rains. This is leading to a change in stream temperatures, which can harm salmon, and changes in ground temperatures, causing the death of forests.

"This is an incredible landscape in a relatively compact area we have as much biomass carbon as 8% of the lower 48 states put together," said Buma. "The 200-foot trees, the deep soils--it's just layers and layers of life. And that land is so intertwined with the water that any change in one means massive change in the other, downstream and into the ocean."

Why is this important? Forests absorb more carbon than they release. Trees absorb carbon during photosynthesis, removing large amounts of carbon from the atmosphere. Since the forest is growing faster as the climate warms, a lot of that carbon "leaks" out through the creeks and rivers. This carbon powers downstream and marine ecosystems, which thrive on the flow of energy off the land.

"This region is immensely important to global carbon cycles and our national carbon strategy, but we still don't know the direction overall carbon stocks and movement will take as the world warms," said Buma. "While there is ample research identifying how important this area is, more work is needed to determine where this large reservoir will trend in the future."

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Credit for the research paper is attributed to a workshop organized by the Coastal Rainforest Margins Research Network, supported by the National Science Foundation, the University of Washington Freshwater Initiative, the Hakai Institute, and the University of Alaska Southeast.Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

How India's rice production can adapt to climate change challenges

UNIVERSITY OF ILLINOIS COLLEGE OF AGRICULTURAL, CONSUMER AND ENVIRONMENTAL SCIENCES

Research News

 

IMAGE: FARM WORKERS PLANT RICE TRANSPLANTS AT THE BORLAUG INSTITUTE FOR SOUTH ASIA'S RESEARCH FARM IN BIHAR, INDIA. view more 

CREDIT: UNIVERSITY OF ILLINOIS.

URBANA, Ill. ¬- As the global population grows, the demand for food increases while arable land shrinks. A new University of Illinois study investigates how rice production in India can meet future needs by adapting to changing climate conditions and water availability.

"Rice is the primary crop in India, China, and other countries in Southeast Asia. Rice consumption is also growing in the U.S. and elsewhere in the world," says Prasanta Kalita, professor in the Department of Agricultural and Biological Engineering at U of I and lead author on the study.

"If you look at where they traditionally grow rice, it is countries that have plenty of water, or at least they used to. They have tropical weather with heavy rainfall they depend on for rice production. Overall, about 4,000 liters of water go into production and processing per kilogram of rice," he states.

Climate change is likely to affect future water availability, and rice farmers must implement new management practices to sustain production and increase yield, Kalita says.

The United Nations' Food and Agriculture Organization (FAO) estimates the world population will grow by two billion people by 2050, and food demand will increase by 60%.

"We will need multiple efforts to meet that demand," Kalita states. "And with two billion more people, we will also need more water for crop production, drinking water, and industrial use."

Kalita and his colleagues conducted the study at the Borlaug Institute for South Asia's research farm in Bihar, India. Farmers in the region grow rice during the monsoon season, when heavy rainfall sustains the crop.

The researchers collected data on rice yield and climate conditions, then used computer simulations to model future scenarios based on four global climate models. The purpose of the study was to estimate rice yield and water demand by 2050, and evaluate how farmers can adapt to the effects of climate change.

"As the weather changes, it affects temperature, rainfall, and carbon dioxide concentration. These are essential ingredients for crop growth, especially for rice. It's a complicated system, and effects are difficult to evaluate and manage," Kalita states.

"Our modeling results show the crop growth stage is shrinking. The time for total maturity from the day you plant to the day you harvest is getting shorter. The crops are maturing faster, and as a result, you don't get the full potential of the yield."

If farmers maintain current practices, rice yield will decrease substantially by 2050, the study shows. But various management strategies can mitigate the effects of climate change, and the researchers provide a series of recommendations.

Traditional rice farming involves flooding the fields with water. Rice transplants need about six inches of standing water. If fields aren't level, it requires even more water to cover the crops, Kalita says. However, if farmers use direct-seeded rice instead of transplants, they can increase production while using significantly less water.

Another practice involves soil conservation technology. "The soil surface continuously loses water because of temperature, humidity, and wind. If you keep crop residue on the ground, it reduces the evaporation and preserves water. Furthermore, when the crop residue decomposes, it will help increase soil quality," Kalita explains.

The researchers also suggest implementing strategies to prevent post-harvest crop losses. FAO estimates about 30% of crops are lost or wasted after harvest, so efforts to reduce those losses can further increase crop availability and food security.

Overall, the best approach to achieve a 60% increase in rice production while minimizing additional irrigation needs is a combination of conservation strategies and a 30% reduction in post-harvest loss, the researchers conclude.

###

The Department of Agricultural and Biological Engineering is in the College of Agricultural, Consumer and Environmental Sciences and the Grainger College of Engineering, University of Illinois.

The article, "Predicting the water requirement for rice production as affected by projected climate change in Bihar, India" is published in Water.

Authors are Ranjeet Jha, Prasanta Kalita, Richard Cooke, Praveen Kumar, Paul Davidson, and Rajkumar Jat.

This research was partly funded by the University of Illinois at Urbana-Champaign and USDA National Institute of Food and Agriculture.

 

THIRD WORLD USA

Multiple factors synergistically drive socioeconomic disparities in flu burden

Computational modeling identifies areas where inequities are most severe and overlooked

PLOS

Research Ne

 

IMAGE: FLU view more 

CREDIT: FLOCKINE, PIXABAY

A comprehensive modeling study sheds new light on socioeconomic-based mechanisms that drive disparities in influenza burden across the U.S. Casey Zipfel of Georgetown University in Washington D.C. and colleagues present this analysis in the open-access journal PLOS Computational Biology.

People of lower socioeconomic status experience increased burden of influenza. Past studies have identified various factors that underlie this health inequity, including decreased flu vaccination, lack of access to paid sick leave, lack of healthcare access, increased susceptibility to infection, and different exposure patterns. However, no previous study has considered all of these factors at once.

For the new study, Zipfel and colleagues considered how multiple underlying factors independently and synergistically drive health disparities in influenza burden. They combined large-scale disease datasets and observations from past studies to develop data-driven computational models, enabling them to explore how various factors impact influenza transmission and burden for people of varying socioeconomic status across the U.S.

The analysis showed that people of lower socioeconomic status bear a disproportionate burden of influenza infection in the U.S., and this disparity arises from the synergistic combination of multiple social-economic and healthcare factors. The researchers also identified geographic regions where disparities are most severe and where existing systems to track influenza tend to overlook flu cases among people of low socioeconomic status.

"As the divide in health disparities grows wider across the world, it is imperative that we continue to understand how social determinants impact health, and how this is reflected geographically," Zipfel says. "Our work spotlights inequities in respiratory disease transmission, currently on display due to the COVID-19 pandemic."

The new findings could help inform efforts to eliminate public health disparities due to socioeconomic status and systemic racism. Meanwhile, the researchers note the need to collect better data on healthcare access and usage among people of low socioeconomic status in order to validate their model findings and inform future research and public health efforts.

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Peer-reviewed; Simulation / modelling

In your coverage please use this URL to provide access to the freely available article in PLOS Computational Biology: https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1008642

Citation: Zipfel CM, Colizza V, Bansal S (2021) Health inequities in influenza transmission and surveillance. PLoS Comput Biol 17(3): e1008642. https://doi.org/10.1371/journal.pcbi.1008642

Funding: Research reported in this publication was supported by the National Institute Of General Medical Sciences of the National Institutes of Health under Award Number R01GM123007 (SB, https://www.nih.gov/). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We also acknowledge support from the PhRMA Foundation, the Chateaubriand Fellowship Program, and the Georgetown Global Health Initiative (CMZ, https://www.phrma.org/en, https://www.chateaubriand-fellowship.org/, https://globalhealth.georgetown.edu/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist

 

USA

Mapping the best places to plant trees

CELL PRESS

Research News

 

IMAGE: THIS IMAGE SHOWS THE REFORESTATION HUB TOOL. view more 

CREDIT: THE NATURE CONSERVANCY AND AMERICAN FORESTS

Reforestation could help to combat climate change, but whether and where to plant trees is a complex choice with many conflicting factors. To combat this problem, researchers reporting in the journal One Earth on December 18 have created the Reforestation Hub, an interactive map of reforestation opportunity in the United States. The tool will help foresters, legislators, and natural resource agency staff weigh the options while developing strategies to restore lost forests.

"Often the information we need to make informed decisions about where to deploy reforestation already exists, it's just scattered across a lot of different locations," says author Susan Cook-Patton, a Senior Forest Restoration Scientist at the Nature Conservancy. "Not everybody has the computer science experience to delve into the raw data, so we tried to bring this information together to develop a menu of options for reforestation, allowing people to choose what they would like to see in their community, state, or nation."

The culmination of these efforts is the Reforestation Hub, a web-based interactive map that color-codes individual counties by reforestation opportunity or level of potential for successful reforestation. And the results show that there is a great deal of reforestation opportunity in the United States.

"There are up to 51.6 million hectares (about 200,000 square miles) of opportunity to restore forest across the United States after excluding productive cropland and other places where trees are infeasible," she says. "Those additional forested areas could absorb the emissions equivalent to all the personal vehicles in California, Texas, and New York combined."

In addition to quantifying the amount of land that could yield viable forests, the Hub also identifies trends in how this opportunity is distributed throughout the country.

"While there's no single best place to restore forest cover, we did find a particularly high density of opportunity in the Southeastern United States," says Cook-Patton. "This is a region where carbon accumulation rates are high, costs are low, and there is a lot of opportunity to achieve multiple benefits like creating habitats for biodiversity, improving water quality, and climate mitigation."

The map also quantifies the acreage of 10 individual opportunity classes--or categories based on land ownership and quality. Some of these include pastures, post-burn lands, and floodplains. "The choice to plant trees really depends on what people want out of the landscape, whether it's controlling flood waters, improving urban environments, or recovering forests after a fire," she says.

The researchers hope to create similar maps for other countries, an important next step for combating the global problem of climate change.

"We have about a decade to get climate change in check," Cook-Patton says, "and I am excited about the potential for this study to help accelerate decisions to invest in reforestation as a climate solution."

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The research was supported by the Doris Duke Charitable Foundation and the Rodney Johnson and Katharine Ordway Stewardship Endowment. The Reforestation Hub was created with support from American Forests and the Sant Foundation.

The Reforestation Hub can be found at https://www.reforestationhub.org/

One Earth, Cook-Patton et al.: "Lower cost and more feasible options to restore forest cover in the contiguous United States for climate mitigation" https://www.cell.com/one-earth/fulltext/S2590-3322(20)30603-5?utm_source=EA

One Earth (@OneEarth_CP), published by Cell Press, is a monthly journal that features papers from the fields of natural, social, and applied sciences. One Earth is the home for high-quality research that seeks to understand and address today's environmental Grand Challenges, publishing across the spectrum of environmental change and sustainability science. A sister journal to Cell, Chem, and Joule, One Earth aspires to break down barriers between disciplines and stimulate the cross-pollination of ideas with a platform that unites communities, fosters dialogue, and encourages transformative research. Visit http://www.cell.com/one-earth. To receive Cell Press media alerts, contact press@cell.com.

Making green energy the default choice can help tackle climate change, study finds

UNIVERSITY OF WARWICK

Research News

 

Researchers studying the Swiss energy market have found that making green energy the default option for consumers leads to an enduring shift to renewables and thus has the potential to cut CO2 emissions by millions of tonnes.

The study, published today in Nature Human Behaviour, investigated the effect of changes in the Swiss energy market that presented energy from renewable sources as the standard option for consumers - the 'green default.'

Both business and private customers largely accepted the default option, even though it was slightly more expensive, and the switch to green sources proved a lasting one.

Professor Ulf Liebe (University of Warwick), Doctor Jennifer Gewinner and Professor em. Andreas Diekmann (both ETH Zurich) analysed data from two Swiss energy suppliers who between them supplied around 234,000 households and 9,000 businesses in urban and rural areas.

Both companies restructured their products to offer a choice between conventional power, renewable power and "renewable plus," one company in 2009 and the other in 2016. Consumers were assigned the renewable package unless they opted out, a behavioural mechanism known to have success in a range of settings.

• Supplier A saw a drop in private customers on the conventional tariff from 97 per cent to 15 per cent following introduction of the green default. By year 6, 80 per cent of households were still on the green tariff

• For SMEs, the fall was smaller - from 97 per cent to 23 per cent, with 71 per cent still on the green option in year 6.

• Supplier B saw similar results, with a change from 98.8 per cent of households using conventional energy to just 11 per cent after the introduction of the green default.

• For SMEs supplied by company B, the fall was from 99.3 per cent to 15.3 per cent on the non-renewable package.

Further analysis of customer data in the household sector showed that women were around 6 per cent more likely than men to accept the green default, while women business owners were 8 per cent more likely to stick with the renewable package.

It is sometimes argued that the introduction of green energy defaults leads to an increase in energy use - because the energy is 'clean' consumers are more relaxed about using it. Analysis of six years of energy consumption data showed no evidence of this.

Commenting on these results, Professor Liebe said: "Our study shows that 'green defaults' have an immediate, enduring impact and as such should be part of the toolkit for policymakers and utility companies seeking to increase renewable energy consumption, not only among household customers but also in the business sector."

Large green default effects can considerably reduce CO2 emissions in countries with high fossil fuel share in their energy mix. Taking Germany as a case study and assuming a default effect of 80% in the household sector, the study calculated a CO2 reduction of about 45 million tonnes and a positive welfare effect of €1,240 million. While the impact of default effects can be massive, the exact CO2 reduction figures and welfare gains depend on the CO2 emission factor and social cost of carbon.

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NOTES

Liebe, U., Gewinner, J., Diekmann, A. Large and persistent effects of green energy defaults in the household and business sectors. Nat Hum Behav 5 (2021). https://dx.doi.org/10.1038/s41562-021-01070-3. This link will go live after the embargo lifts.

The full listing of authors and their affiliations for this paper is as follows:

Ulf Liebe: University of Warwick, University of Warwick

Jennifer Gewinner: ETH Zurich

Andreas Diekmann: ETH Zurich, University of Leipzig

The following funding acknowledgements from the authors appear at the end of the paper:

Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)

 

Firefly tourism takes flight, sparking wonder and concern

First comprehensive review on the growing global phenomenon of firefly tourism

TUFTS UNIVERSITY

Research News

 

IMAGE: IN NORTH CAROLINA USA, MALE BLUE GHOST FIREFLIES (PHAUSIS RETICULATA) GLOW WHILE SEARCHING FOR MATES. THEIR FLIGHTLESS FEMALES ARE HIGHLY VULNERABLE TO TRAMPLING, AS THEY REMAIN HIDDEN ON THE FOREST... view more 

CREDIT: SPENCER BLACK

Firefly beetles rank among the world's most charismatic creatures, with luminous courtship displays that have now turned them into a popular attraction for wildlife tourists. In the first comprehensive review of firefly tourism, published in the journal Conservation Science and Practice, an international team of biologists led by a Tufts University researcher, reveal that an estimated 1 million people now travel each year to witness bioluminescent performances starring some two dozen firefly species around the world.

But the authors also point out that while this unique, insect-based tourism can bring economic, social, and psychological benefits to local communities and tourists alike, it also threatens to extinguish some local firefly populations unless adequate protections are put in place.

"With this review of the current state of firefly tourism and the declining health of their habitats, we are putting out a call to action to engage local communities and governments, as well as the tourists themselves, to act as guardians of the fireflies," said lead author Sara Lewis, professor of biology at Tufts University and co-chair of the International Union for the Conservation of Nature's (IUCN) Firefly Specialist Group, which conducted the review. The IUCN firefly group works to identify key threats and conservation issues facing fireflies in different geographic regions, and advocates for the most threatened species at national and global levels. Lewis' earlier work on fireflies with the IUCN has drawn considerable attention and fascination among the public and other researchers, with media coverage including CNN and The Washington Post.

In recent years, the number of tourists has skyrocketed at several sites in Mexico, India, Taiwan, Malaysia, Thailand, and the United States. "In Mexico, the rapid growth of firefly tourism over the past decade is thrilling but also alarming," said Tania López-Palafox, graduate student at Universidad Nacional Autónoma de México and co-author of the review. "The COVID pandemic gave them a momentary respite, but we have witnessed the harm that too much tourism can do."

Aimed at site managers, tour guides, and tourists, the report highlights the need to recognize ecological requirements across all firefly life stages. To promote the breeding success of firefly adults, sites should minimize light pollution: bright lights from buildings, vehicles, flashlights, and even cell phones - all of which can disrupt firefly courtship rituals.

CAPTION

Females of many firefly species lack functional wings, making them especially vulnerable to accidental trampling in areas of heavy foot traffic.

CREDIT

Radim Schreiber

Protection of nearby habitats also plays an essential role. Fireflies spend most of their life cycle in a juvenile, larval stage. These juveniles require several months or even years to develop into their adult form and, depending on the species, spend this time living below ground, in leaf litter or sometimes underwater. The authors describe former firefly sites along mangrove rivers where commercial development and excessive motorboat traffic have degraded riverbank habitat that had been essential for supporting firefly larvae.

At some sites, the reproductive cycle of firefly populations is threatened by tourists inadvertently trampling female fireflies and degrading larval habitats. Females in many species can't fly, and so are particularly susceptible to tourist foot traffic. Learn more about the mating rituals of fireflies studied by the Tufts research team in this video.

The report noted the popularity of displays created by several kinds of synchronous fireflies found in Southeast Asia and North America, where hundreds or thousands of firefly males captivate females - and tourists, too - by flashing their lights together in unison. According to co-author Anchana Thancharoen, lecturer at Kasetsart University in Bangkok, "With such mesmerizing lights, the firefly display trees make tourists fall in love at first sight. Our aim with this call to action is to channel that love into support for conservation efforts."

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Other recommendations by the authors include:

1) Tailored conservation practices to protect the habitats for all life stages to thrive
2) Involvement of local communities as ecological and economic stakeholders
3) Training programs for guides
4) Educational materials for visitors and best practices for transforming tourist behavior

Whether managed by local governments or run by commercial enterprises, well-managed tourism should educate global visitors to become allies in protecting firefly populations.

"There is also a larger opportunity here," said Lewis. "Fireflies hold a special fascination for people, and their fading lights make an obvious and visible case for conservation. But fireflies can also be a gateway bug to get tourists interested in conserving many other insects, which might not be so charismatic, yet still are essential building blocks for healthy ecosystems."

CAPTION

At Nanacamilpa in Mexico, tourists follow guides into the forest to view courtship displays of synchronous roving fireflies Photinus palaciosi

CREDIT

Tania López-Palafox