Proven for the first time: The microbiome of fruit and vegetables positively influences diversity in the gut

In a meta-study, a research team from the Institute of Environmental Biotechnology at Graz University of Technology has provided evidence that the consumption of fruit and vegetables contributes positively to bacterial diversity in the human gut.

Peer-Reviewed Publication

GRAZ UNIVERSITY OF TECHNOLOGY

 

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GABRIELE BERG AND WISNU ADI WICAKSONO FROM THE INSTITUTE OF ENVIRONMENTAL BIOTECHNOLOGY AT TU GRAZ

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CREDIT: WICAKSONO - TU GRAZ

Bacterial diversity in the gut plays an important role in human health. The crucial question, however, is where are the sources of this diversity? It is known that an important part of the maternal microbiome is transferred to the baby at birth, and the same happens during the breastfeeding period via breast milk. Further sources were yet to be discovered. However, a team led by Wisnu Adi Wicaksono and Gabriele Berg from the Institute of Environmental Biotechnology at Graz University of Technology (TU Graz) has now succeeded in proving that plant microorganisms from fruit and vegetables contribute to the human microbiome. They report this in a study published in the journal Gut Microbes.

You are what you eat

The authors were able to demonstrate that the frequency of fruit and vegetable consumption and the variety of plants consumed influences the amount of fruit- and vegetable-associated bacteria in the human gut. Early childhood in particular represents a window of opportunity for colonisation with plant-associated bacteria. It was also demonstrated that the microorganisms of plant origin have probiotic and health-promoting properties.

A microbiome is the totality of all microorganisms that colonise a macroorganism (human, animal, plant) or a part of it, for example the intestine or a fruit. While the individual microbiomes are becoming better understood, little is known about their connections. “The proof that microorganisms from fruits and vegetables can colonise the human gut has now been established for the first time,” explains first author Wisnu Adi Wicaksono. This suggests that the consumption of fruit and vegetables, especially in infancy, has a positive influence on the development of the immune system in the first three or so years of life, as the intestinal microbiome develops during this time. But even after that, a good diversity of gut bacteria is beneficial for health and resilience. “It simply influences everything. Diversity influences the resilience of the whole organism; higher diversity conveys more resilience,” says Institute head Gabriele Berg.

Several billion sequences

In order to be able to determine that the consumption of fruits and vegetables and their microbiomes actually leads to changes in the intestinal microbiome, the team first created a catalogue of microbiome data from fruits and vegetables which enabled them to assign their bacteria. They compared these with publicly available data from two studies on intestinal flora. The TEDDY project looked at the development of babies in a long-term study and the American Gut Project studied the intestinal microbiome of adults – both projects also collected data on the food intake of the test persons. In total, the researchers had metagenome data from around 2500 stool samples at their disposal, each of which contained between one and ten million sequences – several billion sequences were thus evaluated. Using this extensive data set, the presence of fruit and vegetable microflora in the gut could be demonstrated. This evidence is a crucial building block in proving the WHO’s One Health concept, which closely links human, animal and environmental health.

Follow-up study on three continents

To further explore this connection, together with international colleagues and within the EU-funded HEDIMED project (www.hedimed.eu) Gabriele Berg at the Institute of Environmental Biotechnology is already working on an intervention study in which people on three continents eat exactly the same things for a certain period of time, following which their excretions are analysed. But even beyond that, Gabriele Berg sees many areas that could be influenced on the basis of the study’s findings. This starts with food production, as soil, fertiliser and pesticides affect the plant microbiome. “Fresh fruit and vegetables will always have the best microbiome; agriculture or processing companies already have a major influence here. And the storage and processing of food must also be critically reconsidered,” explains Berg. Depending on the findings of the planned study, there could also be exciting applications for individuals. “Every fruit and vegetable has a unique microbiome. So maybe at some point a personalised diet can be put together based on that.”

This research is anchored in the Field of Expertise "Human & Biotechnology", one of five strategic foci of TU Graz.

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JOURNAL

Gut Microbes

DOI

10.1080/19490976.2023.2258565 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The edible plant microbiome: evidence for the occurrence of fruit and vegetable bacteria in the human gut

 

Small but mighty: the hidden power of broccoli sprouts

Broccoli sprouts have been discovered to contain seven times more polysulfides than mature broccoli

Peer-Reviewed Publication

OSAKA METROPOLITAN UNIVERSITY

 

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THE STUDY REVEALED THAT THE TOTAL POLYSULFIDE CONTENT OF BROCCOLI SPROUTS WAS SIGNIFICANTLY HIGHER THAN THAT OF MATURE BROCCOLI

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CREDIT: OSAKA METROPOLITAN UNIVERSITY

Remember when your parents used to say, “Eat your greens, they are good for you”? Well, they were really onto something. Several studies have shown that higher intakes of cruciferous vegetables like broccoli, one of the most widely consumed vegetables in the United States, are associated with reduced risks of diseases such as diabetes and cancer, thanks to their organosulfur compounds, such as glucosinolates and isothiocyanates that exhibit a broad spectrum of bioactivities including antioxidant activity. However, few studies have focused on the endogenous content of polysulfide in broccoli sprouts.

A research team led by Assistant Professor Shingo Kasamatsu and Professor Hideshi Ihara of the Graduate School of Science at Osaka Metropolitan University, investigated the amount of polysulfides in broccoli sprouts during the process of their germination and growth. Building upon their previous work, where the research team demonstrated the abundance of polysulfide molecules in cruciferous vegetables.

The team found that total polysulfide content in broccoli sprouts significantly increased during germination and growth, with an approximately 20-fold increase in polysulfides on the fifth day of germination. Furthermore, they discovered a number of unknown polysulfides with indeterminate molecular structures. These findings suggest that the abundance of polysulfides in broccoli sprouts may contribute to their well-known health-promoting properties.

Dr. Kasamatsu stated, “The discovery of the significant increase in polysulfide content during the sprouting process from broccoli seeds was completely by chance and very surprising. This finding suggests that polysulfides may play an important role in the process of plant germination and growth. Further investigation of the pharmacological function of these unknown polysulfides could lead to the development of new preventive and therapeutic approaches and medicines for neurodegenerative diseases, stroke, cancer, inflammation, and other oxidative stress-related diseases.”

The results of this research were published in Redox Biology.

 

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About OMU 

Osaka Metropolitan University is a new public university established in April 2022, formed by merger between Osaka City University and Osaka Prefecture University. For more research news visit https://www.omu.ac.jp/en/ or follow @OsakaMetUniv_en and #OMUScience.

 

 

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JOURNAL

Redox Biology

DOI

10.1016/j.redox.2023.102875 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Untargeted polysulfide omics analysis of alternations in polysulfide production during the germination of broccoli sprouts

NEWS RELEASE 24-OCT-2023

Children as young as four eat more when bored

Peer-Reviewed Publication

ASTON UNIVERSITY

• A new study carried out at Aston University found that children as young as four eat 79% more calories on average when they are bored
• Children with more emotional temperaments whose parents used food to soothe them ate five times more calories when bored
• It is the first study to link children’s emotions and parental feeding habits in this way.

A new study carried out at Aston University has shown that children as young as four years old eat 79% more calories when they are bored, compared to when they are in a neutral mood.

Despite boredom being a common emotion experienced by many children, no research to date has looked experimentally at how much more children eat when bored. On average, the study shows that children who were feeling bored ate 95 kcal when they were already full, compared to children in a neutral mood condition who ate just 59 kcal. The pioneering research was led by Dr Rebecca Stone as part of her PhD, supervised by Professor Claire Farrow and Professor Jackie Blissett from Aston University, and Professor Emma Haycraft from Loughborough University.

Children’s eating behaviour is shaped by their genetics, temperament, and a range of other factors, including the feeding practices they experience. In previous research, the authors have explored the behaviours that make children more likely to eat when they experience negative emotions. Often when children experience negative emotions such as boredom or sadness, adults will use food to soothe them. However, this behaviour, which is known as emotional feeding, appears to enhance the likelihood of children eating more when they are upset, potentially teaching children to seek food when their mood is low. 

As part of the study the researchers asked parents about the feeding practices that they used with their child and about their child’s temperament. Children and parents were given a standard meal that they ate until they were full. Children then took part in a series of everyday conditions where their mood was assessed and one of these conditions was boring for the children. The researchers found that if parents reported using food to soothe their child’s emotions often and their child was highly emotional children ate five times more kilocalories when feeling bored (104 kcal) compared to in a neutral mood (21 kcal).

Dr Stone said:

“If children are eating this many more calories during one instance of boredom induced in a laboratory (a four-minute period), given that boredom is a commonly experienced emotion in children, the potential for excess calorie intake in response to being bored across one day, one week, or one year, is potentially very significant in a food abundant environment.”

Previous studies on what can influence eating behaviour in children have tended to be based on questionnaires, with all negative moods, including sadness, anger and anxiety, grouped together. Boredom is easily identifiable, and generally easily rectified, so helping parents to deal with children’s boredom without using food would be a potentially helpful way of reducing less healthy snacking. 

Dr Stone stresses that the experience of boredom is important in the development of children’s sense of self and creativity, so does not recommend that children could or should avoid being bored. Instead, she suggests that children need to learn to experience boredom without turning to food, and that parents could try to divert their child’s attention away from food when feeling bored, or restructure the home food environment to make it less likely that children turn to food when they are bored. 

Professor Farrow said:

“It is commonly assumed that children tend to turn to food when bored and that some children are more likely to do this than others. This is the first study to experimentally test this in the laboratory. Whilst there do appear to be individual differences between children in terms of their eating when bored, it is helpful to know that the feeding practices that adults use around food might shape the likelihood of this happening. Although it is tempting to use food as a tool to comfort children, research suggests that emotional feeding might lead to greater emotional eating in the future. It is important that parents and caregivers are aware that this short-term fix could create future challenges.” 

The research team are interested in exploring other negative mood states in children and in developing advice and support for families to find effective ways to manage challenges around child eating behaviour. 

For more information and support about fussy eating in children, visit The Child Feeding Guide website.

Food Quality and Preference DOI: 10.1016/j.foodqual.2023.105008

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JOURNAL

Food Quality and Preference

DOI

10.1016/j.foodqual.2023.105008 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Emotional eating following a laboratory mood induction: The interaction between parental feeding practices and child temperament

ARTICLE PUBLICATION DATE

1-Dec-2023

Traditional chinese medicine compound (tongxinluo) and clinical outcomes of patients with acute myocardial infarction

JAMA

Peer-Reviewed Publication

JAMA NETWORK

About The Study: In this randomized clinical trial of 3,777 patients with ST-segment elevation myocardial infarction (STEMI; a type of heart attack), the Chinese patent medicine Tongxinluo, as an adjunctive therapy in addition to STEMI guideline-directed treatments, significantly improved both 30-day and 1-year clinical outcomes. Further research is needed to determine the mechanism of action of Tongxinluo in STEMI. 

Authors: Yuejin Yang, M.D., Ph.D., and Runlin Gao, M.D., of the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, are the corresponding authors.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jama.2023.19524)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article 

https://jamanetwork.com/journals/jama/fullarticle/10.1001/jama.2023.19524?guestAccessKey=66aee3a0-78fc-415c-846c-56ca5356da82&utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=102423

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JOURNAL

JAMA

Tai Chi may curb Parkinson’s disease symptoms and complications for several years

Associated with slower disease progression and lower doses of required drugs

Peer-Reviewed Publication

BMJ

Tai Chi, the Chinese martial art that involves sequences of very slow controlled movements, may curb the symptoms and complications of Parkinson’s disease for several years, reveals research, published online in the Journal of Neurology Neurosurgery & Psychiatry.

Its practice was associated with slower disease progression and lower doses of required drugs over time, the findings show.

Parkinson’s disease is a debilitating and progressive neurodegenerative disorder, characterised by slowness of movement, resting tremor, and stiff and inflexible muscles.

It is the fastest growing neurological condition in the world, with the numbers of those affected projected to reach nearly 5 million by 2030 in China alone. In the UK 2 people are diagnosed with the disease every hour according to the charity, Parkinson’s UK.*

As yet, there is no cure for Parkinson’s, and while drugs can improve clinical symptoms, they don’t treat all the manifestations of the disease. And there’s no evidence that they slow progression either, explain the researchers.

Previously published research suggests that Tai Chi eases Parkinson’s symptoms in the short term, but whether this improvement can be sustained over the long term isn’t known.

In a bid to find out, the researchers monitored two groups of patients with Parkinson’s disease for more than 5 years from January 2016 to June 2021.

One group of 147 patients practised Tai Chi twice a week for an hour, aided by the provision of classes to improve their technique. The other group of 187 patients continued with their standard care, but didn’t practise Tai Chi.

Disease severity was formally assessed in all the participants at the start of the monitoring period, and disease progression, including increases in the need for medication, were subsequently monitored in November 2019, October 2020, and June 2021. 

The extent of movement and other symptoms, such as autonomic nervous system function (to include bowel movements, urinary and cardiovascular issues); mood, sleep quality, and cognition; and the prevalence of complications, such as dyskinesia (involuntary movement); dystonia (abnormal muscle tone); decline in responsiveness to drug treatment over time; mild cognitive impairment; hallucinations; restless leg syndrome were also tracked, using validated scales.

Disease severity, medication use, sex, age, and education level, were similar in both groups.

Disease progression was slower at all monitoring points in the Tai Chi group, as assessed by three validated scales to assess overall symptoms, movement, and balance.

The number of patients who needed to increase their medication in the comparison group was also significantly higher than it was in the Tai Chi Group: 83.5% in 2019 and just over 96% in 2020 compared with 71% and 87.5%, respectively. 

Cognitive function deteriorated more slowly in the Tai Chi group as did other non-movement symptoms, while sleep and quality of life continuously improved. 

And the prevalence of complications was significantly lower in the Tai Chi group than in the comparison group: dyskinesia 1.4% vs 7.5%; dystonia 0% vs 1.6%; hallucinations 0% vs just over 2%; mild cognitive impairment 3% vs 10%; restless legs syndrome 7% vs 15.5%.

Falls, dizziness, and back pain were the three side effects reported by study participants, but these were all significantly lower in the Tai Chi group. While 23 people sustained a fracture, these all occurred during routine daily life and were fewer in the Tai Chi group: 6 vs 17.

This is an observational study, and as such, can’t establish cause and effect. And the researchers acknowledge that the number of study participants was relatively small and they weren’t randomly assigned to their group.

But they conclude: “Our study has shown that Tai Chi retains the long-term beneficial effect on [Parkinson’s disease], indicating the potential disease-modifying effects on both motor and non-motor symptoms, especially gait, balance, autonomic symptoms and cognition.”

They add: “[Parkinson’s disease] can worsen motor function and non-motor symptoms progressively with time, resulting in disability and influencing the quality of life. The long-term beneficial effect on [the disease] could prolong the time without disability, leading to a higher quality of life, a lower burden for caregivers, and less drug usage.” 

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JOURNAL

Journal of Neurology Neurosurgery & Psychiatry

DOI

10.1136/jnnp-2022-330967 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Effect of long-term Tai Chi training on Parkinson’s disease: a 3.5-year follow-up cohort study

ARTICLE PUBLICATION DATE

24-Oct-2023

 

Child care centers unlikely source for COVID-19 transmission, study finds

Peer-Reviewed Publication

UNIVERSITY OF PITTSBURGH

 

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TIMOTHY SHOPE, M.D., M.P.H., PROFESSOR OF pediatrics at the University of Pittsburgh School of Medicine AND PEDIATRICIAN AT UPMC CHILDREN’S HOSPITAL OF PITTSBURGH.

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CREDIT: UPMC

Children in child care centers are not spreading COVID-19 at significant rates to caregivers or other children at the center, nor to their households, according to a study led by University of Pittsburgh School of Medicine and UPMC Children’s Hospital of Pittsburgh pediatrician-scientists and published today in JAMA Network Open.

The findings suggest that recommendations to test symptomatic children for SARS-CoV-2, the virus that causes COVID-19, and keep positive children home from child care for prolonged periods can be revised to align with those for other serious respiratory viruses.

“We need to have an open discussion at the national level about the benefit of recommending SARS-CoV-2 testing for every child with respiratory symptoms who attends a child care program,” said lead author Timothy Shope, M.D., M.P.H., professor of pediatrics at Pitt’s School of Medicine and pediatrician at UPMC Children’s. “No one wants to give up on controlling SARS-CoV-2 spread, but focusing on testing and long exclusion periods for children in child care centers appears to be unnecessary, while subjecting families to the expense of frequent testing, absence from work and lost wages, and loss of education and socialization for children.”

Current recommendations from the U.S. Centers for Disease Control and Prevention advise that any child with congestion, runny nose or other respiratory symptoms be tested for COVID-19 and, if positive, be kept home from child care for at least five days. For influenza and respiratory syncytial virus—equally serious respiratory viruses that infect and spread among children in child care centers at higher rates—recommendations are for the child to return to child care when symptoms are resolving and they have been fever-free for 24 hours.

The study included 83 children in 11 child care centers in two cities and their household contacts – 118 adults and 16 children – as well as 21 child care providers. They were followed from April 22, 2021 through March 31, 2022. Participants received weekly COVID-19 testing and completed symptom diaries. Child care center directors reported weekly, deidentified, self-reported COVID-19 cases for all care providers (402) and children (1,154) at their center.

The research team found that SARS-CoV-2 transmission rates within child care centers was low, about 2% to 3%, indicating that neither children nor caregivers were often spreading COVID-19 to others in the centers. Child care attendance was also a minor cause of COVID-19 in households, since only 17% of household infections resulted from children who got COVID-19 at their child care centers. Most household cases were acquired from outside the child care center.

In contrast, once someone in a household had COVID-19, transmission to other household members was high, at 50% for children and 67% for adults.

“It is interesting that such a contagious virus was transmitted at low rates in child care centers and was an uncommon reason for household infections because it goes against conventional wisdom and medical knowledge we have about other serious respiratory viruses,” Shope said. “In households, the higher rates can be explained by much more prolonged and closer contact, especially with sick children.”

In addition, the team found that only 1 in 20 symptomatic children attending child care centers tested positive for SARS-CoV-2.

The researchers explained that the purpose of this study did not include evaluating the efficacy of COVID-19 vaccines because they were not yet available for children under 5 when the study was conducted. Nevertheless, the study’s results point to the importance of vaccinating children against COVID-19, which other research has shown to be safe and effective.  

“Though we found COVID-19 transmission was low in child care centers, our study shows that transmission was very high in households, and young children still often contracted COVID-19 from people outside the child care center,” said Shope. “I strongly recommend the COVID-19 vaccine for young children to disrupt the high rates of transmission that occur in households and the missed school and work that can result.”

Additional authors on this study are Khalil Chedid, M.D., Ph.D., Andrew N. Hashikawa, M.D., M.S., and Emily T. Martin, Ph.D., all of the University of Michigan; and Mary Ann Sieber, R.N., Gabrielle Des Ruisseau, B.S., John V. Williams, M.D., Sarah E. Wheeler, Ph.D., Monika Johnson, M.S., Myla Stiegler, B.S., Helen D’Agostino, M.Sc., G. K. Balasubramani, Ph.D., Kristin A. Yahner, M.S., and Anna F. Wang-Erickson, Ph.D., all of Pitt, UPMC or both. Williams and Wang-Erickson also are affiliated with the Institute for Infection, Inflammation and Immunity in Children.

This study was supported by Merck Investigator Studies Program grant 60418, the Henry L. Hillman Foundation and Flu Lab.

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JOURNAL

JAMA Network Open

DOI

10.1001/jamanetworkopen.2023.39355 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Incidence and Transmission of SARS-CoV-2 in US Child Care Centers After COVID-19 Vaccines

ARTICLE PUBLICATION DATE

24-Oct-2023

 

Making chemistry more accessible at the University of Oxford by providing period products

Peer-Reviewed Publication

CELL PRESS

 

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HOW YOUR DEPARTMENT CAN IMPLEMENT A SUSTAINABLE PERIOD PRODUCT SCHEME IN FIVE STEPS.

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CREDIT: TRENDS IN CHEMISTRY, GARDNER ET AL.

When it comes to the question of who gets to be a scientist, gender disparities are well-documented in many fields. Patching the infamous “leaky pipeline” can be a thorny problem, but during the 2022–2023 school year, the Department of Chemistry at the University of Oxford took a simple and practical step forward: they began offering period products in the department’s bathrooms. In an article publishing October 25 in the journal Trends in Chemistry, three students involved in the Oxford Period Project and their supervising professor share the project’s success and offer advice for how others can implement this accommodation at their own institutions.

Before October 2022 in Oxford’s chemistry department, period products were available in some female bathrooms, but they were more expensive than products sold elsewhere. And while food vending machines in the department had been updated to take card payments, the department’s period products still needed to be purchased with coins.

“In the worst-case scenario, a student needing period products would have to ask peers for spare coins or products or leave the department to find or buy products elsewhere. Both options are stressful alternatives and often not compatible with the high number of contact hours a chemistry degree involves,” write Elba Feo, Sofia Olendraru, Charlie H. Simms, and Michael O’Neill, three chemistry students at Oxford and their chemistry professor.

Inspired by a 2018 report from the Royal Society of Chemistry, the students lobbied to make free period products available to all chemistry students and faculty. The department administration had some misgivings about the project, including concerns about people "hoarding" free products. Nevertheless, pads and tampons were made available in open baskets near the sinks of female bathrooms beginning in fall 2022.

The feedback has been positive. “Students feel supported, especially during long lab sessions where the few short breaks make it difficult to mitigate period emergencies if products are inaccessible,” writes the team.

The authors offer some suggestions to help make future projects even more successful. They note that the current products provided are not eco-friendly and are presently only stocked in female bathrooms. Going forward, they suggest providing a sign-up for free menstrual cups as a more sustainable option and underline the importance of using inclusive language to both reduce the stigma around periods and to be inclusive of people of all genders who menstruate.

The authors hope that their project can inspire other university departments to take this first step towards inclusivity. They write, “Access to free period products has been incredibly well received by students and staff, and it is an easy and practical way to improve the experience of studying chemistry for those with periods.”

 

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This work was supported by funding from the Royal Society of Chemistry.

Trends in Chemistry, Gardner et al. “Periods and practicals: how to help your students.” https://www.cell.com/trends/chemistry/fulltext/S2589-5974(23)00221-6

Trends in Chemistry (@TrendsChemistry), published by Cell Press, is the first Trends reviews journal in the physical sciences. The journal publishes thoughtfully designed review, opinion, and short articles covering the breadth of chemistry and its subdisciplines in an accessible, educational manner. Visit: https://www.cell.com/trends/chemistry/home. To receive Cell Press media alerts, please contact press@cell.com.

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JOURNAL

Trends in Chemistry

DOI

10.1016/j.trechm.2023.09.003 

METHOD OF RESEARCH

Case study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Periods and practicals: how to help your students

ARTICLE PUBLICATION DATE

24-Oct-2023

 

Bumblebees visit flowers with more difficult-to-access nectar for immediate benefit to the colony

Peer-Reviewed Publication

CELL PRESS

 

IMAGE: 

FLORAL BIOMECHANICS INFLUENCE BEE FORAGING DECISIONS VIA ENERGETICS

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CREDIT: ISCIENCE/PATTRICK AND SYMINGTON ET AL.

If you’ve ever watched a bumblebee move from flower to flower, you might wonder how they decide which flower to choose and how long to stay. Now, researchers reporting in the journal iScience on October 24 have new insight based on their observations of bumblebees’ interactions with slippery artificial flowers. They found that the bumblebees make choices to maximize the rate of energy return, or the amount of sugar collected each minute.

“Bumblebees can make decisions ‘on the fly’ about which nectar sources are the most energetically economical,” said Jonathan Pattrick, first author of the study and now based at the University of Oxford, U.K. “By training bumblebees to visit artificial slippery flowers and using different ‘nectars’ with high, medium or low amounts of sugar, we found that they could make a trade-off between the energy content of the nectar and how difficult it was to access.”

In other words, bumblebees choose nectar sources that maximize their immediate return of sugar to the colony, instead of optimizing the energy efficiency of their foraging. That’s different from earlier findings in honeybees, which show that honeybees maximize energy efficiency instead.

“Bumblebees have a different lifestyle to honeybees: they only store a small amount of nectar in the nest and so have to make the most of every available opportunity to forage,” Pattrick said. “This difference between species may be why the bumblebees adopt a strategy such that their foraging is of more immediate benefit to the colony, even if it means they have to work harder, while honeybees take a relatively more measured approach to how hard they work – this should prolong their working lifespan.”

“Identifying the currency used by nectar-foraging bumblebees helps provide a framework for understanding how bumblebees make foraging decisions,” said Pattrick. “This information can be used to make predictions about the sorts of flowers the bees are likely to be visiting. In turn, this could inform choices of the flowers to plant in field margins and is also relevant to crop breeders who want to make varieties which are ‘better’ for bumblebees.”

In work carried out at the University of Cambridge, UK, Pattrick and his colleagues used vertically and horizontally oriented slippery-surfaced artificial flowers to test whether bumblebees could make a trade-off between the difficulty in handling a particular flower and its nectar sugar concentration.

A custom computer program allowed them to measure the split-second timing of bumblebee behavior as they decided whether to collect high-sugar nectar from slippery flowers, which required them to expend energy hovering, or lower-sugar nectar from flowers on which they could land. Overall, they captured 60,000 separate behavioral observations, allowing them to precisely estimate foraging energetics.  Earlier studies on bumblebee foraging currencies had been based mainly on watching what bees do naturally, making it difficult to distinguish how their decisions were being made.

The data showed that bumblebees chose flowers that were either hard to handle or had a low concentration of sugar, depending on which was more energetically favorable. Their decisions fit with a model in which their critical currency is the rate of energy return as opposed to energetic efficiency, the researchers report.

The researchers say future work should investigate whether bumblebees consistently use this currency, even when the foraging context changes. They are also fascinated by the insects’ intelligence: “we find it amazing that, even with a relatively simple brain, bumblebees are able to make such complex energetic decisions,” Pattrick says.

Bumblebees visiting artificial [VIDEO] | 

This work was supported by the Biotechnology and Biological Sciences Research Council.

iScience, Pattrick et al. “Bumblebees negotiate a trade-off between nectar quality and floral biomechanics” https://www.cell.com/iscience/fulltext/S2589-0042(23)02148-X

iScience (@iScience_CP) is an open-access journal from Cell Press that provides a platform for original research and interdisciplinary thinking in the life, physical, and earth sciences. The primary criterion for publication in iScience is a significant contribution to a relevant field combined with robust results and underlying methodology. Visit http://www.cell.com/iscience. To receive Cell Press media alerts, contact press@cell.com.  

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JOURNAL

iScience

DOI

10.1016/j.isci.2023.108071 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Bumblebees negotiate a trade-off between nectar quality and floral biomechanics

ARTICLE PUBLICATION DATE

24-Oct-2023