Bee nutrition and human food security

Is it not ironic that while we increase agriculture in efforts to increase food production, we jeopardise some of nature’s most important pollinators?  Honeybees are the world’s most important pollinators of food crops. It is estimated that one third of the food we consume each day relies on pollination – mainly by bees.[1]

Managed honeybee colonies are on the decline. Research has revealed that disease and the use of pesticides are among the reasons for their declining numbers. Currently researchers at the University of Pretoria (UP) are investigating another factor that may affect the survival of these valuable pollinating insects, namely nutrition.

As is the case with human beings, a healthy diet is able to boost the immune systems of bees. Poor nutrition is proving to be one of the reasons why honeybee numbers are declining. With the loss of their natural habitat and the increase in monoculture crops, bees are no longer able to obtain the necessary variety in their diets and have consequently become more susceptible to the effects of pesticides and diseases.

The Department of Zoology and Entomology’s Prof Sue Nicolson, her colleague Prof Christian Pirk, and the Honeybee Research Group are investigating how bees cope with varying diets. Using hives maintained at UP’s experimental farm, the researchers focus on how bees respond to the quantity and quality of macronutrients (carbohydrates, proteins and fats), and especially to variations in the ratio of carbohydrates to proteins. Bees from different colonies are kept in small cages, placed in a dark incubator to mimic an actual hive, and fed various diets. Their food consumption, survival and other parameters are then measured.

Due to the abundance of mass-flowering crops or monocultures, which are characteristic of agriculture today, the research group looks at how bees respond to unbalanced diets. In the case of sunflower crops, the pollen is low in protein. As UK researchers have explained, bees feeding on monoculture crops can be compared to humans eating only sardines, chocolate or parsnips for a month![2] Apart from the fact that such crops cannot provide the required nutritional variety, mass-flowering crops also expose bees to pesticides.

While it is true that adult bees do not need much protein in their diets, Prof Nicolson stresses the importance of protein and its functional role within a honeybee colony. Bee larvae, also known as the brood, are dependent on protein to grow. Larvae rely on the adult worker-bees to consume pollen from varied plant sources and convert it to the jelly that they then feed on. Honeybees thrive on carbohydrate-rich nectar and their immune systems are strengthened by a diet that is comprised mainly of sucrose with a small amount of protein. Bee nutrition is proving to be an important component in their ability to fight disease-causing pests and parasites.

Nicolson stresses the importance of ensuring that South Africa’s honeybee populations, both wild and managed, have enough dietary diversity. Her research affirms that a mixed-pollen diet is much better than a single-pollen source and will strengthen their immunity.

Regardless of whether these little yellow and black insects interest you or not, it is important to take note of the fact that bees play a vital role in the agriculture industry and that without them human food security will be in serious jeopardy.

Researchers

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  Professor Sue Nicolson

  Professor Sue Nicolson was born in New Zealand and studied at the University of Auckland before doing her PhD at Cambridge University in the UK. She worked in the Zoology Department at the University of Cape Town for 20 years before moving to the University of Pretoria (UP) in 2001. She was Head of the Department of Zoology and Entomology from 2003 to 2011. In Pretoria, she continued research on nectar and sunbirds that had been started in Cape Town, but also began working on honeybee physiology, collaborating with Prof Christian Pirk of the Social Insects Research Group.
  
  Between 2011 and 2014, Prof Nicolson’s research on honeybee nutrition was supported by the UK’s Insect Pollinators Initiative, and funded by the Biotechnology and Biological Sciences Research Council and four other British organisations. This led to ongoing international collaborations.
  
  The focus of her research is the ecophysiological aspects of pollination. Major areas of interest have included the nutritional value of nectar and pollen, the extreme osmotic and energetic challenges for birds drinking dilute nectars, and honeybee nutritional physiology and the effects of nectar toxins and pesticides (nicotine and neonicotinoids) on pollinators. Her current work concerns the mechanisms of drinking in honeybees, the digestive physiology of nectar-feeding birds, and the chemical composition of nectar and pollen.
  
  Prof Nicolson is a fellow of the Royal Society of South Africa. In 2011, she was awarded the Zoological Society of Southern Africa’s Gold Medal, and received the Chancellor’s Award for Research at UP in 2013. She is currently a senior research fellow at UP’s Centre for the Advancement of Scholarship.
  
  How did you first become interested in entomology and in bees in particular?
  
  I have been fascinated by insects from a very young age; I grew up in New Zealand, where bumblebees, which were originally introduced to pollinate clover, were cute and conspicuous.
  
  What is the most fascinating thing about bees that most people don’t know?
  
  They don’t realise the hard work that goes into making honey – collecting nectar, carrying it back to the hive, and evaporating most of the water in it.
  
  You’ve made many interesting findings about bees over the years. Which one are you particularly proud of?
  
  Bees obtain carbohydrates from nectar and protein from pollen. We showed that, like other animals, they regulate their food intake around specific proportions of macronutrients, and that too much protein is bad for their survival.
  
  Which finding concerns you?
  
  Many of the problems affecting honeybees are due to the interaction between malnutrition and other stressors, especially diseases and pesticides.
  
  Which of your findings do you think have been key in understanding bees better?
  
  We demonstrated that the pollen carried by honeybees to the hive is half nectar. Chemical analyses of these pollen pellets cannot therefore be used as a substitute for those on fresh pollen (which is harder to collect).
  
  How can bee farmers or the agricultural sector, for instance, make practical use of some of your findings?
  
  Bee populations are threatened by habitat loss, intensive agriculture and pesticides. Farmers need to ensure that bees have access to diverse floral resources for the sake of good nutrition.
  
  With the widespread use of pesticides, there’s been a lot of talk of bees going extinct. Do you think it is imminent and likely?
  
  This is a big question! The short answer is that where honeybees are concerned, I do not think extinction is imminent or very likely, or solely due to agriculture. However, other bees are more threatened, such as bumblebees and solitary bees.
  
  Do you work exclusively on bees?
  
  No, a large part of my research has been on nectar-feeding birds, especially sunbirds. The white-bellied sunbirds so common around Pretoria make excellent experimental subjects, and we have learned a lot about their ability to handle dilute nectar diets (bird nectars have a lower sugar concentration than bee nectars).
  
  Which part of your research do you enjoy the most?
  
  Writing, which is perfect for working from home.
  
  What do you do in your spare time?
  
  I enjoy oil painting.

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  Professor Christian Pirk

  Professor Christian Pirk heads the Social Insects Research Group in the Department of Zoology and Entomology at the University of Pretoria (UP). Born in Berlin, Germany, he studied Biology and Mathematics at the Technical University of Berlin before embarking on his PhD studies at Rhodes University in South Africa.
  
  His research focuses on the behavioural and chemical ecology of social insects, in particular honeybees. He is involved in international networks with an interest in pollinator and honeybee health, collaborating with colleagues in Europe, Asia, America and Africa.
  
  Prof Pirk is Vice-President of the Entomological Society of Southern Africa; serves on the management committee of the international COLOSS network, a honeybee research association; and is a council member of the International Society of Chemical Ecology.
  
  He has published over 130 peer-reviewed articles, five book chapters and a monograph on honeybees, and has reviewed for more than 40 peer-reviewed journals and organisations such as the German Research Foundation, the EU-COST Association and South Africa’s National Research Foundation.
  
  Prof Pirk provides an excellent research base for students who are interested in chemical ecology, mathematical modelling, nutrition and social insects, and has supervised more than 40 postgraduates. To date, 19 BSc (Hons), 17 MSc and 13 PhD students have completed their degrees under his supervision. All BSc (Hons) students undertook further postgraduate studies either at UP or another tertiary institution, and have published or will publish their results in international peer-reviewed journals.
  Prof Pirk is currently supervising four MSc and 10 PhD students – five of whom are linked to the African Regional Postgraduate Programme in Insect Science at the International Centre of Insect Physiology and Ecology in Kenya – and mentoring two postdoctoral fellows. He serves on the editorial boards of the Journal of Insect Behaviour and Scientific Reports; is editor of Frontier in Insect Science; and is a member of the Academy of Science of South Africa.
  
  1. How did you first become interested in entomology, social insects and bees in particular?
  I studied Biology and Mathematics at the Technical University of Berlin for my MSc. The application of game theory in the evolution of social insects perfectly combined both aspects. It led me to social insects. My first visit to South Africa in 2000 put me in touch with the country’s fascinating honeybees. It is fascinating to study insects, to understand how much is needed to make complex decisions and exhibit complex behaviour, like keeping the temperature at 34°C (honeybees) or organise raids on termites (ants). It is interesting to understand how pheromones are used to communicate and affect the behaviour and physiology of the receiver.
  
  2. Share a fascinating fact about the social life of bees that most people don’t know.
  Being social is based on being selfish. Working together is their best selfish approach. It’s like our fight against climate change or the pandemic – it can only be done together on a global scale.
  
  3. Which of your many interesting findings concerns you?
  Tackling the challenges of ensuring enough pollination service to maintain food security, especially in Africa. Climate change and the large-scale uniformed use of pesticides are the main challenges.
  
  4. In which practical ways does your research help bee farmers and the agricultural sector?
  One of our focus areas is the “capensis calamity”, also known as the “capensis clone”. It began when Cape honeybee colonies were brought to the northern parts of South Africa, into the native range of the savannah honeybee. Due to the unique characteristics of the Cape honeybee, it resulted in a clonal lineage of parasitic Cape honeybee workers. These capensis clones, all genetically identical, take over the colonies of any other honeybee subspecies and kill its queen. Since these clones only reproduce and do not work, the host colony slowly dies. The capensis clone is a unique South African problem. Research into it was started by my UP colleague Prof Robin Crew. It helps to address the negative impact the clone has on the agricultural sector. Our work on pesticides and diet is directly addressing burning local and global issues.
  
  5. What lessons can people take from bees in terms of task orientation and social interaction, for instance?
  Nothing – because the systems are too different. We tend to “push” biological systems into what we believe they should be. For example, despite our knowledge of them, it took a while to accept the fact that the queen is female and that the only task of males is to transport sperm to the next female. Only in the late 17th century was it slowly established that the “head” of the colony is female. It took even longer to change the idea that there is a king and princes in the colony. I would even say that the term “queen” does not exactly describe the role of the queen. A honeybee colony is the interaction of thousands of female individuals that work together. Some have the task of reproducing, and others have foraging duties. So I would say the lesson is this: work together to solve small and global problems.
  
  6. Do you do transdisciplinary work?
  Together with Prof Catherine Sole (Department of Zoology and Entomology, UP) and Dr Ida Breed (Department of Architecture, UP), we research the role of urban environments on pollinators and insect diversity, and how to create areas within the urban space to protect and nurture our pollinators. Along with Prof Pieter de Villiers (Department of Electrical, Electronic and Computer Engineering, UP), I am looking into ways of remotely monitoring the activities and health of individual colonies.
  
  Being part of bigger networks – either within an institution, like being part of FABI [UP’s Forestry and Agricultural Biotechnology Institute], or as part of international networks like COLOSS or SUPERB – facilitates inter- and transdisciplinary work. I am currently part of a consortium working on an application for an EU-COST action on bee research communication.
  
  7. COLOSS is an international honeybee research association. How does such collaboration strengthen your work?
  Being actively involved in research means having an international network of collaborators and colleagues. Pollinator decline is a global issue, which is affected by other global questions. Being part of COLOSS allows for easy networking and being part of setting standards like the COLOSS bee book, to which several of the Social Insects Research Group members contributed. We published a recent paper on the effects of COVID-19 on bee research. We also prepared a cost action proposal on communicating bee research to beekeepers. Being a member allows for increased communication and finding like-minded researchers around the world. As an executive committee member, I can put forward an African perspective on global issues related to honeybees.
  
  8. Which part of your research do you enjoy most?
  
  Mentoring the next generation of academics and researchers, and answering questions, especially if one is the first to answer a particular question.
  
  9. What do you do in your spare time?
  
  I read anything, from autobiographies, fantasy and history to scientific books. I take advantage of the excellent weather in Pretoria by swimming.
  

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Related Photo

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  A honeybee on an aloe flower