NOVEMBER 2018 • COUNTRY LIFE IN BC


Sunflower pollen can help improve colony health


Anything to help bees maintain their health is a huge bonus, especially given all the challenges they have faced in the past decade. But recent research from scientists at


Research by MARGARET EVANS


North Carolina State University as well as the University of Massachusetts, Amherst, has shown how valuable something as readily available as sunflower pollen can be to lower infection rates against pathogens in bumble bees and honey bees. Pollinators are essential for


plant growth and diversity and the role of bees is the gold standard in crop pollination worldwide. In Canada, the value of honey bee pollination for agricultural production is estimated between $3.15 billion and $4.39 billion. But bees have had a rough go of it in recent years from population loss to complete colony collapses. This study showed that bumble bees and honey bees fed a supplement diet of sunflower pollen not only dramatically lowered infection rates of specific pathogens but also promoted better colony health than bees fed on other flower pollens. Sunflowers belong to perhaps the largest plant family (Asteraceae), with more than 30,000 named species across most of the globe. Now, research has unveiled its medicinal value. The study showed it reduced infection of Crithidia bombi, a widespread parasite in bumble bees. The pollen also protected honey bees from Nosema ceranae, a widespread pathogen known to be associated with colony declines and more recently linked to infected larval honey bees. The caveat, however, is that sunflower pollen is important only within the context of being included in a diverse wildflower mix. “Pollen is a source of


protein, lipids, vitamins, minerals and other important nutritional macromolecules for bees, as well as other non- bee insects,” explains Jonathan Giacomini, PhD student in applied ecology at NC State. “Traditionally, sunflower pollen has been thought of as a low-quality food source for bees due to its relatively low protein content and a few


missing essential amino acids that bees need. However, it’s important to note that insect nutritional needs are far more complex than just protein and require the careful consideration of combinations of different macromolecules and the roles they play during the different life stages of the insect. Some insects have been shown to greatly prefer


a balanced diet, not necessarily the highest protein diet, that ultimately yields greater fecundity and reproductive fitness.” According to the study, pollen consumption by bees is affected not only by the pollen’s availability but also by bee preference. Normally, bumble bees like plants that produce pollen with a high protein to lipid ratio. But they will change their foraging choices when infected by the pathogen Crithidia. Honey bees increase their


foraging habits on sunflowers when infected with Nosema. And, since sunflower pollen showed an ability to protect honey bees from the pathogen, the shift in foraging suggests a self- medicating behaviour. That does not take away from the fact that honey bees also forage on other plants such as corn, clover and flowering trees, but it’s an indicator of the importance of sunflower pollen in a honey bee’s diet. The researchers are looking at possible theories as to exactly how sunflower pollen


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The addition of sunflowers to a garden or crop system may be a simple and effective way to promote bee health without relying on toxic chemicals. JONATHAN GIACOMINI/NORTH CAROLINA STATE UNIVERSITY PHOTO


helps to lower infection. First, sunflower pollen has conspicuous spines on its outer coat. Since Crithidia is a gut parasite that attaches to the hindgut wall, the pollen may be scouring the hindgut of parasite cells. Second, if sunflower pollen has laxative qualities, it may be flushing out parasites from bumble and honey bees before they can attach to the hindgut. Third, the researchers are looking at whether sunflower pollen affects the bees’ immune responses. And, fourth, research is being done to see if sunflower pollen may increase bee resistance to pathogens by changes in the gut microbiome, or environment. “Future research in our lab will be aimed at understanding how sunflowers affect pathogen dynamics of not just a few


individual bee species, but also the entire bee community,” says Giacomini. “For example, some bee species are considered generalist foragers, meaning that they consume a wide array of available resources, while other species are specialists that stick to a select set of resources. Furthermore, foraging behaviors can be greatly affected by pressures from predators and parasites, ultimately playing a major role in shaping plant-pollinator networks. Thus,


understanding the costs and benefits of including sunflowers in a habitat as it


pertains to a variety of bee species with various life history strategies and stressors will elucidate better conservation strategies aimed at protecting bee communities as a whole.” Giacomini stresses that


there is a critical need to move beyond simply documenting pollinator declines to identifying solutions to reduce bee disease and improve bee health. The management of bees requires careful


consideration of plant species that play a critical role in protecting pollinators against stressors.


Tim Armstrong Memorial Bursary in Agriculture and Journalism


APPLICATION DEADLINE: NOVEMBER 30 Farming can be solitary work


Whether it’s watching rolling fields from the comfort of your cab, or seeing your herd crest a hill from across the valley, there’s something special about that time in the wide, open spaces.


But there’s a difference between being and feeling alone.


Farming is an amazing way of life, but sometimes it can be as draining mentally as it is physically.


Make sure your well-being is a priority and talk to somebody if you or someone you know needs help.


Agriculture is rooted in strength – the strength to take care of our families and ourselves.


For more resources, visit DoMore.Ag. #RootedInStrength


The $1,000 Tim Armstrong Memorial Bursary is open to students who are residents of BC and are enrolled in the second year or higher of a full-time agriculture or journalism program at a university, institute or regional college in Canada.


See [www.bcfwa.ca/resources] for more information.


Proudly sponsored by the BC Farm Writers’ Association Ronda Payne, Scholarship Chair | ronda.eyben@shaw.ca


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