Sunflower pollen has medicinal and protective effects on bees

With declining bee populations, a new study is giving hope for a relatively simple mechanism to promote the health and welfare of bees: providing bees with access to sunflower.

The study, conducted by researchers at North Carolina State University and the University of Massachusetts at Amherst, showed that two different species of bees receiving a sunflower pollen diet had significantly reduced infection by some pathogens. Bumblebees on the sunflower diet usually have better colony health than bees fed with other flower pollen diets.

The study showed that sunflower pollen reduces infection with a particular pathogen (Crithidia bombi) in drones (Bombus impatiens). Sunflower pollen also protects European bees (Apis mellifera) of a different pathogen (Nosema ceranae). These pathogens have been implicated in slowing down the growth rates of bee colonies and in increasing bee mortality.

The study also showed a deleterious effect, as honey bees in the sunflower diet had mortality rates roughly equivalent to those of non-pollen-fed honey bees and four times higher than buckwheat pollen-fed bees. . This mortality effect has not been observed in bumblebees.

Jonathan Giacomini, Ph.D. A student in Applied Ecology at NC State and corresponding author of an article describing the research, said that bees seem already able to collect sunflower pollen. Each year, about two million acres in the United States and 10 million acres in Europe are devoted to sunflower, he said, making sunflower pollen a ready and relevant bee feed.

"We have tried other monofloral pollens, or pollen from a flower, but we seem to have hit the jackpot with sunflower pollen," said co-author Rebecca Irwin, professor of 39 ecology applied to NC State. "None of the others we studied have had this constant positive effect on the health of bumblebees."

Sunflower pollen is low in protein and some amino acids. It should therefore not be considered an independent flour for bee populations, Irwin said. "But sunflower could be a good addition to a diverse population of wildflowers for bees," she said, especially generalists like bumble bees and bees.

NC State researchers now plan to follow the study to determine whether other bee species show the positive effects of sunflower pollen and to evaluate the mechanism of the predominantly positive effects of sunflower pollen.

"We do not know if sunflower pollen helps host bees fight pathogens or if sunflower pollen acts on pathogens," said Irwin. Future research aims to determine this.

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Sunflower pollen protects bees from pests

More information:
Jonathan J. Giacomini et al, Medicinal value of sunflower pollen against bee pathogens, Scientific reports (2018). DOI: 10.1038 / s41598-018-32681-y