Sunflower pollen protects bees from infection
A new study led by North Carolina State University has revealed that sunflower pollen makes bees less susceptible to infection and disease. The researchers found that bees had dramatically lower rates of infection by specific pathogens when they were fed a diet of sunflower pollen.
In bumble bees, sunflower pollen was found to reduce infection by a particular pathogen, Crithidia bombi. Sunflower pollen protected European honey bees from a different pathogen, Nosema ceranae. Both pathogens have been shown to stunt the growth of bee colonies by increasing the rate of fatalities.
Honey bees, however, were also negatively impacted by the sunflower pollen diet. These bees had mortality rates roughly equivalent to honey bees not fed a pollen diet, and death rates four times higher than honey bees fed buckwheat pollen.
This mortality effect was not observed in bumble bees. In fact, bumble bees showed improved colony health when fed the sunflower pollen compared to pollen from other flowers.
Study co-author Jonathan Giacomini said that bees already seem to be skilled at collecting sunflower pollen. According to Giacomini, around two million acres in the United States and 10 million acres in Europe are devoted to sunflowers annually.
“We’ve tried other monofloral pollens, or pollens coming from one flower, but we seem to have hit the jackpot with sunflower pollen,” said co-senior author Professor Rebecca Irwin. “None of the others we’ve studied have had this consistent positive effect on bumble bee health.”
Professor Irwin explained that sunflower pollen should not be considered as a standalone meal for bee populations because it is low in protein and some amino acids. She said that sunflower could be a good addition to a diverse wildflower population for bees, particularly bumble bees and honey bees.
“We don’t know if sunflower pollen is helping the host bees fight off pathogens or if sunflower pollen does something to the pathogens,” said Professor Irwin. The NC State team plans to analyze this in further detail, and will also investigate whether other species of bees show any positive effects from sunflower pollen.
The study is published in the journal Scientific Reports .
Image Credit: Jonathan Giacomini, NC State University