Dr. Zachary Huang out of Michigan State University recently wrote a review titled “Pollen nutrition affects honey bee stress resistance.” Frustratingly, it is one of those papers where you need to either pay $35 to get access to it or have access via a University library. Since it is hard to get ahold of, I am going to review it since I think the content is really interesting and important.
Dr. Huang first talks about what makes a good pollen. There are two components that bees need: crude protein and 10 essential amino acids. The best pollens have over 25% protein and the complete set of the 10 amino acids. There are few types of pollen with all the amino acids, so bees tend to do best when they have access to a variety of pollens.
Dr. Huang’s paper showed that when bees have a better diet they are more resistant to many different stressors. If bees have good pollen diet, they have a lifespan almost twice as long as bees without and pollen affects genes for antimicrobial peptides. Bees exposed to Nosema apis or Nosema ceranae have a longer lifespan if they had a pollen diet verses infected bees without the pollen diet. Bees feed a pollen supplement had lower Deformed Wing Virus titers that those fed only sugar syrup. A pollen diet also had a positive effect on colony populations in the presence of Varroa mites, although the mites had a larger effect.
In cage trials, bees exposed to different pesticides were less sensitive if they had a quality pollen diet versed a poor pollen diet. However, this research was done in 1983 (by Walh and Ulm) and the pesticides they used aren’t common anymore. As Dr. Huang points out, it would be really interesting to see a study done with pesticides that are commonly used today.
Overall, Dr. Huang’s paper showed pretty conclusively that a better pollen diet leads to more robust bee colonies. Not necessarily groundbreaking, but it provides a really good argument for why plant diversity is important to help our bees be healthier.