Entomology Today January 13, 2015
Exactly what plants do honey bees visit on their daily forages for food? A research team from Ohio State University has found that the answer lies in the pollen collected by the bees, and they have developed a new method that utilizes DNA metabarcoding to analyze pollen to determine its origin. Their new protocol has been published in the journal Applications in Plant Sciences.
“Understanding honey bees’ pollen preferences can provide insights to what a colony needs and help improve the quality of foraging habitats,” said Dr. Chia-Hua Lin, one of the co-authors.
Their work should provide other researchers with a foundation for uncovering information from pollen DNA, and it will also enable bees to do some environmental science fieldwork.
“A honey bee colony is like an army of research assistants — thousands of enthusiastic, flying research assistants that work all day and trespass with impunity,” said Doug Sponsler, another co-author. “While foraging each day, bees are unknowingly monitoring plants in their surrounding landscapes, some hard to reach by researchers, and collecting valuable data in the form of pollen. They can also serve as bioindicators of pollution and pesticides.”
According to his colleague and co-author Rodney Richardson, traditional methods of analyzing pollen data under the microscope suffer from being difficult, slow, and often imprecise.
“There’s a huge bottleneck in the workflow because ultimately every sample needs the undivided attention of one expert behind a microscope,” Richardson said.
DNA metabarcoding is a promising alternative because it allows rapid identification of the genera or even species present in a mass DNA sample of multiple organisms. The technology has been gaining popularity across many fields of biology, and Richardson and colleagues are among the first to apply it to pollen analysis.
“It’s a first attempt that lets other researchers know what to expect, using the ITS2 marker in particular,” said Richardson.
Metabarcoding resulted in higher sensitivity and resolution, and identified twice as many plant families than microscopic analysis of the same pollen samples. However, it lacks the ability to quantitatively assess the relative proportions of each pollen type, something that will need to be addressed in future advancements.
For now, a combination of traditional microscopic analysis with DNA metabarcoding offers a deeper look into bee foraging behavior than either method alone. For scientists, this is only the beginning of uncovering the secret life of bees. For the bees, it is only the beginning of their work as research assistants.