Picky eaters...bumble bees and pollen

[Gloria]

Another story that gives us insight into why native species may be better for wildlife. When they have a choice bees can find the nutrient rich plants and control the balance necessary for optimal health.

Picky eaters: Bumble bees prefer plants with nutrient-rich pollen | Penn State University

According to Anthony Vaudo, a graduate student in entomology who led the study, scientists previously believed that bees' preferences for flowering plants were driven by floral traits, such as color, scent, morphology or nectar concentration.
"Here we show that bumble bees actually choose a plant for the nutritional quality of its pollen," said Vaudo. "This is important because pollen is bees' primary source of protein and lipids."

The researchers observed and recorded bumble bees as they foraged for pollen among host-plant species in an outdoor arena where the bees were restricted to only those plants. They then determined the carbohydrate, protein and lipid concentrations, as well as protein-to-lipid ratios (P:L), of the pollen from all the plants within the arena. The team analyzed the relationship between the foraging rates and the nutritional quality of the pollen. They report their results in today's (June 27) issue of the Proceedings of the National Academy of Sciences.

According to Grozinger, many studies have shown that other animal species regulate their diets to make sure they get enough -- but not too much -- of their key nutrients to stay healthy. "Bees likely get the majority of their carbohydrates from nectar, and then need to selectively feed on different kinds of pollen to get the right amounts of both protein and lipids," she said.
The plants with highest visitation by bumble bees in this study included American senna, spiderwort and Culver's root.

"It is likely that bumble bee workers sense the protein and lipid content of pollen with two strategies," said Vaudo. "First, there is a chemically complex substance on the outside of pollen called the pollenkitt that includes free amino acids and fatty acids. It is likely that the bees taste pollen quality directly from the pollenkitt with chemotactile receptors on their antennae or mouthparts. Second, after the bees consume pollen, the nutrient concentrations of proteins, lipids and carbohydrates in their bodies change and can cause an increase or decrease in the sensitivity of their taste receptors for those nutrients."

The North American Pollinator Protection Campaign Bee Health Improvement Project,
the USDA Agriculture and
Food Research Initiative National Institute of Food and Agriculture,
and an anonymous donor to the Center for Pollinator Research
supported this research.
Other authors on the paper include Harland Patch, research scientist and lecturer in entomology;
David Mortensen, professor of weed and applied plant ecology;
and John Tooker, associate professor of entomology.

By Sara LaJeunesse
June 27, 2016

[dapjwy]

I love your posts, Gloria.

Thank you for sharing.

Always good to know what research is finding...especially regarding the vital connections that wildlife have with native plants.