Sick bees eat healthier

In the study, published recently in the journal Microbial Ecology, the researchers first gave groups of bees different kinds of pollen. They found that sick bees, and not healthy bees, lived longer when they had access to the pollen that was more nutritious, even though it also increased the number of parasites found in their gut.

"The real question then was -- when the bees had the opportunity to select their own food, would they choose what was good for them?" said Jade Ferguson, the student who conducted the project for her Honours degree.

The answer was yes. When given the option to forage on artificial flowers with either high quality pollen, lower quality pollen, or sugar water, healthy bees showed no pollen preference. However, twice as many infected bees selected the higher quality pollen than the lower quality pollen.

"Nosema ceranae is one of the most widespread parasites of adult honey bees in the world, and a lot of studies have investigated its effects on bee physiology. Ours is the first study we're aware of to investigate effects on floral choice," said Dr. Lach.

It is still unclear how the bees distinguish between pollens of different quality. However, the choices bees make will likely affect the native and crop flowers they visit. Flowers vary greatly in the quality of pollen they offer and are often competing for pollinators. Parasites appear to be one more factor that may influence which flowers are visited.