California’s native bee populations may be suffering from a poor diet and loss of habit. An interesting piece from Sierra Magazine suggests these causes to be the most important factors to their survival. What researchers find could help all of us support bee populations by making sure our gardens have the right plants to sustain bees. See more in the piece below:
According to S. Hollis Woodard, a bumblebee researcher at the University of California, Riverside, bumblebee populations around the globe have crashed over the last two decades. While studies blame introduced pathogens, the overuse of pesticides, and habitat loss, Woodard wondered if something was happening during the vulnerable period when the queens live as solitary bees. Most bumblebee queens, researchers believe, never succeed at setting up a nest. Hollis wondered if the quality of their diet could be one factor that could make or break a queen.
To test that idea, Woodard and her team fed 48 Bombus impatiens, or common eastern bumblebee queens, three different pollen diets: one dominated by flowers in the aster family, one dominated by Cistus or rock rose, and one that was primarily Erica, in the heather family. The queens then went on to found colonies in the lab and raise them for eight weeks.
The researchers found that the type of pollen the queens ate didn’t impact how many eggs they laid or the timing of when they started to build their nest. But it did impact how quickly the larvae reached adulthood, with some of the larvae, especially those eating heather pollen, developing days behind others. While a few days may seem insignificant, it’s not for the bees. The quicker the queen bee has help, researchers believe, the more likely a nest is to survive, and those few days can determine a colony’s success.
Woodard says that the study is by no means comprehensive and wasn’t intended to search out the perfect food for bumblebee queens. The team fed the queens just three diets though there are thousands of different types of pollen available. Instead, she says the research begins to show that the diet of bumblebees matters. And if habitat changes or the loss of biodiversity lead to a floral monoculture in the spring, it could have effects on nest survival.