A balanced diet improves bumblebee health

Bumblebees are important pollinators for many plants. They can fly in colder temperatures than many insects and they’re very hardy. Despite these traits, bumblebees along with many other insects are in a state of decline that is largely associated with human activities. 

Now, new research from the University of Göttingen shows that a diverse diet is important for bumblebee reproduction. The study suggests that a diverse diet of pollen fed to young bumblebees can possibly even help with infestations of parasitic wax moth larvae.  

“Our study shows that it is not individual habitats, such as flower-rich gardens, or semi-natural habitats (such as hedgerows or flower strips), that contribute to reproductive success for the large earth bumblebee Bombus terrestris. In fact, it is rather the diversity of habitats across the entire study landscape that is important,” said first author Sandra Schweiger, a researcher in Functional Agrobiodiversity.

“So a wide variety of flower-rich landscape elements must be present. In addition, a diverse pollen diet can contribute to better colony growth and more offspring, especially for young queens.” 

According to study co-author Professor Catrin Westphal, a balanced pollen diet also reduces the negative effects of parasitic wax moth larvae infestations, which can severely harm the reproductive success of the bumblebees.

For the investigation, the scientists established bumblebee colonies in two regions of Germany and collected pollen samples from bees returning to their hives. The samples were used to research the importance of habitat diversity and thus pollen nutrition in agricultural landscapes as it relates to reproduction. 

Monoculture blooms that provide steady unvaried nutrition as well as landscapes with diverse flowers were both analyzed. The upshot of the research shows that bumblebee bees fare better in diverse landscapes providing a variety of pollen to feed their colonies rather than typical monoculture agricultural fields.   

“Our study showed that high landscape diversity and diverse pollen diets can enhance the reproductive success of bumblebees,” wrote the study authors. 

“A diverse diet even mitigated depredation by wax moths. To sustain vital bumblebee populations and their pollination services, diverse and floral rich habitat types should be conserved or restored in agricultural landscapes.”

The study is published in the journal Agriculture, Ecosystems and Environment.

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By Zach Fitzner, Earth.com Staff Writer