Variety: Spice of life for bumble bees

The yield and quality of many crops benefit from pollination, but it isn't just honey bees that do this work: bumble bees also have a role. However, placing honey bee or bumble bee colonies next to the field does not guarantee that they will visit the desired plants since there may be other plant species flowering at the same time that prove more attractive. A team from the University of G枚ttingen, together with researchers from the University of Applied Sciences Mittweida and the Julius K眉hn Institute, used innovative molecular biological methods and traditional microscopy to investigate the pollen collecting behavior of honey bees and bumble bees in agricultural landscapes. They show that bumble bees take much more pollen from dif-ferent plant species than honey bees to satisfy their need for protein. Furthermore, less pollen from the target鈥攊n this case strawberry plants鈥攊s collected when there are fields of flowering oilseed rape in the surrounding landscape. The results have been published in the journal Molecular Ecology.
The researchers placed honey bee and bumble bee colonies next to strawberry fields in the G枚ttingen and Kassel region and collected pollen from returning honey bees and bumble bees. The bees collect the pro-tein-rich pollen mainly for feeding their offspring. The pollen DNA was investigated working closely with the Division of Molecular Biology of Livestock and molecular Diagnostics at the University of G枚ttingen, and the Department of Biochemistry/Molecular Biology of the Mittweida University of Applied Sciences. "DNA analysis tells us which plant species the bees have visited and how diverse their foraging behavior is. To do this, we sequenced the DNA of the pollen and compared the sequences using a database of regional plant species," says Dr. Svenja B盲nsch, post-doctoral researcher in Functional Agrobiodiversity at the Uni-versity of G枚ttingen.

"Our study shows that honey bees and bumble bees use very different plants to source their pollen in the landscape. In particular, the wide range of bumble bee nutrition, which they find mainly in flower-rich habi-tats, should be taken into account when taking steps to improve nature conservation. Both honey bees and bumble bees, whose colonies can be purchased or rented, are suitable pollinators in strawberry cultivation. However, naturally occurring wild bees should be encouraged as a priority," concludes Professor Catrin Westphal, Head of Functional Agrobiodiversity at the University of G枚ttingen.

More information: Svenja B盲nsch et al, Using ITS2 metabarcoding and microscopy to analyze shifts in pollen diets of honey bees and bumble bees along a mass鈥恌lowering crop gradient, Molecular Ecology (2020).
Journal information: Molecular Ecology
Provided by University of G枚ttingen