Leveraging an insect collection held in the Natural History Museum in the Netherlands, the researcher team around Jeroen Scheper analyzed pollen found on the bodies of insects from 57 different wild bee species collected before 1950. They found that the insects had certain preferred plants for foraging.
The scientists were able to show that the declines in plant diversity led to a decline of some of the domestic and wild bee populations, who lost their favorite host plants through the intensification of agriculture and climate changes in the region.
Pollinator species that are active later in the year are affected the most because they probably have fewer alternatives to choose from as bushes and trees are no longer in bloom. Larger species such as the bumble bee are also affected, most likely because they require more pollen to survive.
Stable or increasing populations are found among those species that prefer to forage on agricultural crop plant families.
“These results indicate that mitigation strategies for loss of wild bees will only be effective if they target the specific host plants of declining bee species,” concludes the study.
Bayer has been emphasizing for several years that lack of forage for nutrition is a key factor which, coupled with other factors, such as changing weather conditions and pest pressures, can combine to have a negative impact on pollinator health.
That is why Bayer has been promoting the planting of blooming strips throughout Europe. To support the effort, Bayer has been providing a special bee-friendly seed mix – the “Bayer Bee Pasture”. Distributed through garden centers, it is designed to encourage local communities, farmers, balcony owners and hobby gardeners to plant flowers that help pollinators and other beneficial insects.
In addition, Bayer has been working on a multi-year field study in Germany, showing how small measures can make a big difference on farms, not just for the thriving insect populations but the farmers who also stand to benefit.
The full study of the Dutch research team was published under the title of “Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in the Netherlands” on the website of PNAS – Proceedings of the National Academy of Sciences.