Climate change influences protein value of pollen
Climate change is a threat not only to humans, but also for pollinators. It directly influences the distribution of many species by shifted temperature as it is shown for bumblebees. A recent study shows that also the nutrition of bees may be affected negatively by rising atmospheric carbon dioxide. A research team around Lewis Ziska has found highly significant correlations between the protein content of goldenrod pollen (Solidago spp.) in North America. They compared the protein contents in pollen over a long time period (1842-2014) by using museum collections. In this period, the pollen protein content decreased from approximately 18 to 12%. This decline was highly significantly correlated to the increase of atmospheric carbon dioxide. This was confirmed also by experimental findings.
Pollen is the only protein source for bees and essential for larval development. In honeybees, late pollen sources are crucial for the overwintering survival. Not only the quantity, but also the quality of the pollen influences this vulnerable phase of the honeybee life history. For larval development, bees need several essential aminoacids. Insufficient provision of these nutrients leads to shorter lifespans of the adult bees, affects the development of the hypopharyngeal glands and the queen’s ovaries and may influence also pathogen susceptibility and detoxification processes. There is further evidence that pollinator health is also linked to nutrition.
This publication adds an additional aspect on the impacts of climate change on pollinators. Further information is needed to confirm that a similar reduction of protein content also in other plant species. The full impact on pollinator health and populations remains unclear. Future research should quantify the consequences for populations in a global perspective. Bees – not only honeybees – have both environmental and economic importance and contribute to food safety. Mitigating the effects of rising carbon dioxide in the atmosphere for pollinators obtains therefore additional importance.