Greenhouse gas threatens nutrition for pollinators
Bees may need their own supplemental protein shakes as increasing carbon dioxide in the atmosphere saps the nutritional quality of pollen.
Pollen collected from plants gives bees their only natural source of protein (nectar is a sugar-shot for energy). Yet protein content in pollen of a widespread goldenrod species (Solidago canadensis) dwindled by a third, from about 18 percent to 12 percent, over 172 years, according to analysis of recently collected flowers and of preserved specimens at the Smithsonian Institution’s National Museum of Natural History. During those same years, CO2 concentrations in the atmosphere increased from about 280 parts per million to 398 ppm, researchers report April 12 in Proceedings of the Royal Society B.
The same themes also showed up in two years of growing the goldenrod at CO2 concentrations up to 500 ppm. More CO2 meant less