According to a New York Times article published November 25, bee specimens collected in North America and Europe and stored in museums and university labs over the past 140 years are shedding light on what’s causing the decline of wild bees. “Nearly a third of bumblebee species in the United States are declining. In the Netherlands, more than half of the country’s 357 species of wild bees are endangered. Many species of plants, including crops, depend on wild bees to spread their pollen. When they lose their pollinators, they may suffer, too,” says author Carl Zimmer.

All told, scientists studied 30,000 specimens. They found that in the Northeastern United States, the diversity of bumblebee species declined by 30 percent, and the diversity of bee species overall, by 15 percent between 1872 and 2011.

A new study by numerous scientists was published in Proceedings of the National Academy of Sciences this week. One of them, Jeroen Scheper, a graduate student at Alterra, a research institution at Wageningen University in the Netherlands, said, “There were a lot more flowers in the landscape before.” In other words, the fate of the diminished or extinct species was tied to the fate of the plants they pollinated, many of which had been replaced by crops. 

Mr. Schleper and his colleagues believe that without the preferred kind of pollen, the bee larvae suffered; and that bigger bees were at greater risk than smaller bees. The story cautions that in addition to the loss of food sources, bee declines may also be due to the loss of nesting sites.