Toxic Pollen, Nectar Could Sting Bees

Selenium, a potent toxin, is showing up in alarming concentrations in the pollen and nectar of two plants common in California’s Central Valley, according to a new study.
If the element is finding its way into bee populations, it could affect the region’s multi-billion dollar agricultural industry, as well as the nation’s food supply.
The rocks, soil and groundwater of California’s San Joaquin Valley contain some of the highest natural levels of selenium found anywhere — in some places up to 14 parts per million.
Some plant species take advantage of these conditions, including Indian mustard (Brassica juncea) and Desert Prince’s Plume (Stanleya pinnata), which build selenium into their tissues as a defense mechanism against predators.
However, the plants rely on bee pollination for reproduction, which is why Kristen Hladun and John Trumble of the University of California, Riverside were surprised to find that nectar and pollen collected from plants grown in a laboratory contained between 108 and nearly 2,000 parts per million of selenium — many times the lethal level for most insects.