A team of British researchers thinks aluminum may be another factor in the disturbing decline in bee populations.
Their study, published on PLOS ONE, says aluminum, is "one of the most significant environmental contaminant of recent times."
Bees typically do not avoid aluminum, which can be found in nectar, so that led researchers to collect pupae samples from natural colonies of foraging bees that were then tested for aluminum content.
Chris Exley and Ellen Rotheray of Keele University worked with Dave Goulson of the University of Sussex and found the pupae were heavily contaminated with aluminum.
Bees have pretty complex brains, and there's evidence to support that there is a presence of memory, a high-level cognitive function. Although aluminum is considered a neurotoxin, and was initially linked to Alzheimer's disease in humans, the Alzheimer's Society in the United Kingdom advises a direct link has not been proven "despite continuing investigation."
The findings are leaving the researchers to question whether high amounts of aluminum-induced cognitive dysfunction is another factor leading to the bees' demise.
Other researchers have linked neonicitinoid seed-treatment pesticides with brain damage to bees.
They normally can remember their way home after foraging for nectar and pollen, but the researchers found that those exposed to neonicitinoids lost that ability and they found some hives completely empty.
The question remains whether the results of either set of studies is confused between aluminum and neonicitinoids as the cause of what they have observed.