An insect form of Alzheimer’s disease caused by aluminum contamination may be one of the causes behind an ongoing decline in populations of bees and other pollinators, according to a study conducted by researchers from the universities of Keele and Sussex and published in the journal PLOS ONE.
The researchers found that honeybees had levels of aluminum in their bodies equivalent to those that could cause brain damage in humans.
“Aluminium is a known neurotoxin affecting behaviour in animal models of aluminium intoxication,” said researcher Chris Exley, an expert on human aluminum exposure, as reported by the UK’s Daily Mail. “Bees, of course, rely heavily on cognitive function in their everyday behaviour and these data raise the intriguing spectre that aluminium-induced cognitive dysfunction may play a role in their population decline – are we looking at bees with Alzheimer’s disease?”
“Pathological” aluminum levels
Researchers from the University of Sussex first collected pupae from colonies of wild-foraging bumblebees, then sent these off to Keele University for analysis of their aluminum content.
Pupae are sacks that bumblebee larvae develop in before emerging into their adult forms. The pupae in the study were found to contain between 13 and 200 parts per million (ppm) of aluminum.
Just 3 ppm is “considered as potentially pathological in human brain tissue,” the researchers said.
Prior studies had shown that bees do not actively avoid aluminum-contaminated nectar while foraging, but the new study was among the first to show the consequences of this behavior.
Bees use sophisticated cognitive processes to forage for food over wide territories, and to communicate with other bees. Because aluminum has been shown to have negative effects of animal cognition, the new study raises the possibility that aluminum poisoning might be contributing to crashing populations of bees worldwide.