Amid the startling find that the bee population is dropping, there are speculations into what is causing this sudden trend. Recently, work by scientists (original article here) have looked beyond pesticides and measured the content of aluminum, a pollutant, in bumblebee pupae (insect stage before it becomes an adult) and found increased amounts. This, they speculate, may be causing cognitive disruption, like Alzheimer’s disease in humans, in bees, possibly leading to their decline.
Aluminum is a known neurotoxin (something that disrupts nerve tissue), however, currently there is no concrete data that definitively proves the involvement of aluminum in Alzheimer’s disease. Though the study shows increased levels of aluminum in bumblebee pupae, it might not be enough to affect the life span or memory of a bumblebee. The current study did not measure the life span or conduct memory tests on the bumblebees to conclusively say the levels of aluminum found in the pupae had a negative effect on the population, however another study done on fruit flies showed that only higher amounts of aluminum than those found in the bumblebee pupae affected the life span of the fruit flies (Wu et al.).
It is therefore not yet certain and perhaps unlikely that aluminum by itself is causing the decline in bee population, although more comprehensive testing still needs to be done.
Written by SITN Waves correspondent Ankita Shastri. Many thanks to Nick Warren and Elizabeth Lamkin for their great insight into the story. Nick is a graduate student in Pharmacology department at Dartmouth and Elizabeth is a graduate student in the Neuroscience department at Harvard.
Exley, C., Rotheray, E., and Goulson, D., Bumblebee Pupae Contain High Levels of Aluminum, PLOS one, 10, (2015)
Wu, Z., et al. Aluminum induces neurodegeneration and its toxicity arises from increased iron accumulation and reactive oxygen species production. Neurobiology of Aging, 33 199.e1-199.e12 (2012)