By Arden Benner
A study released by the Imperial College London’s Department of Sciences last week illustrated the long-term effect pesticides can have on Bumblebee colonies. Neonicotinoids are a water-soluble type of pesticide widely used in global agriculture (although restricted in the EU and some American states). The study found that when young bees are fed nectar tainted with neonicotinoids brought back to the colony by unknowing foragers who picked it up from the flowers they visited, their development is altered. Through direct comparison with unaffected colonies, and even micro CT scans of bumblebee brains (see image below), researchers were able to determine that the bees who consumed the tainted nectar had smaller brains, and a more limited learning ability.
Researchers analyzed the “mushroom body” of 100 bee brains, a portion of the insects’ brains predominantly responsible for learning ability. The bees with smaller volume mushroom bodies (pictured below) were the same ones who had been exposed to the pesticide. The individual damage is comparable to that of an infant exposed to harmful substances while in the womb.
The effects are seemingly irreversible and, hurting the bees’ ability to forage for food and successfully return to the colony. This has led the team to believe that pesticide use could be a major factor in why the bee population has dropped by over 30% in the last two decades. Alongside climate change and habitat degradation, exposure to pesticides could be a debilitating blow to any colony, and have lasting effects on global biodiversity and food pollination.