Scientists have uncovered another clue in the perplexing mystery of worldwide disappearance of honeybees, also known as the Colony Collapse Disorder:
Scientists have found numerous examples of a new phenomenon – bees "entombing" or sealing up hive cells full of pollen to put them out of use, and protect the rest of the hive from their contents. The pollen stored in the sealed-up cells has been found to contain dramatically higher levels of pesticides and other potentially harmful chemicals than the pollen stored in neighbouring cells, which is used to feed growing young bees.
"This is a novel finding, and very striking. The implication is that the bees are sensing [pesticides] and actually sealing it off. They are recognising that something is wrong with the pollen and encapsulating it," said Jeff Pettis, an entomologist with the US Department of Agriculture. "Bees would not normally seal off pollen."
But the bees' last-ditch efforts to save themselves appear to be unsuccessful – the entombing behaviour is found in many hives that subsequently die off, according to Pettis. "The presence of entombing is the biggest single predictor of colony loss. It's a defence mechanism that has failed." These colonies were likely to already be in trouble, and their death could be attributed to a mix of factors in addition to pesticides, he added.