Bees 'entomb' polluted pollen
APRIL 28, 2011: New research has shown that honeybees are 'entombing' hives to protect them against pesticides. By sealing up cells full of contaminated pollen, bees appear to be attempting to protect the rest of the hive, say scientists.
'Entombed' pollen is identified as having sunken, wax-covered cells amid 'normal', uncapped cells. Honeybees are taking these emergency measures to protect their hives from pesticides, in an extraordinary example of the natural world adapting swiftly to our depredations, according to a prominent bee expert. 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 in neighbouring cells 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. 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.