Honey fends off infection in bees

Honey does more than just feed bees, it also activates a host of chemical and immune defense mechanisms, new research has found.

Through their pollination efforts, which boost crop yields, bees are worth over $10 billion annually to the US economy alone. But, globally, these tireless workers are in decline, with keepers of managed colonies reporting up to 30% losses in some areas over the last 5 years.

Colony collapse disorder (CCD) has been blamed for the majority of the decline, although this phenomenon - often manifesting as abruptly empty hives - remains unexplained.

The smoking gun appears to be pointing at increasing exposure to pesticides and parasites, but the actual mechanims are still not clear.

Now, scientist May Berenbaum and her colleagues from the University of Illinois at Urbana-Champaign, writing in PNAS, have discovered that the bee-equivalent of junk food may be to blame.

Analysing the constituents of honey, the researchers have found that a host of plant chemicals, which are naturally present at low levels and come from pollens, have a potent effect on bee metabolism.

Tests on bees fed the compounds and compared with control bees fed just sugar, show that the chemicals, including one called p-coumaric acid, powerfully activate genes for an anti-bacterial factor called abaecin, and enzymes called P450 cytochrome monooxygenases.

The role of these enzymes is to detoxify various chemicals to which bees are naturally exposed in the environment and through their diets.

But these same enzymes can also neutralise pesticides. And because current apiculture practices usually involve removing the bulk of the bees' honey stores from their hives and replacing it with merely a sugar solution, bees are most likely being deprived of the "nutraceutical" stimulus they need to protect themselves.

The solution may therefore be the insect-equivalent of a vitamin pill added to the diet to replace the deficient chemicals in the bee junk food the insects currently receive as a "reward" for the labours...