It is increasingly being recognised that managed bees need food supplements. In some places, a decline in the area of pasture land on which they can forage, the loss of weedy borders and the growth of crop monocultures mean it is hard for bees to find a wide enough range of pollen sources to obtain all their essential amino acids. In extreme cases they may not even find enough basic protein. Writing in Bee Culture this February, Mr Traynor observes that places where crops with low-protein pollens, such as blueberries and sunflowers, are grown are also places where CCD has appeared.I'm ok with them using nutritional supplements, but if it turns out they are really using steroids, I expect a full congressional hearing.
The suggestion is that poor nutrition has weakened the bees’ immune systems, making them more vulnerable to viruses and other parasites. Feeding bees supplements, rather than relying on their ability to forage in the wild, costs time and money. Many beekeepers therefore try to avoid it. Anecdote suggests, however, that those who do fork out find their colonies are far more resistant to CCD.
via The Economist