This has been on conspiracy sites for a good few months.
That is partly because Bee colonies are a good allegory for organization of corporations and civilization.
Seriously though, looking for major environment changes that have occurred recently you have to consider the changes bee keepers must have made in response to the crash of world honey prices.
The hives in China and Argentina have thus far remained healthy. Cheap imported honey from China has been dropping the price since the turn of the century.
http://archives.cnn.com/2000/FOOD/news/ ... .blues.ap/
These days US Bee keepers are trucking their hives around to different locations for the purpose of pollinating crops. Each time the hives are moved by truck you lose some bees especially if the hives are moved during the day.
The bees that have the best navigation skills spend the most time away from the hive. Statistically it would be the bees flying to distant pollen sources who would be left behind when the truck moves the hive.
These bees are probably stronger flyers with more virus tolerance. They would also be valuable teachers since it requires a more elaborate dance to explain where the far off sources of pollen were.
Perhaps the cumulative effect of losing strong virus resistant bees with each hive move weakened the bee colony until it reached some critical point?
The hive abandonment happened over a wide area in the period of just a few months. Since the cause is not known there may be some subtle balance that hives need to keep in order to stay healthy.
For example, beehives maintain a mysterious ratio of females to males that is equal to the golden ratio PHI.
Phi is an irrational number but roughly equal to 1.618. PHI can be expressed by the algebraic formula (X squared - X - 1 = 0). PHI shows up often in relation to the spiral geometry found in nature such as sea shells and DNA.
Maybe importance of PHI is the "Radius squared" in the formula (Pi times the "radius squared = circular area") with an additional cellular radius expansion?
How would bee colonies calculate such a precise headcount ratio? Are they secretly math geeks? Bee hives have maintained this sex ratio for hundreds of thousands of years.
There has not been much in the media about the golden ratio PHI except in the movie "The Davinci Code" and I don't recall learning about it in school.