The reports first started in the latter half of 2006. Huge losses of bees were being reported by commercial bee-keepers in the eastern United States. While it is normal for a bee colony to lose about 5% a year, these colonies were seeing much more massive die-offs. In some cases, losses of 90% and more were being reported.
By 2007, apiaries all over the United States were seeing similar, massive population collapses in their colonies. These were not gradual die-offs, but rather massive, sudden collapses. In 2007, the United States saw a 32% loss in beehives, followed by a 35% drop in 2008 and 29% in 2009.
Since the initial 2007 collapse in the US, commercial beekeepers have seen similar collapses in Europe, Japan and other areas. Notably, however, bee populations in other areas have actually increased in this time frame.
The collapse of bee populations can have a number of impacts. The most obvious is the loss of bee-produced products, like honey and wax, but that is hardly the most important contribution of bees to human agriculture and agricultural products. Bees are the primary pollinator of many human food crops, with up to third of food we eat a result of their activities, especially fruits. Some of the crops that rely on bees for pollination include apples, peaches, soybeans, pears, pumpkins, cucumbers, cherries, raspberries, blackberries and strawberries.
Most grain crops are wind-pollinated, so the decline in bees won’t affect most staple crops. There are also other insect pollinators, though they are not as effective as bees.
A variety of answers have been suggested for Colony Collapse Disorder, and it is quite likely that it is a combination of factors that triggered the collapse. Pesticides are often cited, but they are hardly the only possible culprit. Bees fall victim to a host of diseases and parasites, and are even the subject of predation by various species of wasps and hornets. Several of these vectors have been identified as possible links in CCD. The Israeli Acute Paralysis Virus (IAPV), transmitted by the Varoa mite, is a strong correlative factor in CCD. While it may not cause it by itself, it is present in almost all instances of CCD. Then there is the fungus Nosema ceranae, which can cause dysentery in bees. Colonies actually showed signs of recovery if their hives were irradiated to elminate the fungus. Monoculture farming is another possible cause, leading to malnutrition in the hives. This would manifest itself in particular in situations where the bees are trying to fight off another condition or disease.
Then there is the affect of pesticides, which cannot be understated. A new class of insecticides, known as neonicotinoids, is taken up by bees, but at levels below what are considered lethal. There are concerns about long-term effects of these pesticides, and whether the effects will accumulate. However, this class of pesticides was discontinued in Europe, and yet CCD has continued there. Clearly, this is not a simple problem with simple solutions.
Answering the question of what causes CCD also suggests the solution. However, it is starting to become evident that it is not likely one single cause, but a whole host of them that have simply put too much pressure on the colonies. Ultimately, though, the responsibility comes to rest with human beings, and the agricultural methods we practice. The most effective response to the problem of Colony Collapse is to take a good, hard look at many farming practices, and work towards reforming. This may lead to the bees coming back to the fields. Eventually.