Bees make honey, which is very tasty, but they also cross-pollinate plants, including many of our food crops. Apparently about one third of all the crops in the world rely on bees to pollinate them, including most fruits, nuts and seed crops. If the honeybees were to disappear some of the slack might be taken up by other species including other bees, butterflies, dragonflies and birds. However, none of these do such a good job, and at such volume, as our cultivated honeybees.
Unfortunately, large-scale honeybee loss is not pure speculation, it is an actual, present risk. I've just been reading a book on the subject by Alison Benjamin and Brian McCallum called A World Without Bees, first published in 2008. Benjamin is an environmental reporter for the UK Guardian and McCallum is her partner and fellow hobby apiarist.
A World Without Bees is about a condition known as Colony Collapse Disorder or CCD, which was first observed in the USA in 2006 and subsequently affected hives across the US and Europe. In 2006-07 some US beekeepers lost more than 50% of their colonies to the disorder, and losses occurred on a similar scale in 2007-08. They have continued to take place each year since although on a smaller scale.
CCD has a baffling and disturbing pattern. Colonies that seem healthy and thriving will collapse, with the adult worker bees disappearing leaving behind the queen and unprotected larvae which rapidly starve. There are no bee carcasses, and unlike normal hive abandonments the honey and larvae are not raided by other bees or predatory insects.
Although Benjamin and McCallum wrote their book in 2008, more recent information like this from the US Department of Agriculture suggests that entomologists and apiarists are no closer to understanding the phenomenon in 2015 than they were back then.
A number of causes have been suggested - neonicotinoid pesticides; genetically modified crops such as sunflowers; mites such as varroa and tracheal mite; viruses such as Israeli paralysis virus; intensive management practices such as trucking bees the length of the US and artificially rousing them in February to pollinate California's almond crop; a shrinking gene pool brought on by breeding for docility and honey production; and loss of diversity of flowering plants in their environment due to monoculture and urbanisation.
However, while each of these has been shown to have some connection with the phenomenon none can be shown to cause it, as opposed to simply being correlated with it. It is not even clear if all instances of CCD are the same - is it a disease, or the end result of a number of different problems? It is also possible that a number of these causes may act together to stress the bees to the point where the colony collapses.
My current quest to describe the world through a series of diagrams made me immediately think of a diagram to describe bee collapse. Here it is, with a set of hexagonal boxes to match both the shape of honeycomb and the shape of the lenses in the bees' compound eyes. If you click on it you can read the words.
Colony Collapse Disorder is shown surrounded by a cluster of factors. At the first step out from CCD is the immediate bee-related causes - the mites and viruses, the insecticides and modified plants, the loss of food sources, the factors related to breeding and management.
However, each of these things also have their own causes and factors which aid their spread and these are shown in the second step out from CCD. These are more general factors in the environment and the human societies with which bees co-exist - increasing monocrop agriculture, urbanisation, loss of biodiversity, increasing economic pressure on agriculture, habitat loss, globalisation. My list here is hardly comprehensive, it's just to give you the idea.
What's interesting about this process is that the more steps you take, the larger and more universal become the issues. For instance, varroa destructor is pretty much just a parasite that affects bees. However, the process of global trade which allowed it to spread from bee populations adapted to it to those which were not, and from there around the globe, is pretty much the same process which has led to the spread of a large number of other invasive species. Similarly, the habitat loss which affects bees affects hundreds of other species as well.
No doubt you could also take the diagram out a further step, finding further factors which contribute to these second level causes. You would find that these are the major ecological challenges facing our planet - climate change, pollution, loss of biodiversity, habitat destruction and population growth.
Our global ecology is indeed so fragile that something quite small could bring it down - even something as small as a bee. However, the bee itself is only this fragile because it is connected to a number of crucial aspects of our ecology, all of which we have been damaging with foolish abandon.
In European folklore bees are wise creatures and they need to be kept informed, and listened to carefully. It's time we started listening!