Pollination Crisis: Why Are Our Bees Disappearing?

Bees aren't usually something that we gardeners give a lot of thought to.  They're a welcome sign of Spring and generally go about their business of enjoying the flowers while we plant the crops that they then pollinate for us.  It is all so natural that we may be inclined to take it for granted but soon it may not be that simple. According to warnings from beekeepers, scientists and some government bodies honey bees are on the decline.

For several years honey-bee populations have been dropping but in recent months the situation has become much worse.  Colony Collapse Disorder is the term for the problem where up to 90% of bees in each hive die, destroying the whole colony as it then can’t make it through winter.  North America has lost some 50% of all managed colonies, a situation which has led some experts to predict that we are on the brink of a 'pollination crisis'. 

Globally up to two thirds of major agricultural crops require pollination by insects.  Fruit such as apples, pears and berries completely rely on pollination to bear a crop, whereas peppers, tomatoes, oilseed rape and many others produce much higher yields with good insect pollination.  Bees are the most active agents in this and many farmers are keen to introduce them.  The US Department of Agriculture estimates that one in every three mouthfuls of food is dependent in some way on pollination by bees.  Honey bees are the best at pollination and are experiencing the worst decline, although bumble-bees also face their own problems.

So what is causing the worrying loss of honey bee colonies?  Several threats have been identified:

• The Varroa mite: a parasite that was accidentally introduced, spreading to most parts of the world, is known to be causing long term decline in the number of honey bees.  Colonies infested with the mite suffer much higher levels of viral disease and ‘stress’ in the bees.
• Nosema: a digestive system disease which affects adult honey bees, spread by spores which are difficult to eradicate. A new faster spreading variety which originated in Asia has now been detected in America and Europe.
• Poor weather conditions in the UK (long winter and wet cool summer) have reduced the number of colonies that survived last winter and caused a delayed build-up of population for those that did make it, again reducing production.  For the first time ever British honey supplies are expected to run out by Christmas and a good friend of mine who keeps bees has had just 12lb of honey this year, compared with the usual 300lb harvest.

But none of these factors completely explains the sudden losses that characterise Colony Collapse Disorder.  In a recent press release, the Soil Association is implicating a group of pesticides manufactured by Bayer CropScience.  Already four European countries have banned the group of products known as neonicotinoids.  These work their way through the sprayed plant, attacking the nervous system of insects that come in contact with them.  They can be present in pollen and then build up in the wax bees produce in their hives.  Germany was one of the first to prohibit their use after beekeepers in one region reported losing two thirds of their bees following the application of one of the pesticides.  At least one court cases has been brought against the company.  However these pesticides are some of Bayer's best selling so they may be reluctant to withdraw the products given that they made an €800 million profit last year.

As with most crises, the problems surrounding Colony Collapse Disorder are not yet fully understood.  Pesticides may well have a large role to play, especially as they are widely used on crops such as oilseed rape, which bees love due to the bright flowers and the amount of nectar they produce.  Others believe that the more virulent strain of Nosema is to blame.  But more research urgently needs to be done if the predicted 'pollination crisis' is to be avoided.  Many bee keeping associations are calling for urgent funding to kick start the search for answers.

Gardeners may think that they are largely immune to this problem.  When dealing with growing on a garden scale, pollination can be managed by less insects, or even done by hand (as detailed in our Pollination Guide which gives details of how to do this).  But few of us have enough land to be self-sufficient and even if we did our fruit and bean crops would still be largely reliant on bees (it's not easy to hand pollinate a full grown apple tree!)  If the production of pollinated crops suffers then the looming food supply issues will be worsened.  Far better to try and avert a crisis like that than to deal with the consequences.  Let's hope that those in charge of commissioning research can mobilise the required resources quickly before we have to add bees to the list of problems facing our food production in the coming decade.