Bye bye bees?

Bye bye bees?

Roughly one-third of food production globally, and some two-thirds of major crops, need animals to pollinate them.  Bees are the most important insect pollinators, collecting pollen from flowers, which they feed to developing larvae, transferring pollen grains and collecting nectar.  This means that a decline in bee numbers potentially has extremely serious implications for agriculture. 

Declining bee numbers

In the United States and Europe, since 2006, beekeepers have noticed increasingly large numbers of over-wintering bee colony deaths -- particularly that worker bees, which forage and care for the queen and her offspring, have been disappearing from colonies.  This phenomenon, known as colony collapse disorder (CCD), remains little understood, though several possible explanations have been offered:

• Varroa Mite. The varroa mite, a parasite that lives on honey bees, has been implicated in CCD.
• Honey bee movements.  Large-scale movement of honey bees -- particularly in the United States, where commercial honey bee colonies are systematically rented as agricultural pollinators -- may cause stress, which makes them more susceptible to disease.
• Global warming.  Global warming is a further a possible cause.  It may make bees forage early on warm days between October and February -- when they had formerly been semi-comatose -- but find no food. It might also cause plants that had been honey bees’ first pollen source to blossom before bees emerge.
• IMD.  A recent book, A Spring Without Bees, by Michael Schacker, suggests that one insecticide -- IMD -- is responsible for loss of some 30 per cent of managed bee colonies.

Bee diversity

An additional threat to bees’ pollination capability comes from declining bee biodiversity:

• A team of researchers  including Pat Hoehn from the University of Goettingen, recently showed that plants need different species of bees, visiting at different times, with different forms of behaviour, to achieve optimal pollination.
• Jacobus Biesmeijer, from the University of Leeds, has argued that plants vary in pollination strategies; those with specialised flowers, which need only one or a few pollinator species, are vulnerable if these species’ decline, while those that have open flowers that many species could pollinate need diverse pollinators because different species are active in different climactic conditions.

Outlook

Declining bee numbers have increased awareness of their importance to agriculture:

• Increasing research is likely to pinpoint the causes of CCD and seek a cure. 
• Recent insights into the importance of bee biodiversity are likely to drive increasing efforts to conserve bee species. 

However, even if there are major scientific breakthroughs, the outlook for bee populations in many parts of the world may well be bleak since modern agriculture tends towards monocultures, while the highest pollinator diversity -- and thus the most productive crop lands -- tend to be found in smaller blocks, where agriculture in more varied. As western agricultural techniques continue to be exported, then, the problem may grow -- exactly when demand for food is due to increase.