Getting the buzz on the value of bees
Box 3 | Ensuring sufficient pollinators
(Credit: Rent-A-Bee, Pure Peninsula Honey.)
Farmers have a clear idea of most of the inputs they need to grow their products – such as water, fertilisers and pesticides – but many are less sure about the role of pollination in maximising yields. Not all crops require (or benefit from) honeybees for pollination, but the production of such crops as a percentage of total food production is increasing throughout the world. Pollination by honeybees increases the size, quality and/or stability of harvests for an estimated 70% of the world's main crops. A review of long-term data by CSIRO scientist Saul Cunningham and others showed that an absence of honeybee pollinators would cause a reduction of global food production of up to 8%, while the percentage increase in cultivated land needed to compensate for this shortfall would be several times greater, particularly in developing countries. Given its growing global population and a limit to agricultural expansion, the world can ill-afford a reduction in pollination services.
Since the 1800s, Australian farmers and horticulturalists have relied heavily on feral honeybees for pollination. Although there is uncertainty in the data it is likely that feral honeybees are responsible for about 70% of Australian crop pollination. Given the likely invasion of the Varroa mite and other European honeybee pests, diseases and competitors, Australian farmers could be in the lull before the storm – it would be judicious to investigate other options should the feral honeybee population decline. Research is under way not only to help combat threats to the European honeybee but also to encourage other animals, including native bees, to play a greater role in agricultural pollination. For example, it has been demonstrated that pollination by native insects declines exponentially as the distance from natural habitat increases.
Whilst most native Australian bees are solitary rather than social and so cannot be kept in hives, and the few native species that are social are difficult to keep in large numbers, there are good reasons to promote the role of native bees in agricultural pollination. For example, native bees may be less susceptible than European honeybees to invasive pests. Two species of native stingless bee, Trigona carbonaria and Austroplebeia australis, have been shown to have excellent defences against the small hive beetle, which can have a devastating impact in the hives of the European honeybee. Both use a range of strategies against the beetle, including entombing it (and its eggs and larvae) in droplets of resin known as propolis. (See Box 1 for further information about native bees.)
Boxes
Box 1. Native bees
Box 2. Epigenetics
Box 4. Fighting the Varroa mite
Related sites
Dr Saul Cunningham's CSIRO webpage:
Scientriffic – Pollen under the microscope (By Kate Barnard, March - April 2011 edition, pages 14 - 17)
Exotic pests post pollination threat
Pollination Aware – The real value of pollination in Australia
Pollinator decline not yet limiting yields
The plight of the honey bee - Why the loss of honey bee colonies may sting global agriculture
External sites are not endorsed by the Australian Academy of Science.
Posted August 2011.