What is in this article?:
- Bees under bombardment: Multiple factors behind pollinator losses
- Bees and the Green Economy
- Highlights from the Report
- More than a dozen factors, ranging from declines in flowering plants and the use of memory-damaging insecticides to the world-wide spread of pests and air pollution, may be behind the emerging decline of bee colonies across many parts of the globe.
- Scientists are warning that without profound changes, declines in pollinators needed to feed a growing global population are likely to continue.
Highlights from the Report
Declines in managed bee colonies date back to the mid 1960s in Europe but have accelerated since 1998, especially in Belgium, France, Germany, Italy, the Netherlands, Spain and the United Kingdom.
In North America, losses of honey bee colonies since 2004 have left the continent with fewer managed pollinators than at any time in the past 50 years.
Chinese bee keepers, who manage both western and eastern species of honey bees, have recently "faced several inexplicable and complex symptoms of colony losses in both species".
A quarter of beekeepers in Japan "have recently been confronted with sudden losses of their bee colonies".
In Africa, beekeepers along the Egyptian Nile have been reporting signs of 'colony collapse disorder' although to date there are no other confirmed reports from the rest of the continent.
Habitat degradation, including the loss of flowering plant species that provide food for bees, is among the key factors behind the decline of wild-living pollinators.
An Anglo-Dutch study has found that since the 1980s, there has been a 70 per cent drop in key wild flowers among, for example, the mint, pea and perennial herb families.
Parasites and pests, such as the well known Varroa mite which feeds on bee fluids, are also a factor.
Other parasites include the small hive beetle, which damages honeycombs, stored honey and pollen. Endemic to sub-Saharan Africa, it has spread to North America and Australia and "is now anticipated to arrive in Europe".
- Bees may also be suffering from competition by 'alien species' such as the Africanised bee in the United States and the Asian hornet which feed on European honey bees. The hornet has now colonized nearly half of France since 2004.
Air pollution may be interfering with the ability of bees to find flowering plants and thus food.
- Scents that could travel over 800 metres in the 1800s now reach less than 200 metres from a plant.
Electromagnetic fields from sources such as power lines might also be changing bee behaviour. Bees are sensitive as they have small abdominal crystals that contain lead.
Herbicides and pesticides may be reducing the availability of wild flowers and plants needed for food and for the larval stages of some pollinators.
- Other impacts include poisoning of pollinators and the weakening of honey bees' immune systems.
- Laboratory studies have found that some insecticides and fungicides can act together to be 1,000 times more toxic to bees.
Some insecticides, including those applied to seeds and which can migrate to the entire plant as it grows, and others used to treat cats, fish, birds and rabbits, may also be taking their toll.
- Studies have shown that such chemicals can affect the sense of direction, memory and brain metabolism in bees
- The management of hives may also be adding to the problem.
Some of the treatments against pests may actually be harmful to bees and a growing habit of re-using equipment and food from dead colonies might be spreading disease and chemicals to new hives.
Transporting bees from one farm to another in order to provide pollination services increasingly unavailable from nature could be an additional factor. In the United States, trucks carrying up to 20 million bees are common and each year over 2 million colonies travel across the continent.
- Mortality rates, following transportation, can be as much as 10 per cent of a colony.
The full report, Global Bee Colony Disorders and other Threats to Insect Pollinators, can be downloaded at: http://www.unep.org/dewa/Portals/67/pdf/Global_Bee_Colony_Disorder_and_Threats_insect_pollinators.pdf