We are all aware of the vital role bees play in our ecosystem, as they pollinate an estimated 65% of flowering and seed plants¹.

They are also responsible for pollinating one-third² of all the food we eat each day; including fruit, vegetables and crops like avocados, celery, peaches, melons, blueberries, asparagus, and soybeans.

Other crops like clover and alfalfa, which are fed to cattle, are also dependent on bee pollination, so even the meat and dairy industries need bees.

Overall, bee pollination is estimated to be globally worth more than €153 billion, or AU$240 billion, each year.³

With such a large portion of our food industry and economy dependent on bee pollination, it should certainly be cause for concern that it appears worldwide bee populations are declining.

What are the facts?

In the winter of 2006-07, beekeepers in the USA reported a massive 30-90%⁴ loss of bee hives- the manageable threshold of hive loss is 15%.⁵ American beekeepers continued to suffer huge losses in the following years, and the 2012-13 winter brought an average 45.1% hive loss to beekeepers across the country.⁶

The summer of 2015 saw the first instance of higher bee death rates during summer than during winter.⁷ The US commercial bee population was now down from five million bees to two and a half million, the lowest levels since the 1940s.

Nearly 10 years after the initial crisis, during the 2015-16 winter, American beekeepers were faring marginally better, reporting a 28.1% hive loss.⁸

By this time, hive loss had been reported across the world. The 2015-16 winter also saw Canada report a 16.8% loss, while central Europe and New Zealand lost 11.9% and 10.7% of their hives respectively.

While local bee populations remain ‘resilient’ to this decline, experts still told the ABC⁹ that Australians should always be vigilant of the problems overseas and continue to foster their green thumbs.

Why are worldwide bee populations in freefall?

Researchers, authorities, and beekeepers can’t be sure on a specific cause for the sudden loss in bee colonies and hives over the last decade, but there are several possibilities.

Colony Collapse Disorder

One possible cause (which then also has its own possible causes) is a phenomenon known as colony collapse disorder (CCD). CCD was first coined during the 2006-07 winter, when the initial concern over bee population declines began, and presents as a hive that’s unusually empty – except for the queen and few surviving young.¹⁰ CCD appears to cause the worker bees of a hive to simply fly away, never to return; this suggests that perhaps the disorder affects the bees’ navigation.

The queen and her few surviving young cannot sustain a hive on their own, and so the absence of the worker bees means the hive, and therefore the colony that inhabited it, will eventually die.¹¹

Varroa mite

Another possible cause of bee population decline is the Varroa destructor and Varroa jacobsoni, otherwise known as the varroa mite.¹² The tiny mites infect bee hives by crawling into the brood cells (where bees hatch) and laying eggs – sometimes on the developing bee itself.¹³

Varroa mites cause deformities in these young bees (like deformed wing virus¹⁴), and infections and viruses in the adults by sucking on their ‘blood’ when they leave the brood cell.¹⁵

Varroa mite infestations are thought to be a possible cause of CCD as well as a cause of the general bee population decline.[16]

Pesticides

The use of pesticides has been put forward as another possible cause behind the bee population decline. A particular form of pesticide – neonicotinoid – appears to be particularly toxic to bees,¹⁷ causing a multitude of health problems like:

• compromised immune systems;
• impaired memory and learning functions;
• disorientation;
• delayed development in larvae and shorter adult life cycles; and
• malnutrition caused by disrupted gut microbes

What could happen if the bee populations continue to decline?

A lack of pollinated food, caused by bee population decline, could potentially affect human health, as a 2015 study by researchers from Harvard University and University of Vermont suggested.¹⁸

The study, which evaluated diets in four developing countries, found that a lack of pollinated food can lead to a sharp increase in the risk of nutrient deficiency, particularly a deficiency in vitamin A.

Vitamin A deficiencies cause an estimated 800,000 deaths each year, and can double the mortality rate of conditions like malaria, diarrhoea, and measles. Increased deficiencies in vitamin A could very well have a serious impact on human health and medical systems.

Bee population decline could also have serious impacts on worldwide economies, particularly in the USA. US bee hives are worth approximately US$200 each and as of 2014 beekeepers across the country had collectively lost 10 million hives.¹⁹

This massive loss in hives meant that almond farmers – who in particular need to rent bees from keepers to pollinate their farms, and are responsible for 80% of the world’s almond production – were forking out at as much US$175 per hive in 2009, compared to 2003 when hives were around US$50 each.

What can we do to help?

Fortunately, there are lots of things we as individuals can do to help the bees. In fact, Save Our Bees Australia has outlined²⁰ several of them:

• Consider alternatives to using insecticides and herbicides in your garden. There are other ways to remove weeds from your garden, and there are insecticides and pesticides available that aren’t as toxic, or are non-toxic altogether, to bees
• Plant native and bee-friendly plants to attract bees to your garden and encourage pollination
• Build a bee house in your freshly-planted garden for bees to enjoy
• Support local beekeepers by buying their honey and bee products

Sources

1. Australian Museum – Pollination. March 2017
2. Sustain – Why bees are important. Accessed November 2018
3. ScienceDirect – ‘Economic valuation of the vulnerability of world agriculture confronted with pollinator decline’ by Nicola Gallai et al. January 2009
4. EPA – Colony Collapse Disorder. Accessed November 2018
5. The Conversation – ‘Ten years after the crisis, what is happening to the world’s bees?’ by Simon Klein and Andrew Barron. May 2017
6. National Geographic – ‘The plight of the honey bee’ by Jennifer S. Holland. May 2013
7. National Geographic – ‘What we now know – and don’t know – about honeybees and Colony Collapse Disorder’ by David Max Braun. September 2016
8. The Conversation – ‘Ten years after the crisis, what is happening to the world’s bees?’ by Simon Klein and Andrew Barron. May 2017
9. ABC News – ‘Bees are dying. What can we do about it?’ by Stephen Smiley. June 2018
10. Encyclopaedia Britannica – ‘Colony Collapse Disorder’ by Mike Hood. Accessed November 2018
11. EPA – Colony Collapse Disorder. Accessed November 2018
12. Queensland Government – Varroa mite. July 2018
13. Victorian Government – Varroa – an exotic parasite mite of honey bees. June 2018
14. Wikipedia – Deformed wing virus: transmission by Varroa destructor. May 2018
15. Queensland Government – Varroa mite. July 2018
16. EPA – Colony Collapse Disorder. Accessed November 2018
17. PAN – ‘Bess in crisis’ by Steve Ellis. Accessed November 2018
18. PLOS One – ‘Do pollinators contribute to nutritional health?’ by Alicia M. Ellis et al. January 2015
19. The Obama White House – ‘Fact sheet: the economic challenge posed by declining pollinator populations’. June 2014
20. Save Our Bees Australia – How you can help. Accessed November 2018