Linking the word-wide decline in bees to fears about less food for us is misleading, according to two Australian agriculture experts.
Australian National University’s Professor Saul Cunningham, and regional NSW agronomist Chris Houghton say that more knowledge of how pollination works is needed to get the facts right on food supplies – and bees.
Recent media reports say most of our food crops are dependent on bees for pollination and conclude that crops will fail if there aren’t enough bees around to do the job of pollinating. The truth is that only about a third of our food crops depend on pollinators.
But, while the experts say there’s no need to storm the nearest Costco to stockpile food, they warn plummeting bee numbers in some regions around the world are sounding an alarm we can’t ignore.
The truth about food and bees
The percentage of food crops that actually depend on bees for pollination is most often reported as 75 per cent.
This is a familiar number to ANU’s Director of the Fenner School of Environment and Society Prof Cunningham, who is one of the authors on the research paper containing the much quoted number. The problem? It’s been misquoted.
“The way that number’s been used is a bit misleading, because there are some important distinctions getting lost,” he says.
“We found that around 75 per cent of crops benefit from pollinators. But this percentage is of all crop species, not just the food crops. And this is not the number of crops that depend on pollinators like bees, it’s the number of crops that get some benefit from pollinators.
“The impact of this benefit varies across species, it isn’t an all-or-nothing situation. Without pollinators you’d still get oranges, you’d just get less of them.”
There’s a big difference between a plant species that depends on pollination by pollinators and one that benefits from it. Just as most people don’t realise there are other pollinators besides bees – or more than one type of bee, for that matter – most people don’t know enough about how pollination works to understand the distinction.
Prof Cunningham says most farmers don’t know much about pollination either. “I’ve spoken to farmers and they have a huge amount of knowledge on what they’re growing, whether that’s apples or canola, but they don’t know much about pollination,” he says. “If you talk about fertiliser application rates then their knowledge is expert, but pollination is something they just presume happens.”
Chris Houghton, who’s been an agronomist for 30 years in regional NSW, agrees. “It’s something we know needs to happen but it goes on in the background, so we don’t really think about it much,” he says. “There isn’t much awareness in the industry. Considering how important it is for some crops, probably not as much as there should be.”
Pollination is how plants are fertilised and reproduced, how they make fruit (or vegetables, nuts or grains) and set seed for the next generation. A small percentage of species are self-pollinating, such as peanuts, and don’t need fertilisation with pollen from another plant.
But most plant species, including our food crops, need cross-pollinating, fertilising with pollen from a different plant. This pollination needs to be done by an external agent, either by wind or water, or by an insect or animal, that can carry and transfer the pollen from one plant to another.
“Stories about impending disaster make better reading in the media, I guess, but I think a lot of the misinformation is due to a knowledge gap,” Prof Cunningham says.
“It’s a mixture of truth and exaggeration. It’s definitely true that there’s a link between pollination and food. But the exaggeration is in the impact if we lost pollination, and on the risk that we would lose pollination.
“Most of the staple food crops we rely on across the globe, like corn, rice, oats and wheat, are wind pollinated. This means that claims we’ll run out of food without pollinators like bees simply aren’t true.”
There are food crops that are dependent on pollinators, like almonds and avocados, or that reap commercially significant benefits from pollinator activities, like coffee and cocoa, and most of these foods have cultural, economic, nutritional or gustatory importance. But few, if any, depend entirely on bees, according to Prof Cunningham.
Despite their role as the poster pin-up for pollination, honey bees are only one type of pollinator. Research by Prof Cunningham and colleagues indicates the bulk of pollination is done by the thousands of other pollinating species across the globe, including other insects, birds, bats and even some mammals. But this doesn’t mean that bees aren’t important.
The prominence of bees
The European honey bee, Apis mellifera, has been intentionally introduced onto every continent except Antarctica and is now possibly the most widespread species on Earth. It is certainly a species of great importance to humans, with domestication dating from the earliest historical records.
The honey bee is thus not native to Australia, and was introduced in 1822 to provide honey and pollination services. It’s now established both as a managed population under the care of beekeepers and as a self-sustaining feral bee population.
Honey and other products produced by honey bees, such as wax and royal jelly, have a total value of about $90 million each year in Australia, according to BeeAware. It also says crop pollination by honey bees has a commercial value of about $5 billion annually in Australia and is worth about $240 billion world-wide.
David Bingley, a second-generation beekeeper, is one of the directors of Weerona Apiaries at Sutton in NSW, producing about 300 tonnes of honey each year. Weerona has 1700 hives, which are stationed as far afield as Wagga Wagga in the Riverina region, and Batemans Bay on the NSW south coast.
“Bees forage on flowers to gather pollen and nectar. The pollen gives them their protein and the nectar is their carbohydrates. It’s the nectar that bees turn into honey. Bees are just looking for food, and pollination is a by-product.”
Not unlike humans, bees do best when they get variety in their diet, by foraging on a range of plant species to gather pollen and nectar from diverse sources, Mr Bingley says. Unfortunately, increased urbanisation and modern agricultural practices have reduced diversity of plant species. Agricultural monocultures, large acreages planted with a single species crops like canola, cotton, wheat or almonds, are taking the place of mixed cropping and smaller plantings interspersed with windbreaks, which preserve native plants and habitats.
Weerona Apiaries is primarily a honey producer, and this means it usually puts its bees in areas with access to eucalypts and a mix of forage plants, or near crops such as canola, which can produce good honey yields. They have arrangements with farmers to get access for their hives, for mutual benefit. “Bee pollination improves the canola yield and the oil quality. But bees aren’t critical for canola, so the farmers don’t pay us,” Mr Bingley says. “We get a significant amount of honey though so we’re happy enough to go there.”
Almond crops, which do depend on pollination, are a different story. Except in rare circumstances, almonds don’t produce nectar, and bees don’t thrive when they’re on this crop, according to Mr Bingley. Almond growers have to pay commercial pollinators, and this year, Weerona has put some of its hives on almonds.
“There are thousands of hives on the almonds now. All the almond growers are looking for bees all the time,” Mr Bingley says. “You wouldn’t go near almonds if you weren’t paid though, because it’s hard on the bees.”
Rob Lawless, who is studying a Masters of Environmental Science and is part of the Canberra-based group ACT for bees, has an interest in both honey bees and Australian native bees. He agrees that there’s great demand for pollination services.
“They’ve planted so many almond trees now there’s a pollinator shortage. The trees are reaching maturity and there aren’t enough bees to do the job of pollinating them.”
He also says this practice is hard on bees. “Providing pollination services is pretty bad for bees generally and this is why the farmers have to pay the beekeepers. They take the bees there and the bees suffer, and this is partly from all the pesticides and fungicides that are used.
“In California, in the apple orchards, they use fungicides to protect the fruit and they found out it has an effect on the bees, which they didn’t expect. The bees collected 30 per cent less nectar.”
Exposure to insecticides and fungicides even at sub-lethal levels is a stressor for bees that makes them vulnerable to disease and parasites, Prof Cunningham says. It’s been linked overseas to bee deaths from pest infestations, such as the Varroa destructor mite, and viral and fungal diseases; these in turn are linked with colony collapse disorder, when the worker bees abandon the hive.
Prof Cunningham says, in Australia, the honey bee population isn’t suffering the same decline as in other areas of the world. This is due in part to Australia’s strict quarantine laws and biosecurity program for preventing pests like the Varroa destructor mite from entering the country.
Australia is the only populated continent that’s free from this mite, thanks to preventative measures like the sentinel hives set up near major ports in coastal cities. Despite all these precautions, there’s an acceptance in the industry that these tiny mites will eventually find their way into Australia. Treatment of the mites in managed bee populations will add to beekeeping expenses and could devastate feral honey bee populations.
Bees may be the pollinator most people are most familiar with, but they are not the only one. Australia has thousands of native bees and other pollinating insects that play a more significant role in crop pollination, says Prof Cunningham.
The importance of other pollinators
Most flowering plants are visited by many different types of pollinating insects or animals. This variety is nature’s way of having an each-way bet; if a pollinator species declines, there are others to fill the gap. This is one of the reasons the panic about the fall in bee numbers is misleading, according to Prof Cunningham.
“In Australia, although bees play an important role in pollination, and particularly in commercial pollination activities, most of the pollination of our crops is done by other pollinator species.”
He says that there are about 1600 described and named native bee species in Australia. “We don’t know exactly how many there are because they’re under-studied. We think it’s about 3000 species.”
Australian native bees are distributed according to climate and available habitat, including food supply and suitable nesting sites. These are affected by human activities like land clearing, or other environmental or climate changes. Rob Lawless says he recently saw an Australian native bee, Tetragonula carbonaria, in the Kangaroo Valley in NSW. “That’s at the extreme southern end of their range, and I think it’s a sign that they’re creeping south with the warmer temperatures.”
David Bingley has seen a change in timing of flowering this year that’s hindering their bee husbandry routine. “Almonds flowered late, the middle of August instead of the end of July, so we’re waiting now to get the bees off the almonds. Normally almonds flower before canola but it was the other way around this year.”
The experts agree that the drought is having a significant impact on all pollinators, and that climate change is a factor. “Climate change affects when things flower, how much they flower and the availability of water,” Prof Cunningham says.
Chris Houghton says he’s noticed a significant shift, in particular in the past 20 years. “We’re getting record-breaking temperatures and hotter summers year after year. Increased bushfires and lack of rain are the two big ones. These affect the pollinators too.”
Mr Bingley says temperature and water are critical for bees. “They do need a lot of water in summer and we’ll try not to put the hives in full sun.” He adds that the drought affected the canola crops this year. “It was a long cold winter and it was dry. I think the canola flowered early because it was moisture-stressed.”
The abundance of other pollinators doesn’t make these threats to the continued wellbeing of bees redundant. Many of the threats to managed honey bees are of equal or greater danger to wild pollinators.
There’s agreement that insecticides are a major issue, because they’re lethal to a broad range of insects.
Houghton sums it up neatly. “It’s not a great scenario but unfortunately that’s the blunt instrument we’ve got. We just have to be very careful how we use it.”
The changing landscape
The focus on honey bees means other pollinators continue to fly under the radar.
There is a clear economic motive in protecting the health and productivity of managed honey bees. Unfortunately, the large numbers of unmanaged or wild pollinators aren’t monetised and don’t attract the same interest, Mr Lawless says.
While the thousands of other pollinator species are likely to fill any gap left by a decline in bees, the population and health of local bees are an indicator for all insects. It’s like the proverbial canary in the coal mine; just as a dead bird in a cage warned miners of a build-up of deadly carbon monoxide, dead bees may be the warning sign that all insects are in dire peril.
Domesticated bees are cared for; they’re provided with shade, water, food and protection. Most farmers will notify beekeepers before they spray crops, so the beekeepers can move their hives to safety, Mr Bingley says. Wild insects have no protection, and few advocates.
We won’t run out of food if the bees and the other pollinators decline, because our staple crops rely on wind for pollination, not insects. But our food landscape will look very different, according to beekeeper Mr Bingley.
“Anything that isn’t a grain needs a bee or some other kind of pollinator. We wouldn’t really want to go without fruit and nuts,” he says.
There needs to be recognition of the importance of other insects, and the consequences if they are lost. While we do need to look beyond the bees, we can’t ignore the human factors that are threatening their wellbeing.
If we keep the bees in perspective, we can learn how to protect all of our pollinators and, in the process, the variety of food on our tables.