SINGAPORE - Bees are the most important pollinator, playing a crucial role in producing the succulent fruits and vegetables that feed the people, yet little is known about their species distribution and hot spots outside of North America, Europe and Australia.
To plug the gaps and make way for comprehensive biodiversity studies and conservation policies for the over 20,300 bee species worldwide, researchers from four nations including Singapore have plotted the first "bee map" to chart the creatures' spread and diversity across the continents.
The global bee map is made up of several maps, and the researchers believe one of them is a global first for invertebrates in charting species richness at a national, sub-national or state level in many countries.
The new map - built from hundreds of thousands of bee records and specimens from around the world, and almost six million records from public databases that were filtered for inaccuracies - revealed numerous gaping holes in currently known patterns about bee diversity.
"Bees are reported to be in decline worldwide. And I say 'reported' rather than confirming they are because a lot of these reports are based on the Netherlands, England, or the US," said Assistant Professor John Ascher from the department of biological sciences at the National University of Singapore. He is one of the researchers of the bee map project.
"There is sparse coverage about bees for the rest of the world. They're reporting global declines, but their data set is not really global," added Prof Ascher, who is the main data provider for the bee map.
The other researchers involved in the project are from China, the United Kingdom, and the United States. Their research paper containing the map was published in scientific journal Current Biology on Friday (Nov 20).
Previously, global representation of bee species was skewed. For instance, the map shows that 15 per cent of the world's bee species are found in Asia, but only 1 per cent of Asia's species were represented in the almost six million records in public databases.
"From the map, you can see Africa has 19 per cent of the world's bees, which is a lot, but only 4 per cent, according to the public database. The public database was always underestimating the diversity of bees," added Prof Ascher.
The bee map also confirmed some hypotheses that experts had about bee hot spots.
Most plants and animals are more diverse in the tropical areas, but for bees, they are more prevalent in the regions that are neither too tropical nor too cold. These regions include deserts and wine-growing regions such as France, Spain, Argentina and southern Australia.
Prof Ascher said: "The bees make a strong counter argument against the tropics being the epicentre of diversity.
"Knowing this is very important for conservationists because they may be thinking: 'If we want to conserve biodiversity, we need to save the rainforest.' But we see here the rainforest doesn't really have that many species of bees. In addition to the rainforests, we need to conserve places in the Middle East, in Syria, Jordan. This is where we have incredible numbers of bees."
Since most bees nest in the ground, their larvae can be killed by fungi or harmed by wet soil in rainforests.
"The desert may have far fewer flowers than in Singapore. But when the rain comes the whole desert can be carpeted in flowers. And then, bees will come out in incredible numbers," he added.
To create the map and checklist of bee species around the world, Prof Ascher scoured a range of sources including historical records, specimens in various museums, research papers, and bee sightings by citizen scientists, and also fact checked publicly available records online.
But reading up on the buzzing insects is second nature to him, who began work on compiling global bee data 20 years ago when he was in graduate school.
Moving forward, the researchers hope that the bee map will serve as a springboard for experts to zero in on a particular region, and conduct more in-depth studies on the insects.
For instance, scientists can visit places with low bee diversity, and find out from local experts if the lack of bees is causing a climate or food security risk, since bees play a major role in agriculture.
From there, the scientists and local experts can come up with solutions to maintain pollination, he added.
Adjunct Professor Stephen Buchmann from the University of Arizona's department of ecology and evolutionary biology said bee biologists can also map out bee traits and behaviours in the same way Prof Ascher and his team had done.
Insights from the current map "will have profound implications for bee and flowering plant conservation. It will also help us find out where bees are most at risk due to climate change and global warming", added the pollination ecologist.