World map of bees

Bees play the crucial role of pollination in natural habitats and in crops important to humans. However, there is sparse data about the distribution of bee species around the world. This lack of information affects our ability to deal with bee population declines that threaten ecosystem balance and our food supply.

Assistant Professor John Ascher from NUS Biological Sciences worked with researchers from the Chinese Academy of Sciences and the University of Georgia to plug the gap by making a world map of bee species. They first looked at a list of more than 20,000 known bee species that was earlier compiled by Asst Prof Ascher and made available on the biodiversity portal DiscoverLife.org. They then matched it with almost six million public records of where different species had been found.

The scientists hope the map will help protect bee populations. It also serves as a reference point for further bee research. Their findings were published in the journal Current Biology on 19 November 2020.

“People think of bees as just honey bees, bumble bees, and maybe a few others, but there are more species of bees than of birds and mammals combined,” said Asst Prof Ascher.

As many crops in developing countries rely on local species of bees for pollination, it is essential to understand the geographical distributions of bee species.

The map of bee diversity created by the team showed interesting global patterns. For example, most plants and animals are most diverse in the humid tropics. But this is different for bees, which are more diverse in arid and temperate zones of the world. This is because tropical forest trees are not a reliable food source, compared to low-lying plants and flowers. Previous studies on bee distribution focused on limited geographical areas, so it was difficult to generalise the findings.

However, there is much more to be done, as some areas of the world are still poorly known in terms of bees. Asst Prof Ascher gives a hint, “The United States has by far the most species of bees, but there are also vast areas of the African continent and the Middle East which have high levels of undiscovered diversity, more than in tropical areas.”

The research team is now planning field surveys to ground-truth their data, and looking for new sources of data. They also want to study how climate change will affect pollination and food security, among other things.

They view their work as important steps towards a more comprehensive understanding of global bee diversity, and an important baseline for future, more detailed bee research. They hope their work will help in the conservation of bees as global pollinators.

Asst Prof Ascher also co-authored the book ‘A Guide to the Bees of Singapore’. The book, which was a collaboration between NUS and the National Parks Board, was launched in September 2020.