Bee diversity – you never stop learning!

Every third bite ... – why bees matter

We are in the midst of a biodiversity crisis, during which we are losing species that haven’t even been discovered yet. Thankfully, the public awareness of the importance of living things is rising. This is especially true for insects; once reviled, they are now recognized as essential ecosystem service providers under threat. Numerous studies have suggested insect declines, including bees, but the truth is that we don’t really know the conservation status of most species due to large knowledge gaps.

Among insects, bees are especially important, providing most terrestrial pollination services. Accordingly, you’ve probably seen many ads or campaigns to save the bees. There’s good reason for this, as there’s a common saying suggesting that one in every three bites results from pollination; this is both directly (MANY fruits and vegetables) and through feed for animals we eat. Much of this may not be new for you, but hopefully if you didn’t already think that bees are important, you do now.

Bee-odiversity: Unexpected in many ways!

Until recently, the word “bee” might evoke honey bee hives with workers in their thousands, but with recent public awareness campaigns many more people know of and appreciate the other bees. In fact, there are about 20 000 other kinds of bees spread around the world, everywhere but Antarctica. The vast majority, perhaps 85%, live solitary lifestyles where mother bees essentially provide pollen and nectar for their offspring and then leave them to fend for themselves.

Bees come in all shapes, colours, and sizes (Figure 1, Asian bees), ranging from 1 mm to the biggest bee in the world, Megachile pluto, with a wingspan over 6 cm (Figure 1K). Among these varied forms are even parasitic bees, such as the colorful Nomada (Figure 1H), which invade other bees’ nests and take over. The wide array of bee lifestyles makes them interesting to study well beyond their value as pollinators. However, it also greatly complicates our ability to understand where they live, as different types of bees might have different habitat requirements, such that they show different patterns entirely.

The state of the art

In 2021, we made the first global map of bee species (Figure 2). Surprisingly, we discovered that the highest amount of bee species can be found in deserts. That is unlike the majority of animals, which have most of their species in the lush tropical areas around the equator. It was a huge undertaking, gathering all possible data we could from many different public data sources. Maybe the most difficult aspect of the whole project was figuring out how to reconstruct real global patterns when we had data that were mostly gathered near roads and human settlements. Overall, we showed that most data about bee distribution come from North America and Europe, with relatively little from Asia or the rest of the world. We had expected some data limits, but we were really surprised by how little data existed for much of the world! This challenge strongly motivates my work as a scientist these days, including a grant written this year (2025) to increase identification and data resources across four African countries (DR Congo, Kenya, Madagascar, and Tanzania). If funded, this project could provide substantial, necessary resources for future research in the region.

It can be very difficult to generate reliable data on bee distribution. Many specimens exist from all around the world, housed largely in museums in high-income countries, making it hard for local people in large parts of the world to identify species. Further, there isn’t enough support to “unlock” these data from collection vaults, as it is time-costly to digitize specimen information and expertise is also needed to make sure the identifications of collected specimens are correct. To clean data on bee distribution, we also recently designed a data fixing workflow that everyone can use everywhere. Critically, without museums and the specimens they hold, almost none of our work would have been possible.

Where to from here? Future directions in bee distribution research

In 2024, we took the next step in mapping bee distribution by incorporating how bees behave. Our newest paper focuses on bees that buzz to access pollen. By grasping plants and buzzing, they can access pollen from tight enclosed spaces holding pollen that are otherwise impossible to access. This behavior is found throughout a stunningly wide variety of bees worldwide, making it very difficult to know where and how the behavior evolved. We show the global patterns of the behavior and that the number of species buzzing is linked to the number of plant species most often buzzed. We are now finishing a dataset on the social behaviors that bees exhibit and running analyses, to further our understanding of why bees live where they do.

Conservation is another important aim, as it is only once we know where certain organisms live that we can design targeted management strategies that really benefit them. International Union for the Conservation of Nature (IUCN) status assessments are now being generated for the majority of European species, but they do not exist for much of the rest of the world, even North America. We will begin work on this in the winter, as an important next step toward effectively understanding and protecting the global bee fauna.

Updated information on bee distribution can be found on the DiscoverLife platform:

• Ascher, J. S., & Pickering, J. 2024. Discover life: bee species guide and world checklist (Hymenoptera: Apoidea: Anthophila) http://www.discoverlife.org/mp/20q?guide=Apoidea_species&flags=HAS