When it comes to bees, many people think of the honey bee and maybe also the bumblebee. According to scientists, there are more species of bees than birds and mammals combined. Researchers from China, the USA and Singapore have now created the first map showing all bee species worldwide.
The map was published on November 19th in Current Biology journal.Up to date researchers identified more than 20,000 bee species worldwide. For comparison: there are currently 10,787 existing bird species known, in the case of mammals there are only 6,399 species. However, there has not yet been a map that could show the patterns of bee distribution around the globe.
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Bees prefer dry and mild environments
To create the map, the scientists John Ascher, Michael Orr and Alice Hughes, together with other colleagues, first collected data from the 20,000 different bee species and then compared them with one another. This evaluation gave the researchers an overview of the geographical distribution of different bee species.
In addition to the best-known bee species, the new map also contains six million bees from less known species. Scientists succeeded in proving that bees prefer particularly dry and mild environments. This means that, unlike many other plants and living things, most bee species are native to the northern hemisphere and not the southern. The number of bees increases towards the polar regions and decreases towards the tropics. This pattern of geographical distribution is as the bimodal latitudinal gradient.
However, many bee species are even able to survive in the desert. In fact, there are far fewer species of bees in forests and jungles than, for example, in dry desert environments. This is because flowers and plants on the ground are better sources of food for bees than trees. When it rains in the desert unpredictable mass blooms occur. These blooms literally cover the whole area with “floral carpets”.
Most bee species are found in the United States, followed by Africa and the Middle East. Researchers hope that mapping the distribution of bees will create a basis for further research of the various bee species. Recording species richness and geographical occurrences should help to better analyze these species in the future. This is the only way to preserve their biological diversity, including the important functions these species perform for the environment.
The map was created as part of bee conservation efforts
Many crops, especially in developing countries, depend on native bee species and not on honey bees. So the map is an important first step in assessing the distribution and potential decline of bee populations. Previous scientific data on this was incomplete or difficult to access.
Researchers were surprised at how bad most of the previous global bee diversity data really was. Much of it was just too sketchy or too focused on a small number of countries that prioritized data sharing, in order to be able to use these resources for a large-scale analysis.
Although there is still much to be researched about the individual bee species, the researchers hope that their work will contribute to the conservation of bees as global pollinators. The authors regard this research as an important first step towards a better understanding of global bee diversity and as an important basis for future, more accurate bee research.