Through research into buff-tailed bumblebees collected by amateurs and researchers over a period of 150 years, biologists and climate researchers at Lund University have concluded that the world’s most common bee, the buff-tailed bumblee, is becoming even more common. In 1871, the buff-tailed bumblebee comprised 21 per cent of a group of four species known as the 'Bombus lucorum complex', where the white-tailed bumblebee dominated. In 2015 its proportion had increased to 79 per cent, that is, the buff-tailed bumblebee is now the dominating species.
“The buff-tailed bumblebee is a southern species that thrives in a hot climate. Sweden is located in the northern part of the species’ distribution, so it is actually not particularly surprising that it is benefitting from the increasingly warm climate here,” explains Lina Herbertsson, who led the study.
“It’s positive that the buff-tailed bumblee is managing so well, but we also don’t know whether this increase is happening at the expense of other bees,” she continues, and get support by her research colleague.
"The fact that species are differently affected by climate warming can have consequences for ecosystem functions, such as pollination. An increasing dominance of a few species of bumblebees can, for example, lead to lower levels of pollination for some plant species in the future. This is something we need to find out more about", says Anna Persson, who has also contributed to the study.
It will likely be necessary to tackle climate change in order to preserve the diversity of bees in the long term. To avoid species that can withstand global warming out-competing other species, the researchers point to the importance of plentiful flowers and habitats that offer nesting sites.
As well as the buff-tailed bumblee becoming increasingly common, the study also shows that the bees are now active roughly one month earlier than was the case in the early 1900s. This is likely due to rising temperatures and the increasingly early arrival of spring.
The bees that were investigated are preserved in the collections of the Biological Museum at Lund University.
The article, written by Lina Herbertsson, Reem Khalaf, Karin Johnson, Rune Bygebjerg, Sofia Blomqvist and Anna Persson is published in Basic and Applied Ecology: Long-term data shows increasing dominance of Bombus terrestris with climate warming.