Study: Common Irish bumblebee differs genetically from British counterparts
New research from pollinator experts shows that Irish populations of one of the most commonly sighted bumblebee species show genome-wide differences from those on the island of Britain.
According to researchers, this discovery has important implications for conservation practices and may also inform the way imported commercial populations are managed.
The new research took a deep dive into the population genomics of Irish and British Bombus terrestris audax, locally known as the buff-tailed bumblebee.
In parallel to this species existing in the wild, it has also been domesticated for commercial use.
Commercial colonies are supplied worldwide, including to Ireland and the UK, to boost crop pollination. However, they may pose risks to wild pollinators through disease, competition, or genetic mixing.
This widespread bumblebee already has nine recognised subspecies distributed across Europe and North Africa that vary in their genetics and in their form and function.
And now the experts behind the study believe Irish bees may require distinct classification compared to their British counterparts.
Research
First author, Dr. Sarah Larragy, now based in Trinity College Dublin’s School of Natural Sciences, who led this research as part of her Irish Research Council-funded PhD in Maynooth University, said: “We found clear, genome-wide distinctions between Irish and British Bombus terrestris audax populations.
"We also identified key differences in some of the genes linked to nervous system function and development in the two populations, suggesting variations in natural selection pressures between the two populations.”
These findings build on earlier work by other researchers which first uncovered evidence of genetic differences between British and Irish B. terrestris.
Larragy and her team’s study also indicates that commercial buff-tailed bumblebee lines share more genetic similarity with British populations than with Irish ones, and presents evidence of either historic continental variation or, potentially, interbreeding between wild and commercial bees.
Co-author Joe Colgan, who is assistant professor at Johannes Gutenberg University Mainz, commented on the utility of population genomics in pollinator conservation, saying: “Our study highlights the power of whole-genome resequencing.
"By uncovering genome-wide distinctions and evidence of differential selection between these bumblebee populations, we provide novel insights that can help guide more effective conservation strategies.”
Ireland
Prof. James Carolan, from Maynooth University, is a senior author and was co-supervisor of Dr. Larragy during her doctorate.
He said: “This work provides more evidence of the significance of the genetic barrier of the Irish Sea, which maintains the distinction of many Irish plant and animal populations when compared to our nearest neighbours.
“Lumping groups together because they are found on our two islands ignores this potential genetic integrity, which has some important implications for conservation efforts and our biodiversity in a time when we are wrestling with a global biodiversity crisis.”
While commercial bumblebee colonies are vital for pollinating crops like apples and strawberries, researchers caution that imports could mix with distinct wild populations, spread pathogens, or compete for limited resources.
Although the researchers are not suggesting imports should stop, they feel their findings indicate that responsible management of these imports is essential to protect these unique populations.
