Landscape and Climate-Associated Selection in the Native and Widespread Bumblebee, Bombus terrestris

Area of Science:

• Ecology and evolutionary biology
• Conservation genetics
• Environmental change impacts on wildlife

Background:

• Anthropogenic land-use and climate change create new selection pressures for bees.
• Understanding evolutionary responses, like adaptation, is crucial for species survival.
• The buff-tailed bumblebee (Bombus terrestris) exhibits high adaptive capacity, suggesting plasticity.

Purpose of the Study:

• Investigate genetic structure and local adaptation in Bombus terrestris populations across Sweden.
• Examine evolutionary responses to heterogeneous land-use and climate gradients.
• Identify genes and genetic markers associated with adaptation to environmental changes.

Main Methods:

• Genotyping of Bombus terrestris populations using RADseq.
• Analysis of genetic structure and population differentiation.
• Detection of selection signatures using molecular markers (e.g., Tajima's D, SNPs).

Main Results:

• Genetic structure identified, separating southern from northern Swedish populations.
• Evidence of population expansion, potentially northward and inland, aligning with range shifts.
• Weak but significant local adaptation to climate and agricultural land cover, including genes related to insecticide resistance, olfaction, and immune response.

Conclusions:

• Bombus terrestris successfully adapts to anthropogenic land-use and climate changes.
• Generalist traits likely facilitate phenotypic adaptation to novel environmental conditions.
• The study provides insights into the adaptive capacity of widespread insect species facing global change.