How honey bees evolved to beat the cold?

Our new study in Molecular Biology and Evolution reveals a molecular mechanism that helped honey bees expand from their tropical origins into temperate environments.

Apis cerana and Apis mellifera independently expanded into temperate regions.

Remarkably, we found that both evolved the same strategy for producing more heat: increased mitochondrial proton leakage—diverting more energy from ATP production toward heat generation. 

Comparative genomics led us to PTCD1, where both species independently acquired the same Q208K amino-acid substitution. Functional experiments showed that this single change increases mitochondrial proton leakage and enhances thermogenesis. 

It is a striking example of convergent evolution—from genome to physiology: two honey bee lineages faced similar thermal challenges and independently arrived at the same molecular solution.

Congratulations to first author Ye Xiao, co-corresponding author Shanlin Liu, and our entire collaborative team!

Xiao, Y., L. Qiu, H. Wang, Y. Fan, Z. Zhao, D. Wu, Z. Wang, J. Zhang, M. A. Malik, S. H. Parey, M. Tang, B. Sun, W. Du, X. Zhou, and S. Liu. 2026. Convergent elevation of mitochondrial proton leakage improves thermogenesis in honey bees. Molecular Biology and Evolution 43(8): msag174. https://doi.org/10.1093/molbev/msag174