Assessing the adaptation of Apis mellifera subspecies to Mediterreanean environments

The adaptation of Apis mellifera subspecies to their specific environment is vital for honey bee colony welfare and productivity. The MEDIBEES project, spanning several Mediterranean countries, aims to promote the utilisation of native A. mellifera subspecies, that are naturally suited to their local conditions. Within this project, a comprehensive assessment of intersubspecific behavioural, reproductive, and productive traits at the colony level is underway. This involves comparisons between native subspecies and A. m. ligustica, which is often imported into Mediterranean countries outside its natural range of distribution. In the first year of the MEDIBEES field survey, remarkable cases of environmental maladaptation of A. m. ligustica colonies were observed, which manifested differently across the involved countries compared to local subspecies. Here we present some remarkable cases where the traits exhibited by the foreign subspecies appeared less fitting at the reproductive, productive, or population dynamics level. It is known that A. m. ligustica exhibits reduced defensive behaviour compared to other subspecies, which prompts its widespread importation from Italy by Mediterranean beekeepers. However, this behaviour comes at a cost, potentially impacting colony welfare, increasing mortality rates, susceptibility to diseases, and costs of management. Preserving the biodiversity of native subspecies is imperative, as these result from a unique evolutive adaptation process. Nonetheless, the beekeepers may improve local subspecies genetically, both to keep adaptation traits and reduce the aspects that make them complicated to manage. Although preliminary, these findings from the MEDIBEES project highlight the importance of rearing honey bee subspecies that are tailored to specific environments. Sustainable beekeeping in the Mediterranean region requires the protection of the heritage represented by the native A. mellifera populations. These results are under the project 2011-MEDIBEES, which is part of the PRIMA programme supported by the European Union.