Fatty acid profile of Apis mellifera workers in the face of an immune challenge

Fatty acids (FAs) are important in metabolism and in the maintenance of Apis mellifera colonies. Our objective was to identify the variation in FA composition of the bodies of A. mellifera worker bees after immunological challenges with sterile injections and Paenibacillus larvae vegetative cells. The expression of the hymenoptaecin and abaecin genes was studied and the FAs were identified and quantified. After a challenge with P. larvae, the immune system was activated and abaecin and hymenoptaecin peptide genes were overexpressed. Also, the content of short-chain FAs such as caprylic, capric, and tridecylic acids increased significantly; on the contrary, oleic acid decreased. To the best of our knowledge, this is the first analysis of changes in the FA profile of honey bee workers after immune stimulation with P. larvae. Health status may be a key factor that alters FA composition. More research about the interaction with other stressors affecting the survival of honey bee colonies is needed.