Tissue Specificity in Social Context-DependentlysozymeExpression in Bumblebees

Group living at high densities may result in the enhanced transmission of pathogens.Social insects are obligate group-living species, which often also exhibit high relatedness and frequentsocial interactions amongst individuals, resulting in a high risk of disease spread. Social species seemto exhibit immune systems that provide colonies of social insects with a certain level of flexibility foradjustment of immune activity according to the risk of disease spread. In bumblebees,Bombus terrestris,it was demonstrated that in group-kept individuals, immune component activity and immune geneexpression is increased, potentially as a prophylactic adaptation. Here, I tested whether socialenvironment influences the gene expression pattern of twolysozymegenes, which are componentsof the antimicrobial response of the bumblebee. In addition, I tested gene expression activationin different tissues (gut, fat body). The analysis revealed that the gene, the density of individuals,the tissue, and the interaction of the latter are the main factors that influence the expression oflysozymegenes. This is the first report of a tissue-specific response towards the social environment. This hasimplications for gene regulation, which must be responsive to social context-dependent information