social transfer of pathogenic fungus promotes active immunisation in ant colonies社会转移致病性真菌促进活性免疫蚁群.pdf

Social Transfer of Pathogenic Fungus Promotes Active Immunisation in Ant Colonies 1 1 2 1 1,3 1,3 Matthias Konrad , Meghan L. Vyleta , Fabian J. Theis , Miriam Stock , Simon Tragust , Martina Klatt , 3 2 1 1 Verena Drescher , Carsten Marr , Line V. Ugelvig , Sylvia Cremer * 1 Evolutionary Biology, IST Austria (Institute of Science and Technology Austria), Klosterneuburg, Austria, 2 Institute of Bioinformatics and Systems Biology, Helmholtz Center Munich, Neuherberg, Germany, 3 Evolution, Behaviour Genetics, University of Regensburg, Regensburg, Germany Abstract Due to the omnipresent risk of epidemics, insect societies have evolved sophisticated disease defences at the individual and colony level. An intriguing yet little understood phenomenon is that social contact to pathogen-exposed individuals reduces susceptibility of previously naive nestmates to this pathogen. We tested whether such social immunisation in Lasius ants against the entomopathogenic fungus Metarhizium anisopliae is based on active upregulation of the immune system of nestmates following contact to an infectious individual or passive protection via transfer of immune effectors among group members—that is, active versus passive immunisation. We found no evidence for involvement of passive immunisation via transfer of antimicrobials among colony members. Instead, intensive allogrooming behaviour between naive and pathogen- exposed ants before fungal conidia firmly attached to their cuticle suggested passage of the pathogen from the exposed individuals to their nestmates. By tracing fluorescence-labelled conid