Specificity and transmission mosaic of ant nest-wall fungi

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 105; no. 3; pp. 940 - 943
• Main Authors: Schlick-Steiner, Birgit C, Steiner, Florian M, Konrad, Heino, Seifert, Bernhard, Christian, Erhard, Moder, Karl, Stauffer, Christian, Crozier, Ross H
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 22-01-2008; National Acad Sciences
• Series: From the Cover
• Subjects: Animals; Ants; Ants - microbiology; Ants - physiology; Ascomycetes; Ascomycota; Ascomycota - isolation & purification; Ascomycota - physiology; Biological Sciences; Chthonolasius; Conidia; Dendrolasius; Ecology; Ecosystem studies; Entomology; Evolution; Formicidae; Fungi; Fungiculture; insect behavior; insect colonies; insect ecology; insect fungiculture; Insect nests; Insects; internal transcribed spacers; Lasius; Life Cycle Stages - physiology; microbial growth; Molecular Sequence Data; Mutualism; Mycology; Nesting Behavior; nucleotide sequences; Queen insects; ribosomal DNA; Social insects; Species Specificity; Symbiosis - physiology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0708320105

Mutualism, whereby species interact to their mutual benefit, is extraordinary in a competitive world. To recognize general patterns of origin and maintenance from the plethora of mutualistic associations proves a persisting challenge. The simplest situation is believed to be that of a single mutualist specific to a single host, vertically transmitted from one host generation to the next. We characterized ascomycete fungal associates cultured for nest architecture by the ant subgenera Dendrolasius and CHTHONOLASIUS: The ants probably manage their fungal mutualists by protecting them against fungal competitors. The ant subgenera display different ant-to-fungus specificity patterns, one-to-two and many-to-one, and we infer vertical transmission, in the latter case overlaid by horizontal transmission. Possible evolutionary trajectories include a reversal from fungiculture by other Lasius subgenera and inheritance of fungi through life cycle interactions of the ant subgenera. The mosaic indicates how specificity patterns can be shaped by an interplay between host life-cycles and transmission adaptations.