High diversity and low specificity of chaetothyrialean fungi in carton galleries in a neotropical ant-plant association.
New associations have recently been discovered between arboreal ants that live on myrmecophytic plants, and different groups of fungi. Most of the - usually undescribed - fungi cultured by the ants belong to the order Chaetothyriales (Ascomycetes). Chaetothyriales occur in the nesting spaces provided by the host plant, and form a major part of the cardboard-like material produced by the ants for constructing nests and runway galleries. Until now, the fungi have been considered specific to each ant species. We focus on the three-way association between the plant Tetrathylacium macrophyllum (Salicaceae), the ant Azteca brevis (Formicidae: Dolichoderinae) and various chaetothyrialean fungi. Azteca brevis builds extensive runway galleries along branches of T. macrophyllum. The carton of the gallery walls consists of masticated plant material densely pervaded by chaetothyrialean hyphae. In order to characterise the specificity of the ant-fungus association, fungi from the runway galleries of 19 ant colonies were grown as pure cultures and analyzed using partial SSU, complete ITS, 5.8S and partial LSU rDNA sequences. This gave 128 different fungal genotypes, 78% of which were clustered into three monophyletic groups. The most common fungus (either genotype or approximate species-level OTU) was found in the runway galleries of 63% of the investigated ant colonies. This indicates that there can be a dominant fungus but, in general, a wider guild of chaetothyrialean fungi share the same ant mutualist in Azteca brevis.
Division of Structural and Functional Botany, Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Maximilian
M
Nepel
Division of Systematic and Evolutionary Botany, Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria; Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria.
Hermann
H
Voglmayr
Division of Structural and Functional Botany, Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Jürg
J
Schönenberger
Division of Structural and Functional Botany, Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Veronika E
VE
Mayer
D000818:Animals; D001000:Ants / Q000382:microbiology / Q000502:physiology*; D001203:Ascomycota / Q000502:physiology*; D001483:Base Sequence; D001499:Bayes Theorem; D003364:Costa Rica; D017931:DNA Primers / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005838:Genotype; D025301:Hyphae / Q000502:physiology; D016013:Likelihood Functions; D008855:Microscopy, Electron, Scanning; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009425:Nesting Behavior / Q000502:physiology; D016133:Polymerase Chain Reaction; D031308:Salicaceae / Q000382:microbiology / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013559:Symbiosis
D017931:DNA Primers; D004275:DNA, Ribosomal