Search for: All records

Abstract Escovopsisis a diverse group of fungi, which are considered specialized parasites of the fungal cultivars of fungus-growing ants. The lack of a suitable taxonomic framework and phylogenetic inconsistencies have long hamperedEscovopsisresearch. The aim of this study is to reassess the genusEscovopsisusing a taxonomic approach and a comprehensive multilocus phylogenetic analysis, in order to set the basis of the genus systematics and the stage for futureEscovopsisresearch. Our results support the separation ofEscovopsisinto three distinct genera. In light of this, we redefineEscovopsisas a monophyletic clade whose main feature is to form terminal vesicles on conidiophores. Consequently,E. kreiseliiandE. trichodermoideswere recombined into two new genera,SympodioroseaandLuteomyces, asS.kreiseliiandL.trichodermoides, respectively. This study expands our understanding of the systematics ofEscovopsisand related genera, thereby facilitating future research on the evolutionary history, taxonomic diversity, and ecological roles of these inhabitants of the attine ant colonies. 

Abstract Despite the ubiquity and importance of mutualistic interactions, we know little about the evolutionary genetics underlying their long‐term persistence. As in antagonistic interactions, mutualistic symbioses are characterized by substantial levels of phenotypic and genetic diversity. In contrast to antagonistic interactions, however, we, by and large, do not understand how this variation arises, how it is maintained, nor its implications for future evolutionary change. Currently, we rely on phenotypic models to address the persistence of mutualistic symbioses, but the success of an interaction almost certainly depends heavily on genetic interactions. In this review, we argue that evolutionary genetic models could provide a framework for understanding the causes and consequences of diversity and why selection may favour processes that maintain variation in mutualistic interactions. 

Fungi in the genus Escovopsis (Ascomycota: Hypocreales) are prevalent associates of the complex symbiosis between fungus-growing ants (Tribe Attini), the ants’ cultivated basidiomycete fungi and a consortium of both beneficial and harmful microbes found within the ants’ garden communities. Some Escovopsis spp. have been shown to attack the ants’ cultivated fungi, and co-infections by multiple Escovopsis spp. are common in gardens in nature. Yet, little is known about how Escovopsis strains impact each other. Since microbe–microbe interactions play a central role in microbial ecology and evolution, we conducted experiments to assay the types of interactions that govern Escovopsis–Escovopsis relationships. We isolated Escovopsis strains from the gardens of 10 attine ant genera representing basal (lower) and derived groups in the attine ant phylogeny. We conducted in vitro experiments to determine the outcome of both intraclonal and interclonal Escovopsis confrontations. When paired with self (intraclonal interactions), Escovopsis isolated from lower attine colonies exhibited antagonistic (inhibitory) responses, while strains isolated from derived attine colonies exhibited neutral or mutualistic interactions, leading to a clear phylogenetic pattern of interaction outcome. Interclonal interactions were more varied, exhibiting less phylogenetic signal. These results can serve as the basis for future studies on the costs and benefits of Escovopsis coinfection, and on the genetic and chemical mechanisms that regulate the compatibility and incompatibility observed here.