Fungus-insect symbiosis: Diversity and negative ecological role of the hypocrealean fungus Trichoderma harzianum in colonies of neotropical termites (Blattodea: Termitidae)

• Published in: Fungal ecology Vol. 57-58; p. 101152
• Main Authors: Mendes-Pereira, Thairine, Moreira, Camila Costa, Kloss, Thiago Gechel, Fonseca, Paula Luize Camargos, Elliot, Simon Luke, Loreto, Raquel Gontijo de
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2022
• Subjects: Antagonism; Entomopathogens; Fungal phylogeny; Host-parasite interactions; Social insects; Social insects; Antagonism; Fungal phylogeny; Host-parasite interactions; Entomopathogens
• ISSN: 1754-5048
• DOI: 10.1016/j.funeco.2022.101152

Symbioses between social insects and fungi can drive important processes in both. We show previously unrealised prevalence and diversity of Trichoderma species (Ascomycota: Hypocreales) in individuals of two termite species (Blattodea: Termitidae). Trichoderma is well known for producing cellulolytic and fungistatic compounds, which can be important to protect colonies against entomopathogenic fungi. We hypothesized that Trichoderma species have a positive effect on termite hosts, yet found an unexpected negative effect of Trichoderma harzianum on termite survival, the presence of Trichoderma species was not determinant for termite nutritional status. Although T. harzianum hindered growth of the entomopathogenic fungus Metarhizium anisopliae (Ascomycota: Hypocreales) in vitro, this was not registered for T. virens, suggesting they have different fungistatic roles. Despite the prevalence of Trichoderma species at the colony level being low in termites, we propose that T. harzianum has no specific ecological role that benefits higher termites and might even be a potential opportunistic parasite for termite colonies.
•We added new ecological niches for the fungi Trichoderma, associated with termites•Trichoderma prevalence was low but consistent in termites•Trichoderma was absent from termite juvenile stages•Trichoderma harzianum decreased termite survival, potentially acting as a pathogen•Trichoderma harzianum could act as tertiary defence against Metarhizium anisopliae