Fungi Isolated from Integument and Guts of Coptotermes formosanus and Their Antagonistic Effect on Gleophyllum trabeum

TLDR: It is suggested that green-spored fungi may be carried by termites and that they play a role in suppressing the growth of G. trabeum, and termites may be using parasitic fungi to control a brown rot fungus.

Abstract: In our earlier efforts to demonstrate the spread of a brown rot fungus, Gloeophyllum trabeum (Pers.) Murrill by Formosan subterranean termites, Coptotermes formosanus Shiraki, we found not only that C. formosanus does not spread G. trabeum but also that G. trabeum did not survive in the presence of C. formosanus. Further investigation of this antagonistic interaction between this termite and fungus led to a hypothesis that green-spored fungi may be carried by termites and that they play a role in suppressing the growth of G. trabeum. Fungal cultures were isolated from integument and guts of laboratory-maintained colonies of C. formosanus and groups of C. formosanus freshly collected from the field. Only the green-spored fungi were selected from the many fungi isolated. Green-spored fungi isolated from the integument were identified as Aspergillus flavus Link, Trichoderma harzianum Rifai, Trichoderma virens Miller et al., Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg, and Trichoderma ghanense Y. Doi, Y. Abe & J. Sugiyama. A different set of fungi were isolated from the gut, which included A. flavus, Hypocrea virens Chavarri, Samuels and Steward, T. asperellum cultures along with Penicillium janthinellum Biourge and Cladosporium cladosporioides (Fres.) de Vries. A. flavus was associated with every laboratory maintained colony but was associated only with one replication of one of the field collected groups. Our results suggest that A. flavus may be contaminating the colonies that were maintained in the laboratory and the fungus may become proliferous as the colonies become weak. Dual culture tests showed that all the fungi isolated from the integument, and gut were parasites and/or antagonists and that they effectively controlled the growth of G. trabeum. We think termites may be using parasitic fungi to control a brown rot fungus.