Diversity of cellulolytic and xylanolytic fungi associated with the digestive tract of aquatic insect larvae in streams of the Amazon Forest and Cerrado in Brazil

Abstract

The study of the relationship between fungi and insects brings important contributions to the knowledge of fungal biodiversity and to the understanding of mutualistic ecological interactions. This study reports the occurrence of a community of filamentous fungi in the digestive tract (DT) of mining insect larvae belonging to genus Stenochironomus in streams of two Brazilian biomes. Fungi were obtained from the digestive tract of larvae found on trunks and leaves of low-order streams in the Amazon Forest and Cerrado in the north of Brazil. The fungal community was screened for xylanolytic and cellulolytic activities. The diversity of fungal species in the DT of larvae is possibly related to the diversity of diets of species of that genus and the diversity of substrates in the ecosystems. The diversity and richness of fungal species were influenced by ecological differences between locations more than by the types of substrates in which they were collected (trunk and leaf). Most fungi in the DT of Stenochironomus larvae sampled in leaves exhibited cellulolytic enzyme activity. Such results stress that the mycobiomes of the DT of Stenochiromonus larvae produce enzymes that contribute to the process of breaking down plant remains in their hosts.

Cladosporium—Insect Relationships

“…Connected with the feeding aptitude is the isolation of Cladosporium spp. from the gut of larvae of aquatic shredders of the genera Phylloicus (Trichoptera, Calamoceratidae) and Stenochironomus (Diptera, Chironomidae); these strains displayed cellulolytic and xylanolytic properties in laboratory assays, supporting the hypothesis that they might improve the digestibility of leaves by the insects [63,73,150]. Likewise, Cladosporium spp.…”