The digestive tract of Phylloicus (Trichoptera: Calamoceratidae) harbours different yeast taxa in Cerrado streams, Brazil

Abstract

The interaction between insects, both larval and adult, and yeasts associated with their digestive tract (DT), has been of interest in recent years, since it can be beneficial for both partners. Studies focusing on this habitat have contributed to the expansion of knowledge about diversity, biogeography and functional characterization of yeasts, especially in ecosystems still poorly exploited, such as the Brazilian Cerrado. We investigated the interaction between larvae of Phylloicus spp. (Trichoptera: Calamoceratidae), which is an aquatic insect, and the yeasts isolated from its DT. The larvae were collected from first-order Cerrado streams of two States (Mato Grosso – MT and Para – PA) in Brazil. Yeasts were cultivated and identified based on sequence analysis of the D1/D2 domains of the large subunit of rRNA genes. A total of 20 yeast species, belonging to six genera of Ascomycota and five Basidiomycota, is harbored in the DT of the larvae. The most frequent genera were Candida, Papiliotrema, Rhodotorula (19.3% each) and Issatchenkia (15.8%). Candida parapsilosis and Rhodotorula mucilaginosa were only yeast species isolated from the DT of larvae in both locations. The most species-rich community was that associated with DT of Phylloicus spp. in MT samples (H′ = 1.48) as compared to PA samples (H′ = 0.67). All species were accidental (frequency < 25%), which is indicative of a loose association of these yeasts with their host. This is the first report of the association of yeasts with the DT of the shredders group of aquatic insects.