Diversity and enzymatic capabilities of fungi associated with the digestive tract of larval stages of a shredder insect in Cerrado and Amazon Forest, Brazil

Abstract

Tropical biomes such as Brazilian Cerrado and Amazon Forest have a great diversity of fungi and insects. Interactions between these organisms can be beneficial to both partners. In streams, these interactions contribute to litter decomposition. Studying the digestive tract (DT) of shredder insects as a habitat for fungal microorganisms is an opportunity to obtain fungal strains with biotechnological potential, which may help to understand the symbiotic relationships between these organisms in tropical forests. This study investigated the fungal community in the DT of larvae of Triplectides (Trichoptera: Leptoceridae) collected in low-order streams in the Cerrado and Amazon Forest biomes in Brazil. Forty-nine fungal isolates were obtained and identified among 32 species and 12 genera. The genus Roussoella was only found in the DT of insects in Amazon Forest streams, while 7 genera only occurred in the DT of insects in Cerrado streams. The genus Penicillium (40%) was the most frequent. In the Cerrado, 78% were producers of CMCase, more than two-fold that in the Amazon Forest (35%). And 62% were producers of xylanase, in the Cerrado and 71% in the Amazon Forest. In this context, the fungal community in the DT of Triplectides larvae may play an important role in the insect diet by breaking down lignocellulosic material.

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.…”

Anti-Insect Properties of Penicillium Secondary Metabolites

“…Brazil adult [32] H. hempei Mexico cuticle and gut of females [30] Nomia melanderi western USA diseased larva [41] Parastrongylus megistus Brazil digestive tract [42] Pteroptyx bearni Sabah (Malaysia) eggs [43] T. brasiliensis, T. infestans Brazil digestive tract [25] Triplectides sp. Brazil gut [20] unspecified insect Brazil internal mycobiota [19] V Helicoverpa zea Iowa (USA) dead larva and pupa [22] Ostrinia nubilalis Iowa (USA) dead larva [22] P. megistus Brazil digestive tract [42] T. brasiliensis Brazil digestive tract [25] V C. quinquefasciatus Thailand dead adult [40] Diaphania (Margaronia) pyloalis Japan larva [61] Euops lespedezae Japan mycangia [62] F. polyctena Poland workers [55] Halictus rubicundus India frass [63] Lasioglossum zephyrum India dead larvae [63] Lixus impressiventris South Korea dead insect [54] M. domestica Iran adults [64] M. domestica Brazil diseased adult/larva [36] Periplaneta americana Sumatra (Indonesia) adult [65] Table 1. Cont.…”

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

“…Several authors have reported the abundance of those genera associated with the DT of insects (Belmont-Montefusco et al, 2020a;Teixeira et al, 2022;Romão et al, 2024). Penicillium and Aspergillus, which had the highest occurrence in the DT of larvae from trunks in Cerrado streams, were also frequent in association with mosquito larvae (Diptera: Culicidae) of several types of breeding grounds in municipalities of the Brazilian Amazon (Pereira et al, 2009).…”

“…diversity in taxa as well as the low frequencies of fungal species. Teixeira et al (2022), when studying the DT fungal community of aquatic shredder larvae, recorded a high occurrence of singletons, consequently resulting in a high diversity of fungal species. The authors attributed this to factors such as the influence of different environmental conditions, diets of species, and life cycles of the insects.…”