Diversity of fungi cultured from galleries and bodies of ambrosia beetles ( Gnathotrupes spp.) and carpenter moths ( Chilecomadia valdiviana ) in lenga ( Nothofagus pumilio ) forests in Patagonia

Abstract

Wood-boring insects play an important role in turnover of trees and biomass in temperate forests and interact with a functionally diverse mycobiome. However, the diversity and dynamics of ambrosia beetles, other wood-boring insects, and their fungi remain relatively poorly understood in the forests of temperate South America. Baseline knowledge of insect and fungal diversity is therefore needed to provide a foundation for understanding the potential future dynamics of these critically important ecosystems in the context of global change. This study aimed to docu- ment fungal diversity that could be obtained in culture from larvae, adults, and galleries of ambrosia beetles (Gnathotrupes spp.) and a carpenter moth (Chilecomadia valdiviana) from lenga (Nothofagus pumilio) in northwest Patagonia, Argentina. Long molecular barcodes from fungal cultures isolated from galleries, larvae, and adult insects were obtained using nanopore sequen- cing. Fungal assemblages associated with Gnathotrupes spp. (32 unique taxa) and C. valdiviana (17 unique taxa) differed in structure and composition but shared 11 distinct taxa. Differences were found between fungal assemblages associated with C. valdiviana gut tracts and galleries. Fungal assemblages found in galleries and insect bodies of Gnathotrupes varied among species, seasons, and health conditions of the host crown. Our results also showed that the ophiostomatoid fungi Raffaelea spp. and yeast Cyberlindnera sp. were commonly found with Gnathotrupes spp. whereas Ambrosiozyma angophorae and Oidiodendron sp. were found with C. valdiviana. Species of the blue stain fungi Ophiostoma patagonicum, O. nothofagi, an unidentified Sporothrix sp. and Huntiella decorticans were found with both beetles and moths, and O. patagonicum was the most frequently isolated species. This is the first comprehensive study of microbiota isolated from Gnathotrupes spp. and C. valdiviana.