Comparative Analysis of Fungal Spore Flora Among Birds, Insects and Air in a Temperate Japanese Forest

Fungi play critical roles in ecosystem functioning, yet the mechanisms underlying their spore dispersal, especially via animal vectors, remain underexplored. We investigated the potential of birds and insects as fungal spore vectors in Japanese temperate forests by analysing fungal communities on the feathers of 14 bird species and within 158 insects collected from fungal fruiting bodies. Comparisons were also made with air samples collected from the surrounding forest (n = 124). Microscopy and next generation sequencing (NGS) revealed fungal spores on all bird feather samples, with Cladosporium and Penicillium most abundant when analysed microscopically, and identified 39 assigned fungal species across 381 operational taxonomic units (OTUs), with genera including both common environmental fungi and taxa that contain members with pathogenic potential. Fungal assemblages differed markedly between air and feather samples. Insects, particularly Drosophilidae and Phoridae, carried spores both externally and internally, with notable detection of mycorrhizal Thelephora aurantiotincta spores in Blattodea digestive tracts. Our findings highlight the significant and distinct roles of both birds and insects in dispersing a diverse array of fungi, with potentially important implications for ecosystem processes, public health and forestry.