The mycobiomes of sympatric native and invasive paper wasp species

Many insects are associated with prolific fungal symbionts that are established plant pathogens. However, few insects have been studied for their full associated fungal community. This is particularly true for invasive insects that construct nests—potentially novel fungal habitats. Paper wasps are a group of globally distributed, social hymenoptera that construct nests annually out of macerated plant material and saliva. Disparate studies have suggested that paper wasp nests contain culturable fungi, including a previously uncharacterized fungal species, but the full diversity of these communities remains unexplored. We extend these preliminary studies by investigating the fungal diversity of the bodies and nests of congeneric, sympatric paper wasps in Massachusetts— the native Polistes fuscatus, and the invasive P. dominulus. We measured the fungal abundance and diversity associated with these wasps across multiple nesting locations to investigate how location and species correlate with fungal community patterns. Fungal communities were assessed qualitatively and quantitatively using culture-dependent methods to investigate fungal abundance, specific fungal isolates’ identities, and viability. Additionally, we used culture-independent methods, such as light microscopy and high-throughput sequencing of ITS rDNA, to establish total fungal diversity and abundance. Contrary to the general understanding that these nest habitats are constructed solely out of macerated paper and saliva, our results indicate that paper wasp nests and bodies contain an abundance of diverse, viable fungi. These nests and bodies represent reservoirs of fungi, suggesting that paper wasps are an unexplored contributor to fungal dispersal—including fungi that are potential plant pathogens and symbionts.