Discovery of Gibellula floridensis in infected spiders and analysis of the surrounding fungal entomopathogen community

Abstract

Characterization of fungal spider pathogens has lagged far behind that of insect pathogens. Moreover, little is known about the ecological reservoirs and fungal insect pathogen communities around infection sites. Five infected spider corpses were identified in the tropical climate of north-central Florida, USA, and live fungal cultures were obtained from three of them. Multilocus molecular phylogenetic and morphological characterization revealed that one isolate was a new species of Gibellula, named G. floridensis, and the other two were isolates of Parengyodontium album. To investigate the insect fungal communities, samples from different habitats/trophic levels, including soil, litter, leaves, and twigs around the infection site, were collected and analyzed by ITS amplicon sequencing. These data indicate that the distribution of insect pathogens is widespread but distinct among habitats, with some variability across locations. The genera Metarhizium and Metacordyceps from Clavicipitaceae, Purpureocillium and Polycephalomyces from Ophiocordyceps, and Akanthomyces and Simplicillium from Cordycipitaceae were dominant. However, no sequences equivalent to Gibellula or Parengyodontium were detected even at the genus level. Possible explanations for these findings are discussed. These data highlight a novel discovery of fungal spider pathogens and raise broader questions regarding the environmental distribution and ecological niche of such host-specific pathogens.