Larvae of the Solitary Bee Epicharis bicolor Are a Rich Source of Yeasts, Including Four Novel Species of the Genera Starmerella, Wickerhamiella and Zygoascus

In this study, we sampled 26 larvae of the ground-nesting solitary bee Epicharis bicolor and isolated four candidate novel yeast species belonging to the genera Starmerella, Wickerhamiella, and Zygoascus, which were the most prevalent taxa. The bee E. bicolor collects floral oils from specialized oil-secreting glands, known as elaiophores, predominantly found in Malpighiaceae flowers. Based on sequencing of the ITS and D1/D2 regions of the rRNA gene as well as taxogenomic analyses, the novel yeast species are described here as Starmerella fernandosilveirae f.a., sp. nov. (CBS 19575; MycoBank MB864887), Zygoascus agrestis sp. nov. (CBS 19580; MycoBank MB864888), Zygoascus riopretensis f.a., sp. nov. (CBS 19579; MycoBank MB864958), and Wickerhamiella solitaria f.a., sp. nov. (CBS 19578; MycoBank MB 864959). Our results suggest that solitary bees could represent a rich source of novel yeast species. In addition, our data do not support the proposed genera Casaregolazyma and Entelexis, and four Candida species are formally reassigned to the genera Starmerella and Zygoascus.