Stag beetle (Coleoptera: Lucanidae) females have mycangia that harbor xylose-fermenting yeasts such as Scheffersomyces Kurtzman & M. Suzuki species (Debaryomycetaceae), which are transmitted vertically and transstadially. The associations between stag beetles and yeasts were thought to be species-specific. This research investigates Prosopocoilus astacoides blanchardi (Parry, 1873) (Coleoptera: Lucanidae) in Taiwan. Yeasts were cultured from wild, adult females' mycangia and ovaries, from lab-reared larval midguts and hindguts, and from larval tunnels and cocoon walls. Species identifications and abundance calculations were done. Mycangia contained multiple species, including Meyerozyma guilliermondii (Wick.) Kurtzman & M. Suzuki (Debaryomycetaceae) and Candida spp. (Debaryomycetaceae). Larval guts and tunnels were dominated by strains of Scheffersomyces and Spathaspora N. H. Nguyen, S. O. Suh & M. Blackw. (Debaryomycetaceae). Yeasts isolated from females, larvae, and the cocoon walls varied greatly. The results suggest that the associations with yeast symbionts in P. a. blanchardi are not species-specific and vertical transmission of yeasts may not necessarily be essential in this species.