Currently indistinguishable from M. cicadina outside of genetic analysis, as both are a parasitic fungi that infects either 13 or 17 year periodic cicadas. While the host is still alive, the fungi replaces the hosts abdomen with a spore 'plug' that acts as a source of transmission to other non-infected cicada through copulation. Spores of M. cicadina are capable of germinating and infecting cicadas at as little as one year but may remain dormant for either 13 or 17 years before becoming active. This synchronous cycle corresponds with local periods of cicada emergence. M. cicadina is thought to be the only pathogen that coincides with its host's 17-year life cycle; because of this it is considered to have the longest life cycle of any fungus. M. cicadina resting spores do not require a dormant period: They are capable of germinating and infecting periodical cicadas after less than a year from their introduction into soil. Cicadas are believed to become infected by fungal spores as the nymphs dig tunnels to the soil surface days before their emergence as adults.