Seasonality and host usage of trichomycetes in larval black flies (Diptera: Simuliidae) of southern Alabama, USA

Larval black flies were collected monthly from streams in southern Alabama and assayed for the presence of gut fungi (trichomycetes). Eight trichomycete species were found, each showing seasonality and specific host usage. Trichomycete taxa collected were Genistellospora homothallica, Harpella melusinae, Harpella sp. 1, Pennella hovassi, Pennella simulii, Pennella sp. 1, Simuliomyces microsporus, and Smittium brasiliense, from the hosts Simulium decorum, Simulium jonsei, Simulium tribulatum, and Simulium ubiquitum. Seven trichomycete species were collected in the spring, summer (4), fall (2), and winter (4). S. ubiquitum hosted all 8 species of trichomycetes, S. jonsei (3), S. decorum (3) and S. tribulatum (2). Our results indicate that trichomycetes occupy a restricted subset of potential hosts and vary in prevalence according to season, independent of host prevalence.