Search

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The environmental conditions governing symbioses are poorly known in aquatic systems. Stream conditions associated with the distribution of the black fly (Simuliidae) midgut symbiote Harpella were investigated in southern Alabama and Mississippi streams. Stream conditions that were most useful in predicting the distribution of Harpella spp. in the study area were dissolved oxygen and water temperature. Presence of Harpella species in streams was associated with higher dissolved oxygen and decreased water temperature compared to streams where Harpella spp. was absent. Stream conditions associated with the distribution of Harpella spp. in other regions of the world vary according to conditions other than those elucidated here, indicating that geography, host species, and stream conditions play important roles in the spatial distribution of Harpella species. [Copyright &y& Elsevier]