Distribution and species diversity of trichomycete gut fungi in aquatic insect larvae in two Rocky Mountain streams
At least 20 species of Trichomycetes (Zygomycotina) were dissected from the hindguts and peritrophic membranes of larval Diptera (Simuliidae, Chironomidae), Ephemeroptera, and Plecoptera in two high-altitude streams, and the trichomycete species diversity in the two streams was compared. Periodic sampling of larvae over a 6-week summer period showed that some gut fungi are widely distributed in their respective host types, whereas other fungal species are more localized. Insect populations had infestations that varied from low to as high as 100% of the insects dissected, depending on the fungal species. There was no general increase over time, from early to late season, in fungal species diversity or percentage of larval infestation, nor were larvae in second- and third-order sites of one stream generally more infested than in a first-order site in that stream.