Bionomics, axenic culture, and substrate-related variation in trichospores of Smittium megazygosporum

Abstract

Smittium megazygosporum, previously known only from southern France, was collected in South Carolina, USA, indicating a Holarctic distribution. An axenic culture was obtained from a black fly (Diptera, Simuliidae) that was probably a spurious host. The holdfast, with a refractive secreted-material base, is described for the first time, and verticillate branching in vegetative growth is confirmed. Zygospores, the largest known for the genus, were found in chironomids co-occurring with the black fly host. Trichospore sizes varied significantly depending on the host and medium in which they grew. This host-related size variation could have consequences for species diagnoses of Smittium that often are based on trichospore size.

Key Words:

• Chironomidae
• fungi
• Harpellales
• Simuliidae
• symbiosis
• Trichomycete
• Zygomycota