MINUTE MYCOLOGICAL MYSTERIES - THE INFLUENCE OF ARTHROPODS ON THE LIVES OF FUNGI

Fungi are commonly associated with arthropods in a variety of habitats. Many species of ascomycetes have morphological features, including evanescent asci and passively discharged ascospores, that facilitate ascospore dispersal by arthropods. Based on small subunit ribosomal DNA sequence analysis several lineages appear to have been derived independently by convergence. One monophyletic lineage includes Pyxidiophora and Rickia (Laboulbeniales). Evolution of Laboulbeniales from a Pyxidiophora-like ancestor is viewed perhaps as life cycle simplification to reduce excessive fine-tuning of the life cycle to two disparate hosts and to reduce habitat patchiness. The minute arthropod-borne fungi, Thaxteriola, Endosporella, Laboulbeniopsis, Coreomycetopsis, Amphoropsis, Myriopodophila, and Entomocosma, are included in the Pyxidiophora-Rickia lineage as part of the Pyxidiophora life cycle or as independent organisms on the basis of morphology and life history studies.