Evolution and Distribution of Trichomycete Gut Fungi in Arthropods

毛菌是一种共生真菌，专门生活在各种昆虫、甲壳类动物和千足类动物的内脏中。寄主和生境的多样性、所有科在世界范围内的分布以及某些属的洲际分布表明，这些真菌与节肢动物的关系非常古老。堪萨斯大学的Robert Lichtwardt博士试图了解毛菌是如何以及何时进化的，并与它们的节肢动物宿主一起在地理上分布。来自澳大利亚和新西兰的数据表明，一些真菌分类群可能至少在7000万至8000万年前在冈瓦纳有共同的祖先。将在南美洲南部寻找支持冈瓦纳南方毛菌起源的证据。对海洋、陆地和淡水节肢动物中其他肠道真菌的研究可能会提供证据，证明某些物种与宿主一起辐射了多长时间，以及在异域分布中扩散和变异的作用。毛滴菌属的系统发育分析有助于了解其进化和生物地理学，而来自世界不同地理区域的培养分离株的同工酶表型将提供一些物种变异性的信息。Harpellales的物种只生长在水生昆虫的幼虫阶段，将被研究，看看它们的繁殖体是否能与成虫一起传播。

Trichomycetes are commensalistic fungi that live obligately in the guts of various insects, crustaceans, and millipedes. The variety of host and habitats, the worldwide occurrence of all families, and the intercontinental distribution of some genera of these fungi indicate that the relationship with arthropods is very ancient. Dr. Robert Lichtwardt of the University of Kansas seeks to understand how and when trichomycetes evolved and became geographically distributed with their arthropod hosts. Data from Australia and New Zealand suggest that some fungal taxa may have had common ancestors on Gondwana at least 70-80 million years ago. Evidence to support the Gondwanan origin of austral trichomycetes will be sought in southern South America. Studies of other gut fungi in marine, terrestrial, and freshwater arthropods may provide evidence of how long certain species have been radiating with their hosts, and the roles of dispersal and vicariance in allopatric distributions. Phylogenetic analysis of trichomycete genera will assist in understanding their evolution and biogeography, and isozyme phenotypes of cultured isolates from different geographical regions of the world will provide some information on species variability. Harpellales, whose species grow only in larval stages of aquatic insects, will be studied to see whether or not their propagules can disperse phoretically with adults.