Preface to the Revised Edition

Research on trichomycete gut fungi since 1986, when the first edition of this book was published, has yielded a wealth of new data and information, thanks to the contributions of many researchers. New experiments and methodologies in the laboratory together with fairly extensive field work have resulted in a better—though still incomplete—understanding of interactions of these fungi and their hosts, and better insight into their ecology, diversity, and species richness. New theories on the relationships of trichomycetes to other groups of fungi and among themselves has resulted in some major revisions at various taxonomic levels. The original monograph included 39 genera and 131 species. In the past 15 years an additional 16 new genera and more than 100 new species have been discovered and described, in part due to explorations in new geographic regions, especially in the Southern Hemisphere. The implication resulting from field studies during the past decade and a half is that only a small fraction of extant trichomycetes and host types and their distribution worldwide are known.

We now also realize that some of these fungal symbionts of arthropods are not as benign as they were believed to be. Most significant is the discovery that a few (perhaps all?) Harpellales, which live in the guts of aquatic insect larvae, from time to time invade the developing ovaries of the host and produce cystlike bodies that replace the eggs (see Chapter 8). This affects the fitness of the hosts, and it also provides a mechanism by which the flying adults can disperse the fungi by "ovipositing" the cysts upstream or in new drainages. Research by Horn (see Chapter 9) has also provided a better understanding of the role the hosts play in bringing about extrusion (germination) of sporangiospores from ingested trichospores, thus limiting development of the fungi within the gut of particular host types. This, and other evidence presented in this monograph, attest to the high degree of adaptation that has evolved between fungi and arthropods, apparently through co-evolutionary processes.

Evidence obtained since 1986 confirms that one of the orders of trichomycetes, the Amoebidiales, are protists and consequently are not monophyletically related to the fungal orders Harpellales, Asellariales, and Eccrinales—the true Trichomycetes (see Chapter 12). Nonetheless, we continue to include Amoebidiales in this revised treatise for historical reasons (see Chapter 1), as well as their intimate association with some Harpellales, and because they continue to be found and studied by investigators of the gut fungi. The use of trichomycetes with a lower case t is therefore used to refer to a group of arthropod symbionts in the same sense that we use fungi to conveniently encompass a polyphyletic assemblage of microorganisms that have some features in common.

Publication on the Internet allows us to use several procedures that would be impractical, impossible, or too expensive to incorporate into hard copy book form. Virtually all fungal species and some additional hosts types have now been illustrated with photographs or line drawings. Links have been made to interactive keys and a rather extensive interactive database. A link is also available to the worldwide literature on trichomycetes, whether or not all of the references are specifically cited in the text. Importantly, the flexibility of Internet publication will allow us to update the monograph whenever necessary by adding new taxa and biological information, and new literature citations.

Our research since 1986 has been supported by several grants from the National Science Foundation. We are especially indebted to the latest award, DEB 9521811, from the NSF PEET program (Partnerships for Enhancing Expertise in Taxonomy) to Robert W. Lichtwardt, Principal Investigator, and Leonard C. Ferrington, Jr., Co-Principle Investigator, which has allowed us to conduct research culminating in the publication of this monograph on the Internet.

The web page www.nhm.ku.edu/~fungi lists the personnel who have been involved in this research endeavor. They include the PI and Co-PI; co-authors Matías J. Cafaro and Merlin M. White; Postdoctoral Research Associates Roger D. Grigg, J.K. Misra, and Alexandra M. Gottlieb; trainees Claudia López Lastra, María Gabriela Mazzucchelli, Amy E. Slaymaker, and Barbara L. Hayford. All have made substantial contributions to our understanding of the biology and evolution of Trichomycetes. We are also indebted to collaborators Kerry L. O’Donnell and Stephen W. Peterson, and the many other biologists cited throughout this publication whose investigations have made the monograph more complete than it otherwise would have been.

Contents of this monograph, including errors and omissions, are the responsibility of the three authors. Suggestions, corrections, and comments can be addressed to licht@ku.edu.

August 2001