Lloyd Knutson and Jean-Claude Vala
Cambridge University Press, New York
2011; 506 pages plus DVD
ISBN: 978-0-521-86785-6
Price: $150.00 (hard cover)

“One of the most prominent characters of the Diptera is their stupidity.”

Quoting Delpino (1869) to begin the chapter on host/prey finding, Knutson and Vala spend the book debunking Delpino’s notion. Most of the chapters begin with an interesting and appropriate quote or two. For example, the chapter on habitats, guild structures, and bio-indicators commences with “Flee the advice of those speculators whose reasons have not been confirmed by  experience” (Leonardo da Vinci). Delpino did not have access to the vast majority of papers published on sciomyzid biology (more than 99% were published after 1953), but if he had read this synthesis of sciomyzid knowledge, perhaps the “experience” that da Vinci was referring to would have prevented Delpino from branding Diptera as “stupid.”

This comprehensive tome covers the biology of snail-killing flies in amazing detail. For a small family of fewer than 550 species, this dipteran lineage has been extensively studied, with over 1,800 papers published in 16 languages. The authors have done a tremendous job synthesizing these and other works into a single book, compiling information from the vast majority of sciomyzid literature, making information readily available that was published in difficult-to-obtain journals and/or in other languages. Combined, the authors have over 70 years of research experience studying sciomyzids, have authored over 160 papers, and have collaborated with practically every researcher to make significant contributions to sciomyzid knowledge in the last five decades. These experiences have given Knutson and Vala a unique perspective on most aspects of sciomyzid research, which are elegantly synthesized. Furthermore, every sciomyzid specialist in the world provided input at some stage of the manuscript, making it one of the most thoroughly reviewed books of its kind.

The book begins with an introductory chapter defining how terms such as “parasitoid” and “apotypic” are applied to snail-killing flies and gives a general overview of their molluscan hosts/prey. The next two short chapters summarize the natural enemies of molluscs, focusing mainly on insects other than sciomyzids. These chapters set the stage for the remainder of the book by illustrating how few insect lineages other than sciomyzids are malacophagous (mollusc-feeding) and how little is known about the malacophagous behaviors in these lineages as compared to sciomyzids. Perhaps the most important contribution in these early chapters is the authors’ recognition of 11 categories of malacophagy across Diptera. This classification could be used as a starting point for anyone using modern phylogenetic methods to study the evolution of malacophagy in this diverse insect order.

Chapters 4-14 cover most known aspects of sciomyzid biology, with chapters on life cycles, host/prey finding and preferences, feeding behavior, competition, phenology, reproduction and development, natural enemies, defense mechanisms, population dynamics, and the roles played by morphological and physiological characteristics. These 240 pages integrate the major findings from this large body of literature, and illustrate those findings with hundreds of figures and tables from these studies. In the life cycles chapter, the authors present an updated version of their classification of behavioral groups (Knutson and Vala, 2002) and use aspects of this classification (e.g., habitat, host/prey type) to organize and synthesize the information presented in subsequent chapters, providing broad analyses and new ideas in many cases.

The next three chapters cover systematics, zoogeography, and evolutionary considerations. Illustrated keys to sciomyzid genera (larvae and adults) are presented for each of the major biogeographic regions of the world with additional keys to puparia for the Nearctic and Palaearctic regions. It is a bit unfortunate that this book was published before two manuscripts containing moderately comprehensive molecular sciomyzid phylogenies were completed. As a result, some of the conclusions in the chapters on host/prey use and evolutionary considerations rely on phylogenies built from analyses of morphological/behavioral data containing many relationships with little nodal support. Utilization of these soon-to-be-published phylogenies could have put some of these evolutionary conclusions on firmer ground. However, the book also contains a wealth of previously unpublished information. For example, larval morphological characters scored for the major sciomyzid clades are presented in the systematics chapter; most of these have never been phylogenetically analyzed. Therefore, while the authors’ evolutionary inferences are not based on well-supported trees, they make information available that could improve future phylogenetic analyses.

The remaining chapters cover the use of sciomyzids in biological control of snails, a history of sciomyzid research, and the methods used in sciomyzid investigations. Anyone interested in collecting and rearing sciomyzids would find most of what they need to know in the methods chapter. The accompanying DVD contains a ≈15 minute film produced in the 1970s by C.O. Berg (Cornell University) who, together with his graduate students (Knutson being one), have produced hundreds of sciomyzid publications. This film was made largely to highlight the potential use of snail-killing flies as biological control agents in areas where their prey are intermediate hosts of trematodes that cause schistosomiasis and fascioliasis in humans and cattle. It includes beautiful footage of sciomyzid larvae attacking and killing snails and parasitoid wasps ovipositing into and emerging from sciomyzid pupae.

This book is not just for sciomyzid biologists; rather, it is for anyone integrating biological information for a monophyletic lineage. However, the more closely related to Diptera these taxa are, the more relevant the information will be. Because sciomyzids are so well known biologically (38% have known larval feeding habits), the approach the authors take towards organizing this large body of knowledge is instructive. For example, their classification of behavioral and phenological groups in Sciomyzidae and malacophagy in Diptera could be used as a model for studies of other lineages. While the authors admit that “much of this book is eighteenth century biology from a twenty-first century perspective,” L.V. Knutson (pers. comm.) has expressed interest in including more modern approaches to biological studies in a second edition. However, the authors have nothing for which to apologize. It is my opinion that this beautifully compiled work will serve as the sciomyzid “Bible” for many years to come, being a valuable reference to anyone interested in biological, ecological, and evolutionary studies of Diptera.

References Cited

Delpino, F. 1869. Ulteriori osservazioni sulla dicogamia nel regno vegetale. Parte 2. Atti. Soc. Ital. Sci. Nat. Milano 12: 314.

Knutson, L.V., and J.-C. Vala. 2002. An evolutionary scenario of Sciomyzidae and Phaeomyiidae (Diptera). Ann. Soc. Entomol. Fr. 38: 145-162.

Eric Chapman
Department of Entomology
University of Kentucky
Lexington, KY 40546
E-mail: ericgchapman@gmail.com

American Entomologist
Vol. 58, No.4, Winter 2012