Michael D. Greenfield
Oxford University Press, Oxford, U.K.
2002, 432 pages
Price: $44.50
ISBN: 0-19-513452-4

The millions of species of arthropods signal to one another using an enormous variety of chemical, vibrational, and light signals in an equally enormous variety of environments and contexts. The amount of research on the nature and evolution of these signals has grown rapidly and has steadily incorporated new areas of biology, chemistry, and physics—ranging from pheromone chemistry to theories of signal reliability and redundancy to the molecular basis of signal transduction and to the ecological contexts within which these signals are given.

Despite the bewildering variety of arthropod signals, there is underlying simplicity, and there are unifying concepts that allow us to see the broader picture and to recognize patterns. Signals are used in a few major behavioral contexts, such as courtship and mating. Arthropods use a small set of modalities for signaling, and for every signal there is a standard set of questions to ask—even though the list of questions and the technology that makes it possible to answer them are constantly expanding.
This is the central message of Signals and Receivers, a book from Michael D. Greenfield, who is a behavioral ecologist specializing in sexual selection and insect communication. The book is intended to be a broad and unifying introduction to the subject of arthropod communication, and in this respect it succeeds admirably.

The book is organized into seven chapters. A brief introduction is followed by a concise exposition of basic signal theory in Chapter 2. Then comes the heart of the book in Chapters 4–7, respectively on chemical, sound and vibrational, and light signals—the major modalities used by arthropods. Each type of signal is discussed in relationship to the appropriate sensory channel: the olfactory, mechanical, and visual channels, respectively. The final two chapters deal with the selective pressures and mechanisms of signal evolution.

The central three chapters are long: Chapter 4 alone extends to 120 pages, or just over 40% of the text. The decision to build long chapters, each focused on one channel, reinforces the unifying and simplifying theme of the book; the very simplicity of the table of contents gives the reader encouragement to proceed.

This encouragement is justified by the consistent style and treatment throughout. In case after case, Greenfield reviews the physics of the signal and how it propagates, how information is encoded and extracted, the physiological and molecular bases of signal production and perception, and the behavioral contexts and strategies of signalers and receivers. The details vary, but the general problems and their solutions recur time and again. Always present is the problem of small animals coping with the challenges of orienting, navigating, and searching for food and mates, often for long distances in complex environments.

This is a very conceptual book. Greenfield’s objective is a discussion and analysis of systems, not an exhaustive review of research. Accordingly, many details are lacking, and although this contributes to the readability of the book, it occasionally left me wanting another fact or at least a pointer to the source of that fact. Despite the long list of references, occasional statements are made for which references were clearly called for, and this was distracting.

The final two chapters raise and discuss some important evolutionary issues. These discussions are interesting and well presented, but after the deliberate pace of the rest of the book, they seem much too short and the book ends abruptly with no real conclusion.

In only one respect was the book was a notable failure: it did nothing to alleviate my insomnia. Instead, it is packed with incentives to remain awake. On nearly every page there is an intriguing example from nature, a clear explanation, a thoughtful and novel commentary, a thread leading in an unexpected direction. Greenfield moves smoothly and effortlessly, for example, from the design of receptors to the vagaries of the habitat to the microscopic flows of air over sensilla to the molecular basis of transduction to the interest of the U.S. Department of Defense in moth pheromone research. The drive to organize a broad range of knowledge into a unified, comprehensible scheme is combined with an equal fascination with the details of how each particular system works and the problems that needed to be solved to make it work. This makes for rewarding reading from start to finish.

This book provides an excellent introduction and overview for anyone interested in animal communication. I expect that even active researchers in this field will enjoy and benefit from Greenfield’s synthesis, and for someone entering the field, this would be a good place to start. It will make a great reference for teachers. The book is probably not suitable for an undergraduate course, but would be a terrific choice for a graduate seminar in which, say, the first half of the semester was devoted to this book and the second half to readings from the primary literature. I expect that Signalers and Receivers will occupy a significant place on my bookshelf and many others for at least the next decade.

Samuel Beshers
Department of Entomology
University of Illinois
505 S. Goodwin Ave.
Urbana, IL 61801
American Entomologist
Vol. 50, No.1, Spring 2004