In The Descent of Man, Charles Darwin proposed that an ant’s brain, no larger than a pin’s head, must be sophisticated to accomplish all that it does. Yet today many people still find it surprising that insects and other arthropods show behaviors that are much more complex than innate reflexes. They are products of versatile brains which, in a sense, think. Fascinating in their own right, arthropods provide fundamental insights into how brains process and organize sensory information to produce learning, strategizing, cooperation, and sociality. Nicholas Strausfeld elucidates the evolution of this knowledge, beginning with nineteenth-century debates about how similar arthropod brains were to vertebrate brains. This exchange, he shows, had a profound and far-reaching impact on attitudes toward evolution and animal origins. Many renowned scientists, including Sigmund Freud, cut their professional teeth studying arthropod nervous systems. The greatest neuroanatomist of them all, Santiago Ramón y Cajal—founder of the neuron doctrine—was awed by similarities between insect and mammalian brains. Writing in a style that will appeal to a broad readership, Strausfeld weaves anatomical observations with evidence from molecular biology, neuroethology, cladistics, and the fossil record to explore the neurobiology of the largest phylum on earth—and one that is crucial to the well-being of our planet. Highly informative and richly illustrated, Arthropod Brains offers an original synthesis drawing on many fields, and a comprehensive reference that will serve biologists for years to come.

The definitive textbook and reference guide to the arthropod brain. The material is arranged logically in three sections. Section I, on evolution, includes a discussion on the presence of a fourth component, tetrocerebrum in the insect brain in addition to the three commonly recognized parts, and the evolutionary trends in the central and mushroom bodies in major arthropod groups. A section on structure and function includes detailed ultrastructural studies of the brain as well as studies of the mechanoreceptory centers, peripheral sensory coding and sensilla function, and antennal information processing. Also examines biochemical topics such as bioamines and mucosubstances, their respective roles in brain function, and various techniques of brain research.

Most neurobiological research is performed on vertebrates, and it is only natural that most texts describing neuroanatomical methods refer almost exclusively to this Phylum. Nevertheless, in recent years insects have been studied intensively and are becoming even more popular in some areas of research. They have advantages over vertebrates with respect to studying genetics of neuronal development and with respect to studying many aspects of integration by uniquely identifiable nerve cells. Insect central nervous system is characterized by its compactness and the rather large number of nerve cells in a structure so small. But despite their size, parts of the insect eNS bear structural comparisons with parts of vertebrate eNS. This applies particularly to the organization of the thoracic ganglia (and spinal cord), to the insect and vertebrate visual sys tems and, possibly, to parts of the olfactory neuropils. The neurons that make up these areas in insects are often large enough to be impaled by microelectrodes and can be injected with dyes. Added to advantages of using a small eNS, into which the sensory periphery is precisely mapped, are the many aspects of insect behaviour whose components can be quan titized and which may find both structural and functional correlates within clearly defined regions of neuropil. Together, these various features make the insect eNS a rewarding object for study. This volume is the first of two that describe both classic and recent methods for neuroanatomical research on insect eNS.

More than two thirds of all living organisms described to date belong to the phylum Arthropoda. But their diversity, as measured in terms of species number, is also accompanied by an amazing disparity in terms of body form, developmental processes, and adaptations to every inhabitable place on Earth, from the deepest marine abysses to the earth surface and the air. The Arthropoda also include one of the most fashionable and extensively studied of all model organisms, the fruit-fly, whose name is not only linked forever to Mendelian and population genetics, but has more recently come back to centre stage as one of the most important and more extensively investigated models in developmental genetics. This approach has completely changed our appreciation of some of the most characteristic traits of arthropods as are the origin and evolution of segments, their regional and individual specialization, and the origin and evolution of the appendages. At approximately the same time as developmental genetics was eventually turning into the major agent in the birth of evolutionary developmental biology (evo-devo), molecular phylogenetics was challenging the traditional views on arthropod phylogeny, including the relationships among the four major groups: insects, crustaceans, myriapods, and chelicerates. In the meantime, palaeontology was revealing an amazing number of extinct forms that on the one side have contributed to a radical revisitation of arthropod phylogeny, but on the other have provided evidence of a previously unexpected disparity of arthropod and arthropod-like forms that often challenge a clear-cut delimitation of the phylum.

The arthropods contain more species than any other animal group, but the evolutionary pathways which led to their current diversity are still an issue of controversy. Arthropod Relationships provides an overview of our current understanding, responding to the new data arising from sequencing DNA, the discovery of new Cambrian fossils as direct evidence of early arthropod history, and developmental genetics. These new areas of research have stimulated a reconsideration of classical morphology and embryology. Arthropod Relationships is the first synthesis of the current debate to emerge: not since the volume edited by Gupta was published in 1979 has the arthropod phylogeny debate been, considered in this depth and breadth. Leaders in the various branches of arthropod biology have contributed to this volume. Chapters focus progressively from the general issues to the specific problems involving particular groups, and thence to a consideration of embryology and genetics. This wide range of disciplines is drawn on to approach an understanding of arthropod relationships, and to provide the most timely account of arthropod phylogeny. This book should be read by evolutionary biologists, palaeontologists, developmental geneticists and invertebrate zoologists. It will have a special interest for post-graduate students working in these fields.

In this volume outstanding specialists review the state of the art in nervous system research for all main invertebrate groups. They provide a comprehensive up-to-date analysis important for everyone working on neuronal aspects of single groups, as well as taking into account the phylogenesis of invertebrates. The articles report on recently gained knowledge about diversification in the invertebrate nervous systems, and demonstrate the analytical power of a comparative approach. Novel techniques in molecular and developmental biology are creating new perspectives that point toward a theoretical foundation for a modern organismic biology. The comparative approach, as documented here, will engage the interest of anyone challenged by the problem of structural diversification in biology.

Insect Physiology is currently undergoing a revolution with the increased application of molecular biological techniques to investigate the molecular mechanisms underlying the physiological responses to insect cells. Advances in Insect Physiology has instituted a commitment to the publication of high quality reviews on molecular biology and molecular genetics in areas where they provide an increased understanding of physiological processes in insects. Volume 24 is the first to include such specifically sought articles.