In this book internationally known experts provide a comprehensive view of current knowledge of social insect biology including much previously unpublished information. Particular emphasis is given to the relationships between social insects and humans; sections are devoted to economically important social insects, pollination, foraging, and the role of insects in ecosystems and agroecosystems. The authors also discuss communication, behavior and caste within insect colonies. A special section focuses on the neurobiology of social insects. A series of papers considers the presocial insects, which live in family groups but without caste differences. Also well represented are the fields of sociobiology and the origins and evolution of social behavior. The book will be valuable to agricultural scientists as well as to entomologists, sociobiologists, ecologists, ethologists, and natural historians. Endocrinologists and neurobiologists will also find important new material.

Here is a guide to the ecology of social insects. It is intended for general ecologists and entomologists as well as for undergraduates and those about to start research on social insects; even the experienced investigator may find the comparison between different groups of social insects illuminating. Most technical terms are translated into common language as far as can be done without loss of accuracy but scientific names are unavoidable. Readers will become familiar with the name even though they cannot visualize the animal and could reflect that only a very few of the total species have been studied so far! References too are essential and with these it should be possible to travel more deeply into the vast research literature, still increasing monthly. When I have cited an author in another author's paper, this implies that I have not read the original and the second author must take responsi bility for accuracy! Many hands and heads have helped to make this book. I thank all my colleagues past and present for their enduring though critical support, and I thank with special pleasure: E. ]. M. Evesham who fashioned the diagrams; ]. Free, D. J. Stradling and]. P. E. C. Darlington who supplied photographs; D. Y. Brian and R. A. Weller who were meticulous on the linguistic side; and G. Frith and R. M. Jones who collated the references. List of plates 1. Fungus combs of Acromyrmex octospinosus and Macrotermes michaelseni. 13 2. Mouthparts of larval Myrmica.

In this pathbreaking and far-reaching work George Oster and Edward Wilson provide the first fully developed theory of caste evolution among the social insects. Furthermore, in studying the effects of natural selection in generally increasing the insects' ergonomic efficiency, they go beyond the concentration of previous researchers on the physiological mechanisms of the insects and turn our attention instead to the scale and efficiency of the insects' division of labor. Recognizing that the efficiency of the insect colony is based on a complex fitting of the division of labor to many simultaneous needs, including those imposed by the distribution of resources and enemies around the nest, Professors Oster and Wilson are able to construct a series of mathematical models to characterize the agents of natural selection that promote particular caste systems. The social insects play a key role in the subject of sociobiology because their social organization is so rigid and can be related to genetic evolution. Because of this important consideration, the authors' work has consequences not only for entomology but also for general evolutionary theory.

Social Insects, Volume IV is the last installment of a four-volume treatise and is dedicated to the discussion on wasps and ants. Comprised of four chapters, this volume focuses on the sociality of various types of ants as their group has very diverse habits. The first chapter describes the general biology and behavior of social wasps and discusses the cyclical populations, nest associates, and communal defense of wasps. Chapter 2 introduces the broad and general overview of the biology of ants, including their behavior, food collection, and nest construction. Chapters 3 and 4 present the biology of army and fungus ants, respectively. This volume also explains how ants are defined and identified, including their colony composition and behavior. As with the previous volumes, this volume seeks to be of service to students, researchers, and scientists in various fields of research, particularly entomology, social biology, zoology, and biological science.

Evolution of Castes in Insects l BERNHARD RENSCH The evolution of organisms in the succession of generations has been primarilly achieved through the appearance of new hereditary variants with minor deviations along with the development of stable structures and functions. Harmful mutants were eradicated either immediately or in the subsequent generations through the process of natural selection while unharmful or advantageous ones usually survived. As this process continued, many new races and species developed which possessed structures and functions of a rational nature and which became increasingly independent from their environment. These evolutionary tendencies were also promoted through either geographical, ecological, physiological or genetical isolation of populations. In some phylogenetic lines, there occurred an increase in the number of cells due to additional cellular divisions in the morphogenesis of structures. This opened up the possibility for the development of the division of labour within cellular groups leading to more complicated and consequently more successful functions of tissues and organs. A further advancement in the adaptation of a species to its environment was made possible through specialization for certain functions of whole individuals or groups of individuals.