Water Balance In Land Arthropods

Introduction; Water content; Water loss-cuticular; Water loss-respiratory; Water loss by evaporative cooling; Excretion and osmoregulation; Uptake of liquid water; Metabolic water; Absorption of water vapour; Water balance in eggs; Conclusions; References; General index.

Writers on arthropod water relationships range from bio physicists and biochemists to population ecologists-a fact that gives cause to wonder whether the field is already too heterogeneous to be written about in a single book by a single author. I have partly avoided the problem by concentrating largely on physiological mechanisms and by omitting most aspects of behavioural regulation and most aspects of heat balance and body temperature, except when these impinge directly on water balance. Even within this limited field there has been a lot of work during the past twenty years, as a result of which some problems have been solved (or at least more clearly defined), and many others have been opened up. On the whole there has been a welcome change to a more rigorous experimental approach and it is now possible for water balance people to state their problems in physiological terms. Good progress has been made towards understanding the mechanisms involved in nearly all avenues of water uptake and loss, although problems indeed remain. The cuticle has yielded part of its secrets to electron micrography, but ex ploration by means oflipid biochemistry among other techniques is necessary for a real understanding of cuticle permeability.

This book is intended as a textbook for 3rd year undergraduate students, as well as postgraduate students. It comprises a review of the current opinion regarding the evolution and adaptation of terrestrial arthropods, beginning with the paleontological, embryological, morphological and physiological evidence. The implication of size is then considered in relation to life on land. A discussion of insect phylogeny and the origin of flight is followed by an account of evolutionary trends in reproduction. Further chapters cover adaptations to extreme environments, dispersal and migration, defensive mechanisms and, finally, present arguments for the success of the terrestrial arthropods in general.

This text brings together fundamental information on insect taxa, morphology, ecology, behavior, physiology, and genetics. Close relatives of insects, such as spiders and mites, are included.

Already as a young boy, I used to walk with my late father, an ardent naturalist at heart, though to his regret not by profession, in the fields and woods on Mt. Carmel where we lived. My father, being largely an amateur ornithologist but also loving other vertebrates, was less inter ested in the little creatures(-the invertebrates) so abundant under stones. These were, more often then not, isopods which are particularly abundant in the Mediterranean region of northern Israel, and therefore not difficult to encounter (Fig. 1). Thus, my interest in the terrestrial isopods started at an early stage. Many years later, after graduating from the Hebrew University, Jerusalem, I worked as an assistant to my late friend and colleague, Professor Michael Costa, at the Teachers Seminary in Oranim. One day I found on my desk a copy of Edney's (1954) paper: Woodlice and the land habitat, which my friend left for me knowing of my interest in this group. Therefore, due to the stimulus of Edney's paper, and the many interesting questions it raised in my mind, I developed a lifelong interest in this amazing crustacean group. My research in the ecophysiology of this group followed to a large extent the directions formulated by Edney and Cloudsley-Thompson whose name will be mentioned throughout this book. I am also indebted to the many stimulating discussions with my friends and colleagues C. S. Crawford, K. E. Linsenmair, and E.

The theme of this book is the invasion of land by animal lines which originated in aquatic environments. It brings together physiological and ecological evidence to show both the likely routes taken out of the sea by the aquatic ancestors of terrestrial animals and the changes in structure and function associated with these routes. The author takes an ecophysiological approach, and by using representative examples, provides a novel background against which both the terrestrial adaptations of individual species and the make up and function of terrestrial ecosystems can be considered. Dr Little is the author of the highly acclaimed book The Colonisation of Land, which discusses the phylogeny and physiology of terrestrial and semi-terrestrial animals. The Terrestrial Invasion takes a fresh approach and provides an excellent introduction to the origins of land animals suitable for ecologists, physiologists and evolutionary biologists.

Ecophysiology of Desert Arthropods and Reptiles starts with a new classification of the world's deserts, based upon the type of precipitation and the effect on their faunas of arthropods and reptiles. This is followed by an account of microclimates and the avoidance of environmental extremes. Whereas thermoregulation is primarily behavioural, responses to water shortage are largely physiological. Seasonal activity and phenology are described, adaptations for burrowing, the avoidance of enemies, and defence, are also outlined. A comparative account of interspecific relationships, feeding specializations, and species diversity in the two taxa is described. The purpose of the book is to provide a new and up-to-date analysis that will stimulate further research along these lines.

Insects as a group occupy a middle ground in the biosphere between bacteria and viruses at one extreme, amphibians and mammals at the other. The size and general nature of insects present special problems to the student of entomology. For example, many commercially available instruments are geared to measure in grams, while the forces commonly encountered in stUdying insects are in the milligram range. Therefore, techniques developed in the study of insects or in those fields concerned with the control of insect pests are often unique. Methods for measuring things are common to all sciences. Advances sometimes depend more on how something was done than on what was measured; indeed a given field often progresses from one technique to another as new methods are discovered, developed, and modified. Just as often, some of these techniques find their way into the classroom when the problems involved have been sufficiently ironed out to permit students to master the manipulations in a few laboratory periods. Many specialized techniques are confined to one specific research laboratory. Although methods may be considered commonplace where they are used, in another context even the simplest procedures may save considerable time. It is the purpose of this series (1) to report new developments in methodology, (2) to reveal sources of groups who have dealt with and solved particular entomological problems, and (3) to describe experiments which may be applicable for use in biology laboratory courses.