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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.
Inhaltsverzeichnis
1 Introduction.- A. General.- B. Terrestrial Arthropods.- C. Arthropod Structure.- D. Water.- 2 Water Content.- A. Total Body Water.- B. Water Reserves.- C. Location of Water Reserves.- D. Resistance to Desiccation.- 3 Water Loss-Cuticular.- A. Introduction.- B. Transpiration and Integumental Structure.- C. Ecological Implications.- D. Conclusions.- 4 Water Loss-Respiratory.- A. Introduction.- B. The Tracheal System of Insects.- C. Control of Respiratory Water Loss.- D. Spiracular Control Mechanisms in Dragon-Flies and Other Insects.- E. Intermittent Carbon Dioxide Release.- F. Respiratory and Cuticular Water Loss Compared.- G. Respiratory Water Loss in Arthropods Other Than Insects.- H. Conclusions.- 5 Water Loss by Evaporative Cooling.- A. Introduction.- B. Evaporative Cooling in Laboratory Experiments.- C. Evaporative Cooling in the Field.- D. Conclusions.- 6 Excretion and Osmoregulation.- A. Introduction.- B. Elimination of Nitrogenous Waste.- C. Osmotic and Ionic Regulation.- D. Hormonal Control of Water Balance.- 7 Uptake of Liquid Water.- A. Uptake of Water as a Result of Feeding.- B. Uptake of Water by Drinking.- C. The Question of Absorption Through the Cuticle.- D. Special Organs for Water Absorption.- E. Conclusions.- 8 Metabolic Water.- A. Introduction.- B. The Question of Regulation.- C. Respiratory Quotient and Metabolic Water in Locusta.- D. Metabolic Water in Flying Locusts and Aphids....- E. Conclusions.- 9 Absorption of Water Vapour.- A. Introduction.- B. Distribution of the Faculty Among Arthropods.- C. Limiting Conditions.- D. The Energetics of Absorption.- E. The Site of Absorption.- F. The Rate of Absorption.- G. Possible Mechanisms.- H. Conclusions.- 10 Water Balance in Eggs.- A. Structure.- B. Water Loss by Evaporation.- C. Water Uptake.- D.The Control of Water Uptake.- E. Uptake by Eggs of the Locust Chortoicetes.- F. Conclusions.- 11 Conclusions.- A. General.- B. The Components of Water Loss.- C. The Components of Water Gain.- D. Water Balance.- E. Osmotic and Ionic Regulation.- F. The Water Affairs of Eggs.- G. Water Balance and the Whole Animal.- H. Concluding Remarks.- References.- General Index.
