Introduction to the Study of Animal Populations

In revising this book I have tried to bring the theory of environment up to date in the light of certain important criticisms that have appeared since 1961, especially in papers by T. O. Browning and D. A. Maelzer, and in the light of experience gained while using the book as a text for an undergraduate course in population ecology in the University of Adelaide. As a consequence the order in which the argument is pre­ sented has been altered. Some new material has been introduced to expand the discussion of certain topics, especially resources, pathogens, aggressors and territorial behaviour. But the general approach to the subject and the general theory remains very much the same as in the first edition. I am grateful to Professor F. Fenner and Dr F. N. Ratcliffe and to Cambridge University Press for permission to reproduce Fig. 5.04; to Professor D. O. Chitty and the Ecological Society of Australia for permission to reproduce Fig. 5.05 (with minor modifications); Fig. 3.03 has been modified from a figure in a paper by H. G. Andrewartha and T. O. Browning first published in the Journal of Experimental Biology. Adelaide, 1970 H. G. A. xi Preface to the First Edition My interest in animal ecology was first aroused by reading Elton's Animal Ecology. His definition of the scope of ecology which I quote in section 1.0 is still the best that I have met.

I: Theory.- 1. The history and scope of ecology.- 1.0 Introduction.- 1.1 Population ecology: The Study of the Distribution and Abundance of Animals.- 1.2 The Broad Bases for Population Ecology.- 1.3 How to Write About Ecology.- 1.4 Further Reading.- 2. Environment.- 2.0 Introduction.- 2.1 The Idea that Environment is Divisible into five Components.- 2.2 Further Reading.- 3. Components of environment; resources.- 3.0 Introduction.- 3.1 Relative Shortages.- 3.11 Extrinsic relative shortages.- 3.12 Intrinsic relative shortages.- 3.121 Outbreaks of pests.- 3.2 Absolute Shortages.- 3.21 Territorial behaviour in relation to resources.- 3.211 Territorial behaviour in insects.- 3.212 Territorial behaviour in vertebrates.- 3.3 The distribution and abundance of resources.- 4. Components of environment; mates.- 4.0 Introduction.- 4.1 Shortage of Mates.- 4.2 The prevalence of sparseness.- 4.3 Adaptations that increase the chance of finding a mate when numbers are few.- 5. Components of environment; predators and pathogens: aggressors.- 5.0 Introduction.- 5.1 Predators.- 5.11 The ‘biological control’ of insect pests.- 5.12 Predators of vertebrates.- 5.2 Pathogens.- 5.21 The biological control of rabbits by myxomatosis.- 5.22 The biological control of insect pests.- 5.23 The activity of pathogens.- 5.3 Aggressors.- 6. Components of environment; weather.- 6.0 Introduction.- 6.1 Temperature.- 6.11 The influence of temperature on speed of development.- 6.111 The speed of development at constant temperatures.- 6.12 The lethal influence of temperature.- 6.13 The limits of the tolerable zone.- 6.131 The influence of acclimatization on the limits of the tolerable zone.- 6.14 Behaviour in a gradient of temperature.- 6.15 Adaptations to temperature.- 6.2 Moisture.- 6.21 Behaviour in relation to moisture.- 6.22 Physiological mechanisms for conserving water no.- 6.221 ‘Water-balance’ in aquatic animals no.- 6.222 Conservation of water in terrestrial insects, ticks and snails.- 6.223 Conservation of water in terrestrial mammals.- 6.3 Light.- 6.31 The influence of light in synchronizing life-cycles with each other.- 6.32 The influence of light in synchronizing the life-cycle with the season of the year.- 7. Components of environment; malentities.- 7.0 Introduction.- 7.1 Browning’s definition of hazards.- 7.2 Malentities.- 8. Components of environment; more about the ecological web.- 8.0 Introduction.- 8.1 Some advantages in being one of many.- 8.2 Interactions in the ecological web may be important.- 8.3 Interactions in the ecological web may ramify.- 8.4 Ecological barriers as part of the ecological web.- 9. Theory; the numbers of animals in natural populations.- 9.0 Introduction.- 9.01 The meanings of ‘common’ and ‘rare’.- 9.1 The conditions of ‘Commonness’ and *Rare-ness’ in local populations.- 9.11 The conditions of commonness in local populations.- 9.12 The conditions of rareness in local populations.- 9.13 The way in which weather keeps a local population rare relative to food and other resources.- 9.2 The conditions of ‘Commonness’ or ‘Rare-ness’ in natural populations.- 9.21 General conclusions.- 9.22 Negative feed-back to density.- 9.221 The conditions of negative feed-back in natural populations.- II: Practical Course.- 10. Methods for estimating density, patterns of distribution and dispersal in populations of animals.- 10.0 Introduction.- 10.1 The measurement of relative density.- 10.2 The measurement of absolute density.- 10.21 Counting the whole population.- 10.22 The use of quadrats.- 10.23 The method of capture, marking, release and recapture.- 10.3 The measurement of ‘Aggregation’ in natural populations.- 10.31 A test for randomness: the Poisson distribution.- 10.4 Dispersal.- 10.41 Dispersal by drifting.- 10.411 Dispersal of the bean aphis. Aphis fabae.- 10.412 Dispersal of wingless insects, mites and spiders.- 10.413 The dispersal of locusts.- 10.414 The dispersal of strong-flying insects by winds near the ground.- 10.415 The dispersal of marine species that drift with currents.- 10.42 Dispersal by swimming, walking or flying.- 10.421 The measurement of dispersal.- 10.43 Dispersal by clinging.- 10.44 The special importance of dispersal in insect predators.- 10.45 The general importance of dispersal.- 10.5 Class experiments on the estimation of density, distribution and dispersal.- 10.51 Density.- 10.511 To compare the relative densities of two populations of Paramoecium.- 10.512 To estimate the number of Tribolium in a box of flour.- 10.513 To estimate the number of Tribolium using stratified sampling.- 10.514 To estimate the number of Helix by capture, marking, release and recapture.- 10.515 To estimate the trends in the density of a population of Tribolium using a trellis diagram.- 10.52 Patterns of distribution.- 10.521 To compare the distribution of Saissetia with the Poisson distribution.- 10.522 To compare the pattern of distribution of two colonies of Paramoecium.- 10.53 The measurement of dispersal.- 10.531 To measure the rate of dispersal of Paramoecium.- 10.532 To measure the rate of dispersal of Helix.- 11. Physiological responses to temperature.- 11.1 The influence of temperature on speed of development.- 11.11 To compare the rate of egg-laying of flour beetles over a range of temperature.- 11.12 To measure the influence of temperature on the rate of egg-production by Thrips imaginis.- 11.2 The lethal influence of extreme temperature.- 11.21 To estimate the duration of exposure to 5°C required to kill Calandra granaria.- 11.22 To estimate the duration of exposure to 5°C required to kill the flour beetles Tribolium castaneum and T. confusum.- 12. Behaviour in relation to moisture and food.- 12.1 Moisture.- 12.11 To measure the response of flour beetles to a gradient of moisture.- 12.2 Food.- 12.21 To measure the response of egg-laying females of Pieris to a variety of common garden plants.- 12.22 To measure the response of egg-laying females of Pieris to different species of Brassicae.- 12.23 To measure the response of Helicella virgata to food and shelter.- Bibliography and Author Index.