Environmental conditions change considerably in the course of 24 h with respect to abiotic factors and intra- and interspecific interactions. These changes result in limited time windows of opportunity for animal activities and, hence, the question of when to do what is subject to fitness maximisation.
This volume gives a current overview of theoretical considerations and empirical findings of activity patterns in small mammals, a group in which the energetic and ecological constraints are particularly severe and the diversity of activity patterns is particularly high. Following a comparative ecological approach, for the first time activity timing is consequently treated in terms of behavioural and evolutionary ecology, providing the conceptual framework for chronoecology as a new subdiscipline within behavioural ecology. An extensive Appendix gives an introduction to methods of activity modelling and to tools for statistical pattern analysis.

Inhalt

Section 1 Introduction.- 1 Introduction.- 1.1 Two States of Life.- 1.2 Diel Patterns and the Biological Clock.- 1.3 Doing the Right Thing at the Right Time.- 1.4 History of an Idea.- 1.5 Why Do We Know That Little?.- 1.6 Why Small Mammals?.- 1.7 About this Book.- References.- Section II Theoretical Considerations.- Theoretical Considerations - Introduction.- 2 Activity Patterns and the Biological Clock in Mammals.- 2.1 Introduction.- 2.2 The Circadian Clock.- 2.3 Circadian Clocks in Mammals.- 2.3.1 General Features.- 2.3.2 Temperature Effects on the Circadian Clock.- 2.3.3 Physiological Influences on the Circadian Clock.- 2.4 Entrainment of Rhythms by Light and Other Signals.- 2.4.1 Light.- 2.4.2 Food Availability.- 2.4.3 Non-photic Zeitgebers.- 2.4.4 Social Factors.- 2.5 Localisation of the Circadian Clock in Mammals.- 2.5.1 The Suprachiasmatic Nucleus.- 2.5.2 Anatomy and Neurochemistry of the Suprachiasmatic Nucleus.- 2.6 Overview of the Major Activity Pattern Types in Mammals.- 2.6.1 Terminology.- 2.6.2 Nocturnal.- 2.6.3 Diurnal.- 2.6.4 Crepuscular.- 2.6.5 Ultradian.- 2.6.6 Acyclic.- 2.7 Effects of Semi-natural Environments in the Laboratory on Activity Patterns.- 2.8 Daily Activity Patterns: Flexibility, Variability and Interaction with Other Rhythms.- 2.8.1 Between Species in Their Activity Patterns.- 2.8.2 Species Variability in Activity Patterns.- 2.8.3 Interactions of Circannual Rhythms with Circadian Rhythms.- 2.9 Concluding Remarks.- References.- 3 Activity Patterns and Metabolism.- 3.1 Introduction.- 3.2 The Energy Budget and Its Limits.- 3.3 The Structure of Energy Budgets.- 3.4 Food Acquisition: Foraging Rates, Foraging Costs.- 3.4.1 Indirect Estimates Based on Allometry.- 3.4.2 Foraging Rates Estimated from Activity Budgets.- 3.5 Constraints on Foraging Activity.- 3.5.1 The Model.- 3.5.2 Numerical Solution and Empirical Evidence.- 3.6 Activity Patterns Under High Energy Loads.- 3.7 Concluding Remarks.- References.- 4 Ecological Relevance of Daily Activity Patterns.- 4.1 Increasing Fitness by Activity Timing.- 4.2 Autecological Advantages of Appropriate Timing.- 4.2.1 Shiftwork in the Habitat.- 4.2.2 A Matter of Season.- 4.3 Inter-individual Aspects.- 4.3.1 Community Life.- 4.3.1.1 Spacing Behaviour.- 4.3.1.2 Social Contacts.- 4.3.2 Tied by Conflict.- 4.3.2.1 Prey.- 4.3.2.2 Predators.- 4.3.2.3 Temporal Coevolution?.- 4.3.3 The Temporal Niche.- 4.4 Concluding Remarks.- References.- Section III Empirical Findings.- Empirical Findings - Introduction.- 5 Weasels and Martens - Carnivores in Northern Latitudes.- 5.1 Introduction.- 5.2 Metabolic Consequences of Mustelid Size and Shape.- 5.3 Proximate and Ultimate Effects on Activity.- 5.3.1 Foraging Time, Meal Patterning and Digestive Constraints.- 5.3.2 The Visual System.- 5.3.3 Temperature and Season.- 5.3.4 Competition.- 5.3.5 Predator Avoidance.- 5.3.6 Social and Reproductive Behaviour.- 5.3.7 Prey Availability.- 5.4 Conclusions.- References.- 6 Mongooses, Civets and Genets - Carnivores in Southern Latitudes.- 6.1 Introduction.- 6.2 General Trends in Activity Patterns.- 6.2.1 Overview.- 6.2.2 Relationships Between Activity Patterns and Ecological Attributes.- 6.3 Activity Patterns of Egyptian Mongooses and European Genets.- 6.3.1 Data Collection.- 6.3.2 Start and End of Activity.- 6.3.3 Total Activity Time per 24-h Day.- 6.3.4 Time Budget.- 6.3.5 Relationships Between Predators and Prey Activity.- 6.4 Discussion and Conclusions.- References.- 7 Squirrels - Medium-Sized Granivores in Woodland Habitats.- 7.1 Introduction.- 7.2 The Daily Activity Pattern.- 7.2.1 General Pattern and Seasonal Variation.- 7.2.2 Geographical Variation.- 7.3 Foraging Behaviour and the Activity Pattern.- 7.3.1 Foraging and Activity of Red Squirrels in Coniferous Woods.- 7.3.1.1 Winter (December-February).- 7.3.1.2 Spring (March-May).- 7.3.1.3 Summer (June-August).- 7.3.1.4 Autumn (September-November).- 7.3.2 Habitat Effects.- 7.4 Activity Pattern and Intraspecific Competition.- 7.4.1 Sex Differences Between Adults.- 7.4.2 Age Differences.- 7.5 Conclusions.- References.- 8 Activity Patterns of Kangaroo Rats - Granivores in a Desert Habitat.- 8.1 Introduction.- 8.2 Nocturnality.- 8.3 Mating Effort and Aboveground Activity.- 8.4 Activity Levels and Predation Risk.- 8.4.1 Moonlight Avoidance, Crepuscular Compensation, and Predation Risk.- 8.4.2 Does Predation Maintain Heterogeneity of Activity Profiles?.- 8.4.3 Sex Differential Predation Risk? A Methodological Caveat.- 8.5 An Unresolved Question.- References.- 9 Gerbils and Heteromyids - Interspecific Competition and the Spatio-Temporal Niche.- 9.1 Introduction.- 9.2 Gerbils and Daily Temporal Partitioning.- 9.3 Heteromyids and Seasonal Temporal Partitioning.- 9.4 Concluding Remarks and Synthesis.- 9.4.1 Temporal Partitioning and Its Relation to Species Coexistence.- 9.4.2 Synthesis.- References.- 10 Wood Mice - Small Granivores/Insectivores with Seasonally Variable Patterns.- 10.1 Introduction.- 10.2 Seasonal Patterns of Activity.- 10.3 Environmental and Physiological Influences on Activity Patterns.- 10.3.1 Environmental Influences.- 10.3.2 Physiological Influences.- 10.4 Intra- and Interspecific Influences on Activity.- 10.4.1 Intraspecific Influences.- 10.4.2 Interspecific Influences.- 10.5 Discussion.- References.- 11 Voles - Small Graminivores with Polyphasic Patterns.- 10.1 Introduction.- 10.2 Seasonal Patterns of Activity.- 10.3 Environmental and Physiological Influences on Activity Patterns.- 10.3.1 Environmental Influences.- 10.3.2 Physiological Influences.- 10.4 Intra- and Interspecific Influences on Activity.- 10.4.1 Intraspecific Influences.- 10.4.2 Interspecific Influences.- 10.5 Discussion.- References.- 12 Djungarian Hamsters - Small Graminivores with Daily Torpor.- 12.1 Djungarian Hamsters: Through Cold Winters on Hairy Feet.- 12.2 Measurements of Locomotion, Temperature and Metabolic Rate.- 12.3 Model Calculations.- 12.4 Adjustment of Locomotor Activity Patterns to Environmental Changes.- 12.5 Energy Requirements For Activity - The Impact of Cold Load.- 12.6 Locomotion and Daily Torpor: Interactions.- 12.7 Budgeting of Time and Energy Under Natural Conditions.- 12.8 Constraints, Unknowns, and Alternative Strategies.- References.- 13 Shrews - Small Insectivores with Polyphasic Patterns.- 13.1 Introduction.- 13.2 Methods.- 13.3 Factors Influencing Activity Rhythms.- 13.3.1 Food.- 13.3.2 Light, Weather, and Seasonal Factors.- 13.3.3 Sex and Reproduction.- 13.3.4 Optimal Foraging and Competitors.- 13.4 Conclusions.- References.- 14 Bats - Flying Nocturnal Mammals.- 14.1 Introduction.- 14.2 Flight Activity Patterns under Natural Conditions.- 14.2.1 Recording Methods.- 14.2.2 Timing of Flight Activity.- 14.2.3 Activity Patterns.- 14.2.4 Effect of Environmental Factors on the Timing and Pattern of Flight Activity.- 14.2.4.1 Light.- 14.2.4.2 Ambient Temperature.- 14.2.4.3 Precipitation and Wind.- 14.2.4.4 Food Abundance.- 14.2.5 Effect of Endogenous Factors on the Timing and Pattern of Flight …