Circannual Rhythms

1. Introduction.- 1.1 The Phenomenon of Annual Rhythmicity.- 1.2 Ultimate and Proximate Factors in the Control of Annual Rhythms.- 1.2.1 Ultimate Factors.- 1.2.2 Proximate Factors.- 1.3 Circannual Rhythms.- 1.4 Hierarchical Organization of Proximate Factors.- 1.5 Early Suggestions of Circannual Rhythms.- 1.5.1 Mammalian Hibernation and Avian Migration.- 1.5.2 Yearly Breeding Cycles in Tropical and Temperate-Zone Animals.- 1.5.3 Ten-Month Breeding Cycles in Tropical Birds.- 1.5.4 Plants.- 1.5.5 Development of the Oscillator Analogy.- 1.6 Some Definitions and Delimitations.- 2. Evidence for Circannual Rhythms.- 2.1 Typical Cases.- 2.1.1 Mammals.- 2.1.2 Birds.- 2.1.3 Lower Vertebrates.- 2.1.4 Invertebrates.- 2.1.5 Plants.- 2.2 Atypical Cases.- 3. Properties of Free-Running Circannual Rhythms.- 3.1 Degree of Persistence and Range of Permissive Conditions.- 3.2 Range of Circannual Period Length and Transients.- 3.3 Dependence of Period on External Conditions.- 3.3.1 Temperature.- 3.3.2 Photoperiod.- 3.3.3 Social Factors.- 3.4 Innateness of Circannual Rhythms.- 3.5 Comparison with Circadian Rhythms.- 4. Synchronization of Circannual Rhythms.- 4.1 Zeitgebers.- 4.1.1 Photoperiod.- 4.1.2 Ambient Temperature.- 4.1.3 Social Stimuli.- 4.2 Ranges of Entrainment.- 4.3 Behavoir Within the Range of Entrainment.- 4.4 Comparison with Circadian Rhythms and Some Conclusions.- 5. Mechanisms of Circannual Organization.- 5.1 Interactions with the Circadian System.- 5.1.1 Frequency Demultiplication of Circadian Rhythms.- 5.1.1.1 Relationship Between Circadian and Circannual Period Length.- 5.1.1.2 Effects of Disrupting the Circadian System on Circannual Rhythmicity.- 5.1.1.3 General Properties of Circannual Rhythms in Conflict with the Model.- 5.1.2 Circannual Rhythm of a Circadian Rhythm in Photosensitivity.- 5.1.3 Circannual Variations in the Internal Circadian System.- 5.1.3.1 Relationship Between States of Circadian and Circannual System.- 5.1.3.2 Internal Coincidence Between Circadian Neurotransmitter Rhythms as the Basis of Circannual Changes?.- 5.2 Interrelationship Among Different Circannual Functions. Or: One or Several Circannual Clocks?.- 5.2.1 Differential Degrees of Persistence of Various Circannual Functions.- 5.2.2 Internal Dissociation of Various Circannual Functions.- 5.2.3 Selective Manipulation of Rhythmic Functions.- 5.2.4 Conclusions.- 5.3 Components of Specific Circannual Functions.- 5.3.1 Attempts at Changing Circannual Period by Altering the Duration of Potential Components of the Cycle.- 5.3.2 Attempts at Identifying External and Internal Conditions Under Which Rhythmicity Stops or Continues.- 5.3.3 Identification of Hormones and Central Nervous Structures Involved in the Control of Circannual Rhythms.- 5.4 Conclusions.- 6. Adaptive Significance of Circannual Rhythms.- 6.1 General Advantages of Circannual Rhythms.- 6.1.1 Improvement of Consistency of Seasonal Timing.- 6.1.1.1 Hibernating Mammals.- 6.1.1.2 Migratory Birds.- 6.1.2 Timing of Seasonal Activities in Unpredictable or Constant Environments.- 6.2 Specific Functions of Circannual Timing Mechanisms.- 6.2.1 Timing and Adaptive Programming of Seasonal Activities in Hibernating Mammals.- 6.2.2 Timing and Adaptive Programming of Seasonal Activities in Migratory Birds.- 6.2.2.1 Onset of Vernal Migration.- 6.2.2.2 Onset of Autumnal Migration.- 6.2.2.3 Pattern of Autumnal Migration.- 6.2.2.4 Duration of Autumnal Migratory Activity - A Factor Determining Migratory Distance?.- 6.2.2.5 Migratory Direction.- 6.2.2.6 Photoperiodic Modification of the Program.- 6.3 Conclusions and Perspective.- Appendix. General Oscillator Model and Terminology.- References.- Systematic Index.