The Evolution of Parental CareSynthesizing studies of parental care in a wide variety of animals, this book is the first attempt to provide general answers to the following important questions: Why does the extent of parental care vary so widely between species? Why do only females care for eggs and young in some animals, only males in others, and both parents in a few? To what extent is parental care adjusted to variation in its benefits to offspring and its costs to parents? How do parents divide their resources between their sons and daughters? In this book separate chapters examine the evolution of variation in egg and neonate size, of viviparity and other forms of bearing, and of differences in the duration of incubation, gestation, and lactation. The book reviews theoretical and empirical predictions concerning the evolution of parental care and examines the extent to which these are supported by empirical evidence. The author examines the distribution of parental care among offspring, reviews the empirical evidence that parents invest to different extents in their sons and daughters, and discusses the degree to which parents manipulate the sex ratio of their progeny in relation to the availability of resources. |
Contents
Parental Care and Competition for Mates | 3 |
12 Parental Care and Competition for Mates | 5 |
23 Production of Gametes | 12 |
24 Care of Eggs | 13 |
25 Care of Young without Provisioning from Sources outside the Egg | 17 |
26 Provisioning Young before Hatching or Birth | 18 |
27 Provisioning Young after Hatching or Birth | 20 |
28 Care of Offspring after Nutritional Independence | 23 |
78 Summary | 124 |
82 Models of Parental Care | 138 |
84 Why Dont Males Always Assist with Parental Care? | 143 |
85 Why Do Males Agree to Being the Only Caregiver in Some Monogamous Birds? | 144 |
86 Why Do Males Agree to Polyandry? | 145 |
87 Why Are Males Responsible for All Care in Some Polygynous Birds? | 148 |
88 Summary | 149 |
92 Parental Care and ParentOffspring Relatedness | 155 |
29 Social Assistance to Mature Offspring | 25 |
The Costs of Breeding | 29 |
32 Parental Expenditure | 30 |
33 Correlations between Components of Fitness | 32 |
34 The Limitations of Phenotypic Correlations | 37 |
35 Experimental Manipulation of Parental Expenditure | 39 |
36 Negative Genetic Correlations between Fitness Components | 41 |
37 Summary | 44 |
Propagule Size | 47 |
43 How Much Time Should Be Spent in the Egg? | 52 |
44 Constraints on Propagule Size | 55 |
45 Variation in Propagule Size | 59 |
46 Egg Size and Parental Care | 63 |
47 Is There a Single Optimal Propagule Size or an Optimal Range of Variation? | 64 |
48 Summary | 66 |
52 Viviparity among Invertebrates | 71 |
53 Viviparity in Fish | 72 |
54 Viviparity in Amphibia | 75 |
55 Viviparity in Reptiles | 76 |
56 On the Absence of Viviparity in Birds | 77 |
57 Viviparity in Mammals | 78 |
58 Summary | 80 |
62 Body Size and the Duration of Development Periods | 86 |
63 Incubation | 87 |
64 Gestation and Age at Weaning | 88 |
65 Lactation | 90 |
66 Milk Composition | 92 |
67 Summary | 97 |
Parental Care in Ectotherms | 99 |
72 The Evolution of Parental Care by Males and Females | 100 |
73 The Maintenance of Parental Care by Males and Females | 102 |
74 Parental Care in Invertebrates | 105 |
75 Parental Care in Fish | 109 |
76 Parental Care in Amphibia | 121 |
77 Parental Care in Reptiles | 123 |
93 Parental Care and Brood Size | 156 |
94 Parental Care and Offspring Age | 159 |
95 Parental Care and Offspring Quality | 162 |
96 Brood Reduction | 163 |
97 Brood Desertion | 168 |
98 Summary | 170 |
Restraint or Constraint? | 174 |
104 Reproductive Value and Terminal Investment | 176 |
105 Parental Investment by Males and Access to Mating Partners | 180 |
106 Parental Investment and Conflicts of Interest between Caregivers | 181 |
107 Parental Decision Rules | 186 |
108 Summary | 188 |
ParentOffspring Conflict | 191 |
Predictions | 199 |
114 Summary | 204 |
Parental Investment in Sons and Daughters | 207 |
123 Parental Expenditure and Sex Differences in Early Growth | 211 |
124 Energy Expenditure on Sons and Daughters | 213 |
125 Reproductive Costs of Sons and Daughters | 216 |
126 Sex Allocation or Differential Extraction? | 219 |
127 Sex Differences in Parental Investment and the Population Sex Ratio | 221 |
128 Summary | 224 |
Sex Ratios and Differential Juvenile Mortality | 227 |
132 Sex Ratio Variation at Hatching or Birth | 230 |
133 Sex Differences in Juvenile Mortality | 240 |
134 Summary | 250 |
Conclusions | 253 |
143 Why Does the Extent of Parental Care Vary So Widely among Species? | 255 |
144 Why Do Only Females Care for Eggs and Young in Some Species Only Males in Others and Both Parents in a Few? | 256 |
145 To What Extent Is Parental Care Adjusted to Variation in Its Benefits to Offspring and Its Costs to Parents? | 259 |
146 How Do Parents Divide Their Investment between Sons and Daughters? | 260 |
147 Prospects | 261 |
References | 265 |
Indexes | 331 |