Adaptation in Metapopulations How Interaction Changes Evolution
by Michael J. Wade
University of Chicago Press, 2016
Cloth: 978-0-226-12956-3 | Paper: 978-0-226-12973-0 | Electronic: 978-0-226-12987-7
DOI: 10.7208/chicago/9780226129877.001.0001
ABOUT THIS BOOKAUTHOR BIOGRAPHYREVIEWSTABLE OF CONTENTS

ABOUT THIS BOOK

All organisms live in clusters, but such fractured local populations, or demes, nonetheless maintain connectivity with one another by some amount of gene flow between them. Most such metapopulations occur naturally, like clusters of amphibians in vernal ponds or baboon troops spread across the African veldt. Others have been created as human activities fragment natural landscapes, as in stands of trees separated by roads. As landscape change has accelerated, understanding how these metapopulations function—and specifically how they adapt—has become crucial to ecology and to our very understanding of evolution itself.

With Adaptation in Metapopulations, Michael J. Wade explores a key component of this new understanding of evolution: interaction. Synthesizing decades of work in the lab and in the field in a book both empirically grounded and underpinned by a strong conceptual framework, Wade looks at the role of interaction across scales from gene selection to selection at the level of individuals, kin, and groups. In so doing, he integrates molecular and organismal biology to reveal the true complexities of evolutionary dynamics from genes to metapopulations.

AUTHOR BIOGRAPHY

Michael J. Wade is distinguished professor of biology at Indiana University, Bloomington. He is coauthor of Mating Systems and Strategies.

REVIEWS

Adaptation in Metapopulations is a multifaceted, deeply considered discussion of the current state of our understanding of how evolution proceeds within and among connected populations, including metapopulations and other kinds of groups. It is also a book on whether and how natural selection may act at multiple group levels, rather than solely at the level of selection among individuals. In that sense it evaluates our understanding of the conditions under which group selection could occur. Conceived and written in a unique way, it is simultaneously a synthesis of work on some major scientific questions, a summary of the history of that work, and a personal memoir on Wade’s intellectual trajectory as he probed those questions, all from a scientist who has spent a major part of his career near the center of these discussions, experiments, and controversies.”
— John N. Thompson, University of California, Santa Cruz, author of "Relentless Evolution"

“How do organisms (individuals, kin, or groups) interact, and how does natural selection work? These are the questions Wade attempts to answer. . . . The book is arranged chronologically, starting with his earliest work from the 1970s, and ends with a paper published in 2012. Wade incorporates some biographical details of his own life, usually at the start of a chapter, and then adds thorough descriptions of the work that he, his peers, and his graduate students have conducted. . . . The book is illustrated with very clear diagrams and a few black-and-white photographs. References from the text are arranged alphabetically in a separate section, and the book includes a detailed index. Recommended.”
— L. T. Spencer, Plymouth State University, Choice

TABLE OF CONTENTS

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0001
[gametic selection, genetic interactions, group selection, individual selection, metapopulation]
This chapter traces the history of metapopulation studies from the introduction of the term by Levins in 1970 to its investigation in a variety of field, theoretical and laboratory systems. The prerequisites for group selection in a metapopulation and how genetic interactions affect selection within and among groups of individuals are discussed. The metaphor of the card games war and poker is introduced to illustrate how the meaning of gene effect is changed by interactions. (pages 1 - 20)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0002
[direct fitness effects, family selection, group heritability, heritability, indirect fitness effects, individual selection]
In this chapter, the efficacy of group selection and the debates over it role, if any, in natural populations is discussed from the perspective of two different contexts. One debate is centered on the existence of group adaptations. Individuals are deconstructed into their component adaptations and, for each such trait, the question is asked, “Who benefits?” If a trait benefits individuals, then it evolved as an adaptation for individuals by individual selection. If it is a trait that benefits groups, then it evolved as an adaptation for groups by group selection. The second debate is based in evolutionary genetics and multilevel selection with its roots in quantitative genetics and animal breeding. The genetic basis of a response to individual or group selection is important to one context but not to the other. (pages 21 - 44)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0003
[differential colonization, differential extinction, emergent traits, group selection, group traits, individual traits, Tribolium beetles]
This chapter discusses the dawn of kin selection and its perception as an alternative to group selection in the early 1970ies. Maynard Smith’s distinction between individual and group selection and its role in formulating the design of an experimental study of group selection by the author is dissected. The distinctive role of ‘group heritability’ as opposed to individual heritability is introduced as a method for understanding the experimental outcomes. Several features of this early experimental work were artificial and led to questions that needed to be addressed in subsequent empirical work. (pages 45 - 68)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0004
[genetic variation among populations, Island model, migration, periodic group selection, population fitness, stepping stone model]
The author’s career options and interviews after completing his doctoral dissertation on group selection. The methods and terminology from animal breeding and family selection and their utility in presenting results from the group selection experiments. The processes of kin selection and family selection relative to group selection are discussed. Discussion of the various sources contributing to the origin and maintenance of among-group phenotypic and genetic variation. (pages 69 - 90)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0005
[estimated group heritability, realized group heritability, island model migration, Fst as a measure of group genetic variation, group mean fitness, variation among groups in mean fitness]
In this chapter, the theoretical relationship between the strength of random genetic drift and the rate of increase of group heritability is discussed. The experimental methods for estimating effective population size and the effective migration rate among Tribolium demes in the laboratory are outlined and diagrammed. The author discusses the distinction between genetic variability and heritability at the group level. A discussion of the results of experiments introducing migration at different levels and in different patterns among demes; random drift of population mean fitness for different numbers of founding adults; and the relationship between estimated and realized group heritability. (pages 91 - 112)
This chapter is available at:
    University Press Scholarship Online

6. Population Ecology and Population Heritability

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0007
[coevolution of sociality and mating system, fallacy of cheaters as a universal threat to sociality, group selection, inbreeding, inclusive fitness theory, kin selection, multilevel selection theory]
This chapter contains a discussion of Maynard Smith’s conceptual distinction between kin and group selection. The author discusses the design and experimental study of kin selection for and against cannibalism as a test of the definitional distinction. The fallacy that societies are vulnerable to cheaters is discussed along with the concept of a “kin-selection mutation balance.” The results of models with three levels of selection as well as models of the effect of inbreeding on kin selection are presented. The synergistic coevolution of mating system and sociality are illustrated and the underlying processes governing the run-away evolution of sociality are discussed. The advantage of the multilevel selection perspective over the inclusive fitness perspective is illustrated by drawing from counter-factual predictions of inclusive fitness theory and its inability to account for underlying processes of genetic change. (pages 137 - 162)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0008
[cannibalism, egg-laying behaviour, feeding sites, genetic variation for cannibalism, grouping of larvae, mating behaviour, selection within and between field groups, spatial scale of among-group variation, variation in genetic relatedness within groups]
This chapter contains a discussion of why their life history made willow beetles a perfect field system for studying the evolution of social behaviors. This is an organism that lives in groups and interacts with its kin. When aggregated, the larvae display several primitively ‘social’ traits, including synchronous molting, chemical defence against predators, and the ability, like ants, to follow the trails of other larvae. Like Tribolium, they are also at times intensely ‘anti-social’ or cannibalistic. Thus, their kin structure had ecological and genetic consequences for the group. A decade of field studies with Felix Breden allowed tests of the predicted that the ecology should influence selection within and between larval groups, while the genetics should determine the efficacy of each level of selection. (pages 163 - 182)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0009
[Fisherian individual selection, interdemic selection, periodic versus continuous interdemic selection, realized group heritability, Sewall Wright, Shifting Balance Theory, social learning models, the adaptive landscape, variation in migration and Fst]
This chapter contains a discussion of the ecological and the genetic basis for Sewall Wright’s Shifting Balance Theory. It also relays discussions of the author with Wright about how to experimentally test his theory using flour beetle metapopulations. The experimental design used by Wade and C. J. Goodnight to test Wright’s theory and to estimate realized group heritabilities is illustrated. The surprizing finding that interdemic selection every-other generation produced a larger response than selection at every generation was interpreted as evidence of non-additive effects on population mean fitness. (pages 183 - 212)
This chapter is available at:
    University Press Scholarship Online

- Michael J. Wade
DOI: 10.7208/chicago/9780226129877.003.0010
[individual and group mean variation of fitness, open questions remaining, Ora Lee Lucas, gene interactions and speciation, epistatic genetic variation, indirect genetic variation]
This chapter presents the results of crosses between beetles from high and low reproducing populations in relation to the fitness landscape of flour beetle laboratory populations. The chapter presents the results of experimental studies of inbreeding to show that differences in inbreeding among the metapopulations were not responsible for the surprizing results of the Shifting Balance Experiment. The empirical differences between individual and population mean fitness are discussed and were estimated experimentally. The finding that the among-population genetic variation in fitness was 50-fold greater than predicted by standard theory is discussed in the context of empirical results. Lastly, the unique signature that among-group selection leaves on gene sequences is discussed and illustrated with genomic data. Suggestions for future research into metapopulation genomics are presented in conclusion. (pages 213 - 230)
This chapter is available at:
    University Press Scholarship Online

Acknowledgments

Reference List

Index