Polygyny and Sexual Selection in Red-Winged Blackbirds:

Polygyny and Sexual Selection in Red-Winged Blackbirds:

WILLIAM A. SEARCY
KEN YASUKAWA
Copyright Date: 1995
Pages: 330
https://www.jstor.org/stable/j.ctt7ztqd3
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    Polygyny and Sexual Selection in Red-Winged Blackbirds:
    Book Description:

    The purpose of this book is to explain why red-winged blackbirds are polygynous and to describe the effects of this mating system on other aspects of the biology of the species. Polygyny is a mating system in which individual males form long-term mating relationships with more than one female at a time. The authors show that females choose to mate polygynously because there is little cost to sharing male parental care in this species, and because females gain protection against nest predation by nesting near other females. Polygyny has the effect of intensifying sexual selection on males by increasing the variance in mating success among males. For females, polygyny means that they will often share a male's territory with other females during the breeding season and will thus be forced to adapt to frequent female-female interactions.

    This work reviews the results of many studies by other researchers, as well as presenting the authors' own results. Studies of red-winged blackbirds have ranged from long-term investigations of reproductive success and demography, to research on genetic parentage based on modern molecular methods, to a variety of experimental manipulations of ecological circumstances and behavior. Since the red-winged blackbird is one of the best studied species of any taxa in terms of its behavior and ecology, the authors have a particularly extensive body of results on which to base their conclusions.

    Originally published in 1995.

    ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

    eISBN: 978-1-4008-6393-8
    Subjects: Ecology & Evolutionary Biology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. List of Figures and Tables
    (pp. ix-xvi)
  4. Acknowledgments
    (pp. xvii-2)
  5. 1 Introduction
    (pp. 3-25)

    The behavior of red-winged blackbirds in the wild has been studied as extensively as that of any species of bird in the world. Given the traditional prominence of birds in ethology and behavioral ecology, this means that “redwing” behavior is as well known as that of any species of any taxa. That so much attention has been paid to red-winged blackbirds is due in part to certain practical advantages they offer for field study: they occupy open habitats, where they are easy to observe, and in most locales their nests are easy to locate, so that reproductive success can be...

  6. 2 Parental Care
    (pp. 26-49)

    Parental care and mating system have a reciprocal relationship, each influencing the other. On the one hand, the form of the mating system affects the balance of costs and benefits of performing parental care. A major cost of parental care to males is lost opportunity to perform other activities, such as mate attraction, mate guarding, extrapair courtship, and territory defense. In general, the fitness payoffs of these alternative activities increase as the degree of polygyny increases. By influencing the benefit of these alternative activities, the degree of polygyny of the species can affect the amount of effort that males devote...

  7. 3 Territoriality
    (pp. 50-76)

    The mating system of red-winged blackbirds is territorial polygyny, a type of polygyny in which the prolonged association between one male and several females occurs on the male’s territory. As is typical in territorial polygyny, male red-winged blackbirds establish their territories first, and females settle on territories later (for an interesting exception, see Davies 1992). Female red-winged blackbirds make extensive use of the resources provided by the territory, and there is good evidence that their choice of mate is in large part determined by the quality of those resources (see chapter 5). By affecting female choice, variation in territory quality...

  8. 4 Female Reproductive Success
    (pp. 77-99)

    Understanding the factors that determine female reproductive success is crucial to understanding the mating system of red-winged blackbirds because these factors, whatever they are, should determine where females settle, and female settlement determines whether social polygyny occurs. Reproductive success of female vertebrates has three main components: longevity, fecundity, and offspring survival (Clutton-Brock 1988). Studies of female red-winged blackbirds have provided a wealth of data on fecundity and on offspring survival up to fledging but relatively little data on offspring survival after fledging or on adult longevity. Data on adult female longevity are difficult to gather because of the relatively long...

  9. 5 Female Choice of Breeding Situation
    (pp. 100-132)

    Female choice of mates has long been a controversial subject. Soon after Darwin (1859, 1871) first proposed female choice as an evolutionary force, his ideas were attacked by Wallace (1889) and others, who doubted that female choice existed. Such doubts persisted well into the twentieth century (Huxley 1938), but in the past two decades they have been buried under an avalanche of data demonstrating that female choice does occur in a great variety of species (Andersson 1994). With the reality of female choice established, the focus of the controversy has shifted to the evolution of female preferences, particularly of female...

  10. 6 Polygyny
    (pp. 133-159)

    We will now attempt to answer one of the two major questions addressed in this book: why are red-winged blackbirds polygynous? As we stated in chapter 1, we emphasize the social, rather than the genetic, mating system. Furthermore, we continue to make a distinction between short-term models of polygyny, which seek explanations for the present occurrence of polygyny given existing conditions, versus long-term models, which seek to explain how polygyny might have originated in the past, under hypothetical past conditions.

    In this chapter we will first review some earlier attempts to use data from red-winged blackbirds to test short-term models...

  11. 7 Sexual Selection in Progress
    (pp. 160-194)

    Darwin (1859, 1871) proposed that dimorphism in traits associated with display, ornamentation, and fighting have evolved due to sexual selection, in most cases acting on males. He also suggested that sexual selection is stronger in polygynous species, such as red-winged blackbirds, than in monogamous ones (see chapter 1). In this chapter and the next, we examine whether dimorphic traits can be explained by sexual selection acting on males in red-winged blackbirds. We employ two general sorts of tests, corresponding to Grafen’s (1988) distinction between studies of selection in progress and studies of adaptation. As discussed in chapter 1, studies of...

  12. 8 Adaptations for Sexual Selection
    (pp. 195-230)

    An adaptation is “a characteristic of an organism whose form is the result of selection in a particular functional context” (West-Eberhard 1992). An adaptation for sexual selection, then, is a characteristic whose form is the result of sexual selection. In this chapter we consider evidence that certain traits of male red-winged blackbirds are in this sense adaptations for sexual selection.

    A variety of methods can be used to test whether a trait is an adaptation (Curio 1973, West-Eberhard 1992). One is to compare “naturally occurring variants” as to their “efficiency or reproductive success” (West-Eberhard 1992). This is essentially the method...

  13. 9 Polygyny, Sexual Selection, and Female Red-winged Blackbirds
    (pp. 231-258)

    In the last two chapters we discussed the effects of polygyny on male red-winged blackbirds in terms of the intensified sexual selection that polygyny imposes on males. We now turn to effects of polygyny on female red-winged blackbirds. The key feature of territorial polygyny, as a social system, is that multiple females breed on the territory of a single male. This places females in close proximity to one another for several weeks, in a situation in which they are almost forced to interact in one way or another. Female redwings do in fact interact frequently with fellow harem-members, mostly in...

  14. 10 Conclusions
    (pp. 259-278)

    We have now reviewed what is known about polygyny and sexual selection in red-winged blackbirds. In doing so, we have stuck rather narrowly to our focal species, only looking at cross-species comparisons when we could use such comparisons to shed light on the evolution of the behavior and morphology of red-winged blackbirds. In this final chapter we will reverse this process and consider what light can be shed on other species by what we have learned about redwings. In other words, we will examine how well our conclusions about polygyny and sexual selection in red-winged blackbirds generalize to other species....

  15. Common and Scientific Names
    (pp. 279-280)
  16. References
    (pp. 281-302)
  17. Indexes
    (pp. 303-312)