Mate Choice in PlantsT actics, Mechanisms, and Consequences

270 Pages·1983·21.852 MB·English

by  Nancy Burley, Mary F. Willson

Mate Choice
in Plants
MONOGRAPHS IN POPULATION BIOLOGY
EDITED BY ROBERT M. MAY
1. The Theory of Island Biogeography, by Robert H. Mac-
Arthur and Edward O. Wilson
2. Evolution in Changing Environments: Some Theoretical Ex-
plorations, by Richard Levins
3. Adaptive Geometry of Trees, by Henry S. Horn
4. Theoretical Aspects of Population Genetics, by Motoo Ki-
mura and Tomoko Ohta
5. Populations in a Seasonal Environment, by Stephen D. Fret-
well
6. Stability and Complexity in Model Ecosystems, by Robert M.
May
7. Competition and the Structure of Bird Communities, by Mar-
tin L. Cody
8. Sex and Evolution, by George C. Williams
9. Group Selection in Predator-Prey Communities, by Michael
E. Gilpin
10. Geographic Variation, Speciation, and Clines, by John A.
Endler
11. Food Webs and Niche Space, by Joel E. Cohen
12. Caste and Ecology in the Social Insects, by George F. Oster
and Edward O. Wilson
13. The Dynamics of Arthropod Predator-Prey Systems, by Mi-
chael P. Hassell
14. Some Adaptations of Marsh-Nesting Blackbirds, by Gordon
H. Orians
15. Evolutionary Biology of Parasites, by Peter W. Price
16. Cultural Transmission and Evolution: A Quantitative Ap-
proach, by L. L. Cavalli-Sforza and M. W. Feldman
17. Resource Competition and Community Structure, by David
Tilman
18. The Theory of Sex Allocation, by Eric L. Charnov
19. Mate Choice in Plants: Tactics, Mechanisms, and Conse-
quences, by Mary F. Willson and Nancy Burley
Mate Choice
in Plants
TACTICS, MECHANISMS,
AND CONSEQUENCES
MARY F. WILLSON AND
NANCY BURLEY
PRINCETON UNIVERSITY PRESS
PRINCETON, NEW JERSEY
1983
Copyright © 1983 by Princeton University Press
Published by Princeton University Press,
41 William Street, Princeton, New Jersey
In the United Kingdom: Princeton University Press,
Guildford, Surrey
ALL RIGHTS RESERVED
Library of Congress Cataloging in Publication Data will be
found on the last printed page of this book
ISBN 0-691-08333-9
ISBN 0-691-08334-7 (pbk.)
This book has been composed in Linotron Baskerville
Clothbound editions of Princeton University Press books are printed on
acid-free paper, and binding materials are chosen for strength and du-
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not usually suitable for library rebinding.
Printed in the United States of America by
Princeton University Press, Princeton, New Jersey
It is a favourite popular delusion that the scientific
inquirer is under a sort of moral obligation to abstain
from going beyond that generalization of observed
facts which is absurdly called "Baconian" induction.
But any one who is practically acquainted with sci-
entific work is aware that those who refuse to go be-
yond fact, rarely get as far as fact; and any one who
has studied the history of science knows that almost
every great step therein has been made by the "an-
ticipation of Nature," that is, by the invention of hy-
potheses, which, though verifiable, often had very lit-
tle foundation to start with; and, not unfrequently, in
spite of a long career of usefulness, turned out to be
wholly erroneous in the long run.
T. H. Huxley, 1896,
Method and Results; Essays.
FRONTISPIECE. "Lek on a Stigma.'
Preface
This monograph attempts to address two audiences: bot-
anists with interests in either population biology or subor-
ganismal (developmental, physiological, and cellular) proc-
esses and that group of evolutionary biologists (almost all
of whom are zoologists) whose interests center on intra-
population interactions of a "sociobiological" nature. Be-
cause there is so little intellectual exchange between these
groups, writing for both has proved challenging. We are
aware that we are vulnerable to misinterpretation from
both groups, particularly from botanists, because we apply
a sociobiological perspective to materials notably bereft of
this evolving body of theory. This book is about sociobot-
any.
As is common in sociobiological writing, our language
sometimes appears anthropomorphic. Although plants are
unable to make cognitive decisions, we are confident that
they can and do make decisions routinely, using various
physiological processes that are almost unexplored in this
light. It makes little sense to avoid such simple descriptive
terms as "choice," "decision," "conflict," and "tactic" just
because humans engage in conflict and decision making in
ways that seem distinct from most other species. Moreover,
it would be awkwardly pretentious to coin new jargon that
means the same thing but might prove more palatable sim-
ply because it is unfamiliar. What, for example, would be
served by inventing a new word for "cuckoldry"? In many
cases use of the semantic shorthand of sociobiology is a
convenient way to avoid a long-winded circumlocution.
Consider the term "tactic." The dictionary at hand defines
a tactic as "an adroit device for accomplishing an end." In
this monograph "tactic" refers to a means of increasing its
PREFACE
owner's fitness, especially in response to a particular chal-
lenge from the biological environment. Tactics thus are
adaptations, fashioned by natural selection, favoring the
genetic bearers of superior adroit devices. Use of such a
word in this way does not imply any conscious intent or
planning; it is a post facto shorthand description of a re-
sponse. There is no need to ascribe human versions of such
words or attendant human emotions to any other organism;
indeed, such ascription might be seen as a far greater an-
thropocentrism than the use of the words in the first place.
Those uncomfortable with our use of language might wish
to consult George Williams' discussion of "teleonomy" in
his classic book, Adaptation and Natural Selection (1966).
Higher plants can be distinguished from most animals
in several ways (for example, the immobility of adult in-
dividuals) that may have implications for understanding
their sexual and social interactions. We draw analogies from
animal behavior not to paper over the evident differences
between plants and animals but to generate some new pos-
sible interpretations of certain fundamental processes.
Here we present a conceptual perspective on female choice
of mates and to a lesser extent on inter-male competition;
the perspective generates numerous hypotheses, many of
which are testable. The purpose of this exercise is to permit
the collection of data in new and meaningful ways. A novel
perspective on what has been, historically, an independent
area of investigation, such as plant embryology, leads to
the formation of alternative explanatory hypotheses, an
essential step in the proper pursuit of science (e.g., Platt,
1964). Our framework is summarized in a theory map (Fig-
ure 12) in which the relative importance, relationships, and
centrality of the hypotheses are indicated.
Our discussion is aimed at exploring possible adaptive
bases of some aspects of plant reproduction. We are delib-
erately speculative at many points in our discussion. This
viu