Table Of ContentPollination and Floral Ecology
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Pollination and Floral Ecology
Pat Willmer
PrincEton UnivErsity PrEss
PrincEton and oxFord
Copyright © 2011 by Princeton University Press
Published by Princeton University Press, 41 William Street,
Princeton, New Jersey 08540
In the United Kingdom: Princeton University Press, 6 Oxford Street,
Woodstock, Oxfordshire OX20 1TW
press.princeton.edu
Jacket photograph: The bee Eucera longicornis foraging on the sweet pea
Lathyrus. (c) Andrej Gogala
All Rights Reserved
Library of Congress Cataloging-in-Publication Data
Willmer, Pat, 1953-
Pollination and loral ecology / Pat Willmer.
p. cm.
Includes bibliographical references.
ISBN 978-0-691-12861-0 (cloth : alk. paper) 1. Pollination. 2. Polli-
nation by insects. 3. Pollination by animals. 4. Plant ecology. I. Title.
QK926.W55 2011
571.8'642—dc22 2010049061
British Library Cataloging-in-Publication Data is available
This book has been composed in Times
Printed on acid-free paper ∞
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
contEnts
Preface vii
acknowledgments ix
PART I ESSENTIALS OF FLOWER DESIGN AND FUNCTION
chapter 1 Why Pollination is interesting 3
chapter 2 Floral design and Function 11
chapter 3 Pollination, Mating, and reproduction in Plants 55
chapter 4 Evolution of Flowers, Pollination, and Plant diversity 88
PART II FLORAL ADVERTISEMENTS AND FLORAL REWARDS
chapter 5 advertisements 1: visual signals and Floral color 105
chapter 6 advertisements 2: olfactory signals 134
chapter 7 rewards 1: the Biology of Pollen 154
chapter 8 rewards 2: the Biology of nectar 190
chapter 9 other Floral rewards 221
chapter 10 rewards and costs: the Environmental Economics of Pollination 234
PART III POLLINATION SYNDROMES?
chapter 11 types of Flower visitors: syndromes, constancy, and Effectiveness 261
chapter 12 generalist Flowers and generalist visitors 288
chapter 13 Pollination by Flies 304
chapter 14 Pollination by Butterlies and Moths 322
chapter 15 Pollination by Birds 337
chapter 16 Pollination by Bats 356
chapter 17 Pollination by nonlying vertebrates and other oddities 370
chapter 18 Pollination by Bees 378
chapter 19 Wind and Water: abiotic Pollination 418
chapter 20 syndromes and Webs: specialists and generalists 434
vi • Contents
PART IV FLORAL ECOLOGY
chapter 21 the timing and Patterning of Flowering 483
chapter 22 living with other Flowers: competition and Pollination Ecology 503
chapter 23 cheating by Flowers: cheating the visitors and cheating other Flowers 524
chapter 24 Flower visitors as cheats and the Plants’ responses 542
chapter 25 the interactions of Pollination and Herbivory 554
chapter 26 Pollination Using Florivores: From Brood site Mutualism to
active Pollination 565
chapter 27 Pollination in different Habitats 575
chapter 28 the Pollination of crops 605
chapter 29 the global Pollination crisis 620
appendix 639
glossary 643
references 663
subject index 751
index of animal genera 768
index of Plant genera 771
PrEFacE
When I irst became interested in pollination biology ers in the ield: Jones and Little (1983) began the trend
around thirty years ago, there was essentially just one with Handbook of Experimental Pollination Ecology,
book to consult for core information, the classic by while Lloyd and Barrett (1996) produced Floral Biol-
Faegri and van der Pijl, The Principles of Pollination ogy: Studies on Floral Evolution in Animal Pollinated
Ecology, which has been the inspiration to genera- Systems, opening up a broader and more ecological
tions, its last edition appearing in 1979 but still struc- and evolutionary perspective on the whole subject.
tured around the 1966 original. But twenty years on I Then two collected contributions came along in 2006,
became frustrated that there had been no single vol- picking up the themes that had been emerging in the
ume since that date which covered the ield. This is preceding decade: Waser and Ollerton in Plant-Polli-
particularly extraordinary given that the subject itself nator Interactions: From Specialization to General-
has expanded and blossomed prodigiously, both in its ization, and Harder and Barrett in Ecology and Evolu-
own right and as a testing ground for wider theories, as tion of Flowers. These have been seen as especially
well as having assumed greater importance in both sci- important in expounding new approaches and expos-
entiic circles and as a wider public concern. ing older assumptions to a more critical analysis. The
It has not been all quiet on the publishing front debates about generalization and specialization, and
since the 1970s of course. There have been excellent the usefulness of the syndrome concept or of alterna-
books with more of a natural history approach (M. tive modeling approaches, have been particularly
Proctor et al. 1996; Buchmann and Nabhan 1996) and thought-provoking, so that anyone starting out as a re-
botanical books concentrating on loral structures searcher in pollination ecology will ind much to en-
(Barth 1985; Endress 1994) or on loral development gage them from the authors represented in those two
(Glover 2007). Over the same period many extremely books.
useful edited volumes have also appeared, each with Those readers, however, would not get the back-
chapters contributed by experts updating readers on ground information, the core material of pollination
particular themes, such as nectar and nectaries (Bent- and loral biology. A beginner would still have to ex-
ley and Elias 1983; Nicolson et al. 2007), anthers and plore very widely across the mass of scientiic jour-
pollen (D’Arcy and Keating 1996; Dafni et al. 2000), nals, hoping to light upon a reasonably up-to-date re-
and loral scents (Dudareva and Pichersky 2006). Sev- view article. And in the last decade the primary
eral books have compiled useful reviews on practical literature has undergone an extraordinary explosion in
techniques (Dafni 1992; Kearns and Inouye 1993; volume, almost more than in any other ield, partly be-
Dafni et al. 2005) or on applied aspects of crop polli- cause of the practical and applied environmental prob-
nation (Free 1993), while Chittka and Thomson (2001) lems now seen to be emerging with pollination ser-
took a fresh approach by assembling chapters on as- vices, and partly because around twenty-ive years ago
pects of pollinator cognition and learning. interest began to spread much more widely beyond the
But perhaps most important have been a select few European and North American temperate pollination
edited volumes with broader pollination coverage and systems, with expertise emerging especially in the
sometimes a more eclectic assemblage of contribu- New and Old World Tropics, in southern Africa and
tions. Here the editors have been very much the lead- Australia, and in Japan and China.
viii • Preface
For all these reasons, it seemed to me timely to at- those highly respected authors whose work I draw
tempt a book that would cover the subject more thor- heavily on. Some, seeing pollination biology as pio-
oughly, providing chapters on every key topic, and neering a new era where ecological modelers have
serve both as an introduction for anyone coming into more to tell us than old-style ield workers, might
the ield as advanced undergraduate or postgraduate ind my approach too traditional. But at least those
and as a source book for professionals. Begun half coming in to the ield hereafter may gain a better un-
way through the decade, it has inevitably burgeoned derstanding of the foundations on which models can
beyond the original intentions as the expanding litera- be built and so will better see where the key issues
ture burst around my ears, to the distress of my pub- may lie.
lishers. But the resulting book will, I hope, achieve at
least part of its aims and will not too greatly annoy Pat Willmer, November 2009
acknoWlEdgMEnts
It is a pleasure to begin by thanking the many genera- Peter Gibbs, Aubrey Manning, Gidi Ne’eman, Sue Ni-
tions of students and postgraduates who have let me colson, Samy Zalat, Theodora Petanidou, Chris
know when I taught them in ways that inspired their O’Toole, and Rob Raguso.
interest and when I merely confused them. From Several of these colleagues have read and com-
them, I realized where the real fascinations of pollina- mented wisely on outlines, drafts, or chapters for me,
tion lay and where my own interests were too biased and to them I owe enormous gratitude and an apology
or quirky for a wider audience—I have tried, not al- where I have insuficiently taken on their criticisms;
ways successfully, to play down those quirks. Many the misconceptions or infelicities that remain are en-
former postgraduates and postdocs, now running re- tirely my fault. Particular thanks to Clive Nuttman on
search groups of their own and blossoming into major color and scent issues, Peter Gibbs on incompatibility
players in the world pollination and mutualism de- and on general issues of specialization and syndromes,
bates, have been especially important to me, and I Francis Gilbert (especially for updating my dipteran
thank them all for discussions, arguments, and the taxonomy), and Jonathan Pattrick for taking a broad
chance to read and learn from their own works; in par- beginner’s view of the book and being even more per-
ticular I must pay tribute to Graham Stone (GS) and snickety about semicolons than I am!
Simon Potts (SP), and more recently to Clive Nutt- I am deeply grateful to many who have allowed me
man (CN), Betsy Vulliamy, Gavin Ballantyne (GB), to use their photographs, which usually put my own
Caroline King, and Jonathan Pattrick, and to those efforts to shame. All are acknowledged by initials in
whose names are followed by initials for use of their the plates, and all of course retain their copyrights in
photos. the photos reproduced here. Susie Whiten (SW), Ali-
On a wider front, I confess to being a very poor son Fernie (AF), Ian Johnston (IJ), and Sandy Edwards
networker, so that I know the pollination biologists of (SE) were generous with their own photographs from
the world far less well on a personal level than I should, the UK and abroad. Special thanks to Steve Johnson
which is my loss. My communications with them have (SJ), Dino Martens (DM), Karen Sarkisyan (KS), and
nevertheless been wonderfully invigorating, and I Andrej Gogala (AG) for supplying superb photographs
thank so many of them for their generosity in exchang- of the more dificult animal visitors. I also owe a mas-
ing ideas. In particular, I have beneitted at various sive debt of gratitude to my illustrators, especially
times from conversations about bees or pollination or Dawn Toshack for most of the pictures of lowers and
wider mutualisms, whether prolonged or brief (and visitors and their detailed structures, and Caroline
some so brief they will scarcely remember me!), with King for reproducing most of the graphical igures
Jane Memmott, Steve Johnson, Judith Bronstein, Sally from other published works, as well as to Dimitri Kar-
Corbet, Florian Schiestl, Dick Southwood, Naomi etnikov for advice on igures in general. I must also
Pierce, Amots Dafni, Nigel Raine, Ingrid Williams, thank others at Princeton University Press who have
Cathy Kennedy, Francis Gilbert, Dino Martens, John patiently supported my efforts to complete this work;
Free, Jette Knudsen, James Cresswell, Steve Bullock, for the initial enthusiasm of Robert Kirk especially,
James Cook, Peter Yeo, Scott Armbruster, Mo Stanton, and the subsequent diligence of Stefani Wexler, Beth
Spencer Barrett, Dini Eisikowitch, Barbara Gemmill, Clevenger, Gail Schmitt, and Jennifer Slater, as well as
