Deceit Pollination and Fruit Set in the Endemic
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DIVERSITY AND RARITY IN AN ANDEAN CLOUD FOREST: DECEIT POLLINATION AND FRUIT SET IN THE ENDEMIC ORCHID, CHONDROSCAPHE EMBREEI by ALEXANDER A. REYNOLDS Under the direction of C. Ronald Carroll ABSTRACT Diversity and rarity of orchid species were assessed in an Andean cloud forest, the Maquipucuna Reserve, Ecuador (00°02’-08’N; 78° 35’-38’W). Over 322 species are reported with 56 endemic species, an increase of 117 species over the last published list. General mechanisms for diversity and rarity of orchids discussed include pollinator relationships, biogeography, and microclimatic variation. During a one-year monitoring program, interseasonal euglossine bee population dynamics were surveyed using chemical baits, and the pollination ecology of an endemic orchid, Chondroscaphe embreei was determined by observing the phenology of three subpopulations. Pollination success rates, 7.3% (male) and 1.0% (female) were as low as recorded for any tropical orchid. C. embreei is deceit pollinated by a male euglossine bee, Euglossa trinotata. Low fruit set results from low pollinator visitation, a natural consequence of its non-rewarding strategy. Potential conservation strategies for endemic species are discussed, including micropropagation, reintroduction, and environmental education. INDEX WORDS: Orchid, Diversity, Euglossine bee, Pollination ecology, Deceit pollination, Maquipucuna, Ecuador, Conservation, Rarity, Micropropagation, Reintroduction, Fruit set DIVERSITY AND RARITY IN AN ANDEAN CLOUD FOREST: DECEIT POLLINATION AND FRUIT SET IN THE ENDEMIC ORCHID, CHONDROSCAPHE EMBREEI by ALEXANDER A. REYNOLDS B.S., The University of Georgia, 2000 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2004 © 2004 Alexander A. Reynolds All Rights Reserved DIVERSITY AND RARITY IN AN ANDEAN CLOUD FOREST: DECEIT POLLINATION AND FRUIT SET IN THE ENDEMIC ORCHID, CHONDROSCAPHE EMBREEI by ALEXANDER A. REYNOLDS Major Professor: C. Ronald Carroll Committee: James Affolter Ted Gragson Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia August 2004 iv ACKNOWLEDGEMENTS I would like to thank anyone who has helped nuture, support, or even endure my fascination with tropical ecology over the last few years. First, I’d like to thank my graduate committee: Ron Carroll, Jim Affolter, and Ted Gragson, whose guidance over the last two years has been invaluable; the Institute of Ecology and all its students and staff for all the support and comments on my work as it developed into this present form; and equally important, Rodrigo Ontaneda, Rebeca Justicia, and everyone with Fundación Maquipucuna who have provided whatever I needed to carry out the projects involved, especially Juan Carlos Unda, Francisco Prieto, Fernando Echeverria, Mariel Araujo, and the Niño Naturalista program which provided the fragrances for the first chemical baiting experiments. My field assistant Patricio Oña deserves special thanks for carrying out the orchid monitoring while I could not be in the field. I am deeply indebted to the Ron Determann and Ron Gagliardo and the Atlanta Botanical Garden for first inspiring my interest in orchids and continuing to support my work in every way and to Larry Wilson at Emory University who encouraged me to visit the tropical rain forest for the first time. To all the other orchidologists that have supported my work – at Florida: Mark Whitten, Norris Williams, Robert Dressler, and Mario Blanco; at Selby Gardens: Cal Dodson; at PUCE: Lorena Endara; at USC: Robert Raguso – as well as Lou Jost, Alex Hirtz, and Eric Hágsater for orchid identifications. To Jim Carr at National Geographic for the euglossine bee footage. And finally to my family and friends that have supported me and will continue to support me in all my attempts long before and long after this work is completed – you have my love and gratitude. Thanks... v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS........................................................................................................... iv LIST OF TABLES........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1 INTRODUCTION: ORCHIDOLOGY 101....................................................................1 Overview and Purpose of the Study.......................................................................1 Orchidaceae: One Big, Happy Family...................................................................4 Ecological Considerations: Pollination and Dispersal...........................................6 Epiphytism: Ecological Constraints and Adaptations...........................................9 2 ORCHID DIVERSITY AND RARITY IN AN ANDEAN CLOUD FOREST............13 Coevolution..........................................................................................................14 Biogeography.......................................................................................................17 Microclimatic Variation.......................................................................................18 Rarity and Endemism – Potential Mechanism.....................................................21 Site Description: The Maquipucuna Reserve, Ecuador ......................................23 Methodology: Orchid Diversity Surveys.............................................................27 Results: Maturation of a Flora .............................................................................28 Discussion: Orchid Diversity and Rarity in an Andean Cloud Forest.................34 vi 3 EUGLOSSINE BEES (APIDAE: EUGLOSSINI) OF THE MAQUIPUCUNA RESERVE, ECUADOR .......................................................38 Introduction..........................................................................................................38 Euglossine Pollination of Orchids ........................................................................43 Chemical Baiting Methods ...................................................................................50 Results of Euglossine Bee Surveys.......................................................................51 Discussion: Population Dynamics and Orchid Diversity......................................57 4 DECEIT POLLINATION AND FRUIT SET OF CHONDROSCAPHE EMBREEI ...63 Deceit Pollination and Its Significance to Orchids...............................................63 Evolution of Deceit Mechanisms..........................................................................66 Natural History of Chondroscaphe embreei.........................................................69 Orchid Pollination Monitoring Program: Methodology ......................................73 Site Descriptions ...................................................................................................75 Results of Monitoring Program of C. embreei......................................................77 Discussion: Deceit Pollination and Fruit Set ........................................................81 5 CONCLUDING REMARKS: WHEN IS IT OK TO BE RARE?...............................87 Conservation Strategies for Rare Orchids.............................................................87 Micropropagation and Responsible Markets ........................................................88 Why Reintroduce Orchids?...................................................................................89 Research, Environmental Edcuation, and Public Outreach ..................................92 LITERATURE CITED ..................................................................................................................95 APPENDIX: 2004 ORCHID LIST OF THE MAQUIPUCUNA RESERVE, ECUADOR.....................105 vii LIST OF TABLES Page Table 2.1: Species additions to the Maquipucuna orchid list ........................................................29 Table 2.2: Endemic species at the Maquipucuna Reserve, Ecuador..............................................33 Table 3.1: Results of euglossine bee surveys at Maquipucuna Reserve........................................52 Table 3.2: Interseasonal euglossine bee abundance at specific chemical baits ............................55 Table 4.1: Pollination success of C. embreei, 2003-2004.............................................................78 viii LIST OF FIGURES Page Figure 1.1: Deforestation in Ecuador since WWII ..................................................................3 Figure 1.2: Floral dissection of Chondroscaphe embreei flower ............................................5 Figure 2.1: Map of the Maquipucuna Reserve, Pichincha, Ecuador ......................................24 Figure 2.2. Relief map of the Maquipucuna Reserve ............................................................25 Figure 2.3: Monthly precipitation in Nanegal (1200msl) and Nanegalito (1630msl) ............26 Figure 2.4: Photos of representative orchid genera at Maquipucuna......................................35 Figure 3.1: Representative euglossines of each genus at the Maquipucuna Reserve .............40 Figure 3.2: Euglossa trinotata at dimethoxybenzene bait ......................................................43 Figure 3.3: General euglossine anatomy.................................................................................45