Adaptations to ecological interactions. Item Type text; Dissertation-Reproduction (electronic) Authors Becerra-Romero, Judith Xiutzal Ixtlilxochil. Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 25/09/2021 17:15:53 Link to Item http://hdl.handle.net/10150/186239 INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. 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Contact UMI directly to order. U·M·I University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. M148106-1346 USA 3131761-4700 800/521-0600 Order Number 9322769 Adaptations to ecological interactions Becerra-Romero, Judith Xiutzal Ixtlilxochil, Ph.D. The University of Arizona, 1993 V·M·I 300 N. Zeeb Rd. Ann Arbor, MI 48106 ADAPTA TIONS TO ECOLOGICAL INTERACTIONS by Judith Xiutzal Ixtlilxochil Becerra-Romero A Dissertation Submitted to the Faculty of the DEPARTMENT OF ECOLOGY AND EVOLUTIONARY BIOLOGY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 1 993 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by____ J_U_D_I_T_H_X_I_U_T_Z_A_L __I_,_B_E_C_E_R_RA_-_R_O_M_E_R_O __ _ entitled __A_D_A_PT_A_T_I O_N_S_T_O_EC_O_L_O_G I_C_A_L _I_N_T_ER_A_C_TI_O_N_S _________ and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of DOCTOR OF PHILOSOPHY /tJ4ci f9 MICHAEL ROSENZ Date CVV1-~ LD 3/10/7< DR. DIANA WHEELER Date -]:duh/./Jror.4tz!;;nj 2-/2/93 DR ~UDITH BRONSTEIN Date d- Hi cz? 7T-4.Lav II ~ Date Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I read this dissertation prepared under my direction and it be accepted as fulfilling the dissertation 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. 4 ACKNOWLEDGMENTS This dissertation was carried out with the support of several people and institutions. First, I want to express my gratitude to my husband Larry, for his love and constant support. I also thank my parents Beatriz and Antonio for their continual encouragement. I am deeply indebted to the members of my committee, Judith Bronstein, Ted Fleming, and Diana Wheeler. Special thanks to Michael Rosenzweig, my major advisor, for his guidance, patience, and support. I also appreciate the help of David Lloyd in the completion of the research of the first chapter of this thesis. I appreciate the encouragement and assistance I have received from my friends during the time I have been a student in Tucson. Among them, I am especially grateful to Susan Fansler, Henar Alonso, Peter Smallwood, Peter Sundt, Francisco Ornelas, Eric Dyreson, Gerardo Cebollas, Bob Holmes, Cathie Pake, Sarah Mesnick, Dan Beck, and Katrina Mangin. Logistic assistance was given by the University of Canterbury, New Zealand, and by Daniel Pinero and Exequiel Ezcurra from the Centro de Ecologia, UNAM, Mexico. Paty Gaytan and Alejandro Moron helped me in many ways every time I did research in Mexico. Financial support for my graduate studies was provided by the following institutions and foundations: Consejo Nacional de Ciencia y Tecnologia (CONACyT), Mexico, Organization of American States, The Center for Insect Science, U. of A., the William C. McGinnes Foundation, Sigma Xi, The National Audubon Society, and the Department of Ecology and Evolutionary Biology, University of Arizona. 5 To Beatriz, a feminist before her time. 6 T ABLE OF CONTENTS Page LIST OF ILLUSTRATIONS ................................. 9 LIST OF TABLES ....................................... 10 ABSTRACT ........................................... 11 GENERAL INTRODUCTION. .. 13 CHAPTER I. .. 18 Competition-dependent abscission of self­ pollinated tlowers of Phormium renax (Agavaceae) .................. 18 Introduction. .. ................ 19 Materials and Methods ............. 21 Patterns of fruit set. 23 Results ......................................... 30 Patterns of fruit set. 30 Discussion . .. 36 Quantitative measures of self-incompatibility .............. 36 Thinning and closeness of competition .................. 38 The adaptive signiticance of competition-dependent selting ..... .43 CHAPTER II. .................... 45 "Squirt-gun" defense in BurseI'([ and the chrysomelid counterploy ......... 45 7 TABLE OF CONTENTS (continued) Introduction .. 46 Materials and Methods . .. 48 The plant . 48 The herbivore . .. 49 Response variation among plants . .. ............ 50 The Natural patterns . .. 51 Experimental patterns. .. 54 Results . 55 Natural patterns . .. 55 Experimental patterns ....................... 57 Discussion . 62 The costs of canal deactivation ....... 63 The behavioral and morphological components of vein-cutting . 64 Effectiveness of Bursera's canals in defense.. .. 67 CHAPTER III. .. ........... 68 Interactions among plants, ants, and homopterans . .. 68 Introduction . .. 69 Ants and plants. .. 71 Ants and Homoptera . .. 72 Ants, plants, and Homoptera. .. 71 8 TABLE OF CONTENTS (continued) An alternative . .. .. 72 Directions for further investigation . .. 77 LITERA TURE CITED . .. .... 79 9 LIST OF ILLUSTRATIONS Page Figure 1.1. An individual of Phomlium lenax . ... 22 Figure 1.2. Assignment of parentage and position treatments . 29 Figure 2.1. Scatterplot of the exponential daily rate of mortality of larvae against the frequency of leaf response. .................. 56 Figure 2.2. Linear regression of the logarithmic daily growth rate of larvae as a function of the frequency of leaf response. .. .. 58 Figure 2.3. Linear regression of the percentage of leaves with scars as a function of the frequency of leaf response. 59 Figure 2.4. Linear regression of the percentage of time larvae spend cutting veins as a function of the frequency of leaf response. .. 60 Figure 2.5. Linear regression of the larval logarithmic daily mortality rate as a function of the frequency of leaf response.. 61 Figure 3.1 Effects on plant fitness of changes in the factors considered in the ant-guard hypothesis and the ant distraction hypothesis. .. 74 10 LIST OF TABLES Page Table 1.1 Average percent fruit set and the numbers and sizes of seeds after self- and cross-pollinations (untransformed means). .. 31 Table 1.2 Patterns of fruit set (% retention) resulting from thinning, position and timing differences (untransformed mean percentages).. 33 Table 1.3 Variation in the percentages of fruit set from self- and cross­ pollinations (untransformed means) and the relative selfing success (Self-incompatibility Index) associated with the inflorescence level the presence or absence of previous fruit at that level. 35 Table 2.1 Results of regression analyses for the logarithmic daily rate of larval mortality, as a function of the plant's frequency of leaf response an the initial length of larvae. .. 62 11 ABSTRACT Three different aspects of plant adaptations to ecological interactions are examined. The first one is in the area of plant breeding systems. The adaptations investigated in this study involved interactions between male gametes competing for fertilizations on Phormillm tenax, an agavoid of New Zealand. In this system I discovered a new type of