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INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text direct^ from the orignal or copy submitted. Thus, some thesis and dissertation copies are in typewriter free, vdiile others may be fi"om any type of computer printer. The quality of this reproduction is dependent upon the qualityr of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerograpliically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Infomiaticn Conqiany 300 North Zed) Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 THE CONSERVATION GENETICS OF GREEN TURTLES {ÇHELONIA MYDASy. CONSEQUENCES OF PHILOPATRT AND MATING BEHAVIOR DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy In the Graduate School of The Ohio State University By Tlgeiin Peare $ * $ $ $ The Ohio State University 1996 Dissertation Committee: Approved by Professor Patricia Parker, Adviser Professor Thomas Grubb Professor Thomas Hetherington Adviser Professor Allison Snow Department of Zoology m n Nimber: 97 1 0 6 4 3 UMI Microform 9710643 Copyright 1997, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zed> Road Ann Arbor, MI 48103 ABSTRACT Genetic tools can provide information about behavior and demographics of endangered species with intractable life histories like the green turtle {Chelonia m ydas ). This project exam ined the degree of precision in natal philopatry and the mating system of turtles from two nesting populations (Tortuguero, Costa Rica and Melbourne, Florida. U.S.A) by applying high-resolution molecular techniques. In Tortuguero. multilocus minisatellite DNA fingerprinting revealed a significant negative correlation between genetic similarity of pairs of nesting females and the distance between their nest sites both within years (r^ = 0.273: P < 0.001) and between years (r^ = 0.578; P < 0.001). In addition. 12.3% of 122 female pairs scored for Tortuguero had genetic similarity values resembling those of mother-offspring pairs. In the Melbourne population, however, no relationship between genetic similarity and distance was found (r^ = 0.017; P = 0.075) and none of the 66 female pairs scored for this population had genetic similarity values that resembled those of first-order relatives. 11 These results indicate that females from Tortuguero exhibit low levels of dispersal from natal sites, and that nestmates return independently to nest near their natal sites. The lack of genetic structure in the Melbourne population suggests that females from this population may not return to natal sites with comparable precision. Higher levels of disturbance or mortality, lower quality of homing cues, or younger rookery age may also be responsible for the absence of distance-related local genetic structure within Melbourne. To characterize the mating system of green turtles, single-locus microsatellite technology was used to analyze paternity in 18 clutches from the two rookeries. Five of eight Tortuguero families and five of 10 Melbourne families contained more alleles among hatchlings than would be expected if each nest had a single father. A statistical approach (developed by Dr. Mark Irwin, Department of Statistics, The Ohio State University) estimated that the number of fathers represented in each Tortuguero nest ranged from one to three while the number for each Melbourne clutch was either one or two. These results suggest that green turtles from these breeding aggregations exhibit a promiscuous mating system. Hatching success data revealed that multiply-fertilized clutches produce a higher proportion of offspring than singly-fertilized clutches (Mann-Whitney U = 3, p = 0.028). This su^ests that females may iii benefit firom mating with several partners through fertilization insurance, or the enhancement of sperm competition among ejaculates. The potential detrimental effects of genetic isolation due to strong female philopatry may be ameliorated by a mating system that features multiple paternity. iv To my parents and my good teachers ACKNOWLEDGMENTS This work would have been impossible without the help of many people and agencies. 1 thank my academic advisor, Patricia Parker, for support, ideas and constructive criticism. My other committee members, Tom Grubb, Tom Hetherington and Allison Snow provided additional encouragement emd insight. My co-workers in the laboratory, Nidia Arguedas, T. J. Jones, and Kim Lundy were extremely cooperative and supportive. Thcinks to José Diaz for always saying “No problem” no matter what the request. 1 am especially grateful to Julie Rieder for her friendship, cooperation, hours of discussion and for plodding through months of microsatellite woes with me. For suggestions and other assistance with lab work, I thank Hans EUegren and Colin Hughes. 1 also thank Lynn Kramer and Doug Warmolts at the Columbus Zoo for their assistance. 1 am indebted to Charlie Luthln who gave me my first break. 1 appreciate aU the help I received in the field from Mary Bell, Cathi Campbell, Ray Carthy, Llew Ehrhart, Elizabeth Giuliano, Laine Gonzales, Nancy Israel, Steve Johnson, Tracy Lenihan, Allison Leslie, Rebecca Morse, Ann Peterka, Jessy Rabenold, Andy Rabenold and Janet Winbome. Special thanks to Kennedy Champos cind Lloid Taylor for being bodyguards and “big brothers” during the 1993 season. Vi Monica Guevara was exceptionally helpful during my 1991 and 1992 field seasons, her intelligence, humanity and flair for singing show tunes provided comic relief and gave me a better understanding of the conflict between human requirements and ecosystem limits. Mark Irwin invested a tremendous amount of time creating a computer program to analyze the microsatellite data, and was extremely patient and helpful in explaining the likelihood analyses. I also thank Brian Bowen for his ideas, suggestions, enthusiasm, and humor, and for standing as an exeunple of what one can accomplish with modesty, cooperation and integrity. I am especially grateful to my firiends who made graduate school a lot easier. Gentry Holloway. Jen Knight and Tania Oberyszyn collectively provided me with unconditional support, boundless energy and enthusiasm, recreation, amusement and excellent advise. Finally, I would like to thank my parents for their support and encouragement and Zydeco for teaching me that sleeping and playing in the park are sometimes more important than going to the lab. This study was supported by grants firom Sigma Xi. the American Museum of Natural History, Wildlife Conservation International, and the Caribbean Conservation Corporation awarded to me and funds firom the National Science Foundation #DEB-9322544. awarded to my adviser. Patricia Parker. My parents also provided me with a loan for the 1993 field season. vu VITA July 30. 1967 ...................................................... Bom - Pointe-a-Plerre, Trinidad, West Indies 1989 ....................................................................... B. S. Natural Resources, Cornell University, Ithaca, New York 1990-199 1 .............................................................Teaching Associate, Departm ent of Biology Purdue University West Lafayette, Indiana 1991-1992 and 1995-1996 ..................................................... Research Associate, Department of Zoology The Ohio State University 1993-1994 and 1996 .......................................... Teaching Associate, Department of Zoology The Ohio State University viii PUBLICATIONS Peare, T. and P. G. Parker. 1996. Local genetic structure within two rookeries of green turtles {Chelonia mydas ). Heredity (in press) Peare. T. and P.O. Parker. 1996. The use of multilocus minisateUite DNA fingerprinting to assess local genetic structure in green turtle rookeries. In: Proceedings of the International Symposium on Sea Turtle Conservation Genetics. B. W. Bowen and W. N. Witzel, eds. NCAA Technical Memorandum. NMFS-SEFSC (in press). Parker. P. G.. T. A. Waite and T. Peare. 1995. Paternity studies in animal populations. In: Molecular Genetic Approaches to Conservation. T. B. Smith and R. K. Wayne, eds. Oxford University Press. FIELD OF STUDY Major Field: Zoology Focus: Conservation Genetics IX t a b l e o f c o n t e n t s ABSTRACT.................................................................................................. ii DEDICATION.............................................................................................. v ACKNOWLEDGMENTS............................................................................. vi VITA..............................................................................................................