Fluctuating Craniodental Asymmetry in the Southern African Cheetah Acinonyx Jubatus Jubatus Stephanie J

Harriet L. Wilkes Honors College Honors Theses Florida Atlantic University Libraries Year Fluctuating craniodental asymmetry in the southern African cheetah Acinonyx Jubatus Jubatus Stephanie J. Sabshin Florida Atlantic University, This paper is posted at DigitalCommons@Florida Atlantic University. http://digitalcommons.fau.edu/wilkes theses/27 FLUCTUATING CRANIODENTAL ASYMMETRY IN THE SOUTHERN AFRICAN CHEETAH ACINONYX JUBATUS JUBATUS By Stephanie Julia Sabshin A Thesis Submitted to the Faculty of The Wilkes Honors College in Partial Fulfillment of the Requirements for the Degree of Bachelor of Arts in Liberal Arts and Sciences with a Concentration in Pre-Veterinary Studies Wilkes Honors College of Florida Atlantic University Jupiter, Florida May 2007 FLUCTUATING CRANIODENTAL ASYMMETRY IN THE SOUTHERN AFRICAN CHEETAH ACINONYX JUBATUS JUBATUS by Stephanie Julia Sabshin This thesis was prepared under the direction of the candidate’s thesis advisor, Dr. Jon Moore, and has been approved by the members of her/his supervisory committee. It was submitted to the faculty of The Honors College and was accepted in partial fulfillment of the requirements for the degree of Bachelor of Arts in Liberal Arts and Sciences. SUPERVISORY COMMITTEE: ____________________________ Dr. Jon Moore ____________________________ Dr. Terje Hoim ______________________________ Dean, Wilkes Honors College ____________ Date ii ACKNOWLEDGEMENTS I would like to offer my sincerest gratitude to the entire faculty and staff of the Harriet L. Wilkes Honors College who have been instrumental in helping me find my direction. I would like to specifically thank Dr. Moore for being a patient and encouraging thesis advisor from the very beginning conversations about thesis topics. You consistently indulged my most creative, and often unfeasible, thesis ideas, giving me a great sense of confidence in my abilities. Also, thank you Dr. Fitchett and Dr. Hoim, for giving me an appreciation for the value of mathematics that will be invaluable in my future. Furthermore, I couldn’t have made it through these four years without my friends; friends who made me work when all I wanted to do was play, and friends who made me play when all I thought I had time to do was work. You have brought balance to my life and I will miss you all greatly. Finally, the most important recognition has to go to my family. You all have allowed me to explore different interests and find my own way, even when my own way resulted in my complete occupation of the dining room table with books, summers abroad, significant additions to the family, and random ideas gone astray. For your unwavering support, I am eternally grateful. iii ABSTRACT Author: Stephanie Julia Sabshin Title: Fluctuating Craniodental Asymmetry in the Southern African Cheetah Acinonyx jubatus jubatus Institution: Wilkes Honors College of Florida Atlantic University Thesis Advisor: Dr. Jon Moore Degree: Bachelor of Arts in Liberal Arts and Sciences Concentration: Pre-Veterinary Studies Year: 2007 The cheetah (Acinonyx jubatus) continues to be an object of intensive study with respect to its genetic heterozygosity and its drastic decline in the wild. Fluctuating asymmetry (FA) has been used to evaluate the levels of inbreeding and monomorphism in the cheetah. A measurement of craniodental FA was undertaken to compare the southern African cheetah (Acinonyx jubatus jubatus) with previously collected craniodental FA measurements from the East African cheetah (Acinonyx jubatus raineyi). Unlike their counterparts, the southern African cheetah did not show significant asymmetry. These findings suggest that fluctuating asymmetry cannot be used as a determination of genetic depletion in cheetahs. iv To those who are motivated by the understanding that in the brief moment of but a blink, the spots once seen will be gone forever. v TABLE OF CONTENTS Introduction………………………………………………………………..………………1 Materials and Methods……………………………………………………...……………..3 Results……………………………………………………………………….…………….6 Discussion………………………………………………………………….…………….10 References…………………………………………………………….………………….13 Appendix I Description of skulls…….....………………………….…………………17 Appendix II A written description of each measurement...……...……….………..…..19 Appendix III Raw Data (in cm)………………………………………..……………….21 TABLES . Table 1. Age and sex of individuals used in this study……………………...……...3 Table 2a. Student's t-test values for significant directionality of asymmetry for each sex………………………………………………….………………...6 Table 2b. Student's t-test values for significant directionality of asymmetry for each age group………………………………………….…………………7 Table 3a. Means (in cm), sample sizes (n), and standard deviations of asymmetry for males and females…………………………………………8 Table 3b. Male and female composite mean asymmetry values for each measurement……………………………………………..………………..9 Table 4. F-ratios from a univariate analysis of variance testing for significant differences in asymmetry due to age and sex and interactions among them……………………………………………………....………………10 FIGURES Figure 1. Cranial, tooth and mandibular measurements used to examine fluctuating asymmetry in Acinonyx jubatus from Namibia…………..…...5 vi Introduction Fluctuating asymmetry (FA) is a measure of deviations from ideal symmetry between bilaterally paired traits. Because symmetry is expected to be the ideal state, FA is not likely to be adaptive. It is characterized by a leptokurtic distribution of small random deviations around a mean of zero (Van Valen, 1962; Soulx, 1967; Palmer & Strobeck, 1986, Palmer, 1996; Gangestad & Thornhill, 1999). This is opposed to directional asymmetry, where all individuals develop a right or left bias, and anti- symmetry, where some individuals develop a left bias and some develop a right. Anti- symmetry is due to genetic predisposition rather than stress (Palmer & Strobeck, 1986). FA also is not the same as the asymmetry seen in frequency-dependent natural selection (Hori 1993). FA has been shown through studies to increase in inbred and relatively monomorphic populations (Dobzhansky & Wallace, 1953; Lerner, 1954; Soule, 1967; Kat, 1982; Leary et al., 1983, 1985; Leamy, 1984). It has therefore been proposed that FA may be a useful tool in conservation biology to help determine whether a species’ survival may be compromised by the loss of genetic diversity (Wayne et al., 1986; Leary & Allendorf, 1989; Parsons, 1992; Sarre et al., 1994; Clarke, 1995; Palmer, 1996). There is considerable evidence for a negative correlation between fluctuating asymmetry and success with respect to sexual selection in numerous species, which may act to improve offspring viability by choosing more favorable genes (Møller & Thornhill, 1998). Wayne et al. (1986) have discussed evidence indicating a high level of genetic monomorphism in the southern African cheetah, Acinonyx jubatus jubatus. This genetic 1 monomorphism was a consequence of an acute evolutionary bottleneck which resulted in more recent inbreeding (O’Brien et al., 1985; Menotti-Raymond & O’Brien 1993). Wayne et al. (1986) evaluated the level of craniodental fluctuating asymmetry in the East African cheetah subspecies compared with certain other felid species. Their data showed a significant elevation of fluctuating asymmetry in the cheetah compared with other tested felids. They interpreted the results as being evidence for a decreased developmental stability. However, confirmation of this interpretation with respect to the southern African cheetah subspecies was needed. Kieser and Groeneveld (1991) evaluated the fluctuating odontometric asymmetry in the southern African cheetah subspecies. Contrasting the conclusions drawn by Wayne et al. concerning the East African cheetah, their data gives evidence that the cheetah did not show higher levels of fluctuating asymmetry than the other felids tested, but rather, frequently reduced levels of asymmetry. Because craniodental FA was measured in the East African cheetah, but only odontometric FA was measured in the southern African cheetah population, it seemed appropriate to measure the craniodental FA in the southern African cheetah subspecies in order to determine if the conclusions drawn by Wayne et al. (1986) with respect to the East African population can be applied to the larger southern African population. Perhaps it is the case that odontometric FA cannot be used in felid species as a measure of developmental stability due to dental irregularities (Marker and Dickman, 2004; Marker, 1997). As noted in Wayne et al. (1986) and as was discovered in this study, cranial measurements have tended to show more asymmetry than odontometric measurements. 2 Materials and Methods Data were obtained from museum processed dried skulls of 61 Namibian cheetah Acinonyx jubatus jubatus (see Appendix 1). The skulls were all collected between 1993 and 2006 and stored at the Cheetah Conservation Fund in Otjiwarango. The specimens were separated into the sexes and age groups as presented in Table 1 according to Marker and Dickman (2003). Additionally, for analysis purposes, an age group 9 was added to encompass all the adults (combining age groups 5-8) since these individuals are all fully grown, and therefore, growth should not be a possible factor in the fluctuating asymmetry for these individuals. Table 1. Age and sex of individuals used in this study. Age Group Class Age No. No. (months) Males Females 1 Young cubs 0-6 4 3 2 Large cubs >6-12 3 2 3 Adolescents >12-18 5 1 4 Newly >18-30 4 5 independent 5 Young adults >30-48 12 3 6 Prime adults >48-96 8 3

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