DOCSLIB.ORG

Measuring and Interpreting Sexual Selection Metrics: Evaluation and Guidelines

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Measuring and Interpreting Sexual Selection Metrics: Evaluation and Guidelines Methods in Ecology and Evolution 2016 doi: 10.1111/2041-210X.12707 REVIEW Measuring and interpreting sexual selection metrics: evaluation and guidelines Nils Anthes*,1,InesK.Haderer€ 1,NicoK.Michiels1 and Tim Janicke2 1Animal Evolutionary Ecology Group, Institute for Evolution and Ecology, University of Tubingen,€ Auf der Morgenstelle 28, 2 72076 Tubingen,€ Germany; and Centre d’Ecologie Fonctionnelle et E´volutive, UMR 5175, CNRS, University of Montpellier, 1919 Route de Mende, 34293 Montpellier Cedex 05, France Summary 1. Routine assessments of overall sexual selection, including comparisons of its direction and intensity between sexesorspecies,relyonsummarymetricsthatcapturethe essence of sexual selection. Nearly all currently employed metrics require population-wide estimates of individual mating success and reproductive success. The resulting sexual selection metrics, however, can heavily and systematically vary with the chosen approaches in terms of sampling, measurement, and analysis. 2. Our review illustrates this variation, using the Bateman gradient, a particularly prominent sexual selection metric. It represents the selection gradient on mating success and – given the latter’s pivotal role in defining sexual selection – reflects a trait-independent integrative proxy for the maximum strength of sexual selection. Drawing from a recent meta-analysis, we evaluate potential biases arising from study design, data collection and parame- ter estimation, and provide suggestions to mitigate such biases in future studies. 3. With respect to study design, we argue that currently almost inexistent manipulative studies must complement the dominating correlative studies to inform us about causality in sexual selection. With respect to data collec- tion, we outline how different measures of mating and reproductive success affect the components of sexual (and natural) selection that are reflected in standard summary metrics. With respect to parameter estimation, we show the potential impact of decisions about data inclusion and the chosen quantitative approach on inferences of sex- ual selection and its sex difference. 4. We expect this meta-analytical review to aid future studies in providing less biased and more informative esti- mates of sexual selection. Key-words: Bateman gradient, causality, selection gradient, sex difference, sexual selection components from other forms of selection, accepting a Introduction focus on precopulatory (or pre-spawning) selection episodes Quantifying sexual selection and its effects on trait evolu- (but see section ‘Mating success: definition and meaning’). tion is central to contemporary mating system research. Previous empirical work has been dominated by summary The vastly dominating approach rests on Angus J. Bate- metrics proposed to reflect the opportunity for, and strength man’s (1948) idea to interpret variances in, and the linear of, sexual selection (Table 1). Recent overviews (Jones 2009; relationship between, mating success and reproductive suc- Mobley 2014; Henshaw, Kahn & Fritzsche 2016) accessibly cess as ‘signs’ and ‘causes’ of sexual selection, respectively. summarize their conceptual basis and calculation, and recapit- Later work has formalized his ideas within selection theory ulate a lively debate on the validity of variance-based as well as and clarified the degree to which Bateman’s proxies reflect trait-based metrics to capture sexual selection (refs. in opportunities for, rather than actual, selection (Wade 1979; Table 1), none of which we intend to reiterate or evaluate. Yet, Wade & Arnold 1980; Arnold & Duvall 1994; Jones 2009; while compiling a meta-analysis on sex differences in sexual Table 1). In essence, Bateman metrics echo Darwin’s selection (Janicke et al. 2016), we realized that the existing (1871) conception that sexual selection comprises those empirical work varies remarkably in key aspects of study components of total selection that are mediated through design and analysis. Some approaches can generate inappro- mating success (Arnold 1994). Modern definitions of sexual priate interpretations of sexual selection metrics, or estimates selection also include post-copulatory competition for that are not comparable between sexes, populations, or species. access to gametes. For this review, we stick to ‘mating’ as While earlier work addresses several individual challenges in the anchor that distinguishes sexually selected fitness isolation, we lack a comprehensive and quantitative assess- ment of the methodological pitfalls associated with the quan- *Correspondence author. E-mail: [email protected] tification of routine sexual selection metrics. © 2016 The Authors. Methods in Ecology and Evolution © 2016 British Ecological Society 2 N. Anthes et al. Table 1. Quantitative metrics commonly used to characterize sexual selection and mating systems independent of specific traits, and references dis- cussing their calculation and interpretation (modified and extended from Klug et al. 2010 and Mobley 2014) Metric Description Key references Opportunity for selection (I) Intra-sexual variance in relative reproductive Crow (1958), Wade (1979), Arnold & success. Its square root captures the upper limit of Wade (1984b) and Jones (2009) total linear selection on standardized traits Opportunity for sexual selection (Is) Intra-sexual variance in relative mating success. Its Wade (1979), Wade & Arnold (1980), square root captures the upper limit for mating Jones (2009); recent reviews in differentials m’, i.e. the covariance between Klug et al. (2010), Krakauer et al. (2011), standardized traits and mating success Jennions, Kokko & Klug (2012) and Evans & Garcia-Gonzalez (2016) Bateman gradient (bss) Linear slope of a least squares regression of relative Arnold & Duvall (1994), Andersson & reproductive success on relative mating success, Iwasa (1996) and Jones (2009) describing the average fitness gain associated with each additional mating. Technically represents a selection gradient on mating success, often seen to reflect the average ‘strength’ of directional sexual selection pffiffiffiffi b Jones index (s’max)Calculatedasss Is. Defines the upper limit for Jones (2009) and Henshaw, sexual selection differentials in units of phenotypic Kahn & Fritzsche (2016) standard deviations (=maximum standardized sexual selection differential) Morisita index (Id) Observed variance in mating (or reproductive) Morisita (1962) success relative to the expected variance under uniform mate acquisition probabilities Index of resource monopolization (Q) Ratio of observed to maximum variance in mating Ruzzante et al. (1996) (or reproductive) success Upper limit to the opportunity for selection Estimated maximum gain in reproductive success in Lorch (2005) idealized mating interactions, independent of mate fecundity We scrutinize the quantification of (sex differences in) sexual Study design selection metrics with respect to three components: the under- lying study design (section ‘Study design’), data collection (sec- This section treats pitfalls that researchers encounter when tion ‘Data collection’), and parameter estimation (section designing a study to quantify sexual selection. We discuss the ‘Parameter estimation’). For each component, we discuss pit- degree to which Bateman gradients reflect causality, the need falls during data acquisition, analysis, and interpretation, to estimate sexual selection across a meaningful range of mat- where possible quantify their empirical prevalence and statisti- ing frequencies, and the significance of field vs. laboratory cal consequences using our meta-analysis database (Janicke studies. et al. 2016), and propose guidelines to help prevent these prob- lems in future studies. CAUSALITY VS. CORRELATION IN BATEMAN GRADIENTS Throughout, we exemplify those issues with a focus on the Bateman gradient (bss), representing a widely used integrative Arnold & Duvall’s (1994) path diagrammatic view of sexual proxy of sexual selection (Klug et al. 2010). Contrary to purely selection focuses on two multiplicative fitness components. variance-based proxies such as I and Is (Table 1), Bateman The mating differential, m’ (as defined by Jones 2009), quanti- gradients are considered to reliably capture the overall direc- fies the covariance between candidate traits and mating suc- tion and intensity of, and sex difference in, sexual selection cess, and thus identifies traits that aid individuals in increasing (Jones et al. 2005; Janicke et al. 2016). One proxy directly access to mates. The sexual selection gradient or Bateman gra- derived from the Bateman gradient, the Jones index s’max, dient, bss, quantifies the expected fitness gain associated with shows particularly good performance (Henshaw, Kahn & each additional mating, averaged across the investigated mat- Fritzsche 2016; Table 1) and captures upper limits to sexual ing success range. Their product, m’ bss, describes the standard- selection differentials on any given trait (Jones 2009). We wish ized sexual selection differential on a given trait (Jones 2009). to stress that our methodological arguments extend to all other While both fitness components are routinely quantified in cor- recently advocated metrics of sexual selection (Table 1) that relative studies, we argue that they capture sexual (vs. other share a necessity to quantify individual reproductive success forms of) selection only if they signify causality. We focus our and individual mating success in a population. This includes argumentation on the Bateman gradient, but note that the
Load more

Recommended publications
  • Benefit of Polyandry in a Monandrous Species When Females Mate with Already Mated Males
    King, BH. 2018. Benefit of polyandry in a monandrous species when females mate with already mated males. Behavioral Ecology and Sociobiology For additional accessible full text of publications by BH King, go to http://niu.edu/biology/about/faculty/bking/bking-publications.shtml This is a post-peer-review, pre-copyedit version of an article published in Behavioral Ecology and Sociobiology. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00265-018-2508-4 Benefit of polyandry in a highly monandrous species when females mate with already mated males B. H. King Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA e-mail: [email protected] ORCID 0000-0003-0435-5928 Abstract Female mating frequency varies among animal taxa. A benefit to females of remating has usually been found, but almost all tests have been with polyandrous species. A species being monandrous does not guarantee that mating only once benefits the female, instead the monandry may result from sexual conflict, where her failure to remate benefits her mate, but not her. The parasitoid wasp Spalangia endius (Hymenoptera: Pteromalidae) is highly monandrous. Females do not benefit from either immediate or delayed remating when their first mate is virgin. However, some females are likely to mate with already mated males because sex ratios are female-biased. Here the effect of experimentally-induced polyandry on female fitness was examined for females whose first mate had already mated four times, i.e., for fifth females. Fifth female S. endius produce significantly fewer daughters than first females. Production of daughters, but not sons, requires sperm in hymenopterans.
    [Show full text]
  • Sperm-Limited Males Continue to Mate, but Females Cannot Detect the Male State in a Parasitoid Wasp
    Behavioral Ecology and Sociobiology (2019) 73: 52 https://doi.org/10.1007/s00265-019-2653-4 ORIGINAL ARTICLE Sperm-limited males continue to mate, but females cannot detect the male state in a parasitoid wasp Jun Abe1 Received: 7 September 2018 /Revised: 25 February 2019 /Accepted: 26 February 2019 /Published online: 28 March 2019 # The Author(s) 2019 Abstract Female mating frequency and male ejaculate allocation are likely to interact. Females may adjust their propensity for remating based on the amount of provided sperm to ensure a sufficient sperm supply, and males may determine sperm allocation based on female availability and female mating frequency. In this study, I investigated male and female mating behaviors in the parasitoid wasp Anisopteromalus calandrae. The wasp exhibits the haplo-diploid sex determination, in which sperm-depleted females are constrained to produce only sons by laying unfertilized eggs. The first experiment showed that a rapid succession of male mating decreased the production of daughters (fertilized eggs) by the inseminated females, suggesting that sperm-limited males provided an insufficient amount of sperm to the females. Although the males appeared to replenish their sperm store after 6 h, they mated upon encountering females despite their sperm shortage. The second experiment showed that copulation reduced the subsequent mating receptivity of the inseminated females irrespective of whether the females received a sufficient amount of sperm. Moreover, although approximately 26% of females accepted a second mating and recovered a certain degree of daughter production, remating was independent of the mating status of their first mating partner or the social environment.
    [Show full text]
  • A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries
    ARTICLE IN PRESS A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries Patricia L.M. Lee*, Gail Schofield*, Rebecca I. Haughey*, Antonios D. Mazaris†, Graeme C. Hays*,1 *Centre for Integrative Ecology, Deakin University, Geelong, VIC, Australia †School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece 1Corresponding author: e-mail address: [email protected] Contents 1. Background 2 2. Sea Turtles as a Model Group for Exploring Patterns of Multiple Paternity 3 3. The Incidence of Multiple Paternity vs Species and Rookery Size 5 4. Case Studies: The Extent of Individual Movements Across Rookeries 16 5. Packing Density and Incidence of Multiple Paternity 17 6. Movement Appears Critical to Estimating Density and Mate Encounter Rate 19 7. Conclusion 22 Acknowledgement 23 Authors’ Contributions 23 Competing Interests 23 Funding 23 References 24 Abstract Why females would mate with multiple partners and have multiple fathers for clutches or litters is a long-standing enigma. There is a broad dichotomy in hypotheses ranging from polyandry having benefits to simply being an unavoidable consequence of a high incidence of male–female encounters. If females simply give in to mating when it is too costly to avoid being harassed by males (convenience polyandry), then there should be a higher rate of mating as density increases. However, if females actively seek males because they benefit from multiple mating, then mating frequency, and consequently the incidence of multiple paternity of clutches, should be high throughout. To explore these competing explanations, here we review the incidence of multiple paternity for sea turtles nesting around the World.
    [Show full text]
  • Evolution of Female Multiple Mating: a Quantitative Model of the “Sexually Selected Sperm” Hypothesis
    ORIGINAL ARTICLE doi:10.1111/evo.12550 Evolution of female multiple mating: A quantitative model of the “sexually selected sperm” hypothesis Greta Bocedi1,2 and Jane M. Reid1 1Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, United Kingdom 2E-mail: [email protected] Received June 5, 2014 Accepted October 1, 2014 Explaining the evolution and maintenance of polyandry remains a key challenge in evolutionary ecology. One appealing explana- tion is the sexually selected sperm (SSS) hypothesis, which proposes that polyandry evolves due to indirect selection stemming from positive genetic covariance with male fertilization efficiency, and hence with a male’s success in postcopulatory competition for paternity. However, the SSS hypothesis relies on verbal analogy with “sexy-son” models explaining coevolution of female preferences for male displays, and explicit models that validate the basic SSS principle are surprisingly lacking. We developed analogous genetically explicit individual-based models describing the SSS and “sexy-son” processes. We show that the analogy between the two is only partly valid, such that the genetic correlation arising between polyandry and fertilization efficiency is generally smaller than that arising between preference and display, resulting in less reliable coevolution. Importantly, indirect selection was too weak to cause polyandry to evolve in the presence of negative direct selection. Negatively biased mutations on fertilization efficiency did not generally rescue runaway evolution of polyandry unless realized fertilization was highly skewed toward a single male, and coevolution was even weaker given random mating order effects on fertilization. Our models suggest that the SSS process is, on its own, unlikely to generally explain the evolution of polyandry.
    [Show full text]
  • Hemideina Crassidens
    UNIVERSITÉ DU QUÉBEC À MONTRÉAL LE MAINTIEN DE STRATÉGIES ALTERNATIVES CHEZ LE WELLINGTON TREE WETA (HEM/DE/NA CRASSIDENS): TESTER LES PRÉDICTIONS DE L'HYPOTHÈSE DE POLYMORPHISME GÉNÉTIQUE MÉMOIRE PRÉSENTÉ COMME EXIGENCE PARTIELLE DE LA MAÎTRISE EN BIOLOGIE PAR SARAHNASON JANVIER 2019 UNIVERSITÉ DU QUÉBEC À MONTRÉAL Service des bibliothèques Avertissement La diffusion de ce mémoire se fait dans le respect des droits de son auteur, qui a signé le formulaire Autorisation de reproduire et de diffuser un travail de recherche de cycles supérieurs (SDU-522 - Rév.07-2011). Cette autorisation stipule que «conformément à l'article 11 du Règlement no 8 des études de cycles supérieurs, [l'auteur] concède à l'Université du Québec à Montréal une licence non exclusiye d'utilisation et de publication de la totalité ou d'une partie importante de [son] travail de recherche pour des fins pédagogiques et non commerciales. Plus précisément, [l'auteur] autorise l'Université du Québec à Montréal à reproduire, diffuser, prêter, distribuer ou vendre des copies de [son] travail de recherche à des fins non commerciales sur quelque support que ce soit, y compris l'Internet. Cette licence et cette autorisation n'entraînent pas une renonciation de [la] part [de l'auteur] à [ses] droits moraux ni à [ses] droits de propriété intellectuelle. Sauf entente contraire, [l'auteur] conserve la liberté de diffuser et de commercialiser ou non ce travail dont [il] possède un exemplaire.» UNIVERSITÉ DU QUÉBEC À MONTRÉAL THE MAINTENANCE OF ALTERNATIVE STRATEGIES IN WELLINGTON TREE WETA (HEMIDEINA CRASSJDENS): TESTING THE PREDICTIONS OF THE GENETIC POLYMORPHISM HYPOTHESIS MÉMOIRE PRESENTED IN FULFILLMENT OF MASTER'S IN BIOLOGY BY SARAHNASON JANUARY, 2019 REMERCIEMENTS 1 would like to thank my supervisor Dr.
    [Show full text]
  • The Evolution of Pueriparity Maintains Multiple Paternity in a Polymorphic Viviparous Salamander Lucía Alarcón‑Ríos 1*, Alfredo G
    www.nature.com/scientificreports OPEN The evolution of pueriparity maintains multiple paternity in a polymorphic viviparous salamander Lucía Alarcón‑Ríos 1*, Alfredo G. Nicieza 1,2, André Lourenço 3,4 & Guillermo Velo‑Antón 3* The reduction in fecundity associated with the evolution of viviparity may have far‑reaching implications for the ecology, demography, and evolution of populations. The evolution of a polygamous behaviour (e.g. polyandry) may counteract some of the efects underlying a lower fecundity, such as the reduction in genetic diversity. Comparing patterns of multiple paternity between reproductive modes allows us to understand how viviparity accounts for the trade-of between ofspring quality and quantity. We analysed genetic patterns of paternity and ofspring genetic diversity across 42 families from two modes of viviparity in a reproductive polymorphic species, Salamandra salamandra. This species shows an ancestral (larviparity: large clutches of free aquatic larvae), and a derived reproductive mode (pueriparity: smaller clutches of larger terrestrial juveniles). Our results confrm the existence of multiple paternity in pueriparous salamanders. Furthermore, we show the evolution of pueriparity maintains, and even increases, the occurrence of multiple paternity and the number of sires compared to larviparity, though we did not fnd a clear efect on genetic diversity. High incidence of multiple paternity in pueriparous populations might arise as a mechanism to avoid fertilization failures and to ensure reproductive success, and thus has important implications in highly isolated populations with small broods. Te evolution of viviparity entails pronounced changes in individuals’ reproductive biology and behaviour and, by extension, on population dynamics1–3. For example, viviparous species ofen show an increased parental invest- ment compared to oviparous ones because they produce larger and more developed ofspring that are protected from external pressures for longer periods within the mother 4–7.
    [Show full text]
  • Sexual Selection in the Field: Pre- and Postcopulatory Dynamics in a Hawaiian Cricket
    SEXUAL SELECTION IN THE FIELD: PRE- AND POSTCOPULATORY DYNAMICS IN A HAWAIIAN CRICKET A Dissertation Presented to the Faculty of the Graduate School of Cornell University In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Biz R. Turnell February 2016 © 2016 Biz R. Turnell SEXUAL SELECTION IN THE FIELD: PRE- AND POSTCOPULATORY DYNAMICS IN A HAWAIIAN CRICKET Biz R. Turnell, Ph. D. Cornell University 2016 When females mate multiply, male reproductive success depends not only on mating success but also on fertilization success, which is mediated by postcopulatory processes like sperm competition and cryptic female choice. Although postcopulatory sexual selection has the potential to be a major force in driving evolution, very few studies have estimated its strength in the wild, or measured it in such a way as to enable a quantitative comparison with precopulatory sexual selection. Likewise, though polyandry is widespread across taxa and is the focus of a growing body of research, estimates of natural female mating rates are still limited in number. I used extensive behavioral observations of a semi-natural population of Hawaiian swordtail crickets, Laupala cerasina, combined with molecular paternity assignment, to quantify pre- and postcopulatory selection in this population (Chapter 1). The opportunity for postcopulatory selection was over four times as great as for precopulatory selection. To corroborate the patterns I found in this experiment, I also genotyped the sperm stores and offspring of a group of wild adult females, estimating the number of males each female mated with, the number of males that sired her offspring, and the paternity skew among these sires (Chapter 2).
    [Show full text]
  • Polyandry Enhances Offspring Viability with Survival Costs to Mothers Only When Mating Exclusively with Virgin Males in Drosophila Melanogaster
    Received: 10 March 2017 | Revised: 19 April 2017 | Accepted: 24 April 2017 DOI: 10.1002/ece3.3152 ORIGINAL RESEARCH Polyandry enhances offspring viability with survival costs to mothers only when mating exclusively with virgin males in Drosophila melanogaster Sergio Castrezana1,3 | Brant C. Faircloth1 | William C. Bridges4 | Patricia Adair Gowaty1,2,3 1Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Abstract Los Angeles, CA, USA A prominent hypothesis for polyandry says that male–male competitive drivers induce 2 Institute of the Environment and males to coerce already- mated females to copulate, suggesting that females are more Sustainability, University of California, Los Angeles, Los Angeles, CA, USA likely to be harassed in the presence of multiple males. This early sociobiological idea 3Smithsonian Tropical Research Institute, of male competitive drive seemed to explain why sperm- storing females mate multi- Washington, DC, USA ply. Here, we describe an experiment eliminating all opportunities for male–male be- 4Department of Mathematical Sciences, Clemson University, Clemson, SC, havioral competition, while varying females’ opportunities to mate or not with the USA same male many times, or with many other males only one time each. We limited each Correspondence female subject’s exposure to no more than one male per day over her entire lifespan Patricia Adair Gowaty, Department of Ecology starting at the age at which copulations usually commence. We tested a priori predic- and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA. tions about relative lifespan and daily components of RS of female Drosophila mela- Email: [email protected] nogaster in experimental social situations producing lifelong virgins, once- mated Funding information females, lifelong monogamous, and lifelong polyandrous females, using a matched- NSF IOS Grant # 1121797 to PAG provided treatments design.
    [Show full text]
  • Identifying the Influence of Selective Episodes and Mechanisms on Reproductive Success in Tribolium Castaneum and Drosophila Melanogaster
    Syracuse University SURFACE Dissertations - ALL SURFACE May 2016 IDENTIFYING THE INFLUENCE OF SELECTIVE EPISODES AND MECHANISMS ON REPRODUCTIVE SUCCESS IN TRIBOLIUM CASTANEUM AND DROSOPHILA MELANOGASTER Elizabeth Metta Droge-Young Syracuse University Follow this and additional works at: https://surface.syr.edu/etd Part of the Life Sciences Commons Recommended Citation Droge-Young, Elizabeth Metta, "IDENTIFYING THE INFLUENCE OF SELECTIVE EPISODES AND MECHANISMS ON REPRODUCTIVE SUCCESS IN TRIBOLIUM CASTANEUM AND DROSOPHILA MELANOGASTER" (2016). Dissertations - ALL. 427. https://surface.syr.edu/etd/427 This Dissertation is brought to you for free and open access by the SURFACE at SURFACE. It has been accepted for inclusion in Dissertations - ALL by an authorized administrator of SURFACE. For more information, please contact [email protected]. Abstract: Parsing out what makes some individuals more reproductively successful than others is a key pursuit in evolutionary biology. While reproductive success can ultimately be defined as the number of offspring produced over an individual’s lifetime, there are many selective episodes that shape this outcome. Because the majority of animals have multiple mates, achieving matings is but one influence on reproductive success. After copulation occurs, sperm from multiple males compete within the female reproductive tract to fertilize eggs, while females morphologically or behaviorally bias fertilization to preferred males, further shaping reproductive success. Additionally, the act of mating itself may influence parental lifespan or rate of offspring production. Here, I investigate the influence of multiple selective episodes on different aspects of reproductive success in two insects: the fruit fly, Drosophila melanogaster and the red flour beetle, Tribolium castaneum. Established genomes in both systems enabled the generation of transgenic, fluorescently labeled lines: green fluorescent protein (GFP) driven by a ubiquitin promoter in D.
    [Show full text]
  • The Life History of the Southern Lanternshark, Etmopterus Granulosus, from the Southwestern Indian Ocean
    San Jose State University SJSU ScholarWorks Master's Theses Master's Theses and Graduate Research Spring 2019 The Life History of the Southern Lanternshark, Etmopterus granulosus, from the Southwestern Indian Ocean Melissa Nehmens San Jose State University Follow this and additional works at: https://scholarworks.sjsu.edu/etd_theses Recommended Citation Nehmens, Melissa, "The Life History of the Southern Lanternshark, Etmopterus granulosus, from the Southwestern Indian Ocean" (2019). Master's Theses. 5011. DOI: https://doi.org/10.31979/etd.bdm2-twwy https://scholarworks.sjsu.edu/etd_theses/5011 This Thesis is brought to you for free and open access by the Master's Theses and Graduate Research at SJSU ScholarWorks. It has been accepted for inclusion in Master's Theses by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN A Thesis Presented to The Faculty of Moss Landing Marine Laboratories San José State University In Partial Fulfillment of the Requirements for the Degree Master of Science by Melissa C. Nehmens May 2019 © 2019 Melissa C. Nehmens ALL RIGHTS RESERVED The Designated Thesis Committee Approves the Thesis Titled THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN by Melissa C. Nehmens APPROVED FOR THE DEPARTMENT OF MARINE SCIENCE SAN JOSÉ STATE UNIVERSITY May 2019 Dr. David A. Ebert Moss Landing Marine Laboratories Dr. Scott L. Hamilton Moss Landing Marine Laboratories Dr. Kenneth H. Coale Moss Landing Marine Laboratories ABSTRACT THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN by Melissa C.
    [Show full text]
  • Evolution of Reproductive Traits in Sharks and Rays
    EVOLUTION OF REPRODUCTIVE TRAITS IN SHARKS AND RAYS A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy (PhD) in the School of Medical Sciences, Faculty of Biology, Medicine and Health 2018 AMY ROWLEY FACULTY OF BIOLOGY, MEDICINE AND HEALTH 2 Contents LIST OF FIGURES 6 LIST OF TABLES 9 LIST OF APPENDICES 12 GENERAL ABSTRACT 13 DECLARATION 14 COPYRIGHT STATEMENT 15 ACKNOWLEDGEMENTS 16 1. GENERAL INTRODUCTION 19 1.1 SEXUAL SELECTION 19 1.2 SPERM COMPETITION 22 1.3 CRYPTIC FEMALE CHOICE AND SEXUAL CONFLICT 33 1.4 OUTSTANDING QUESTIONS IN HOW SPERM COMPETITION INFLUENCES THE EVOLUTION OF REPRODUCTIVE TRAITS 34 1.4.1 SPERM NUMBER 35 1.4.2 SPERM MORPHOLOGY 36 1.4.3 SPERM VARIANCE 37 1.4.4 GENITAL MORPHOLOGY 38 1.5 STUDYING EVOLUTIONARY RESPONSES OF REPRODUCTIVE TRAITS TO SPERM COMPETITION 39 1.6 SPERM COMPETITION AND EVOLUTIONARY RESPONSE IN SEXUAL TRAITS IN ELASMOBRANCHS 39 1.6.1 ELASMOBRANCHS 40 1.6.2 SHARKS VS RAYS 41 1.6.3 REPRODUCTIVE BEHAVIOURS IN ELASMOBRANCHS 41 1.6.4 GENETIC MATING SYSTEMS 43 1.6.5 VARIATION IN REPRODUCTIVE TRAITS 46 1.7 REPRODUCTIVE VARIATION IN MALES 47 1.7.1 TESTES 47 1.7.2 SPERM MORPHOLOGY 48 1.7.3 CLASPERS 49 1.8 REPRODUCTIVE VARIATION IN FEMALES 50 1.8.1 REPRODUCTIVE MODE 50 1.8.2 FECUNDITY 51 1.8.3 SPERM STORAGE 52 1.9 CHALLENGES IN STUDYING ELASMOBRANCH REPRODUCTION 54 1.10 AIMS OF THE THESIS 55 1.11 REFERENCES 56 2. TESTES SIZE INCREASES WITH SPERM COMPETITION RISK AND INTENSITY IN BONY FISH AND SHARKS 72 2.1 ABSTRACT 73 2.2 INTRODUCTION 74 2.3 METHODS 76 3 2.3.1 DATA COLLECTION 76 2.3.2 PHYLOGENY 78 2.3.4 PHYLOGENETIC ANALYSES 79 2.4 RESULTS 81 2.4.1 VARIATION IN SPERM COMPETITION RISK AND INTENSITY AMONG FISHES 81 2.4.2 SPERM COMPETITION RISK, INTENSITY AND TESTICULAR INVESTMENT 83 2.5 DISCUSSION 87 2.6 ACKNOWLEDGMENTS 89 2.7 REFERENCES 89 CHAPTER 2: SUPPORTING INFORMATION 96 SUPPORTING INFORMATION REFERENCES 105 3.
    [Show full text]
  • Multiple Paternity and the Number of Offspring: a Model Reveals Two Major Groups of Species
    Received: 11 September 2020 Revised: 17 December 2020 DOI: 10.1002/bies.202000247 PROBLEMS & PARADIGMS Prospects & Overviews Multiple paternity and the number of offspring: A model reveals two major groups of species Hannah E. Correia1,2 Ash Abebe3 F. Stephen Dobson4,5 1 Harvard Data Science Initiative, Harvard University, Cambridge, Abstract Massachusetts, USA Parentage analyses via microsatellite markers have revealed multiple paternity within 2 Department of Biostatistics, Harvard the broods of polytocous species of mammals, reptiles, amphibians, fishes and inver- University, Boston, Massachusetts, USA 3 Department of Mathematics and Statistics, tebrates. The widespread phenomenon of multiple paternity may have attending Auburn University, Auburn, Alabama, USA relationships with such evolutionary processes as sexual selection and kin selection. 4 Department of Biological Sciences, Auburn However, just how much multiple paternity should a species exhibit? We developed University, Auburn, Alabama, USA Bayesian null models of how multiple paternity relates to brood sizes. For each of 114 5 Centre National de la Recherche Scientifique, Institut Pluridisciplinaire Hubert Curien, species with published data on brood sizes and numbers of sires, we compared our Université de Strasbourg, Strasbourg, France null model estimates to published frequencies of multiple paternity. The majority of Correspondence species fell close to our null model, especially among fish and invertebrate species. F.Stephen Dobson, Department of Biological Some species, however, had low probabilities of multiple paternity, far from the pre- Sciences, Auburn University, 331 Funchess Hall, 350 College Avenue, Auburn, AL 36849, dictions of the null model, likely due to sexual selection and environmental constraints. USA. We suggest a major division among species’ mating systems between those with close Email: [email protected] to random mating and high levels of multiple paternity, and those with constraints that Funding information produce low levels of multiple paternity.
    [Show full text]