Thesis Submitted for the Degree of Doctor of Philosophy University of Bath Department of Biology and Biochemistry
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University of Bath PHD Breeding system evolution in relation to adult sex ratios Carmona Isunza, Cristina Award date: 2017 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 07. Oct. 2021 Breeding system evolution in relation to adult sex ratios María Cristina Carmona Isunza A thesis submitted for the degree of Doctor of Philosophy University of Bath Department of Biology and Biochemistry September 2016 COPYRIGHT Attention is drawn to the fact that copyright of this thesis rests with the author. A copy of this thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that they must not copy it or use material from it except as permitted by law or with the consent of the author. This thesis/portfolio may be made available for consultation within the University Library and may be photocopied or lent to other libraries for the purposes of consultation Signed on behalf of the Department of Biology and Biochemistry 1 Contents Acknowledgments………………………..………………………………………………..3 Summary………………………………………………………………………………….....4 Chapters: 1 Introduction……………………………………………………………..…...5 Dissertation outline……………………………………………..….10 2 Adult sex ratio and operational sex ratio exhibit different temporal dynamics in the wild……………………………………………………..…14 3 Courtship behaviour differs between monogamous and polygamous plovers…………………………………………………………………..…..42 4 Does social environment predict duration of female care in a polygamous bird? .................................................................................61 5 Breeding schedule of males and females in monogamous and polygamous plover populations………………………………………….82 6 Discussion…………………...…………………………………………....102 Appendices: I Morphological and genetic differentiation among Kentish Plover Charadrius alexandrinus populations in Macaronesia………………112 II High fidelity: extra-pair fertilisations in eight Charadrius plover species are not associated with parental relatedness or social mating system................................................................................................132 III Sexual Maturity Relates to Mate Competition and Adult Sex Ratios in Birds…………………………………………………….………………....163 2 Acknowledgments The long process of completing a PhD involves many people who in a small or large scale help to shape the good or bad outcome of a thesis. I want to thank all the people involved in mine and will briefly mention some of them. First of all I sincerely thank my supervisor, Professor Tamás Székely for his guidance into trying to shape my PhD into a good one. I thank my two examiners: Nick Priest and Michael Jennions for reading my thesis, for their helpful comments and making the viva an interesting and enjoyable talk. I thank my country Mexico and it’s great institution CONACyT (PhD scholarship number 216052/311485) which keeps helping Mexican students move around to pursue higher academic levels. I also thank the support given in two consecutive years by SEP-DGRI (Programa beca complemento). I thank my husband, Sergio Ancona for all his strength and support through this tough period and for pushing me to pursue my dreams always. I also thank him for all his valuable scientific input, comments and discussions which were essential to the completion of my PhD. I thank my family for their continuous support, specially my parents for their fair-minded support and guidance always. I thank my friends in the UK that turned into my family while away from my own: Jennifer, Ornela, Santiago, Viviana, Oscar, Amine, Leda, Itandehui, Carles, Andrea, Katie and Jon. I also thank Helen Haste for opening her house and her heart to me and being supportive and generous always. All my colleagues at the Biodiversity Lab, past, present and vagrant. Special thanks to Kate Ashbrook and Mohammed Almakhi who guided me upon arrival. Special thanks to co-authors and people who made significant contributions to ideas and methodologies specially: Clemens Küpper, Luke Eberhart-Phillips, Alfonso Ramallo, Horacio González, András Kosztolanyi and Martín Alejandro Serrano-Meneses. I thank all the people in FMB (Maio Biodiversity Foundation) who made fieldwork enjoyable and more important, possible; specially Franzisca Koenen, Arnau Teixedor and Sergio Portugués for all the support given. DGA for providing permits and constant support for fieldwork in Cape Verde. I thank all project managers, field assistants and volunteers who have helped build the invaluable plover databases: Medardo Cruz, Sama Zefania, Luke Eberhart-Phillips, Orsolya Vinzce, Edinho Inés, Alex Tavares, Phillipa Harding, Keeley Seymour, Carlos Reis, among many others. People who carried out laboratory analysis: Natalie Dos Remedios, Katy Maher, Teresa Santos, Luke Eberhart-Phillips. 3 Summary The study of breeding system evolution has been prolific given the broad subjects that it embraces, from the social environment and sexual selection to courtship behaviour and parental care. The general objective of this dissertation was to test empirically ideas shown in recent models of breeding system evolution. Using plovers Charadrius spp. as model organisms, which show remarkable variation in breeding systems, I investigate how adult sex ratio (ASR) and operational sex ratio (OSR) are linked together and relate to two major components of breeding systems: courtship behaviour and parental care. Experimental studies have led to equate ASR and OSR, but they are not necessarily the same and the way they correlate in nature is unknown. Here I show that in a wild polygamous plover population these ratios seem to be uncorrelated (Chapter 2). Differences in the social environment and the degree of mating competition between monogamous and polygamous populations could also be reflected in their courtship behaviour; higher courtship rates in a polygamous plover than in a monogamous closely-related plover support this prediction (Chapter 3). OSR may be more variable throughout time than ASR, and therefore be less reliable as a cue to the social environment. In support of this prediction ASR was better than OSR at predicting the duration of female brood care in a polygamous plover where females have variable care (Chapter 4). Sex-specific timing of breeding could differ according to the social environment and the level of mating competition in a population, I compared six populations of five closely-related plover species with varying breeding systems (Chapter 5); only one polygamous population showed sex-specific differences in arrival date and the length of time spent in the breeding grounds. Finally, I discuss the contribution of these results to the understanding of breeding system evolution and suggest potential future lines of research. 4 Introduction Chapter 1 Introduction 1 Breeding systems Breeding systems comprise any behavioural strategy to obtain mates, reproduce and care for progeny in any sexual animal (Reynolds 1996). It describes the mating strategies: form of courtship and competition, number of mates, duration of pair bonds and the post-mating behaviours like the form and duration of parental care (Reynolds 1996). Although originally referred to as mating systems in previous literature (e.g. Darwin 1871; Emlen and Oring 1977) the difference between these two terms, as Reynolds (1996) suggests, relies in the reproductive stage one wants to address: the mating strategies (‘mating system’) or both the mating strategies and the post-mating behaviours (‘breeding system’). In most species, male’s and female’s competitiveness for mates (i.e. sex-roles) are different, usually being males the most competitive sex (Parker and Pizzari 2015) and these differences have typically been attributed to the size of the gametes (Lehtonen et al. 2016) and the level of parental investment ("any behaviour that increases offspring survival at the cost of parent’s survival or future reproduction", Trivers 1972). Early theory suggests that these differences in parental investment create a mating differential between the sexes, giving rise to different costs and benefits for males and females that shape the different mating strategies and different sex-roles found in nature (Andersson 1994; Alcock 2005). These theoretical arguments are built upon Bateman’s (1948) study in which he showed that males’ fitness depends on the number of mates it has, although females’ fitness is unrelated to number of mates (but see next section) and can increase with e.g. mechanisms that discriminate between high/low quality mates. Given the reproductive differences between males and females, the sex