Insights into the mating systems of green turtle populations from molecular parentage analyses

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Insights into the mating systems of green turtle populations from molecular parentage analyses

Show simple item record Wright, Lucy Isabel en_US 2012-08-13T11:52:55Z en_US 2013-03-21T10:49:44Z 2012-05-23 en_US
dc.description.abstract Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain. en_GB
dc.description.sponsorship Natural Environment Research Council en_GB
dc.description.sponsorship Society for the Protection of Turtles in North Cyprus en_GB
dc.identifier.uri en_US
dc.language.iso en en_GB
dc.publisher University of Exeter en_GB
dc.rights.embargoreason To allow publication of unpublished chapters en_GB
dc.subject Chelonia mydas en_GB
dc.subject marine turtle en_GB
dc.subject mating system en_GB
dc.subject polyandry en_GB
dc.subject microsatellites en_GB
dc.subject sex ratio en_GB
dc.subject Temperature-dependent sex determination en_GB
dc.subject multiple paternity en_GB
dc.title Insights into the mating systems of green turtle populations from molecular parentage analyses en_GB
dc.type Thesis or dissertation en_GB 2013-08-10T03:00:13Z
dc.contributor.advisor Broderick, Annette en_US
dc.contributor.advisor Tregenza, Tom en_US
dc.publisher.department Biosciences en_GB
dc.type.degreetitle PhD in Biological Sciences en_GB
dc.type.qualificationlevel Doctoral en_GB
dc.type.qualificationname PhD en_GB

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