Breeding systems encompass a diverse range of mating and parental care strategies that develop in relation to reproductive success. However, which factors determine the reproductive strategy that will achieve success, in terms of Darwinian fitness, is still a controversial issue in theoretical and empirical behavioural ecology. I argue in this dissertation that animal reproductive strategies depend on variation in the social environment, which is influenced by the number of available mates in a population. The purpose of this thesis was therefore to investigate the role of mating opportunities, in breeding system evolution by testing current theoretical models. First, I studied different contributory factors that have been proposed to influence variation in mating opportunities, including, brood attendance (chapter two) courtship (chapter three) and pair bond stability (chapter three) in four closely related plover species of genus Charadrius: Kentish plover, C. alexandrinus; Kittlitz’s plover, C. pecuarius; Madagascar plover, C. thoracicus; and white-fronted plover, C. marginatus. Second, I investigated whether mating opportunities differed between these plover species that exhibit different mating and parental care patterns yet have similar life histories and ecology (chapter three). Third, I also studied the spatial movements of plovers when searching for a mate (chapter four). Consistent with theoretical models, mating opportunities were highly variable between species suggesting that mating opportunities are an important component of the social environment. Since mating opportunities are linked to operational sex ratios (OSR, the ratio of sexually active males to females), this suggests that OSR exhibits substantial variation among closely-related species that may influence the direction and intensity of courtship and mate searching behaviour (chapter three and four) and whether to care for or desert offspring (chapter two). These results from wild populations suggest that a demographic property of the populations, OSR, influences mating opportunities, and in turn, facilitate different intensities of sexual selection and parental care patterns.
|Date of Award||26 Jan 2015|
|Supervisor||Tamas Szekely (Supervisor)|