Female Reproductive Strategies in the Ruff (Philomachus pugnax)

Sammanfattning: Traditionally, females have been considered to be strictly monogamous. Today, we know that females in the majority of species actively seek out and mate with several males. Trying to understand female preferences, including what benefits mate choice entails, has been the focus of intense research during the last decades. Females can gain both direct (e.g. access to better territories or paternal care) and indirect (i.e. genetic) benefits. The aim of this thesis is to further our understanding of the female reproductive strategies in the ruff, Philomachus pugnax (Aves, Scolopacidae). The ruff is a lekking wader, where males gather on leks to display to females that come there to mate. Males do not provide any paternal care to the offspring. Lekking systems are ideal for studying indirect benefits of female choice, as females do not gain any direct benefits from males.Females mated with several males and 50% of the broods were fathered by at least two males. The level of genetic similarity between two parents has previously been shown to be an important source of variation in offspring fitness. Males that were less closely related to the female fathered more offspring in broods with multiple paternity, such that females that mated multiply gained in terms of receiving more outbred offspring. There did not, however, appear to be an overall female preference for less closely related males. There are two genetically determined male reproductive strategies in the ruff, that differ in behaviour and morphology. There was no evidence for females taking male strategy into account when choosing a partner.Female post-fertilisation strategies may also influence fitness, e.g. through differential investment in eggs, gender of the offspring and choice of breeding habitat. Females allocated sex in a non-random manner dependent upon body condition, such that females in good condition had more daughters.Females were found to nest in higher than average vegetation and in areas with higher than average abundance of insects, factors likely to influence predation rates on both eggs and young, as well as foraging opportunities for the precocial young. Further, females were faithful to their previous breeding site and usually nested within meters of their previous nest. Hatching success did not, however, affect a female’s decision to return or not.