Document Type


Degree Name

Master of Science (MSc)



Program Name/Specialization

Integrative Biology


Faculty of Science

First Advisor

Tristan A.F. Long

Advisor Role



The ability to discriminate between prospective mates is potentially important not only for the avoidance of unsuccessful or incompatible matings, but also for the selection of higher “quality” mates. Inbreeding, reproduction between closely related individuals, has long enjoyed the attention of biologists, and has classically been associated with fitness consequences that are primarily negative, termed “inbreeding depression”. Indeed, the costs of mating with a relative are well documented across a wide variety of species. If individuals are capable of kin recognition, it is expected that species should evolve to avoid consanguineous matings. However, a number of recent models suggest circumstances in which inbreeding might be favoured or at least not result in substantial fitness penalties. In support of these models, several recent studies have reported that in the model species Drosophila melanogaster, males and females are either indifferent with respect to the degree of relatedness of their mates, or favour closely related mates when exercising mate choice. Other work has suggested that relatedness might also serve to reduce sexual conflict. However, these studies are not without their limitations. In some cases, relatedness has been confounded with developmental environment, and it is not possible to determine if relatives are preferred as mates, or if there is a positive association between individuals who are developmentally familiar. In a number of these studies, the fitness consequences associated with such matings have not been quantified. Overwhelmingly, all studies have addressed intra- and inter-sexual relatedness in isolation from each other, and have neglected to assess the interplay between these factors. In chapter one, I assess intra- and inter-sexual relatedness and the short- and long-term fitness consequences of inbreeding and interacting with kin. In chapter two, I focus on the reproductive behaviour of males, and how kinship might modulate conflict and ultimately fitness over the lifespan of an individual. The results of each of these studies suggest that, in our study populations, individuals hold no bias towards kin. Inbreeding depression does occur, but the magnitude of this cost is small, and is balanced by the benefits to inclusive fitness. Ultimately, outcomes and preferences for inbreeding are likely highly context-dependent.

Convocation Year


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