Mate choice decisions have long-term effects on both party's well-being as well as reproductive outcomes. Consequently, evolutionary biology and psychology devoted a large body of research on investigating human mate choice. The evolutionary psychology of human partner selection can be perceived as inter-connected processes, such as mating strategy, mate preferences, and mate choice. This dissertation thesis consists of two larger segments. The first segment is an Introduction to my four original research papers in the second segment. In the Introduction, I discuss heterosexual partner selection in two parts. First, I describe how mating strategies affect mate preferences, what the key mate preference dimensions are - both positive and negative factors of partner evaluations -, how stable they are, and how they change over time within a person. Further, I review the concept of mate value and how mate preference factors are weighing in the overall perception of mate value on the mating market. In the second part, I discuss how partner preferences are integrated into mate choice, also known as the mate choice integration models. The Additive and Threshold models of mate choice, the Euclidean distance model, and Assortative mating will be discussed in detail since they are the most commonly applied...

The proposed thesis is comprised of eleven papers connected by the employment of the evolutionary psychological approach in research on various aspects of human sexuality. The aim of the first monothematic part is to demonstrate the evolutionary-psychological approach to one recent phenomenon in female sexuality - the use of oral contraceptives (OC). OC use has been shown to suppress psychological mechanisms that are considered to be adaptive in the fertile period of the natural menstrual cycle. In particular, OC users' ratings of male stimuli that provide the cues of genetic quality and compatibility are lower in comparison with normally cycling women. Moreover, the increase in sexual desire and in the prevalence of proceptive behaviour observed during mid-cycle in normally cycling women is diminished. However, the impact of this phenomenon on mate-choice and relationship dynamics in an ecological context has not been studied. In the first study, we have analyzed the data of Czech women obtained via representative sampling within the Czech National Survey of Sexual Behavior. Results indicated that normally cycling women had a significantly higher number of one-night stands during the last year in comparison to OC users even when living in a long-term relationship. OC usage was also shown to have...

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Particularly lacking in the current body of sexual selection literature are studies based on reptile species and intrasexually selected mating systems. Because the life history traits and ecology of reptiles are dramatically different from other animal taxa, current models of sexual selection are insufficient for predicting how sexual selection should influence the behavior and mating systems of lizards. Similarly, intersexually selected mating systems (i.e., based on female choice) are inappropriate predictive models for examining species with intrasexually selected mating systems (i.e., based on consexual contests). I investigated three aspects of Anolis carolinensis behavior and mating system (communication signals, male mate preference, and reproductive energetics) to contribute to a theoretical model for sexual selection based on a lizard with an intrasexually selected, polygynous mating system. In my first study, I quantified the structure and use of signals exchanged by both sexes, compared signal structure and use during heterosexual interactions to that of other social contexts (e.g., male-alone, male-male, female-female), then related signal structure and use to the species mating system. During heterosexual interactions, both sexes performed three kinds of stereotypic headbob displays with equal precision that were essentially identical to those previously documented for other social contexts. Thus, there is no courtship-specific headbob display for A. carolinensis. However, male and female signal use was extremely dimorphic. For the purpose of indicating sexual identity, the sexually dimorphic patterns of signal use were excessively redundant, yet equivocal. Although the male pattern of signal use reliably conveys sexual identity, the female pattern of signal use conveys ambiguous sexual identity. Based on circumstantial evidence from other studies, I propose the hypothesis that the female pattern of signal use may permit female-sized, nonterritorial males to mimic female signals. Small males may be selected to use female mimicry to gain access to the territories of larger males and mating opportunities with resident females, while females may be indirectly selected to use a signaling pattern that provides them with an alternative mating option. From field and laboratory data on A. carolinensis signal behavior during other social contexts and the species' female-defense mating system, I evaluate proposed functions for heterosexual signaling from a perspective of intrasexual selection. In my second study, I tested the prediction that males should include a preference for mating with novel females (PNF) as part of their mating strategy. This prediction was supported by both laboratory and field manipulations. Compared to their encounters with resident females, males during laboratory encounters with novel females significantly increased their display rate, volley frequency, volley length, and significantly decreased the distance and number of movements traveled away from the female. My laboratory data also suggest that males discriminated novel females from resident females independently of female behavioral or chemical cues. Similarly, compared to their interactions with resident females, free-ranging males responded to introduced novel females by significantly increasing the proportion of time spent in female-directed activities and the proportion of displays directed toward novel females, and significantly decreasing the proportion of time spent in territorial activities and the proportion of displays used in territorial activities. Data from both experiments indicate that males appear to distinguish among individual females, and use this ability to increase reproductive success by identifying and preferentially pursuing novel females over previously inseminated resident females. I suggest that males are able to cognitively identify individual resident females, and use this ability to control mating decisions within their territories. In my third study, I examined the energy expenditure of males and females during breeding and postbreeding seasons. I used laboratory respirometry to determine resting metabolic rates, and the doubly-labeled water technique to determine field metabolic rates in free-ranging lizards. Resting metabolic rates were significantly influenced by body mass and season, but not sex. Field metabolic rates were significantly influenced by body mass, but not sex or season. I attributed the ~40% seasonal increase in resting metabolic rates to a seasonal increase in feeding rates and the effect of specific dynamic action. Resting and field metabolic rates were used to calculate energy budgets for each sex during breeding and postbreeding seasons, and to calculate the energy expended by each sex for reproduction. Despite having 40% smaller body mass, females expended 46% more energy for reproduction than males, and a similar amount of total maintenance energy as males. The total maintenance energy of males was similar during both seasons, however that of females decreased 44% from breeding to postbreeding season. I found both seasonal and sexual differences in the amount of energy lizards allocated to resting and activity. Anolis carolinensis had field metabolic rates that were similar to tropical and temperate species of lizards, and higher than lizards from arid/semiarid environments. Anolis carolinensis also expended more energy on eggs, and more total energy during the breeding season, than lizards from arid/semiarid habitats. / Ph. D.

Over the past twenty years there has been an exponential increase in the investigation of maternal effects. Understanding the adaptive function of maternal allocation strategies is integral to interpreting the evolutionary outcomes of sexual selection. Thus, model animal systems that facilitate experimental manipulation and controlled investigation of the physiological and behavioural mechanisms underlying maternal effects are important to evolutionary biologists. The zebra finch (Taeniopygia guttata) has been used as a model to investigate avian life-history, signalling behaviour, neurophysiology, mate choice, and more recently, maternal effects. However, a potentially influential and rarely addressed problem with this species is the process of domestication. Within this thesis we aimed to both test current predominant maternal allocation hypotheses, but for the first time in both domesticated and wild zebra finches. Chapter 2 develops on earlier work using domesticated zebra finches that has demonstrated differential allocation of maternally derived yolk androgens and antioxidants in eggs dependent on paternal attractiveness. This chapter specifically tests the ratio of these two yolk resources within individual eggs and shows that the balance of androgens to antioxidants varies by offspring sex and paternal attractiveness. Specifically, we found that mothers allocated a smaller androgen to antioxidant ratio to daughters when paired to green ringed (unattractive) males compared to red ringed (attractive) males. This pattern was reversed for sons, where mothers allocated a larger ratio of androgen to antioxidant when paired to red ringed (attractive) compared to green ringed (unattractive) males. We also show that brood sex ratio depended on both female condition and male attractiveness. It is concluded that investigating female allocation of individual resources within egg yolks may lead to incorrect assumptions on offspring fitness consequences, and that individual female state is an important consideration when predicting a resource allocation strategy. Throughout this thesis colour bands are used as a method to manipulate male attractiveness. In chapter 3 the influence of these bands was further tested to elucidate whether they affect male behaviour or quality. Wild birds were used for this chapter as preferences for bands based on colour have only once been demonstrated in wild birds and it was felt this should also be replicated. We confirmed a female preference for males based on colour bands worn in mate choice trials, with red bands preferred over green. Interestingly, we also found that colour of bands worn by males for an extended period in the single sex aviary influenced both their song rate and condition. Males that had worn red bands sang more in mate choice trials than both green banded or un-banded males. In addition red banded males were found to be in significantly better physical condition. These data suggest that earlier experiments in which it has been assumed that colour bands do not manipulate any form of intrinsic male quality should be re-evaluated. The final two data chapters, 4 and 5, return to investigating maternal allocation in response to male attractiveness, but for the first time in wild birds. Chapter 4 presents an experiment that was conducted on a wild, nest box breeding population of birds. Maternal resources allocation was investigated in both an experimental manipulation of male attractiveness, and also by correlating resource allocation with paternal phenotypic traits. A limited sample size meant few conclusions could be drawn from the experimental study, but significant positive correlations were found between both egg size and yolk testosterone (T) concentration and male phenotypic traits. This suggested that wild zebra finches may follow a positive investment strategy but requires further investigation. In chapter 5 experiments were repeated on wild birds that had been brought into captivity, to allow both an improved sample size and further control of influential environmental features. Again, female allocation strategies are tested using colour bands to manipulate male attractiveness, to allow direct comparisons with work on domesticated zebra finches. We found that females laid significantly heavier eggs for attractive compared to unattractive males, supporting the positive investment hypothesis. In addition we found an interaction between offspring size and paternal attractiveness treatment, with daughters of red banded (attractive) males being smaller than sons. This experiment is the first to demonstrate the influence of colour bands on maternal allocation in wild zebra finches and also provides further support for the positive investment hypothesis in this species. The final chapter discusses how overall patterns of female allocation were shown to be similar among wild and domesticated populations. It is concluded that demonstrated variations between populations and/or contexts reported in these studies cannot be explained by inherent differences between wild and domesticated individuals. Thus, the zebra finch remains a robust and reliable model for testing the evolution of avian maternal allocation strategies.

The invasion of individuals into new habitats can pose a major threat to native species and to biodiversity itself. However, the consequences of invasions for native populations that are not fully reproductively isolated from their invaders are not yet well explored. Here I chose the Trinidadian guppy, Poecilia reticulata, to investigate how different population traits shaped the outcome of Haskins's introduction, a well-documented invasion of Guanapo river guppies into the Turure river. I especially concentrated on the importance of behaviour for invasive success. I investigated if the spread of Guanapo guppies is due to superiority in behaviour, life-history and/or genetics, or if the outcome of this translocation is due to chance. Despite the fact that by today the invasive front has passed the Turure's confluence with the River Quare many kilometres downstream of the introduction site, and the original genotype only survives in small percentages, as was revealed by genetic analysis in this and other studies, no obvious differences between invasive and native populations could be detected in any of the tested behavioural, life-history and genetic traits. When tested for mate choice, neither Guanapo nor Oropuche (Turure) males seemed to be able to distinguish between the population origin of females, but courted and mated at random. At the same time, females did not prefer to school with individuals of the same population over schooling with more distantly related females. The formation of mixed schools after an invasive event is therefore likely. Because female guppies showed a very low willingness to mate, even after having been separated from males for up to six months, sperm transfer through forced copulations will become more important. Taken together, these behaviours could increase the speed of population mixing after an invasion without the need for behavioural superiority of the invasive population. When tested for their schooling abilities, offspring of mixed parentage, in contrast to pure breds, displayed a large amount of variety in the time they spent schooling, a circumstance that can potentially influence survival rates and therefore the direction of gene pool mixing. Guanapo fish did not show reproductive superiority in a mesocosm experiment, where both populations were mixed in different proportions. On the contrary, in two out of three mixed treatments, the amount of Oropuche (Turure) alleles was significantly higher than expected from the proportion of initially stocked fish. The almost complete absence of distinguishable traits other than genetic variation between the examined populations that belong to different drainage systems, opposes the recent split of the guppy into two different species following drainage system borders, as is argued in this thesis. However, the successful invasion of the Turure by Guanapo guppies and the nearly entire disappearance of the original population can be explained in absence of differing population traits. Here I demonstrate how behavioural and genetic interactions between subspecies influence the outcome of biological invasions and second, how factors other than population traits, such as the geographic situation, can produce an advantageous situation for the invader even in the absence of population differences.

Chez les espèces où mâles et femelles portent des traits voyants et élaborés, les traits observés chez les femelles peuvent être des sous-produits non-fonctionnels de la sélection sexuelle exercée sur les traits mâles ou alors être directement soumis à la sélection. Cette thèse a eu pour objectif de tester l'hypothèse de sélection sexuelle chez les femelles de Mésange bleue (Cyanistes caeruleus) sur trois traits présents chez le mâle et la femelle : (1) la coloration structurelle UV/bleue de la tête, (2) la coloration jaune basée sur les caroténoïdes de la poitrine et (3) l'agressivité. Pour cela, nous avons testé expérimentalement (1) le lien entre les traits colorés et le transfert de composants potentiellement bénéfiques dans les ufs, (2) la condition-dépendance des traits colorés, (3) l'utilisation de la coloration du plumage dans les interactions femelle-femelle et (4) le lien entre l'agressivité des femelles et leur investissement dans la reproduction. Enfin, nous avons exploré le rôle potentiel des couleurs femelles dans le choix de partenaires mâle en testant le lien entre la couleur UV/bleue des femelles et le nombre de jeunes issus de copulations hors couple et l'appariement selon la couleur bleue et jaune dans notre population. Nos résultats suggèrent (1) qu'il existe un lien entre la qualité maternelle et la coloration de leur plumage, (2) que les couleurs UV/bleues et jaune du plumage sont conditions-dépendants, (3) que les UV/bleus de la tête sont utilisés comme badge de statut dans les interactions femelle-femelle, (4) qu'il pourrait exister un compromis entre l'agressivité femelle et son investissement dans la reproduction et (5) qu'il existe un potentiel choix mutuel de partenaires basés sur les couleurs. Au final, cette thèse a ainsi permis de mettre en évidence que chez une espèce où mâles et femelles sont ornementés, les traits colorés femelles ont le potentiel d'évoluer sous l'effet direct de la sélection sexuelle. / In mutually ornamented species, female conspicuous traits could be non-functional by-products of sexual selection acting on male traits or could be directly under selection. The aim of this PhD was to test the hypothesis of sexual selection in Blue tit (Cyanistes caeruleus) females on three traits present in both males and females: (1) the structural coloration of the UV/blue crown, (2) the yellow chest coloration based on carotenoids and (3) aggressiveness. To do so, we experimentally tested (1) the links between plumage coloration and the transfer of potentially beneficial components in egg yolks, (2) the condition-dependence of the plumage coloration, (3) the use of the plumage coloration in female-female interactions and (4) the link between female aggressiveness and investment in reproduction. Finally, we explored the role of female plumage coloration in male mate choice by testing the link between female UV/blue crown coloration and the n umber of extra-pair young in the nest and by estimating whether the individuals were assortatively mated in respect of their yellow and blue coloration in the studied population. Our results suggest that (1) there is a link between female plumage coloration and maternal quality, (2) plumage UV/blue and yellow coloration is condition-dependant, (3) the UV/blue crown is used as a badge of status in female-female interactions, (4) there could be a trade-off between female aggressiveness and female investment in reproduction and (5) there is a potential mutual mate choice based on both coloration. So, this PhD supports the hypothesis that in a mutually ornamented species, female ornaments are potentially under direct sexual selection.

Studies of the evolution of the major histocompatibility complex (MHC) have been central to the understanding sexual selection and pathogen-mediated selection. The European badger Meles meles is well suited for exploring such questions because of its life history characteristics, reproductive biology and mating system. In this thesis, I examined both MHC class I and class II genes. Seven putatively functional sequences were found for class I genes and four for class II DRB genes. Evidence of past balancing selection of both genes was demonstrated by the d_Nd_S ratio, by positive selection at the antigen-binding site (ABS) and by trans-species polymorphism of alleles within other mustelids and carnivores. MHC class I genes also showed evidence of concerted evolution, but domains showed different evolutionary histories. MHC genes may influence microbiota and odour of an individual and influence mating preferences. I examined the bacterial community of the subcaudal gland secretion and demonstrated a high number of bacterial species (56 operational taxonomic units), which cubs exhibited a higher diversity than adults. The microbiota may lead to an individual-specific odour as a cue signaling the MHC genotype of potential mating partners. I report the first evidence for a MHC- based mating preference in carnivores. Female badgers showed a MHC-assortative mate choice towards breeding with males that had functionally similar MHC genes, for MHC class II DRB genes. This applied to neighbouring-group matings. I also found considerable annual fluctuation in the occurrence of MHC-based mate choice. Based on genome-wide background in the same mating randomizations I found no evidence of inbreeding, which indicated that MHC similarity was apparently the actual target of mate choice. In line with MHC-assortative mate choice, MHC heterozygosity had no influence on the co-infection status. Individual MHC alleles did, however, associate with resistance and susceptibility to specific pathogens, suggesting that MHC diversity may be driven and maintained by pathogen-mediated selection through rare-allele advantages and/or fluctuating selection. My study of genetic characteristics, mate choice and pathogen pressures in a wild population revealed past and contemporary evolutionary process of the MHC genes. This increases knowledge of how the MHC may affect mating behaviour and sexual selection, ultimately influencing population processes.