Sexual selection is a frame of reference that attempts to explain exaggerated signaling traits, including acoustic signals between male and female animals. Contemporary studies in the field of sexual selection are focused on the evolution of female mating preferences, with particular emphasis being placed on the good genes models of sexual selection. Here I investigate whether sexual selection is in operation in the acoustic communication system of the field cricket, Gryllus bimaculatus. Through development of new methodology I show that female crickets have a distinct and repeatable preference and selectivity for certain male song traits. For sexual selection to operate in acoustic communication systems, males must advertise some aspect of their phenotype that will influence female choice. I demonstrate that the basis for arguments invoking sexual selection for spectral song traits in a sister species, G. campestris, which is that tegmen harp area predicts song frequency, is an invalid assumption for sound production in G. bimaculatus. As a result of this finding I investigated what aspects of male song were condition- and morphology-dependent. Temporal and spectral male song traits did not convey information regarding body condition, body size or the ability to withstand developmental instability (as indicated by fluctuating asymmetry). I was unable to detect handicap sexual selection for spectral characteristics of male song despite repeatable female preference for male song frequency. Furthermore, female preference for spectral bandwidth of male song, thought to be a sexually selected trait, was shown to be governed by preference for frequency and therefore not a distinct preference. The lack of detectable sexual selection, together with observed patterns of phenotypic variation in signals and the equivalent response system, suggest that some of the male song traits function for mate recognition. However, sexual selection for call traits not considered here (e.g. duration of calling) is probable. / Dissertation (MSc (Zoology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

The use of exchange theory as it applies to human relations has escalated dramatically in the past 20 years. The present study applies exchange theory as the basis of mate selection in contemporary society. Whereas an actual barter system was used in the past and families played a major role in choosing prospective mates, participants in the mate selection process are not virtually on their own and must rely upon their own bargaining skills to present their assets on the marriage market. A number of characteristics are thought to enhance or detract from a person's "worth" on the marriage market. Over 900 college students from nine universities across the united states were surveyed in order to ascertain what they considered valuable in a potential mate, and important variables in the mate selection process were determined. Comparisons were made among gender, race, marital status, family size and configuration, socioeconomic status, religious orientation, and geographical region of the United States. The results indicate that important differences exist among the various groups concerning what characteristics enhance or detract from an individual's worth on the marriage market in contemporary America. Finally, it was determined that marital worth of individuals can theoretically be measured.

Sexual selection shaped psychological mechanisms in both sexes to assess potential mates for evidence of mate quality (Buss, 2005). Attraction preferences are one such mechanism (Sugiyama, 2005) and physical attraction preferences are sensitive to fitness-promoting traits present in a potential mate. Physically attractive traits are thought to act as signals of good genetic quality (Neff & Pitcher, 2005) and are preferred because of the advantage such quality bestows towards reproductive success. Specifically, genetic quality is proposed to be a biological requirement necessary for physically attractive traits to develop and be maintained (Johnstone & Grafen, 1993). Furthermore, genetic quality is heritable to offspring, thereby increasing offspring reproductive success (Orr, 2009). All mating decisions inherently involve trade-offs due to costs inflicted on time and resources when choosing a long-term mate. Assessing a mate for genetic quality is imperative to ensuring one selects a quality mate with heritable fitness benefits towards offspring reproductive success (Buss, 2005). In order to minimize costs and maximize benefits when making mate selection decisions, humans use multiple and redundant signals of mate quality (Fink & Penton-Voak, 2002; Møller & Pomiankowski, 1993). Accordingly, this study supposed that siblings act as redundant signals of genetic quality that would factor into mating decisions. Because genetic quality is heritable (Houle, 1991) and visible through physical attractiveness (Thornhill & Gangestad, 1999), this study explored the possibility that knowledge of relatedness influenced attractiveness judgments of human faces. Supporting the main hypothesis of the current study, siblings affected judgments of physical attractiveness for target faces. Analyses showed this effect to be driven entirely by female raters for both male [t(62)=3.87, p<.001] and female [t(61)=2.24, p=.029] target faces. Secondary analyses examining the effects of sibling pair attractiveness differences (low vs. high) showed that relatedness significantly increased female ratings of facial attractiveness for both low and high facially attractive male and low facially attractive female target faces. Results offer two possible conclusions as to the role relatedness may serve in mate quality assessments that align with parental investment as well as kin selection assumptions.

Eavesdropping occurs when a receiver extracts information from an interaction without directly engaging with the signaler. Eavesdropping has been shown to be an effective way of evaluating the quality of potential mates and their abilities in male-male competition, without having to directly interact with them, thereby reducing energy costs and mating harassment. Girardinus metallicus is a livebearing poeciliid fish endemic to Cuba whose mating system is dominated by mating harassment in the form of sneak copulations, persistent displaying, and male-male aggression. G. metallicus has a male specific polymorphism in both melanin coloration and behavior. Males with melanin coloration are known as black morphs. Black morph males show persistent displaying and higher aggression, whereas plain morph males, the most common morph, do not have pronounced melanin patches and mate solely by sneak copulation. Plain morph males exhibit lower levels of aggression than black morph males. In Chapter 1, we created groups consisting of a female and two males differing in body size and exposed them to dichotomous choice tests of female preference before and after the females witnessed the males interacting with each other. We hypothesized that: 1) male morphological traits are sexually selected via female choice in G. metallicus because these traits indicate quality; 2) female G. metallicus eavesdrop on male aggression to make mate choice decisions because aggression may indicate the quality of the male and his propensity to harass females; and 3) male size classes differ in behavior and morphology (saturation, brightness, and gonopodium size), consistent with other poeciliid studies showing that body size influences phenotype and that these traits are intercorrelated. We predicted 1) females will associate more with more colorful males, males with shorter gonopodia, and the larger male, before eavesdropping on male-male interactions, after, or both; 2) females will spend more time associating with males that subsequently delivered more chases and bites to a competitor male; and 3) larger males would be more active, more persistent in mating attempts, be more aggressive, and have a larger gonopodium size, and greater saturation and brightness of their posterior, ventral, and dorsal body regions. We found that females prefer to associate with males whose body regions are highly saturated, before eavesdropping on the two males interacting, but females did not prefer saturation after eavesdropping. We also found that females had a preference for smaller gonopodia relative for a males’ body size after eavesdropping. We also found that as male size increases, gonopodium length is proportional to their standard length. This study is the first to show female preference for coloration traits within any morph of G. metallicus, suggesting that plain morph males are not as plain to females as their name suggests. Individual animals consistently vary in the average level of behavior exhibited across a range of contexts, which is also known as personality. Behavioral syndromes are correlations among personalities grouping them together. Personality traits have implications for mate choice, fitness, and predator avoidance. In Chapter 2, we addressed behavioral traits and personality in females and whether they influence how males respond to different degrees of boldness, activity, and aggression. We assessed female latency time to emerge from a refuge chamber, activity level, and aggressiveness to another female, on three successive days. We then quantified the degree of mating harassment each female experienced, when tested with a male. We hypothesized the following: 1) female G. metallicus exhibit personality across behavioral contexts (risk, activity, and resource competition), consistent with findings in other poeciliids including male G. metallicus; 2) the rank orders of boldness, activity, and aggression are positively correlated, consistent with other poeciliid studies that found evidence for behavioral syndromes; and 3) female personality traits mitigate male harassment because females that exhibit those personality traits are better at avoiding/retaliating against male harassment. We predicted that: 1) behavioral traits (latency time to emerge, boxes entered, and chases, bites, and fin flares delivered to a female competitor) measured within each context would be repeatable; 2) female rank orders of boldness, activity, and aggression personalities would be positively correlated with each other; 3) that larger females would experience less harassment; and 4) when females directly interact with a male, females that are bolder, more active, and more aggressive (bites and chases delivered to the male) are better able to mitigate male harassment. We found support for the hypothesis that some behavioral traits are repeatable in females; however, we found no evidence for behavioral syndromes. We found evidence to suggest that females that are less bold and less aggressive received less mating harassment from males, possibly because those females are of lower quality and not as attractive to males. Our most novel finding in this study was that activity and aggression were both consistent behavioral traits in females, and therefore constitute personalities; however, these personalities did not have a correlation grouping them together into a behavioral syndrome. Maybe there is a tradeoff: good females are bold and aggressive and get more food, but receive more mating harassment, whereas bad females are submissive and get less food, but avoid mating harassment.

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While the marriage prospects of educated African American women are of particular interest to the media and scholars alike, very rarely do these two groups examine the ways in which African American men understand and perceive marriage. In particular, though they have successfully provided socio-cultural and historically specific examinations of the topic, scholars of African American Studies have not conducted in-depth empirical analyses of African American dating and marriage practices. Simultaneously, social scientists, while providing significant empirical data, have not supported their work with a cultural analysis specific to African American people. In an effort to merge these two areas of scholarship, this dissertation investigated the dating and relationship ideals of college-educated Black men and women. The purpose of this study was to: (1) discover what traits and criteria males and females consider most important in a potential mate, (2) understand the role that the current social and marriage market conditions such as sex ratio, socioeconomic status and education level play in mate selection among college educated Black men and women and (3) develop a culturally specific theory of Black marriage. Through the use of surveys administered online and in face-to-face sessions, this dissertation sought to explore how predictor variables such as age, sex, family economic status and education level influence how 123 college-educated Black males and females ages 18 and over view their dating and marriage prospects and the types of characteristics they assign to the ideal mate. Preliminary findings showed that participants placed a high level of importance on getting married, had positive attitudes toward marriage and were optimistic about their marriage prospects. Additionally, factors such as mate availability, educational attainment and economic ability were of particular importance to participants and play a role in their choices about if, when and who they would marry. Lastly, the author articulated a theory of marriage, the Preliminary Intersectional Factor Theory of Marriage Attitudes and Marital Behavior. Based on the findings, it was argued that the proposed preliminary theory of marriage takes into account the structural, economic and cultural factors that intersect to shape the lives, marital attitudes and marital behavior of Black men and women in America. / African American Studies