A great challenge that biology faces is in integrating phenomena from different scales. On the micro scale of the spectrum, we can measure subcellular processes, like gene expression and regulation. On the macro scale, we can measure species level variation, ecological interactions, and the like. The challenge biology faces is in following the causal threads that lead individuals, populations, and ultimately, species to the variation in traits that we see in nature. The idea that there are cascades of causality that reduce to a microscopic scale is often referred to as the Genotype to Phenotype map (Houle and Govindaraju 2010). The Genotype to Phenotype map is ultimately a problem of measurement; what do we need to measure at each scale of interest in order to understand and, more importantly, predict variation elsewhere on the spectrum? This thesis is focused on two parts of the genotype-phenotype spectrum. The first chapter focuses on the macro scale, specifically on how traits maintain stasis across species. Here we use Drosophila melanogaster wing shape as a model to test whether stasis is explained by constraint or by stabilizing selection. We test for constraint with an artificial selection experiment on wing shape. We then test for stabilizing selection by measuring flight differences among selected and unselected flies and by testing for mate preference. In the second chapter, I focus on the micro scale by describing a method to measure the spatial properties of gene expression patterns. Quantitative measures of gene expression currently focus on mutations in the genome and/or the magnitude of expression. This ignores the spatial components of gene activity that are critical in the formation of pattern and the maintenance of growth during development. I describe methods to measure the spatial characteristics of genes that form discrete and continuous patterns of expression. I then give three examples of the method by quantitatively disrupting three genes and estimating the effects on a discrete and a continuous expression pattern. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2014. / November 04, 2014. / Includes bibliographical references. / David C. Houle, Professor Directing Thesis; Wu-Min Deng, Committee Member; Michelle N. Arbeitman, Committee Member.

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Understanding the evolution of cooperative behaviors is a major goal of evolutionary biology, but the majority of research in this field has focused on why helpers assist others. Helpers’ reproductive costs introduce a clear paradox to our understanding of natural selection as helpers in cooperative systems apparently sacrifice reproductive opportunities to increase others’ fitness. This puzzle in cooperative behaviors has led to significant advances in our understanding of indirect and delayed fitness benefits for helpers. However, as cooperation results from the interaction of individuals that may have very different incentives for participation it is equally important to understand whether and how cooperation benefits the dominant recipients of this help. There has been relatively little attention paid to why the recipient of the apparent help participates in the cooperative relationship, in part because the advantage to the dominant individual seems apparent in many systems. Existing work reveals a variety of potential benefits for dominant individuals and that the benefits for dominants may be less obvious than assumed. To date investigations into costs and benefits of cooperation to dominant individuals have been largely limited to cooperative breeding behavior. My dissertation research investigates the fitness consequences of cooperative courtship display for dominant individuals, in the White-ruffed Manakin, Corapipo altera. Manakins (Aves: Pipridae) are small, primarily lekking passerines, and, in some species, males cooperate in their courtship displays. Previous work on manakin cooperative display behavior has focused on benefits to subordinate males. The fitness consequences of cooperation for dominant individuals has not yet addressed in a system with variation in cooperative strategies. I found strong evidence of cooperation among male C. altera. I also found that, within a single population of C. altera on the Atlantic slope of Costa Rica, some males participate in coordinated display with other males (45.4±20% were classified as cooperative in any given year), while other males appear to only display singly. My dissertation research investigated the causes and consequences of cooperation by dominant C. altera males by quantifying aspects of the males' fitness including how inclusive fitness benefits may facilitate the maintenance of cooperative display coalitions and the consequences of cooperative display coalitions for males’ annual reproductive success, survival, and social status — important parts of lifetime fitness for long-lived, iteroparous species including C. altera. I found that cooperative males were not more closely related than expected at random from the population. Males that cooperated did not have higher annual reproductive success than males that displayed solo nor was there a significant difference in the frequency of copulations after a solo courtship display and a courtship display by multiple males. In a survival analysis, cooperation did not significantly affect the survival of dominant males. There was no consistent pattern of cooperation (or non-cooperation) among males across their tenure as dominant male: some were always cooperative, some always non-cooperative, but many males with multi-year tenures switched between cooperative and non-cooperative statuses. However, more males than expected employed strictly solo strategies across their tenure as dominant individuals, given the population-wide rates of survival and cooperation. The degree to which males cooperated, defined as the proportion of tenure classified as cooperative, was unrelated to variation in lifespan or length of tenure as a dominant male. Additionally, the proportion of total tenure classified as cooperative did not explain the patterns of lifetime reproductive success. Together, these results reject the hypotheses that dominant males in cooperative partnerships gain indirect or direct fitness benefits from their associations with subordinate males. Seeking to understand processes underlying patterns of fitness consequences from cooperative behaviors, I conducted three experiments to determine if males at sites where the dominant male was cooperative were faster or more intense in their response to an experimental stimulus. Cooperative males were not faster to respond to a female at the display site nor were they faster to respond to the vocalization of an unknown male conspecific at the display site. Cooperative males were not significantly more likely to respond to a predator model, however, they were significantly more likely to spend time near the snake and lizard models. There could be benefit of sociality in the detection of terrestrial predators. This research addresses previously unexplored aspects of cooperative courtship display, and therefore represents a significant contribution to the more general understanding of the costs and benefits of cooperation. The variation in the amount of cooperation expressed by different individuals of this species offers a unique opportunity to separate the fitness consequences of cooperation by comparing differences in success not only among individuals, but also those among displays in different cooperative contexts by the same individual. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2017. / July 17, 2017. / cooperation, Corapipo altera, lek, Pipridae / Includes bibliographical references. / Emily H. DuVal, Professor Directing Dissertation; Mike Mesterton-Gibbons, University Representative; Kimberly H. Hughes, Committee Member; David Houle, Committee Member; Scott J. Steppan, Committee Member.

Clonality is the general term that encompasses all manner of pinching, splitting, budding, and fragmenting behaviors by which organisms divide their somatic body tissues into more or less independent units. It can be as straight forward as fragments of a sponge surviving after being rent apart by a hurricane or as convoluted as the telescoping generations of parthenogenic aphids. Clonality is a widespread feature of animal life cycles and the degree of clonal investment is expected to affect everything from spatial genotypic and genetic structure to evolutionary dynamics and ecology interactions. Yet, the shear diversity and complexity of clonal behavior has hampered efforts to develop a general understanding of how and why clonality evolves as the adaptive benefits of these behaviors may be as idiosyncratic as the mechanisms by which cloning occurs. Contrary to some past formulations of the problem, the production of clonal progeny is not typically an alternative to sexual reproduction, as most clonal organisms also reproduce sexually. While there is often an immediate tradeoff where a unit of energy can either be invested in gametes or clonal progeny at any given time, there is not inherently a tradeoff between asexual and sexual reproduction over the span of a lifetime. Dividing somatic tissue in to separate units can be a way of increasing total lifetime fecundity by increasing total biomass, more efficiently colonizing open space or promoting longevity by spreading the risk of mortality over spatially-separated somatic units. With this perspective, understanding the adaptive value of clonality becomes a matter of analyzing the holistic suite of fitness effects that arise from variation in allocating energy among unitary growth, clonal propagation and gametogenesis. The amount of energy available and the fitness value of a particular investment strategy are governed in large part by the environment and so understanding the environmental context is key to understanding the forces shaping life cycle evolution. Temperature, in particular, affects the metabolic cost of maintaining body tissues and is key in determining the energetically optimal body size for a unitary animal. Where temperatures fluctuate seasonally or where clonal replicates may spread across a heterogeneous landscape, the reaction norm of fission rate, body size or traits associated with gamete production may be an important target of selection, influencing which life cycle patterns can evolve. In this dissertation I examine the influence of seasonal and geographic temperature variation on fission rate, body size and gamete production of the clonal sea anemone, Diadumene lineata (Verrill 1869), to better understand the constraints and tradeoffs that govern the evolution of resource allocation strategy; and ultimately, the factors that drive the evolution of clonality in this species. Through a combination of laboratory experiments, field observations, optimality modeling and genetic tools I demonstrate that (1) fission rates are strongly temperature dependent, resulting in seasonal and geographic variation in clonal behavior, (2) the production of gametes is closely tied to body size and shows an inverse latitudinal pattern with fission rate, (3) the observed reaction norm of fission rate with temperature is consistent with selection to maximize gamete production across the locally experienced range of temperatures, as opposed to selection for maximum clonal proliferation, per se, and (4) there is a latitudinal decrease in genotypic richness and diversity that corresponds with changes in fission rate, suggesting that variation in fission rate leads to changes in the spatial structure of genetic variation among sites. Together, these results are consistent with the hypothesis that clonality is adaptive under conditions where individual body size is constrained by the environment. Under these conditions more gametes may be produced over a lifetime by genets dividing somatic tissue into multiple small units rather than remaining a single large unit. In this species, there is an immediate cost to dividing a large body into two pieces as the number of gametes produced by two small individuals sums to less than those produced by a large individual, yet, the lost reproductive potential may be able to be compensated for over time by an increased growth rate at a smaller body size. Additional costs and benefits imposed by changes in mortality rate, competitive ability or mate choice as fission rate changes remain to be investigated and may be equally important in understanding and predicting the evolution of clonal behavior in this and other species. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2017. / June 19, 2017. / asexual reproduction, clonality, Diadumene lineata, life cycle, phenotypic plasticity, sea anemone / Includes bibliographical references. / Thomas E. Miller, Professor Directing Dissertation; Markus Huettel, University Representative; Kim Hughes, Committee Member; Don Levitan, Committee Member; Janie Wulff, Committee Member.

Non-random mating is presumed to be an important mechanism that allows for the maintenance of genetic variation. Assortative mating has been studied extensively in organisms that possess defined ways in which sperm is transferred to eggs (e.g. via copulation, courtship or vector assisted pollination in plants), but rarely in broadcast spawners. Broadcast spawning is perceived as a mating event that allows for mixing of gametes and promotes random mating. However, there are multiple pathways in which spawning adults can affect fertilization of gametes in non-random ways. For example, positive assortative mating can occur in broadcast spawners if similar phenotypes spawn closer together in space or time, or possess similar gamete recognition proteins that expedite fertilization. Here, I propose to examine assortative fertilization, patterns of aggregation and gamete recognition protein genotype of the sperm bindin gene as a function of spine color in the sea urchin Lytechinus variegatus as well as evaluating deviations from Hardy-Weinberg Equilibrium (HWE) based on color. Results indicate that laboratory crosses of urchins within color morphs yielded higher fertilization success than crosses between color morphs. Field surveys determined that these sea urchins are aggregating by color at times of their reproductive season when they are more likely to spawn. Tests for HWE using field data of urchin phenotypes suggest strong deviations from HWE. However, DNA sequences of regions of the sperm bindin gene for sea urchins of different color do not show evidence of genetic structure of the population. Paternal success in broadcast spawners is largely determined by the proximity of males to spawning females and the compatibility between them at the time they release their gametes. Selection is predicted to favor traits and behaviors that increase the likelihood of spawning near a more compatible neighbor. These results provide strong evidence for assortative mating and an explanation for the maintenance of color variation in this species. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2017. / July 18, 2017. / assortative mating, broadcast spawning, color variation, fertilization success, genetic variation / Includes bibliographical references. / Don R. Levitan, Professor Directing Thesis; Kimberly A. Hughes, Committee Member; Scott Burgess, Committee Member.

Understanding how environmental forces, genetic variation, and developmental process combine to mold adaptations remains a core challenge in evolutionary biology. Our research is answering this challenge. More specifically we focused on how these three drivers of adaptation have shaped the evolution of body morphology in poeciliid fish. The body morphology of poeciliid fish has been shown to be under strong ecological selection and sexual selection. In the poecilid fish Poecilia reticulata, body morphology can evolve rapidly, over a span of four to five years. These attributes makes it an ideal system to study the processes leading to adaptive evolution. Here we studied this adaptive evolution in poeciliid fish at two scales: among populations of a single species and within populations of a single species. At the broadest scale, we investigated local adaptation among populations of a single poeciliid species, Heterandria formosa. We quantified patterns in morphological variation among populations and tested for associations between this variation and ecological data, which are derived from long term population censuses. Results from this study illustrate the complicated construction of multivariate phenotypic variation and suggest that different agents of selection have acted on different components of body morphology. These patterns in inter-population phenotypic variation can be evidence of local adaptation; however, they can also be reflective of patterns in phenotypic plasticity induced by environmental or maternal effects. The role of maternal effects are especially relevant in H. formosa as females are live bearing and provide nutrients to developing embryos via a placenta. We used a common garden experiment and a large factorial breeding experiment to explicitly test for genetically based differences among populations in their responses to environmental variation (norms of reaction). This laboratory work allowed a definitive diagnosis of which features actually represented local adaptations among populations of Heterandria formosa. Results showed that male body morphology has a significant genetic component and signs of population specific response to both the environment during post-parturition development and in response to the maternal environment during embyronic development. The narrowest scope of our work focuses on the evolution of body morphology within an experimental population of the Trinidadian guppy. Interestingly, the strength and direction of selection on phenotypic variation is not the same among all individuals within a population. In particular, genetic correlations between the sexes can produce intralocus sexual conflicts (ISC) when selection favors different trait values in the genders. This form of sexual conflict can inhibit the evolution of males and females so that neither sex can reach its optimal trait value. Theory suggests that ISC will have a minimal effect in populations off there adaptive peak such as those in a novel or variable environment. However, ISC is likely to have an inhibitory effect in populations in a stable environment near their adaptive, thereby limiting adaptive evolution. Here we used an experimental population of Trinidadian guppies in a novel environment to unravel the emergence of sexual conflict as populations adapt to novel environments. Guppies from a high predation environment were translocated to a drainage with minimal predation. The phenotypic evolution of the population was tracked monthly. This work incorporates mark-recapture methods, complete pedigree reconstruction using high throughput sequencing, and geometric morphometric shape analysis. Results indicate that there are fitness differences among individuals and different optimal values in males and females but the role of sexual conflict within this population is currently negligible. To conclude, our work investigated the environmental and genetic factors influencing the evolution of body morphology in poeciliid fish. We demonstrate the complicated nature of selection with different selective agents acting on different aspects of body morphology. We found that populations of fish have unique environmental maternal effects which may ultimately be adaptive. We also conclude that while there are optimal trait value differences in males and female guppies but being off the adaptive peak limits the influence of ISC on morphological evolution. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2018. / July 13, 2018. / Local Adaptation, Morphometric, Poeciliid, Sexual Conflict / Includes bibliographical references. / Joseph Travis, Professor Directing Dissertation; Dennis Slice, University Representative; Emily DuVal, Committee Member; Gregory Erickson, Committee Member; Kimberly Hughes, Committee Member.

Species interactions can regulate a population’s density and therefore can act as a selective force on that population. Such evolutionary responses have the potential to feedback and change ecological interactions between species. For species that compete for resources, the interaction between ecological and evolutionary dynamics will regulate the stability of the species interactions, determining whether competing species can coexist. The outcome of competition between species is determined by two factors: (1) niche overlap, or the similarity in how species use resources and are affected by their environment, and (2) fitness differences, or differences in how efficiently each species uses resources in their environment. Decreasing niche overlap will decrease competitive interactions, thereby stabilizing coexistence. Decreasing fitness differences makes species more equal in their competitive abilities, facilitating coexistence. In the absence of evolutionary constraints, both niche overlap and fitness differences among species are subject to change as a consequence of evolution among competitors, and thus ecological dynamics between two species will also change. In this dissertation, I develop a broader understanding of (1) how niche overlap and fitness differences between species change after evolution in response to competition, (2) how changes in niche overlap and fitness differences are mediated through changes in resource use of protists, and (3) what role evolutionary history plays in shaping ecological and evolutionary dynamics. I address these goals with a suite of approaches including theoretical models, an experimental lab system, and comparative methods. I constructed a quantitative genetic model of trait evolution, where the trait of a species determined its resource use, and found that species are prone to change in their niche overlap as well as their fitness differences as a result of trait evolution. However, the magnitude of changes in niche overlap and fitness differences were determined by the resource availability within the environments. When resources were broadly available, species changed more in their niche overlap, whereas when resources were narrowly available, species changed more in their fitness difference. To test these predictions, I developed a system in the laboratory where protists competed for a bacterial resource. Species were allowed to evolve in either monoculture or a two-species mixture; the effects of evolution on competition, niche overlap and fitness differences were quantified using parameterized models. In general I found that species tended to converge in their niche as a result of evolution, however, changes in fitness differences between species were larger and more influential on coexistence than changes in niche differences. Both increases in niche overlap, and increases in fitness differences decreased coexistence among species pairs. By describing the bacterial communities associated with these protists before and after selection I determined that protists tended to converge or not change in which bacteria they were consuming as a result of selection. Additionally, for eleven protist species, I determined whether traits or relatedness predicted competitive ability by placing species on a molecular phylogeny and conducting pairwise competition experiments for all pairs. I found no correlations, suggesting neither traits, nor evolutionary history was informative for explaining current ecological and evolutionary interactions in this deeply divergent clade. There are two major conclusions from this dissertation: (1) when species evolve in response to competition, changes in fitness differences may often be more important than changes in niche overlap, (2) evolution can, and may be likely to, decrease the ability of species to coexist through increases in niche overlap and increases in fitness differences. This work suggests that one must simultaneously consider the role of evolutionary and ecological processes to understand community processes. Specifically, when researchers are attempting to explain mechanisms of coexistence between species, they must consider how evolutionary dynamics may change the ecological interactions within communities of competitors. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2017. / August 4, 2017. / Coexistence, Competition, Evolution, Fitness Difference, Niche Overlap, Selection / Includes bibliographical references. / Thomas Miller, Professor Directing Dissertation; Richard Bertram, University Representative; Brian Inouye, Committee Member; Scott Steppan, Committee Member; Alice Winn, Committee Member.

Understanding how environmental forces, genetic variation, and developmental process combine to mold adaptations remains a core challenge in evolutionary biology. Our research is answering this challenge. More specifically we focused on how these three drivers of adaptation have shaped the evolution of body morphology in poeciliid fish. The body morphology of poeciliid fish has been shown to be under strong ecological selection and sexual selection. In the poecilid fish Poecilia reticulata, body morphology can evolve rapidly, over a span of four to five years. These attributes makes it an ideal system to study the processes leading to adaptive evolution. Here we studied this adaptive evolution in poeciliid fish at two scales: among populations of a single species and within populations of a single species. At the broadest scale, we investigated local adaptation among populations of a single poeciliid species, Heterandria formosa. We quantified patterns in morphological variation among populations and tested for associations between this variation and ecological data, which are derived from long term population censuses. Results from this study illustrate the complicated construction of multivariate phenotypic variation and suggest that different agents of selection have acted on different components of body morphology. These patterns in inter-population phenotypic variation can be evidence of local adaptation; however, they can also be reflective of patterns in phenotypic plasticity induced by environmental or maternal effects. The role of maternal effects are especially relevant in H. formosa as females are live bearing and provide nutrients to developing embryos via a placenta. We used a common garden experiment and a large factorial breeding experiment to explicitly test for genetically based differences among populations in their responses to environmental variation (norms of reaction). This laboratory work allowed a definitive diagnosis of which features actually represented local adaptations among populations of Heterandria formosa. Results showed that male body morphology has a significant genetic component and signs of population specific response to both the environment during post-parturition development and in response to the maternal environment during embyronic development. The narrowest scope of our work focuses on the evolution of body morphology within an experimental population of the Trinidadian guppy. Interestingly, the strength and direction of selection on phenotypic variation is not the same among all individuals within a population. In particular, genetic correlations between the sexes can produce intralocus sexual conflicts (ISC) when selection favors different trait values in the genders. This form of sexual conflict can inhibit the evolution of males and females so that neither sex can reach its optimal trait value. Theory suggests that ISC will have a minimal effect in populations off there adaptive peak such as those in a novel or variable environment. However, ISC is likely to have an inhibitory effect in populations in a stable environment near their adaptive, thereby limiting adaptive evolution. Here we used an experimental population of Trinidadian guppies in a novel environment to unravel the emergence of sexual conflict as populations adapt to novel environments. Guppies from a high predation environment were translocated to a drainage with minimal predation. The phenotypic evolution of the population was tracked monthly. This work incorporates mark-recapture methods, complete pedigree reconstruction using high throughput sequencing, and geometric morphometric shape analysis. Results indicate that there are fitness differences among individuals and different optimal values in males and females but the role of sexual conflict within this population is currently negligible. To conclude, our work investigated the environmental and genetic factors influencing the evolution of body morphology in poeciliid fish. We demonstrate the complicated nature of selection with different selective agents acting on different aspects of body morphology. We found that populations of fish have unique environmental maternal effects which may ultimately be adaptive. We also conclude that while there are optimal trait value differences in males and female guppies but being off the adaptive peak limits the influence of ISC on morphological evolution. / A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2018. / July 13, 2018. / Local Adaptation, Morphometric, Poeciliid, Sexual Conflict / Includes bibliographical references. / Joseph Travis, Professor Directing Dissertation; Dennis Slice, University Representative; Emily DuVal, Committee Member; Gregory Erickson, Committee Member; Kimberly Hughes, Committee Member.

The Andes, along with the Amazon and Atlantic forests, harbor the richest avifauna in the world with roughly one third of all the world's species of birds. Many biogeographical studies have sought to explain the origin and diversification of Andean taxa. However, because of the Andes' extensive latitudinal span and complexity, there is no one single cause of origin or of diversification that can explain the diversity found in them. Along the Andes, multiple biogeographic patterns of disjunction between highland and lowland sister-groups have been linked to Andean uplift. For example, Ribas et al. (2007) provided evidence that the spatio-temporal diversification in the monophyletic parrot genus Pionus is causally linked to Andean tectonic and palaeoclimate change through vicariance. Thus, if the Andes uplift is responsible for some of the patterns of montane-lowland disjunctions, it may be one of the mechanisms underlying the taxonomic assembly of the Andean montane avifauna. In this dissertation I explored whether the origin and diversification of three groups of Andean birds--the exclusively Andean parrot genera Hapalopsittaca, the subclade of mangoes containing Doryfera, Schistes, and Colibri, and the ovenbirds of the tribe Thripophagini--can be linked to Earth history. The results show that the origin of these Andean taxa can be explained through vicariance from their lowland sister-groups, mediated by the uplift of the Andes. Thus, this thesis proposes that geological events are directly responsible for originating diversity throughout montane environments. Once in the Andes, the diversification of these montane taxa can be explained by events such as the tectonic evolution of the Andes--which created canyons and valleys that may have caused the vicariance of continuous populations--as well as by the climatic oscillation of the Pleistocene, which caused altitudinal shifts, expansion, and contraction of the montane vegetation belts during the climatic oscillations of the Pleistocene. In summary a significant part of the temporal patterns of origins and diversification of the three groups of birds included in this study can be linked to Earth history, both in terms of the tectonic history of the Andes and of the climatic events of the Pleistocene.

Adolescence is the time when humans begin utilizing mating strategies (e.g., flirting, fighting or rumor spreading about competitors) to attract and keep mates. Consistent empirical evidence shows that some adolescent boys are on a developmental pathway in which they utilize aggression and risky behaviors in their mating strategies, but there is little research on adolescent girls' use of aggression and risk-taking in mating. This study hypothesized that ethnically diverse, young adolescent girls nominated consistently as flirters were also more likely to be nominated as aggressive and report higher levels of risk taking behaviors (e.g., drug use, delinquency) than girls not nominated as flirters. This study assessed mating effort via a new approach: peer-report of flirting behavior, which is dissimilar to previous studies that asked participants to report on their mating effort behaviors or report on peers who were not participants in the study. It is proposed that flirting behavior will increase yearly from 6th to 8th grade, coinciding with the start of puberty. It is also predicted that consistent flirters will endorse dating more frequently, as mating behavior and mate success are strongly linked in the literature. This study also investigated the relationship between attractiveness, which is an aspect of mate value, and mating effort. Researchers have found that mating effort and mate value increase one's mating success and they are positively correlated. Also, this study analyzed the relationship between adolescents' familial adversity and their mating effort as previous research found that familial adversity has a causal influence on teenage sexual risk taking behaviors, earlier start of puberty, and earlier sexual debut. Sixth graders in two large middle schools in a low income, ethnically diverse, northeastern school district were followed for three years for a larger longitudinal study. This study uses data from a subsample of 190 adolescent girls with complete data for 7th and 8th grades. Measures were administered in language arts or social studies classes during the fall of each year. Measures included a peer-report of flirtatiousness and aggressive behavior via the Revised Class Play (Masten, Morrison, & Pelligrini, 1985), self-report of dating frequency, and self-report of risk taking behaviors including substance and alcohol use (Winters, 1992) and delinquency (Elliot, Huizinga, & Ageton, 1985). Attractiveness was assessed via peer-report ratings of yearbook photos and self-reports of body image and appearance satisfaction (Cash, 2000). Adverse familial background was measured as self-report of psychological aggression from parents (Straus, Hamby, Finkelhor, Moore, & Runyan, 1998) and living arrangements in 6th grade.