Master of Science (MS), Ohio University, 2017, Biological Sciences (Arts and Sciences)

Evolutionary theory predicts a trade-off between sexual selection and natural selection on secondary sexual traits. Understanding the relationship between mating success and predation risk can give insight into the evolutionary dynamics that interact to promote or constrain phenotypic change, yet it has been little studied in the wild. I conducted a two-year cross-sectional field study on the Banded Demoiselle damselfly (Calopteryx splendens) to test for trade-offs between sexual selection and predation risk, and to assess variation in sexual and natural selection. At the study population, the White Wagtail (Motacilla alba) captures C. splendens in flight, then flies to feeding stations where it removes the wings and consumes the body. I used geometric morphometric techniques to quantify damselfly wing morphology, and compared wing shape and secondary sexual traits of wings from feeding stations to a random sample of wings from the population to quantify the strength, mode, and direction of natural selection on males. Simultaneously, I measured wing traits from individuals caught in the act of mating and compared them to a random sample of wings from the population to quantify the strength, mode, and direction of sexual selection on male wings. By comparing natural selection and sexual selection on wing traits simultaneously, I tested for trade-offs between types of selection. My results suggest that predator-mediated selection fluctuates through time, and is especially variable in how it operates on the size of secondary sexual traits displayed by males. Sexual selection operated almost exclusively on secondary sexual traits, and was consistent across years. Predator-mediated selection acted differently on fore- and hindwings, favoring males with long, narrow forewings and short, broad hindwings. A trade-off between natural and sexual selection was revealed on wing patch characteristics, with males possessing larger and darker wing patches experiencing higher preda (open full item for complete abstract)

Committee: Shawn Kuchta PhD (Advisor); Willem Roosenburg PhD (Committee Member); Kelly Johnson PhD (Committee Member) Subjects: Animal Sciences; Biology; Ecology; Entomology; Evolution and Development

MS, University of Cincinnati, 2012, Arts and Sciences: Biological Sciences

Chapter 1: That male genital morphology evolves via postcopulatory sexual selection is a widely held view. In contrast, the precopulatory sexual selection hypothesis for genital evolution has received less attention. Here, we test the hypothesis that male genital spines of Drosophila ananassae promote competitive male copulation success. Using laser surgery to manipulate trait size, we demonstrate that incremental reductions of spine length progressively reduce male copulation success: males without spines failed entirely to copulate because of an inability to couple the genitalia together, whereas males with halfway ablated and blunted spines suffered reductions in copulation success of 87% and 13%, respectively. The decrease in copulation success resulting from spine length reduction was markedly stronger in sexually competitive environments than in non-competitive environments, and females expressed resistance behaviors similarly toward competing male treatments, demonstrating directly the role of genital spines in promoting competitive copulation success. Because these spines are widespread within Drosophila, and because genital traits with precopulatory function are being discovered in a growing number of animal taxa, precopulatory sexual selection may have a more pervasive role in genital evolution than previously recognized. Chapter 2: The contemporary explanation for the rapid evolutionary diversification of animal genitalia is that such traits evolve via postcopulatory sexual selection. The most common debate within this framework has been over the relative importance of three non-mutually exclusive evolutionary mechanisms: sperm competition, cryptic female choice, and sexual conflict. The first two of these are strictly postcopulatory mechanisms, whereas sexual conflict could operate before, during or after copulation. We investigate the potential for male genital spines in Drosophila ananassae to function in postcopulatory sexual selection. Whereas previ (open full item for complete abstract)

Committee: Michal Polak PhD (Committee Chair); John Layne PhD (Committee Member); George Uetz PhD (Committee Member) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 2024, Evolution, Ecology and Organismal Biology

Great and Lesser Prairie-Chickens are part of the genus Tympanuchus, who are known for their rapid foot-stomping behavior that creates a non-vocal drumming noise and their bright bare-part ornaments with ultraviolet reflectance. Both of these non-vocal components are prominent during their courtship displays along with other morphology and vocal traits. Females and other males may use multiple male signals from their display to assess multiple components of the male quality for mate choice and competition purposes. The central theme of this work is to investigate two non-vocal signals under the mechanisms of sexual selection intersexual mate choice and intrasexual competition. Signals are usually only considered under one of the mechanisms, typically intersexual mate choice or their impacts on social behavior has not been considered under any context. In Chapter 2, we investigated if foot-stomping could be integral in the communication of both the Greater and Lesser Prairie-Chicken, by using high-speed video cameras and recorders. We found that foot-stomping rate and duration increased with females' presences and only foot-stomping rate differ between the two species with Greater Prairie-Chickens having a higher rate than Lesser Prairie-Chickens. Since we used high-speed videos, we were able to collect simple kinematic measurements and found that both species are lifting their feet up higher when stomping when females are present. Since there was a difference in foot-stomping features when females were present/absent, in chapter 3 we investigated whether foot-stomping would increase the likelihood of a male to successfully mate, by using discrete choice modeling in Lesser Prairie-Chickens only. We added foot-stomping traits (rate and duration) with other behavioral, morphological, territorial, and color variables to run the discrete choice model. We found males increased their likelihood of successfully mating if they had a larger comb, increased aggressive behavior (open full item for complete abstract)

Committee: Ian Hamilton (Advisor) Subjects: Behaviorial Sciences; Ecology; Evolution and Development; Morphology

MS, University of Cincinnati, 2023, Arts and Sciences: Biological Sciences

The Darwin-Bateman paradigm theorizes that males maximize their reproductive success by mating indiscriminately and often, while females benefit by investing in the selection of a smaller number of high-quality males. However, there is increasing recognition that sexual selection occurs on both male and female traits, even within species, and that sex roles operate dynamically on a continuum influenced by numerous factors. Even so, much variation in the strength and direction of sexual selection remains unexplained. This study examines variation in sex roles across the animal kingdom by conducting a synthesis on existing sexual selection research where we model the relative strength of sexual selection between sexes using generally-available predictors including potential reproductive rates and mating systems. The results demonstrate that (1) the commonly-invoked potential reproductive rate is important in modeling sex differences in the Bateman gradient and opportunity for sexual selection, while the importance of sex ratios appears in this study to be eclipsed by other variables, and (2) sex-role models are significantly more robust when interactions between variables are accounted for. We conclude that sex roles are highly context-dependent and should be modeled according to a mix of population and life-history characteristics.

Committee: Stephen Matter Ph.D. (Committee Chair); Michal Polak Ph.D. (Committee Member); Nathan Morehouse Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy, Case Western Reserve University, 2019, Biology

Many animals use elaborate adult traits to attract mates and intimidate rivals. However, the development of these sexually selected traits, and the reproductive interactions that confer their benefits, occur against a complex backdrop of environmental factors. When such features of the habitat modify the costs and benefits of displaying and developing these traits, environmental variation across space and time can shape their diversification. Likewise, sexual selection on these characters may have consequences for how organisms interact with and adapt to different ecological contexts. Here, I explore these themes by investigating the interplay between sexually selected coloration, the external environment, and physiology in dragonflies. I begin by examining the adaptive function of wing pigmentation in a dragonfly (Pachydiplax longipennis), finding that this trait is intrasexually selected. Using this dragonfly system, I then document how interactions between the environment and an organism's physiological state can drive the divergence in its sexually selected wing coloration. I first show that thermal physiology causes the performance benefits of wing coloration to depend on ambient temperature, and, as a result, males in the warmest parts of North America nearly lack this trait all together. I next illustrate how improving an individual's physiological condition to develop better sexually selected coloration can harm its juvenile survival in the presence of predators. I then consider how sexual selection could feed back to influence ecological adaptation by examining links between wing coloration and immune defense. I find that, in addition to several important ecological costs of deploying immune defenses during the larval stage (e.g. predation vulnerability, delayed emergence), producing a strong immune response directly inhibits wing color development. Moreover, when comparing across species, I show that those species with more wing coloration tend to have wea (open full item for complete abstract)

Committee: Ryan Martin Ph.D. (Advisor); Sarah Diamond Ph.D. (Committee Member); Michael Benard Ph.D. (Committee Member); Patrick Lorch Ph.D. (Committee Member) Subjects: Biology; Ecology; Entomology; Evolution and Development; Morphology; Organismal Biology; Physiology; Zoology

Master of Science, The Ohio State University, 2019, Environment and Natural Resources

Worldwide, a major threat to aquatic systems is increased sediment runoff, which can lead to elevated levels of turbidity. In an increasingly variable world, the ability for animals to respond rapidly to environmental disturbance can be critical for survival. Chronic and acute turbidity exposure can have both indirect and direct effects on fish across large and small spatial scales. Indirect impacts include alteration of the sensory environment of fishes (disrupting communications) and shifts in prey availability; while direct impacts include damage to respiratory organs or eliciting physiological compensatory mechanisms that influence fitness-related traits associated with reproduction and survival. I used a combination of field and laboratory studies to examine the effects of elevated turbidity on an African cichlid fish (Pseudocrenilabrus multicolor victoriae). This sexually dimorphic species is widespread across the Nile River basin and is found across extreme environmental gradients (e.g. dissolved oxygen, turbidity). I investigated if within-population variation in diet and male nuptial coloration are associated with turbidity on a microgeographic spatial-scale. Diet was investigated because many cichlid fish depend on dietary carotenoids (red and yellow pigments) for their reproductive displays and other physiological mechanisms associated with health. I found that fish from mostly clear waters ate a higher proportion of plant material and males were more colorful than fish found at more turbid locations. This could indicate that male reproductive traits are plastic across environmental extremes. In the laboratory study, I used a split-brood rearing experiment to investigate the effects of turbidity level (high/low) and dietary carotenoid concentration (trace/low) on reproductive traits in P. multicolor. I found that chronic turbidity and carotenoid diets had differential effects on males and females: nuptial coloration and gonadosomatic index were higher in (open full item for complete abstract)

Committee: Suzanne Gray Dr. (Advisor); Lauren Pintor Dr. (Committee Member); Roman Lanno Dr. (Committee Member); Lauren Chapman Dr. (Committee Member) Subjects: Freshwater Ecology; Physiology

Doctor of Philosophy, The Ohio State University, 2019, Evolution, Ecology and Organismal Biology

Females can vary in their mate choice decisions and this variability can play a key role in evolution by sexual selection. Variability in female preferences can affect the intensity and direction of selection on male sexual traits, as well as explain variation in male reproductive success. I looked at how consistency of female preference can vary for a male sexual trait, song length, and then examined context-dependent situations that may contribute to variation in female preferences. In Chapter 2, I assessed repeatability – a measure of among-individual variation – in preference for male song length in female American goldfinches (Spinus tristis). I found no repeatability in preference for song length but did find an overall preference for shorter songs. I suggest that context, including the social environment, may be important in altering the expression of female preferences. In Chapter 3, I assessed how the choices of other females influence female preference. Mate choice copying, in which female preference for a male increases if he has been observed with other females, has been observed in several non-monogamous birds. However, it is unclear whether mate choice copying occurs in socially monogamous species where there are direct benefits from choosing an unmated male. I found evidence for mate choice copying and suggest that copying occurs when choosing extrapair mates. In Chapter 4, I examine how social relationships among females influence copying. A female may be more likely to copy another female if they are familiar with one another due to shared environments and experiences. I found that females are more likely to copy familiar rather than unfamiliar females, which has not been shown in this context. The latter two chapters show that social context is a source of variation that can cause a female to alter her preferences. This suggests an important potential role of female-female social relationships on male reproductive success and the evol (open full item for complete abstract)

Committee: Ian Hamilton (Advisor); J. Andrew Roberts (Advisor); Jacqueline Augustine (Committee Member) Subjects: Animals; Behavioral Sciences; Biology; Ecology; Organismal Biology; Zoology

MS, University of Cincinnati, 2018, Arts and Sciences: Biological Sciences

Recent studies have shown that animal “personality” demonstrates consistent behavioral variation at the individual level that persists across lifestages and contexts. The most commonly measured behavioral syndrome involves a “bold” to “shy” continuum, in which individuals are evaluated based on their willingness or latency to engage in risk-taking behaviors. I examined bold-shy behavioral syndromes in the brush-legged wolf spider, Schizocosa ocreata. Spiders were repeatedly given open field tests and later exposed to simulated predator stimuli. All spiders were tested as juveniles and adults. Results of open field tests showed individual S. ocreata exhibit consistent behavioral patterns associated with either end of the continuum of bold (exploratory) to shy (freeze) behavioral syndromes. These differences persisted across contexts, as well as lifestages (juvenile, adult). Bold spiders exhibited shorter latency to explore in an open field and to resume exploration after a simulated predator than did their shy counterparts, but also showed more variation in latency to resume exploration after a simulated predator. After reaching maturity, females were given a two-choice test using video playback of male courtship to analyze differences in mate choice, while males were exposed to female cues to assess courtship vigor. While open field behaviors and responses to simulated predators were correlated, personality type did not show significant effects on male courtship in the presence of female cues or female mate preference in the context of video playback. Males and females of differing personality types were also paired in a two-by-two factorial design to assess the effect of personality on overall mating success. No differences in mating success were found, suggesting that personality type measured using bold-shy attributes may affect somatic traits but not reproductive traits in this study.

Committee: George Uetz Ph.D. (Committee Chair); Elke Buschbeck Ph.D. (Committee Member); Nathan Morehouse (Committee Member) Subjects: Behavioral Sciences

Master of Science, Miami University, 2018, Biology

Females often use male signals and cues to locate potential mates and assess their quality. These male signals can be transmitted across one or multiple signaling modalities. In the wolf spider Pardosa milvina, males use a visual courtship display to attract female attention and encourage sexual receptivity. However, whether or not other signaling modalities influence female mate choice in this species is poorly understood. I hypothesized that male chemical cues may play a role in female mate choice in addition to visual cues. I tested females for their ability to detect and assess males based on their chemical cues, both isolated and when combined with a visual signal. Females did not change their activity in the presence of isolated male chemical cues. When presented with males either surrounded by or lacking their chemical cues, I found that while male courtship played a major role in female detection and attraction, females tended to spend less time near males when their chemical cues were present. This research suggests that while male courtship displays are necessary and sufficient for mate attraction, chemical signals may play a limited role by helping females more quickly assess a male's visual display.

Committee: Ann Rypstra PhD (Advisor); Nancy Solomon PhD (Committee Member); Brian Keane PhD (Committee Member) Subjects: Animals; Biology; Zoology

MS, University of Cincinnati, 2017, Arts and Sciences: Biological Sciences

Recent interest in male mate choice has prompted a re-examination of widely held beliefs regarding sex roles in animal mating systems. It is now known that males can be choosy based on female quality – namely with regards to sperm competition and fecundity. However, studies which directly compare aspects of female quality and their influence on male mate choice are relatively rare. The brush-legged wolf spider Schizocosa ocreata (Hentz) has a well-studied, conspicuous male courtship display, within which can be seen evidence of male mate choice based on female mating history and foraging history, as well as possible effects of experience and rearing environment. This makes it an excellent system to compare the importance of these two female states and examine how the choice patterns they give rise to may be influenced by the environment. By examining male courtship and female behavior under different circumstances and across environmental experience conditions, the relative effects of these factors can be inferred. Evidence collected in this study suggests that female mating status is the dominant predictor of both male and female mate choice, with males most often courting virgin females more vigorously regardless of context, as well as females showing higher levels of receptivity when unmated. An important exception to this trend is seen in field-reared males and their female partners, who show no preference or behavioral differences based on female state, suggesting that this preference is not static and may be influenced by experience. Altogether these results fit within the general pattern of two-axis preference studies by showing a trend to the importance of mating status with lesser importance of feeding status. Therefore, these results may help to better understand the influence of male mate choice on female sexual selection across taxa.

Committee: George Uetz Ph.D. (Committee Chair); Eric Maurer Ph.D. (Committee Member); Andrew Roberts Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 2016, Anthropology

Since Darwin first described his theory of sexual selection, evolutionary biologists have used this framework to understand the potential for morphological, physiological, and behavioral traits to evolve within each sex. Recently, researchers have revealed important nuances in effects of sexual coercion, intersexual conflict, and sex role reversals. Among our closest relatives living in complex societies in which individuals interact outside of just the context of mating, the sexual and social lives of individuals are tightly intertwined. An important challenge to biological anthropologists is demonstrating whether female opportunities for mate choice are overridden by male-male competitive and male-female coercive strategies that dominate multi-male, multi-female societies. In this dissertation, I explore interactions between these various mechanisms of competition, coercion, and choice acting on the lives of female olive baboons (Papio anubis) to determine how they may influence expression of female behavioral and vocal signals, copulatory success with specific males, and the role of female competition in influencing mating patterns. I found females solicit specific males around the time of ovulation. Although what makes some males more preferred is less clear, there is evidence females choose males who might be better future protectors – males who will have long group tenures and are currently ascending the hierarchy. Preference translates into higher copulation rates and success at consort takeovers, there is little support that this is simply based on male aggression toward females. Outside the fertile window female copulations were more likely related to male aggression and male dominance rank. Additionally, I found evidence that copulation calls of female olive baboons indicate ovulation and may function to encourage specific males to guard or continue mating with females. However, some of the temporal features of calls indicate a function for paternity c (open full item for complete abstract)

Committee: Dawn Kitchen (Advisor) Subjects: Physical Anthropology

PhD, University of Cincinnati, 2015, Arts and Sciences: Biological Sciences

Studies have revealed that in many animals, females use various male traits in mate choice to assess a male's ability to provide direct and/or indirect benefits. While it is easy to assume that females should always prefer to mate with males with these traits, increasing evidence suggests that females demonstrate plasticity in their mating preferences based on intrinsic and extrinsic factors. This dissertation focuses on how variation in the social environment results in variation in the mating preferences of the brush-legged wolf spider, Schizocosa ocreata. I used video and vibratory playback to simulate variation in the social environment of juvenile female S. ocreata and measure how that affects adult mate preferences. First, female S. ocreata were provided experience during their penultimate instar stage, manipulating the number of courting males per encounter (one or three males) and the encounter rate (every other day or twice per day). When given a choice between a lower quality (small-tufted) and higher quality (large-tufted) male in their adulthood, females were increasingly more selective depending on exposure to cumulatively more mature males during their penultimate social experience. Second, females were provided varying social experience with courting males of various tuft sizes during their penultimate instar stage. In both no-choice and two-choice designs, adult females were more receptive towards small-tufted and large-tufted males, respectively, if they saw small-tufted or large-tufted males during their penultimate stage. Third, female S. ocreata were provided variable sensory experience during their penultimate stage. Specifically, females in this study were provided playback of male courtship using vibratory signals, visual signals, multimodal signals, or no experience at all. When measured for unimodal preferences in no-choice presentations as adults, females demonstrated more receptivity displays towards the `familiar' signal modality. Two add (open full item for complete abstract)

Committee: George Uetz Ph.D. (Committee Chair); Ann Rypstra Ph.D. (Committee Member); John Layne Ph.D. (Committee Member); Stephen Matter Ph.D. (Committee Member); Michal Polak Ph.D. (Committee Member) Subjects: Biology

Bachelor of Science (BS), Ohio University, 2015, Biological Sciences

Sexual selection is comprised of intersexual mate choice and intrasexual competition. In order for female choice to be adaptive, the benefits of being choosey need to outweigh the costs. Females could benefit from preferences for male traits that relay information about male quality and/or that increase offspring fitness. Female preferences are affected by genotype, environment, or a combination of the two. In the study species, Xiphophorus multilineatus, males belong to one of four genetic size classes, and one of two genetic reproductive tactics. Between these alternative reproductive tactics, growth rate may be under disruptive selection. Since growth rate relates to fitness, it is possible that females assess a potential mate's growth rate by evaluating variation in male vertical body bars. I identified two aspects of the vertical body bars that are correlated with male juvenile growth rate. In addition, I demonstrated that females from a population of exclusively sneaker males show a preference for the barring pattern that represents a slower growth rate, which supports the proposed tactical disruptive selection on growth rate. Females from the sneaker line were also choosier in their preferences, which could potentially indicate that the fitness advantage to growing slower as a sneaker male may be greater than the fitness advantage to growing faster as a courter male.

Committee: Molly R. Morris (Advisor) Subjects: Animal Sciences; Aquatic Sciences; Behaviorial Sciences; Biology; Evolution and Development

Doctor of Philosophy, University of Akron, 2014, Integrated Bioscience

A key question in evolutionary biology is the origin and evolution of morphological innovations. Iridescent colors in feathers are produced by the interaction of light refracting through nanostructurally organized arrays of keratin and melanin-containing organelles (melanosomes), and are responsible for the brightest and most diverse colors found in birds. Such diversity arises from minute changes to nanostructural components, and birds have evolved extensive modifications to the shape and composition (hollowness) of melanosomes, providing a labile template for selection to act. Further, feather colors play a crucial role in intraspecific communication, sexual and social selection, and prezygotic isolation. Thus, this system is ideal for examining how complex morphologies arise ontogenetically and how they affect color diversification. I explored how this nanostructural arrangement emerges developmentally, showing that organization takes place in the final stages of feather growth, potentially through self-assembly. This implies that the fine-tuning color-producing structures can result from changes in the relative concentrations of different components and the timing of feather maturation. Further, quantitative variation to the degree of long-range order is responsible for variation in the degree of glossiness. Gloss was negatively associated with the thickness of the keratin layer, and positively with the continuity of the underlying melanosome layer. As a consequence, a continuum from matte black to iridescent colors can be observed. In African starlings, transitions from the ancestral rod-shaped melanosome to more optically complex morphologies occur irreversibly and towards greater optical complexity. As innovations to melanosome morphology evolve, novel colors can evolve up to forty times faster, as the optical complexity of these structures allows for different aspects of coloration to be modified independently. As a consequence, these innovations also provid (open full item for complete abstract)

Committee: Matthew Shawkey Dr. (Advisor); Todd Blackledge Dr. (Committee Member); Richard Londraville Dr. (Committee Member); Jutta Luettmer-Strathmann Dr. (Committee Member); Dustin Rubenstein Dr. (Committee Member) Subjects: Biology; Evolution and Development

MS, University of Cincinnati, 2001, Arts and Sciences : Biological Sciences

Courtship behavior has been studied extensively in the wolf spider Schizocosa ocreata (Araneae: Lycosidae). While much research has tested predictions of sexual selection theory regarding male traits used in female mate choice, some critical assumptions about female behavior remain untested. Because variation in female mating behavior is critical in sexual selection, I studied several aspects of mate choice from the females' perspective: (1) Do females mate more than once? (2) Is female preference for male characters (leg tufts and visual courtship displays) repeatable? (3) Does female receptivity vary with age (post-adult)? Females were paired with multiple males, and re-mating by females was rare (6%) implying that females are primarily monogamous. Males in contrast seem to be polygamous, 62% of males that were paired with more than one virgin female mated more than once. Sexual conflict over optimal mating rate may be inevitable resulting in different mating strategies. To determine repeatability of ma le preference, females were shown videos of courting males (identical in behavior and size, but different tuft sizes) simultaneously in a choice chamber once/day over 4 days. The repeatability of female preference varied with the nature of the choice. Female preference for larger tufts was significant and repeatable (r = 0.65) when choosing between an average male and one with reduced tufts, but not when choosing between an average male and one with enlarged tufts. This may be an indication of a threshold trait. To examine variation in receptivity with age post-adulthood, I studied responses of females to a courting male video. Receptivity varied significantly with age post-adulthood: females were more aggressive and less receptive to video images of courting males in the first week, became significantly more receptive after 3 weeks, and less thereafter. Correlated changes in aggressive and receptivity behavior may suggest a physiological linkage. These studies dem (open full item for complete abstract)

Committee: George Uetz (Advisor) Subjects:

MS, University of Cincinnati, 2010, Arts and Sciences: Biological Sciences

Because developmental instability is the outcome of an individuals inability to buffer against environmental perturbations, the phenotypic outcomes of DI, fluctuating asymmetry and phenodeviance, are thought to be indicators of individual genetic quality. The developmental instability sexual selection hypothesis posits that sexual selection favors reduced DI in secondary sexual traits because reduced DI reveals the genetic quality of potential mates or sexual rivals. The present study evaluates this hypothesis by examining the genotypic and phenotypic effects of developmental instability on fitness using isofemale lines of the fruit fly Drosophila bipectinata exhibiting divergent levels of phenodeviance. I found significant genetic variation for phenodeviance among lines, and confirmed the stability of these differences across multiple generations. These results support the hypothesis that genotypic effects underly developmental instability in the studied population. I then tested flies from these genetic lines for several measures of fitness: preadult survivorship, male mating success, and egg hatch rate. Genetic lines differed in levels of preadult survivorship, but these differences were unrelated to level of developmental instability in each line. Initial mating success assays showed no effect of DI on mating success, but later field-mimic assays showed significant effects of both genotypic and phenotypic developmental instability on mating success. Mating latency was significantly higher for high- developmental instability males in both assays. Finally, I found no significant effects of phenotypic or genotypic paternal DI on egg hatch rate. Although effects of DI were heterogeneous in this study, these results generally fail to support the DI-sexual selection hypothesis as originally formulated. Furthermore, several predictions of the hypothesis have been weakly supported across other studies. Therefore, the DI-sexual selection hypothesis is in difficulty and m (open full item for complete abstract)

Committee: Michal Polak PhD (Committee Chair); Stephanie Rollmann PhD (Committee Member); Elke Buschbeck PhD (Committee Member) Subjects: Biology

PhD, University of Cincinnati, 2010, Arts and Sciences: Biological Sciences

Ecological, behavioral, and evolutionary theory and research is based on a network of assumptions that simplify the otherwise complex physical and natural systems of life. Assumptions are a necessary part of conducting research because they provide a framework from which predictions about these systems can be made and tested through the interpretation of statistical analyses. However, the validity of conclusions drawn from any empirical study is only as good as the assumptions upon which the research design and interpretations were made. The research presented here addresses and tests a number of specific assumptions commonly made in research studies conducted on invertebrate animals, as applied to Schizocosa wolf spiders, an emerging animal model in animal behavior. My research focuses on two species, S. ocreata and S. rovneri well-known in studies of communication and mate choice. In two studies, I examined the traditional assumption that in invertebrates, flexibility of female mate choice behavior is minimal. From the first study it is clear that behavioral plasticity of these invertebrate animals in response to experience is greater than previous recognized. Exposure of female S. rovneri as juveniles to altered male phenotypes resulted in avoidance of familiar and preference for novel phenotypes as adults. However, these studies also show that certain types of experience (chemical vs. visual cues) may affect female mate preferences more than others, and that manipulation of male phenotypes (e.g., with nail polish) can sometimes have unintended consequences. In a second study with both S, ocreata and S. rovneri, the mechanisms that underlie species-level mate recognition (e.g., female mate preference) are more rigidly defined and do not appear to be influenced by social experience. A third study examined how well traditional measurements of body condition of spiders are able to separate out differences in feeding and/or hydration histories. This study provides ev (open full item for complete abstract)

Committee: George Uetz PhD (Committee Chair); Kenneth Petren PhD (Committee Member); Eric Maurer PhD (Committee Member); Elke Buschbeck PhD (Committee Member); Ann Rypstra PhD (Committee Member) Subjects: Ecology

PhD, University of Cincinnati, 2010, Arts and Sciences: Biological Sciences

Condition dependence (CD) of animal behavior is an emerging avenue of study. Because many aspects of animal physiology and life history vary with environmental factors, a variable environment may influence phenotype expression, which may consequently be subject to sexual selection. However, under food limitation, potentially cannibalistic animals like spiders face condition-dependent trade-offs between sexual selection (mate choice) and natural selection (sexual cannibalism). This research investigated the relationship between female feeding history, mate choice, male courtship and reproductive timing in the wolf spider, Schizocosa ocreata (Lycosidae; Hentz). I tested the influence of long- and short-term food stress on female mate choice, by assessing female preference for condition dependent male visual signals – body size and sexual ornaments. Female preference for visual male traits varied as a function of feeding treatment and time post maturity. Females demonstrated different degrees and types of phenotypic selection on males, but ultimately males with relatively large ornaments were selected through mate choice. Male courtship investment also varied with female feeding treatment, as males courted female silk from well-fed, deprived and cannibalistic females differently. However, both male experience and female feeding treatment significantly impacted courtship investment, as male investment in courtship vigor in subsequent encounters depended on the type of female seen in a previous encounter. Emerging from these observations was support for differential male investment and preliminary support for male mate choice in a wolf spider. Feeding history significantly impacted spider growth and induced plastic developmental responses as females matured. Food limited females took longer to develop by adding additional instars and ultimately attained a smaller adult size. Female gonad development coincided with increased female receptivity in well-fed females, suggest (open full item for complete abstract)

Committee: George Uetz PhD (Committee Chair); John Layne PhD (Committee Member); Eric Maurer PhD (Committee Member); Elke Buschbeck PhD (Committee Member); Ann Rypstra PhD (Committee Member) Subjects: Biology

MS, University of Cincinnati, 2006, Arts and Sciences : Biological Sciences

The species Drosophila bipectinata Duda was used in a series of projects aimed at appending empirical support to vital aspects of sexual selection theory, including mechanisms of selection and ‘good genes' models. The first chapter reports no evidence to support that male vigor, as measured by latency and duration of copulation, can explain the mating success of males larger in body and comb size found in a previous field study. Also, no evidence of female cryptic choice was found in this system. The second chapter reports a genetic association between two condition dependent secondary sexual traits; the finding of a positive association between two traits that differ in kind (sex combs vs. courtship song), and thus presumably have different developmental pathways, provides evidence of the presence of ‘good genes' in this system. Future directions include testing for evidence of female choice for male D. bipectinata song and/or comb size.

Committee: Dr. Michal Polak (Advisor) Subjects: Biology, Ecology