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The purpose of this study is to clarify and accurately describe the interactive effects of several amounts of reward and delay on acquisition and extinction or rats in a straight runway. A factorial study involving several levels of reward and delay is presented to further describe and possibly predict what effects these independent variables have on learning curves. The major purpose of this paper, then, is to determine the interactive effects of delay and magnitude of reward, and to present the results in a clarifying and informative manner.

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In this document, a low-cost, portable, non-invasive method of collecting the 3D trajectories of flying bats is first presented. An array of commercially available camera and light components is used alongside a number of well-established calibration and triangulation techniques to resolve the motion of agents through a 3D volume. It is shown that this system is capable of accurately capturing the bats' flight paths in a field experiment. The use of non-visible illumination ensures that a natural cave environment is disturbed as little as possible for behavioral experiments. Following is a transfer entropy analysis approach applied to the 3D paths of bats flying in pairs. The 3D trajectories are one-dimensionally characterized as inverse curvature time series to allow for entropy calculations. In addition to a traditional formulation of information flow between pair members, a path coupling hypothesis is pursued with time-delay modifications implemented in such a way as to not change the Markovianity of the process. With this modification, trends are found that suggest a leader-follower interaction between the front bat and the rear bat, although statistical significance is not reached due to the small number of pairs considered. / Master of Science

Elucidating the mechanisms responsible for driving individual variation in behavior is a foundational question in organismal biology. Answering these types of questions is necessary for understanding how tradeoffs are mediated as well as potential constraints on evolutionary responses to selection. In Chapter I, I synthesize the evidence suggesting that testosterone plays a central role in driving individual variation in cooperative reproductive behaviors and mediating the tradeoff between cooperation and competition. The subsequent chapters of my dissertation then focus on understanding the mechanistic sources of individual variation in the cooperative courtship behaviors of male wire-tailed manakins (Pipra filicauda), a Neotropical lekking songbird. Wire-tailed manakins exhibit cooperative courtship display behaviors wherein both floater and territory-holding males perform coordinated courtship displays. Territory-holding males sire essentially all offspring and, among territory-holders, those that are more cooperative exhibit higher reproductive success. Cooperation also benefits floater males in that more cooperative floater males have a higher probability of becoming a territory-holder. In Chapter II, I detail the difficulties associated with measuring circulating testosterone in free-living animals and develop a new field technique that can improve our ability to accurately account for the effects that the stress of capture has on circulating testosterone levels in birds. In Chapter III, I quantify individual variation in the cooperative courtship behaviors of territory-holding male wire-tailed manakins using video cameras. I then use both observational and experimental approaches to show that among territory holders, high testosterone has antagonistic effects on a male's cooperative behavior. Chapter IV focuses on quantifying how an individual's cooperative behavior relates to their telomere length. Telomeres are the segments of repetitive DNA found at the end of chromosomes. Telomeres shorten in response to both physiological and environmental perturbations, are predictive of an individual's mortality risk and, because of these characteristics, are thought to reflect an individual's biological age (as opposed to chronological age). My results show that short telomeres are associated with increased cooperative behaviors and, given that a male's cooperative behavior is reflective of their reproductive investment, suggest that males with lower future reproductive potential (i.e., shorter telomeres) invest more in reproduction. My last chapter (Chapter V) focuses on synthesizing these results and suggests that future research on cooperative behaviors will need to integrate biomarkers of an individual's condition with mechanisms that reflect an individual's social competence to further understand the sources of individual variation in cooperation. / Doctor of Philosophy / Cooperative reproductive behaviors occur when multiple individuals coordinate their reproductive efforts to gain an advantage over other individuals or those individuals that attempt to reproduce in the absence of cooperation. In this context, some individuals have been found to consistently act more or less cooperative, and outstanding questions regarding the evolution of cooperative reproductive behaviors focus on attempting to understand the intrinsic differences among individuals that consistently vary in their cooperative tendencies. In this dissertation, I focus on measuring individual variation in the cooperative reproductive behavior of male wire-tailed manakins, a passerine found in the Amazon Rainforest, as well as the sources of this individual variation. Male wire-tailed manakins perform acrobatic courtship displays for females. Wire-tailed manakins are especially interesting in that multiple males will perform coordinated courtship displays, but only one male within the group typically reproduces. Individual variation in this cooperative behavior also influences how likely an individual is to reproduce. Chapter I synthesizes the evidence across species to suggest that testosterone, a hormone known for influencing competitive reproductive behaviors, influences an individual’s likelihood of acting in a cooperative or competitive manner. Chapter II describes the difficulties associated with measuring circulating testosterone in wild animals and describes techniques that can be used to overcome some of the difficulties associated with measuring circulating testosterone in free-living birds. Chapter III focuses on understanding the relationship between testosterone and individual differences in the cooperative reproductive behaviors of the wire-tailed manakin. I find that those males with higher testosterone or those with experimentally increased testosterone are less cooperative. I discuss my results in the context of understanding how this relationship could influence the evolution of circulating testosterone levels more broadly. Chapter IV examines the relationship between the cooperative reproductive behavior of male wire-tailed manakins and the repetitive segments of DNA found at the end of chromosomes called telomeres. Telomeres shorten as individuals age and the length of an individual’s telomeres has been found to be predictive of their lifespan and mortality risk. My research shows that those individuals with shorter telomeres (or a higher mortality risk) are more cooperative. Given that an individual’s cooperative behavior is predictive of their probability of successfully reproducing, my research suggests that those individuals that are more likely to perish invest more time and energy in attempting to reproduce. In Chapter V, I conclude by summarizing my results and suggesting future research that can further our understanding of the sources of consistent individual differences in cooperative behavior and the evolution of cooperation more broadly.

abstract: Conditions during development can shape the expression of traits at adulthood, a phenomenon called developmental plasticity. In this context, factors such as nutrition or health state during development can affect current and subsequent physiology, body size, brain structure, ornamentation, and behavior. However, many of the links between developmental and adult phenotype are poorly understood. I performed a series of experiments using a common molecular currency - carotenoid pigments - to track somatic and reproductive investments through development and into adulthood. Carotenoids are red, orange, or yellow pigments that: (a) animals must acquire from their diets, (b) can be physiologically beneficial, acting as antioxidants or immunostimulants, and (c) color the sexually attractive features (e.g., feathers, scales) of many animals. I studied how carotenoid nutrition and immune challenges during ontogeny impacted ornamental coloration and immune function of adult male mallard ducks (Anas platyrhynchos). Male mallards use carotenoids to pigment their yellow beak, and males with more beaks that are more yellow are preferred as mates, have increased immune function, and have higher quality sperm. In my dissertation work, I established a natural context for the role that carotenoids and body condition play in the formation of the adult phenotype and examined how early-life experiences, including immune challenges and dietary access to carotenoids, affect adult immune function and ornamental coloration. Evidence from mallard ducklings in the field showed that variation in circulating carotenoid levels at hatch are likely driven by maternal allocation of carotenoids, but that carotenoid physiology shifts during the subsequent few weeks to reflect individual foraging habits. In the lab, adult beak color expression and immune function were more tightly correlated with body condition during growth than body condition during subsequent stages of development or adulthood. Immune challenges during development affected adult immune function and interacted with carotenoid physiology during adulthood, but did not affect adult beak coloration. Dietary access to carotenoids during development, but not adulthood, also affected adult immune function. Taken together, these results highlight the importance of the developmental stage in shaping certain survival-related traits (i.e., immune function), and lead to further questions regarding the development of ornamental traits. / Dissertation/Thesis / Ph.D. Biology 2012

Master of Science / Department of Psychological Sciences / Mary Cain / Novelty-seeking and sensation-seeking are traits implicated in initial drug experimentation and relapse in human populations. To research the neurobiological substrates that are implicated in novelty/sensation-seeking that predispose an individual to drug use, a rodent model was used. Recently, 50 kHz ultrasonic vocalizations (USV) have been identified as indices of affective state and are evoked by several drugs of abuse, specifically when these drugs of abuse have their pharmacological effects in the mesolimbic dopamine path. Secondly, genetic breeding of high and low vocalizers suggests not only are they different in the calling frequency, but also to drug sensitivity, suggesting ultrasonic vocalizations may be a behavioral marker for individual differences in the mesolimbic dopamine circuit. Two sensation/novelty seeking screens and an ultrasonic vocalization screen were used in rats to predict the locomotor and 50 kHz USV response to a low (.3 mg/kg) and high dose (1.0 mg/kg) of amphetamine. Correlation analysis revealed none of the novelty screens were correlated. Simultaneous regression analyses indicated amphetamine dose-dependently increased locomotor activity acutely and chronically but did not increase 50 kHz USV. The USV assessment predicted USV response to amphetamine acutely and chronically but was not dose dependent. No interactions among any predictors were observed. Previous research has dichotomized the novelty/sensation-seeking trait and found significant differences between high and low novelty responders. The current research provides evidence for maintaining continuous individual difference variables, and suggests each screen measures a different trait implicated in addiction.

The present study, in contrast with previous work that has isolated one or two important factors influencing the status of the zoo, considered the three important zoo reference groups--animals, visitors, and staff members--and their interrelationships within the zoo environment. Two approaches were used to investigate the system of interactions within the zoo. First, an in-depth examination of a new set of naturalistic exhibits was performed. Second, a comparison of two of these naturalistic exhibits with two older, sterile exhibits which housed the same species at the same zoo was made. Multiple methods were used in the present study and included behavior mapping of visitors, staff, and animals, timing of visitor stays at exhibits, tracking of visitors through the exhibits, a visitor questionnaire, and interviews with staff members. One major finding was the lack of correspondence among the major groups as to the acceptability of exhibits. For example, one exhibit which was considered beneficial to the enclosed animals and was well utilized and positively evaluated by visitors presented staff members with great difficulties in animal containment and exhibit maintenance. Comparisons of naturalistic enclosures and sterile cement enclosures housing the same species revealed no consistent, clear-cut differences in animal and visitor behavior, however, attitudinal differences were found for staff members and visitors. Visitors and staff members preferred the naturalistic exhibits and perceived them as more beneficial to animals and visitors. These findings were discussed in terms of theoretical and applied issues relevant to zoo design and management and to research in zoos.