| C E N T E R F O R T H E I N T E G R A T I V E S T U D Y O F A N I M A L B E H A V I O R |
| R E S E A R C H |
| C E N T E R F O R T H E I N T E G R A T I V E S T U D Y O F A N I M A L B E H A V I O R |
| R E S E A R C H |
Between 1991 and 2001, the Program in Animal Behavior trained 48 Ph.D.s and 6 M.A.s. Below are abstracts from these dissertations and theses. While at IU, trainees have also published over 412 publications. Alumni's current research interests and occupations are linked to |more info|.
| Heather L. Eisthen Ph.D. Indiana University 1992 (Psychology | Neural Science) Anatomy of the Peripheral Olfactory and Vomeronasal Systems in Aquatic Salamanders and Its Implications for the Evolution of Vertebrate Chemosensory Systems
ABSTRACT: |
| Daniel A. Cristol Ph.D. Indiana University 1993 (Biology) The Evolution of Differential Migration and the Role of Situational Factors in Social Dominance ABSTRACT: I carried out experiments in the field and aviary to consider the evolution of differential migration, in which classes in a population migrate different distances. I tested the hypothesis that social status determines migration distance using dark-eyed juncos (Junco hyemalis). I tested an alternative hypothesis with red-winged blackbirds (Agelaius phoeniceus). I also focused on the establishment of social dominance in wintering groups of juncos. I asked whether social status was dependent on the situation in which unfamiliar birds encountered one another. Finally, I measured the costs of establishing a position in a new social group. (1) I found no evidence that individual juncos that had made shorter migratory journeys were socially dominant to juncos that had migrated farther. This is inconsistent with a central prediction of the dominance hypothesis. (2) An alternative explanation for differential migration of the sexes is that males face stronger sexual selection for early return to breeding areas than do females, which would cause longer migrations and later return to be less costly for females. To test this hypothesis I delayed the settlement of female blackbirds as they returned to breeding sites. Delayed females exhibited a decline in social status and a slight delay in nesting, but otherwise were as successful as controls, which is consistent with the alternative hypothesis. (3) I demonstrated that the social status of juncos increases when they are deprived of food or have low stored fat reserves. Arriving at a site before a competitor, or prior residence, also increases status. Finally, familiarity with a very high-ranking bird can increase an individual's status relative to that of unfamiliar birds (a 'coattail effect'). (4) By transferring juncos from familiar to unfamiliar flocks I showed that high-ranked birds face a decline in status and an increase in metabolic rate and in corticosterone level. In contrast, low-ranking birds exhibited little change when joining a new flock. Understanding the evolution and maintenance of differential migration will add to our knowledge of animal distribution and dispersal. Further progress in this area will come from studying the social behavior of individuals during migration. |more info| |
| Ilsun M. White Ph.D. Indiana University1992 (Psychology) Behavioral and Electrophysiological Investigations of the Neural Mechanisms Underlying Performance on a Conditioned Avoidance Task ABSTRACT: Converging evidence indicates that a major function of the striatum is the integration of sensory, motor, and motivational processes into behavioral output. Rats were trained on a lever-release version of the conditioned avoidance response (CAR) task, in which an auditory signal elicits a short-latency paw withdrawal, to assess neural mechanisms underlying CAR performance. As an initial test of the hypothesis that the striatum is involved in this specific task, the behavioral effects of established and putative antipsychotic drugs known to disrupt striatal transmission were examined. Systemic injection of haloperidol, clozapine, SCH-23390, BMY-14802, and eticlopride decreased successful avoidance responses and increased avoidance latencies without affecting the latency of escape responses. In contrast, sulpiride, a neuroleptic that has difficulty crossing the blood brain barrier, failed to affect either avoidance responses or avoidance latency. To further assess striatal involvement in CAR performance, neural activity was recorded from 218 sites in the striatum of rats trained on the same CAR task. About 80% of these recording sites showed training-related activity, including neurons that responded to the auditory stimulus, the lever-release response, or both of these events. Histological analysis revealed a predominance of signal-related neurons in medial striatum, whereas lateral recording sites mainly showed response-related activity. To assess the neuronal mechanisms underlying the behavioral effects of haloperidol, the effects of this drug on training-related neuronal activity were also examined. Haloperidol disrupted the avoidance response and attenuated training-related neural activity without altering the spontaneous firing rate. Collectively, these results suggest that the sensory and motor aspects of the CAR task are processed by different striatal regions and that haloperidol disrupts the striatal processing of both sensory and motor information. |more info| |
| Wesley O. White Ph.D. Indiana University 1992 (Psychology) Two Meals Presented at Circadian Intervals Alter Suprachiasmatic Nucleus-Dependent Processes and Entrain Rest-Activity and Food-Anticipatory Rhythms of the Rat ABSTRACT: Humans commonly eat several large meals at relatively fixed times of day. The ways such meals can modify patterns of daily activity and their neural basis were studied in rats, an animal often used to model human physiology and behavior. Rats were separately housed under simulated light-dark cycles in stations consisting of a nest, a running wheel, and food and water sites. In Experiment 1 rats isolated from time of day cues and deprived of food for two consecutive days continued to be especially active at former daily feeding times, indicating that an internal clock had organized meal-associated activity. Only light-dark cycles had been thought to alter activity of the suprachiasmatic nucleus of the hypothalamus (SCN) and thereby entrain the rest-activity rhythm. But during Experiment 2, two meals presented at fixed times of day synchronized the rest-activity rhythms of rats maintained in constant darkness. These meals apparently altered activity of the SCN and, thus, synchronized the host of biological rhythms ordinarily entrained by light-dark cycles. In Experiments 3 and 4 rats were active prior to two daily meals only when the SCN could have timed meal availability, indicating that the SCN was involved in organizing meal-anticipatory activity. Meal-anticipatory activity attenuated or disappeared in constant light or darkness when meals occurred approximately 1 to 1.5 hr earlier, or 0.5 hr later, each day. Rats with complete lesions of the SCN were active around only one or two former feeding times when deprived of food for two days (Experiment 4a) and anticipated two daily mealtimes only when meals were provided at circadian intervals (Experiment 4b). Anticipation of two daily feeding times may have been mediated by a non SCN circadian oscillator and a 'circadian hourglass'. In conclusion, the SCN appears sensitive to both light-dark and meal-availability cycles and contributes to the organization of both rest-activity and meal-anticipatory rhythms. Because such a timing system can produce either stable or variable patterns of day-to-day activity, care should be taken in scheduling human food intake. |more info| |
| Robert F. Madej M.A. Indiana Univeristy 1992 (Biology) Assessing Local Mate Competition in the Parasitoid Wasp, Nasonia vitripennis ABSTRACT: Models of local mate competition (LMC) have received considerable attention over the past two decades. Many laboratory studies of parasitoid wasps have shown agreement with the general prediction of LMC that sex ratios should be female biased when few females contribute progeny to a patch and decline toward 50% daughters as the number of ovipositing females increases. However, little field work on LMC has been conducted. We observed the colonization and oviposition behavior of the parasitoid wasp, Nasonia vitripennis (Pteromalidae) at carcasses placed in the field to determine whether field data would also support LMC. The behavioral data showed that colonizing female numbers varied within and among days in the patch. Since the mechanism by which the wasps assess the number of other wasps in the patch is unknown, we used three different measures of "foundress number": total number of females arriving at a patch, average number of females per day, and average number of females per day excluding the first and last days. Qualitative and quantitative agreement was found between our sex ration data and that predicted by LMC for all three measures of foundresses. Total number of females is the standard measure used in laboratory tests. However, the predicted sex ratio using this measure showed the poorest fit to the field data. In this study, the overall percentage parasitism was 90%. Thus hosts may have been limited and superparasitism an important factor. Other considerations when assessing the fit between theory and data, such as competition for hosts from other parasitoids, host quality and host availability are also discussed. |more info| |
| Cara L. Wellman Ph.D. Indiana University 1993 (Psychology | Neural Science) Changes in Spatial Learning and Neocortical Morphology in Adult and Aged Basal Forebrain Lesioned Rats ABSTRACT: The present studies assessed the separate and interactive effects of aging and lesions of the nucleus basalis (NBM) on behavior and cortical morphology. Experiment 1 assessed spatial learning in adult, middle-aged, and aged rats with and without lesions of the NBM. While performance in a radial arm maze did not vary with age, lesions significantly impaired performance of the task. Experiment 2 assessed changes in cortical morphology in these rats. Neuron number in frontal cortex and the thickness of superficial laminae were reduced in aged rats. Lamina II-III neurons were hypertrophied in middle-aged rats relative to both younger and older groups. In adult rats, lesions moderately reduced the size of lamina II-III neurons in frontal cortex. In middle-aged rats, lesions markedly reduced the size of lamina II-III neurons across cortical areas. In aged rats, lesions increased the thickness of superficial laminae (perhaps due to gliosis), but did not affect neuronal size. Experiment 3 assessed dendritic changes in lamina II-III frontal cortical neurons of adult, middle-aged, and aged rats with unilateral lesions of the NBM. While lesions did not affect dendritic morphology in adult rats, they decreased total dendritic length and branching in middle-aged and aged rats. Again, these effects were most pronounced in the middle-aged rats. Thus, cholinergic denervation produced differential neuronal changes in frontoparietal cortex across ages, with middle-aged rats being most profoundly affected. The neuronal changes seen in middle-aged rats may reflect a compensatory response to expression of other neural changes related to aging, which may affect the ability of cortical neurons to respond to lesion-induced loss of cholinergic input. Therefore, the system of Fischer 344 rats may be a useful model for studying age-related changes in neuronal plasticity. |more info| |
| Inna V. Efimova Larsen M.A. Indiana University 1993 (Psychology) Responses of Lactating and Non-Lactating Females to Rat Pups' Ultrasonic Vocalizations |more info| |
| Charles L. Baube Ph.D. University of Indiana 1993 (Biology) The Perceptual Mechanisms of Sexual Selection in Sticklebacks ABSTRACT: Charles Darwin defined two mechanisms of sexual selection. Intersexual selection results from differential reproductive success due to differential competitive ability among members of the same sex (typically males). Intrasexual selection results from differential reproductive success due to differential attractiveness to potential mates. Parental investment by male Threespine Stickleback fish, Gasterosteus aculeatus, is among the highest in fishes. Only males establish and defend a territory, build a nest from algae and care for the offspring. Males use elaborate displays and nuptial colors to intimidate rivals and court females. I investigate the coevolution of the visual processing system present in females and the visual signals produced by males that are involved in this elaborate form of mating behavior. Combining behavioral, neuroethological and psychophysical experiments with computer modelling techniques, I concentrate on how female visual mechanisms influence the evolution of the male colored nuptial display. From color sensitivity experiments, I conclude that ancestral female threespine sticklebacks were maximally sensitive to red and green light. Mate choice experiments demonstrate that females prefer red males, suggesting that male red coloration likely evolved to take advantage of female red sensitivity. Male-male contests and dietary manipulations demonstrate that redder males are better competitors for breeding territories, mates and, indirectly, food. However, analysis of the female visual system provides no evidence that it evolved in order to accomplish the beneficial task of discriminating among males based on the amount of red they possess. Rather, this ability appears to be a fortuitous result of the properties inherent to the visual system. I consider the extent to which hypotheses for the evolution of male breeding displays by female choice are consistent with these data. |more info| |
| Sheree F. Logue Ph.D. Indiana University 1994 (Psychology | Neural Science) An Examination of the Role of the Hippocampus in the Acquisition and Timing of a Signalled Bar-Press in Appetitive and Aversive Conditioning ABSTRACT: The hippocampus is one of the most intensely studied structures thought to be involved in learning and memory. Based on current data and theories of hippocampal function, the hippocampus appears to be necessary for tasks which require learning complex rules, but does not appear to be necessary for simple associations. Although the hippocampus is not necessary for simple associations it may affect the acquisition of simple associations by being involved in the timing of responses and/or the timing of the stimuli length. The current three experiments were designed specifically to (1) compare the role of the hippocampus in appetitive and aversive instrumental tasks in which the only difference in the tasks is the consequence of the response and (2) to elucidate the role of the HPC in response timing in these conditioning tasks. Use of lesion and recording techniques during training with standard response parameters, demonstrated that the role of the HPC is the same in appetitive and aversive signalled bar-pressing tasks and that the HPC may be responsible for modulating the timing of the signalled responses. Assessment of the effect of hippocampal lesions on training with a response timing requirement and transferring of training from the appetitive to the aversive task and vice versa, revealed that the HPC is not involved in modulation of timing in these tasks. Also, the hippocampus is not necessary for switching the associations between a signal and the appetitive and aversive consequences of the response. These data suggest that the role of the HPC in simple association tasks is modulation of responses during early training. The modulation most likely occurs via the connections of the HPC to the brain areas responsible for the simple aversive and appetitive associations. |more info| |
| Omer Sayeed Ph.D. Indiana University 1994 (Biology) A Behavioral-Genetic Investigation of Magnetoreception in Drosophila melanogaster |more info| |
| Carolyn J. Gerrish Ph.D. Indiana University 1995 (Psychology) Thermal and Behavioral Determinants of Weaning Onset in Norway Rats ABSTRACT: In the present series of experiments I examine potential proximate mechanisms involved in the transition from sucking to independent feeding, a critical stage in mammalian development. In Study 1, I observed weanling-aged rat pups and the dam in a semi-natural habitat to determine events that precede independent feeding bouts. I found that independent feeding reliably followed nursing bouts and that pups showed a dramatic increase in behavioral arousal following termination of a nursing bout. Specific components of nursing stimulated behavioral arousal: withdrawal of the dam's nipple and milk transfer. Milk transfer also produced a slight increase in metabolic heat production in weanling-aged pups. Suckling-induced behavioral arousal contributes to weaning onset (first ingestion of solid food) by stimulating activities performed away from the nest and suckling, such as exploration and feeding. Thus, suckling appears to lead to its own demise. In Studies 2 and 3 I examined the hypothesis that pups' developing thermoregulatory (TR) capabilities might stimulate nest egression and subsequent ingestion of solid food. In Study 2, the dam and her litter were placed in a semi-natural habitat in which food was in an area ('field') separate from the nest. I found that with warmer field temperatures, pups emerged earlier from the nest and ingested solid food at earlier ages. In Study 3, I gave preweanling pups daily exposures to Cold, Moderate and Warm temperatures to modify their TR capabilities. I expected that more mature TR capabilities would lead to earlier nest egression and earlier weaning onset. Instead, I found that Cold-exposed pups showed delayed nest egression, later weaning onset, delayed eye opening, lowered body weight and reduced fur growth compared to Warm-exposed pups. There were no differences in heat production capabilities between the Warm- and Cold-exposed pups. Cold-exposed pups, however, showed a greater frequency of densely packed hair follicles than did Warm-exposed pups. Pups responded to cold exposures as do seasonal animals in winter, by slowing growth and development. Environmental temperature can modulate weaning onset extrinsically by guiding behavior and perhaps intrinsically by affecting the organisms' TR capabilities. |more info| |
| Gregory M. Andraso Ph.D. Indiana University 1996 (Biology) Interactions Among Defensive Morphology, Startle Performance, and Mauthner Cell Size in the Brood Stickleback (Culaea inconstans) ABSTRACT: Predation is an important force in the evolution of morphology and behavior of prey species. This study compared anti-predator morphology, anti-predator behavior, and the neural substrate that mediates this behavior in populations of brook stickleback (Culaea inconstans), a small freshwater fish that is found throughout the midwestern United States. Stickleback from populations with robust defensive structures had poor escape responses, whereas those from populations with small defensive structures had efficient escape responses. Long spines and their supportive structures may therefore help stickleback escape from predators if they are captured, but they may impair the fish's ability to flee from predators. This trade-off helps explain why poorly armored stickleback sometimes occur in environments with high densities of predators. Differences in startle response among stickleback populations may be caused by factors unrelated to defensive morphology. To help control for such factors, I focused on a population of brook stickleback in which some individuals have pelvic spines and pelvic girdles whereas others completely lack these structures. Investigation of spined and spineless fish from this population provided further evidence for a trade-off between robustness of the defensive apparatus and escape performance. As predicted, individuals lacking a pelvic girdle did better in all aspects of startle performance than their fully spined and girdled counterparts. Stickleback startle responses are mediated by a giant interneuron called the Mauthner cell. Predation pressure may act on Mauthner cell size and produce the interpopulational differences in startle performance. However, a comparison of two populations of stickleback that differ in startle performance and that appear to be under different intensities of predation revealed no such differences in Mauthner cell size. The similarity in Mauthner cell size and poor startle performance in the population exposed to high predation was unexpected. Recent isolation and divergence of stickleback populations, coupled with unequal rates of evolution of peripheral structures and neural circuitry may account for these results. |more info| |
| Michael G. Hosking Ph.D. Indiana University1996 (Biology) The Relationships Among Foraging Success, Sexual Selection, and Life History in the Threespine Stickleback (Gasterosteus aculeatus) ABSTRACT: Reproductive male threespine sticklebacks exhibit a brilliant red belly coloration that has been shown to function as an intra- and intersexual signal. This coloration is derived from a number of carotenoid pigments which males cannot synthesize de novo and must obtain from their diet. A critical link thus appears to be established between foraging success and the quality of the male signal. The role of foraging success in the development of the male stickleback's sexual signal was investigated through a diet-treatment study in which two groups of male threespine sticklebacks were fed diets simulating differential foraging success in nature. The physical condition (i.e. weight/unit length) and intensity of the color signals were monitored in both groups of males over the course of a 48 day feeding period, after which these variables were behaviorally assayed through female mate choice tests and staged territorial. Extraction, identification and quantification of the carotenoid pigments present in the males' sexual signals followed the behavioral tests. The low-diet males exhibited brighter color scores, declining physical condition, and higher levels of carotenoid pigments relative to the high-diet males which, although duller in color and with less total carotenoid pigment in their sexual signals, were in better physical condition. High-diet males were dominant in the territorial encounters, but females showed no overall preference for males of either diet treatment. These results indicate that both physical condition and red belly coloration may be important cues for female mate choice in this species, but foraging success is the critical factor in determining male competitive ability. Pigment extraction analyses indicate that the variation among males in the intensity of the red signal is likely to be a function of quantitative rather than qualitative differences in carotenoid pigments, although the influence of the pigment melanin was not considered. The implications of these results for the study of sexual selection in the threespine stickleback are discussed. |more info| |
| Scott L. Kight Ph.D. Indiana University 1996 (Biology) Maternal Behavior in the Burrower Bug, Sehirus cinctus Palisot (Heteroptera: Cydnidae): Integrating Physiology, Ecoloogy, and Organism ABSTRACT: This study examines the reproductive behavior of the subsocial burrower bug Sehirus cinctus Palisot (Heteroptera: Cydnidae) at mechanistic and functional levels. Females defend and maintain physical contact with their eggs throughout embryogenesis, and provision first instar nymphs with food. Maternal females discriminate between their own and strange eggs under appropriate spatial and experiential conditions. Discrimination is likely associated with pheromonal compounds secreted onto the eggs and nest by the mother. The initiation and maintenance of care are strongly associated with cues from eggs. Females terminate care when eggs are removed, but resume brooding if eggs are returned within 48 h. Stimuli from eggs also induce maternal behavior in some nulliparous females. Treatment with the anti-juvenile hormone agent precocene II suggests that egg-contact and defensive behavior are associated with high circulating levels of juvenile hormone. The termination of care is normally associated with hatching of eggs, but duration of care is a function of ambient temperature and light/dark cycling when eggs fail to hatch. |more info| |
| Kathleen M. Silva Ph.D. Indiana Univeristy 1996 (Psychology) Appetitive Behavior During an Interfood Clock ABSTRACT: Eight experiments with rats examined the temporal pattern of responses during an 'interfood clock', which marked successive time periods between food presentations with different external stimuli. Experiment 1 investigated how the distribution of multiple responses during the interfood interval (IFI) changed with and without interfood clocks, which responses were controlled by the clock stimuli, which responses were proportional to the duration of the IFI (scalar), and which responses occurred a fixed time after food presentations (time-bound). Experiments 2, 3, and 4 examined further how the pattern of responding during the IFI was related to the behavior systems concept of sequential motivational states as determinants of appetitive behavior. Experiments 5, 6, 7, and 8 determined the extent to which the individual clock stimuli controlled the responses that occurred within them. The main findings were: (a) Rats showed a multimodal pattern of behavior during the interfood clock. Behavior in, near, and away from the feeder peaked just before, after, and between presentations of food, respectively; (b) The patterns of nosing in the feeder and locomotion remote from the feeder showed scalar properties under different IFI durations; (c) Rats engaged in more nosing in the feeder with an interfood clock than without one, but only at intermediate IFI lengths; (d) Post-food behavior such as rearing and paw-grooming displayed time-bound characteristics, but whether a subject predominantly reared or paw-groomed depended on the IFI length; (e) Rats contacted a moving probe stimulus most when it was paired with the clock stimulus that controlled locomotion away from the feeder; (f) The predictable passage of time alone was often sufficient to produce the pattern of responding across the IFI observed during the interfood clock, but not the absolute levels. The results were consistent with a behavior systems view of appetitive behavior: Rats engaged in preorganized sequences of behavior between food presentations. The temporal patterns of nosing in the feeder and locomotion showed scalar characteristics which were consistent with scalar expectancy theory. |more info| |
| Tracey L. Kast M.A. Indiana University 1996 (Biology) Variation in Sperm Reserves According to Season, Stage of Reproduction and Testosterone Treatment in the Dark-Eyed Junco No abstract |more info| |
| Sherry L. Rich Defended Ph.D. Indiana University 1996 (Medical Science) |more info| |
| C. Alexander Buerkle Ph.D. Indiana University1997 (Biology) Evolutionary History of Migratory and Non-Migratory Populations of Prairie Warblers (Dendroica discolor) ABSTRACT: The cohesion of species is a function of interbreeding among constituent populations. Gene flow smooths clinal variation and must be interrupted for significant population differentiation and speciation to occur. Therefore, within a species, an abrupt, discontinuous geographic distribution of variation suggests an interruption of gene flow and the potential for evolutionary divergence. In this dissertation I describe the geographic pattern of genetic and morphological variation in prairie warblers, a species that exhibits discontinuous geographic variation in migratory behavior. Members of one widely-distributed subspecies are highly migratory (Dendroica discolor discolor), while members of a peripheral subspecies in Florida are sedentary (D. d. paludicola). Their geographic ranges are separated by approximately 200 km. I used mitochondrial DNA sequences to infer the relationship of migratory and non-migratory prairie warblers. A phylogeny of DNA haplotypes indicates that there has been no long-term genetic isolation of these forms. However, a population genetic analysis suggests there is a significant reduction of gene flow between discolor and paludicola. This result is surprising, given prairie warblers' capacity for long-distance movements and no obvious extrinsic barriers to mating. Using museum specimens collected throughout the species' range, I described variation in external morphology. My analysis indicates that the morphologies of migratory and non-migratory populations differ substantially. The pattern of geographic variation in morphology is coincident with variation in migratory behavior. The concordant genetic and morphological data suggest that these behaviorally differentiated taxa may be sufficiently isolated to continue to diverge from one another. Finally, I used computer simulations of gene genealogies to infer parameters of population growth for prairie warblers and two other bird species. These simulations showed that populations of D. d. discolor increased at least ten-fold during the Pleistocene. Calidris alpina and Carduelis chloris showed no evidence of population growth. I also evaluated the efficiency of this method for recovering information historical demographies. These studies add to our understanding of spatial and temporal aspects of population differentiation and speciation. Extensions of this research would involve sampling at a finer geographic scale and studies of development of taxon-specific behavior and morphology. |more info| |
| Todd M. Freeberg Ph.D. Indiana University 1997 (Biology) Cultural Transmission of Behaviors Facilitating Assortative Courtship and Mating in Cowbirds (Molothrus ater) ABSTRACT: Brown-headed Cowbirds (Molothrus ater) are common blackbirds that are brood parasites: young cowbirds are raised by other species. Because of their parasitic nature, many scientists have believed that the behavioral development of cowbirds would be closed to the influence of experience. This research tested whether social experience and cultural background could influence the development of patterns of courtship behavior in cowbirds. Individuals who share the same patterns of courtship behavior pair and mate preferentially with one another: this is known as assortative mating, and it has important implications for the evolution of populations. To test for the social learning influences on the development of courtship behaviors, young cowbirds were housed in different cultural backgrounds. Young females and males from a South Dakota population were housed in large aviaries with either adults of the same South Dakota population (the South Dakota culture) or adults of a behaviorally distinct Indiana population (the Indiana culture). The courtship behaviors of these young cowbirds were influenced by experiential background: during the breeding season birds of the South Dakota culture preferentially paired with one another and birds of the Indiana culture preferentially paired with one another. To address whether courtship behaviors could be culturally transmitted, another generation of young South Dakota cowbirds was tested. These young South Dakota birds were housed with the adults of the first cultural generation: with South Dakota birds from the South Dakota culture or with South Dakota birds from the Indiana culture. The birds of this second cultural generation also paired preferentially with birds that shared a similar cultural background, demonstrating that courtship behaviors can be culturally transmitted. These results point to the importance of social and cultural environments in the inheritance of behavioral systems, even in species with unusual developmental histories. |more info| |
| Ceylan (Jayce) Isgor Ph.D. Indiana University 1997 (Psycholgy)
Effects of Perinatal Gonadal Steroids on Adult Spatial Navigation and Hippocampal Morphology |
| Jennifer Rozema Jenkins Ph.D. Indiana University 1997 (Biology) The Role of Learning in Territorial and Courtship Behavior in Male Threespine Stickleback (Gasterosteus aculeatus) ABSTRACT: Learning has been shown to influence reproductive behavior in many vertebrates, but few researchers have investigated the role of learning in reproductive behavior in threespine stickleback (Gasterosteus aculeatus). I examined how learning influences territorial and courtship behavior in male threespine stickleback. I trained territory-holding males to associate a signal light with the opportunity to view a rival male. Isolated subjects readily learned the association, but subjects with a nearby neighbor male did not because they were apparently distracted by the nearby neighbor. Isolated subjects also learned to associate a signal with the opportunity to view a gravid female. To examine the potential function of learning to predict rivals, I trained males to associate a signal with the opportunity to view a rival. Interspersed with the signaled rival presentations were several non-signaled presentations of the rival. In signaled trials, males approached the rival more quickly and showed more aggressive behavior than they did in non-signaled trials. Such learning may enable males to more effectively defend their territories. Learning may also influence the courtship preferences of threespine stickleback. Naive males prefer to court the more gravid of a pair of female stickleback; so, I examined whether males are capable of altering this preference by punishing males for courting the more gravid of a pair of simultaneously presented female dummies. Punished males modified their courtship behavior, directing a smaller proportion of courtship to the more gravid dummy than did unpunished, control males after punishment training. I also presented males with long-term exposure to 2 female dummies differing in gravidity. As expected, males preferentially courted the more gravid female. In addition, male courtship responses to the less gravid dummy waned, or habituated, but courtship responses to the more gravid dummy remained high. Such differential modulation of courtship behavior could be adaptive because males may learn to ignore (habituate to) non-receptive females, but persistently court receptive females. This project demonstrates that learning influences the reproductive behavior of male threespine stickleback in the laboratory. In nature, learning may be an adaptive mechanism by which males defend territories and court potential mates more effectively. |more info| |
| Edward P. Levri Ph.D. Indiana University 1997 (Biology) The Effects of Parasitism and Predation on the Foraging Behavior of a Freshwater New Zealand Snail ABSTRACT: Modifications of host behavior may be the result of direct manipulation of the host by the parasite to enhance its transmission to subsequent hosts in the life cycle. I have examined the behavioral effect of a digenetic trematode (Microphallus sp.) on the behavior of its intermediate host (the freshwater snail, Potamopyrgus antipodarum). Microphallus-infected snails behaved differently from all other snail groups (brooding and non-brooding females, males and juveniles). Microphallus-infected snails foraged on top of rocks in the early moming, and moved to the bottom of the rocks for the remainder of the day. These results suggests that the parasite alters host behavior by increasing the exposure of infected snails to their waterfowl final host, which feeds most in the early moming. Microphallus-infected snails appear to move to the bottom of the rocks in the late morning, because fish predominantly feed at this time. Fish cannot serve as a host for the parasite, thus ingestion of an infected snail by a fish results in the death of the parasite. Furthermore, snails eaten by fish are less likely to be infected by Microphallus than snails from the population at large. Thus, the behavior induced by Microphallus appears to decrease the probability of the snail being eaten by an unsuitable host. Both transmissible (mature) and non-transmissible (immature) Microphallus induce a change, but only the mature parasites expose the host to waterfowl in the early morning. The induced behavioral change appears to enhance transmission of the parasite because snails infected with immature parasites are less exposed to predation. The behavior induced by Microphallus was significantly different from the behavior induced by two other groups of parasites, and Microphallus-infected snails were found to be on top of rocks in the early morning regardless of food availability. These results indicate that the behavioral change is unlikely to be byproducts of parasitic castration or hunger. Finally, infected snails were found to behaviorally respond similarly to uninfected snails to a fish predator cue, suggesting that behaviors that are beneficial to the parasite are maintained in the host. |more info| |
| Timothy T. Horan Defended Ph.D. Indiana University 1997 (Biology) The Roles of Mate Choice, Competition, and Incitation of Aggression in the Evolution of the Mating System of the Mosquitofish (Gambusia affinis) NO ABSTRACT AVAILABLE |more info| |
| Mark E. Deutschlander Ph.D. Indiana University 1998 (Biology) Behavioral Investigation of the Physiological Basis of Light-Dependent Magnetic Compass Orientation in the Eastern Red-Spotted Newt, Notophthalmus viridescens ABSTRACT: The use of the geomagnetic field for spatial orientation is widespread in animals. Yet, the physiological mechanism(s) for magnetoreception have not been conclusively identified in any terrestrial animal. Three different biophysical models have been proposed which suggest that the geomagnetic field could affect the efficiency of photodetection to produce a photoreceptor-based magnetic compass. Consistent with a photoreceptor-based magnetoreception mechanism, specific wavelength of light have been shown to influence magnetic orientation in an amphibian, an insect, and several species of birds. The goal of this thesis was to determine the approximate anatomical location of the photoreceptors which mediate the light-dependent magnetic compass response of the Eastern red spotted newt, Notophthalmus viridescens. In addition to the photoreceptors of the eye, amphibians also possess extraocular photoreceptors (EOPs) in some areas of the brain (i.e., pineal and hypothalamus). EOPs in the pineal complex of amphibians and lizards have been shown to play a role in orientation behaviors. Furthermore, the pineal of birds and mammals appears to be sensitive to spatial and temporal changes of both earth-strength, and stronger, magnetic fields. Non-invasive behavioral experiments were conducted to determine the role of EOPs in the newt's light-dependent magnetic compass. First, we designed a new experimental protocol and provided a crucial replication of the previous experiments which demonstrate that the newt's perception of the direction of the magnetic field is altered by long wavelength (> or = 500 nm) light. Then by selectively manipulating the wavelength of light reaching EOPs in, and around, the pineal, we were able to show that EOPs mediate the wavelength-dependent magnetic compass of newt. These results support previous findings implicating the pineal as a "magnetosensitive" organ. The implications of these experiments are discussed in relation to (1) the evidence for light-dependent magnetic orientation in birds and (2) the evidence for a non-light dependent, magnetite-based mechanisms for magnetoreception in vertebrates. |more info| |
| Matthew Klukowski Ph.D. Indiana University 1998 (Biology) Effects of Testosterone on Foraging Behavior and Parasite Loads of Two Sceloporus Lizards ABSTRACT: The effects of testosterone on the foraging behavior and parasite loads of two lizards, the northern fence lizard (Sceloporus undulatus hyacinthinus) and the mountain spiny lizard (Sceloporus jarrovi), were examined in a series of field and laboratory experiments. First, plasma testosterone in wild fence lizards peaked in the spring breeding season, declined to basal levels in the summer, and rebounded in the fall. The intensity of territorial behavior in males closely paralleled these changes in testosterone. Further, the intensity of territorial behaviors in males increased dramatically following a 'challenge' from an intruding male but testosterone levels were unaffected. Second, in a separate field study, male fence lizards with experimentally elevated testosterone had both greater sprint speed and greater stamina than control males. This effect may have been mediated through decreased muscle fiber sizes. The field study revealed that elevated testosterone has important costs in the fence lizard, as testosterone-implanted males lost body mass while control males gained body mass. Testosterone-treated males also had smaller fat bodies than control males. Third, male mountain spiny lizards with elevated testosterone had similar distributions of focal distances, as measured by infrared photoretinoscopy, to those of control males and also exhibited very similar strike distances and prey capture success in the laboratory. Fourth, in another laboratory experiment, testosterone-treated male mountain spiny lizards ate significantly fewer crickets in the presence of a sexually receptive female than in trials with an unreceptive female, while controls were relatively unaffected by the female's receptive state. However, none of the other social stimuli combinations (male or unreceptive female conspecific, singly or together) strongly influenced feeding behavior. Finally, in each of two consecutive years, field-active testosterone-treated male fence lizards had significantly greater mite loads than control males. However, there was no correlation between plasma testosterone concentrations and ectoparasite loads in freshly captured mountain spiny lizards from two populations. In neither species did elevated testosterone suppress the humoral immune response in laboratory tests. |more info| |
| Samrrah A. Raouf Ph.D. Indiana University 1998 (Biology) Patterns of Extra-Pair Fertilizations in Dark-Eyed Juncos (Junco hyemalis): The Effects of Testosterone and Age ABSTRACT: Monogamous male birds exhibit a spring peak in plasma testosterone (T) followed by lower levels during the parental phase of the breeding season, while males of polygynous species maintain T at spring levels, court multiple females, and usually provide less parental care. To determine whether T underlies this trade-off between mating and parental effort in dark-eyed juncos (Junco hyemalis), a socially monogamous bird, we placed silastic tubing packed with crystalline T beneath the skin of experimental males (T-males) and compared their annual reproductive success (RS) to that of control males (C-males). T-males had lower apparent annual RS (eggs, nestlings and fledglings) than controls, probably because elevated T reduced parental care. Nevertheless, annual genetic RS of the treatment groups was similar because (1) T-males suffered fewer losses in genetic RS as the result of extra-pair fertilizations (EPFs), and (2) T-males gained more genetic RS through their own EPFs. With respect to male age and treatment, older C-males produced the largest number of fledglings. Older males suffered greater losses to EPFs than did young males, but treatment with T lowered these losses by 50% for both age classes. Older males obtained significantly more RS through EPFs than did young males. Treatment with T enhanced gains for both male age classes. Net annual RS of old males was similar to that of young males, but there was a trend for older males to have higher RS than young males. Because the means of the net annual RS for C- and T-males were similar, we wondered whether T-males could arise naturally and co-exist in a mixed evolutionarily stable strategy (ESS) with C-male juncos. By examining the RS of C- and T-males living among varying proportions of T-males, we cautiously concluded that when rare, the T-male phenotype would not spread in a population of C-males, and that the C-male phenotype would be a pure ESS. |more info| |
| Russell C. Titus Ph.D. Indiana University 1998 (Biology) Song Function and Social Influences on Courtship Behavior in Dark-Eyed Juncos ABSTRACT: Signals used in communication over long and short distances are expected to differ in structure as well as in function. I examined the structure, function, and development of two classes of acoustical signals produced by a territorial passerine bird, the Dark-eyed Junco (Junco hyemalis). The first, short-range songs, are widespread among birds but have not been well-studied. Studies of the second, long-range songs, have contributed greatly to theories of animal learning and communication. I tape-recorded juncos and quantified the structure of their songs as well as variation in song repertoires among individuals. Among wild birds, I found that males produced short-range songs when they were near fertile females and during aggressive interactions with other males. In contrast, males produced long-range songs when far from conspecifics and at a rate independent of reproductive stage of the female. I confirmed that songs are important signals by demonstrating that juncos responded (by approaching speakers and changing their own song rates) to tape-recorded songs of each class more than to tape-recorded song of another species. I examined the effects of early experience on the development of song and other courtship behaviors by housing young birds in two social conditions designed to simulate those experienced in nature. Half were housed in flocks that contained adult males, which served as potential models for the development of behavior. The others were housed in flocks that contained no adult males. Young males housed with adult males were more successful in pairing with females than were those housed without adult males. Young males that were successful in pairing tended to sing short-range songs and engage in tail-spreading and feather-erection displays more often than those that did not pair. Results suggest that development of theses courtship behaviors is subject to social influences. Inclusion of both long- and short-range songs in future studies should lead to a more comprehensive understandings of avian communication. |more info| |
| Daniela S. Monk Ph.D. Indiana University 1999 (Biology) Differential Allocation of Parental Care in Free-Ranging Mountain Bluebirds ABSTRACT: In monogamous species both parents typically contribute to offspring care, but the evolutionary interests of parents and offspring are not necessarily congruent. Males and females may differ in their relatedness to offspring and in many circumstances the parent with lower relatedness should contribute less to care. In addition, parents might be expected to invest equally in male and female offpring and to otherwise treat young equally, while individual siblings might be expected to claim resources for themselves, producing a conflict between parent and offspring. My research addressed how relatedness, offspring sex and potential conflict between parents and offspring affect resource allocation among nestlings of Mountain Bluebirds (Sialia currucoides). I combined field observations with genetic, video, and statistical analyses to study parent and offspring interactions in a natural population. Using DNA fingerprinting, I found that a high proportion of young were sired by males other than the care-giving male. By observing feeding trips to nests, I also found that females provisioned young more than males, especially when broods contained many young unrelated to the male. This may reflect a decrease in male care when relatedness was perceived as low and an increase by females to compensates for lower male effort. In addition to relatedness, sex of the young also influenced parental investment. Female parents laid more female than male eggs, but at fledging there were equal numbers of male and female young. In addition, female parents fed broods that contained more female offspring more frequently than they fed brods with more males when nestlings were young. Male parents, on the other hand, provisioned male-biased broods more often than female-biased broods, but only durin gthe late nestling period. Given that parents are expected to invest equally in offspring of either sex, these results suggests that because daughters are more likely to die during hte period of parental care, parents should produce more sons, and that sons may require more resources than daughters to survive fledging. Interestingly, however, video analysis of feeding episodes to individual nestlings showed that sons and daughters were fed at equal rates by male and female parents. Finally, in collaboration with a statistician, I developed a new model to evaluate which nestling characteristics best predict whether a young will be fed by its parent. I found that the intensity with which a nestling begged was the most important predictor. Also important were the positions of nestlings in the nest. Older nestlings could enhance their liklihood of being fed by moving into favorable positions. Thus as nestlings age, they may influence allocation of resources by controllling position. |more info| |
| Regina Abel Ph.D. Indiana University 2000 (Psychology) Perinatal Experience Facilitates Early Behavioral Organization and Adaptation in Newborn Rats (Rattus norvegicus) ABSTRACT: Within 2 hr of birth, newborn rats commence suckling, an adaptive behavior that depends on a coordinated combination of sensory and motor processes. It had been suggested that the odor of amniotic fluid is a learned cue that enables the pup to recognize the maternal stimulus and to suckle, but the stimulus and response components of the learning process remained unspecified. Previously, my research contributed to a view that the odor of amniotic fluid becomes a conditioned stimulus (CS) for the newborn via its association with compressions during labor, which act as an unconditioned stimulus (UCS). The conditioned response (CR) is manifest as nipple attachment in the presence of a CS. In the present research, I employed a controlled procedure for simulating birth to identify: (a) the unconditioned response (UCR) to compression; (b) the physiological mechanism of the UCR; and (c) a more precise neonatal CR to amniotic odor. Fetal rats responded to compression with torso extensions, or stretching, a salient behavior rarely observed in spontaneous fetal movement, but a common element in appetitive, neonatal behavior. Compression also increased plasma catecholamines (dopamine, norepinephrine, and epinephrine) to levels typical of vaginally-delivered newborns. When haloperidol, a dopamine antagonist, was administered prior to compression, fetal rats responded with torso extension; behavior did not differ from non-compressed controls. When L-Dopa, a dopamine precursor, was administered in the absence of compression, fetal rats exhibited torso extension similar to compressed Ss. Amniotic odor elicited an extension-flexion pattern in newborn rats similar to that observed in compressed and L-Dopa-treated fetuses; without the CS, the neonates' movements resembled those of non-compressed and haloperidol-treated fetuses. Results of the present studies suggest that compression elicits dopamine-mediated torso extension; amniotic odor associated with compression elicits similar torso extension in the newborn. |more info| |
| Carolyn L. Pytte Ph.D. Indiana University 1999 (Biology) Juvenile Vocal Motor Practice Contributes to Adult Song Production and Perception in a Songbird ABSTRACT: Sensory experience during sensitive periods in development may direct the organization of neural substrates and permanently influence adult behavior. In juvenile songbirds, the acquisition of vocal motor patterns for song production takes place during a prolonged period of vocal motor practice. In order to investigate the existence of sensitive periods during song motor development in zebra finches, I temporarily and reversibly paralyzed the vocal muscles using botulinum toxin, disrupting motor practice during selected stages of song development. Temporary interference with motor practice late in development, during the emergence of the adult song motor pattern, compounded the effects of earlier periods of disruption and resulted in permanent motor defects in the adult song. Disruption of motor practice either prior to, or after this period had no discernible effect on the song motor pattern. These results reveal a sensitive period for motor practice during the terminal stage of vocal motor development. During juvenile song practice, neurons in the song system become tuned to acoustic characteristics specific to the bird's song, possible contributing to song perception. To explore a potential perceptual role of vocal practice, I interfered with song development in juvenile zebra finches and tested their perceptual abilities as adults. Juveniles 1) were permanently muted prior to song development or 2) experienced a temporary period of vocal motor paralysis during the sensitive period for song motor development. Phonotactic and heart rate response to conspecific song playback were used as perceptual assays. Phonotactic responses of muted birds differed significantly from those of control siblings, and were no different from chance, suggesting a handicap in perceptual processing. Heart rate responses of birds which had experienced motor disruption during a sensitive period for vocal learning exhibited significantly longer orienting responses following song playback than did sibling control birds. These results suggest that experience during song development contributes to song perception in adulthood. |more info| |
| Matthew R. Blankenship Defended Ph.D. Indiana University 2001 (Psychology | Neural Science) The Effects of Amygdala Lesions on Hippocampal Function and Eye Blink Conditioning in Rats ABSTRACT: The hippocampus and the amygdala have long been associated with memory, emotion and motivated behaviors. The role of each of these brain areas in learning a simple, discrete motor response has been well studied, however a definitive theory concerning their functions remains elusive. The experiment discussed herein involves selective ablation of the central nucleus (CE) or the basolateral nucleus (BA) of the amygdala followed by single-unit analyses of hippocampal CAI subfield activity during eye blink conditioning (EBC) in freely moving rats. Three hypotheses were tested using this experimental design. The results of each facet of the experiment were: (1) The removal of both CE and BA (individually) adversely affect the development of conditioned responding. Measures of CR percentage showed that the lesion groups acquire the task at a significantly slower rate than the non-lesion groups. Response onset measures revealed no differences, however the sham lesion groups had larger response amplitudes than the lesion groups. Therefore, CE and BA lesions do not prevent EBC, but they do retard learning, potentially due to a damaged, fear-mediated reflex facilitation circuit. (2) Activity recorded in the hippocampus during EBC showed that CAI cells become active during the CS-US period. This activity is potentially related to the generation of conditioned behavior, and therefore appears similar to activity observed in rabbit hippocampus. There were however, some differences between activity recorded in rat and what is traditionally seen in rabbit. For instance, response onset and overall activity over pre-CS levels differed. (3) Finally, the CE and BA nuclei appear to have different influences on hippocampal activity during training. CE lesions result in a significant disturbance of activity within the CS-US interval. Despite the behavioral consequences, BA lesions do not disrupt learning-related hippocampal activity seen later in training. Taken together, these results indicate how the hippocampus is operating during EBC in freely moving rats, and how the two major functional components of the amygdala contribute to learning and the function of the hippocampus. The results are interpreted with regard to current theories of limbic system function. |more info| |
| Kristy S. Hamilton Defended Ph.D. Indiana University 1999 (Psychology)
[ Dissertation Title & Abstract Forthcoming ] |
| Marianne S. Engle Ph.D. Indiana University 2000 (Psychology) The Importance of the Social and Acoustic Environment in the Production of Song and Mimicry in the European Starling ABSTRACT: This research program investigated the effects of social and acoustic stimulation on the production of species-specific song organization and mimicry in the European starling, Sturnus vulgaris. The aim of my work was to answer three questions: (1) How do syntax and temporal organization of mature song differ as a function of biasing the social and acoustic environment? (2) How do different social environments affect the production and development of species-typical song characteristics for males? (3) How differences in a bird's social environment affect the content of mimicry? Male starlings were hand-reared, paired with a heterospecific songbird or hand-reared female starling, and placed in human homes for one year, where they were deprived of species-typical song models. The song of home-reared males was then analyzed and compared to that of wild adult male starlings. Home-reared starlings in both groups developed repertoires comparable in size to those of wild birds. This result is in contrast to results reported for isolate birds which develop small repertoires and suggests that conditions of social and acoustic isolation are detrimental to song development and produce song deficits that can not be attributed to the absence of adult conspecific song models. Although the results of song analyses indicated no production deficits, home-reared males in both groups developed anomalies in species-specific temporal and syntactical organization. In many cases, these anomalies represented a shift from starling-typical patterns towards the vocal patterns of the heterospecifics they socialized with, including humans. The quantity of human-related mimicked sounds acquired was positively correlated with the quantity and quality of avian-human interaction, and most sounds that were mimicked were associated with avian-human interactions. Thus, social and acoustic stimulation appears to facilitate imitation of temporal and syntactical patterns, as well as song content, and may be sufficient for the development of a large song repertoire, even if the source of that stimulation is heterospecific. |more info| |
| Kimberly J. Bolyard Ph.D. Indiana University 1999 (Biology) Internal and External Factors Influencing Visually Mediated aggression in Male Threespine Stickleback, Gasterosteus aculeatus ABSTRACT: During the breeding season, male threespine stickleback fish (Gasterosteus aculeatus) develop nuptial coloration, defend a territory, and build a nest, which is crucial to their reproductive success. My research focused on the territorial interactions among males and how attributes of the subject male, rival, and encounter context influence attack and escape behavior. I found that color and behavior of the rival affect a subject male's aggression. Males attack a bright red rival more than a moderately or dull red rival when on their territory but not when off their territory. Males respond to a courting rival more than to a feeding or resting rival by attacking and directing courtship signals back to the rival. Male response to rivals depends on encounter location and past experience. A male shifts from attacking to escaping from its neighbor as encounters occur farther from his nest and closer to his neighbor's nest. A male that has fought a rival or spent time with another fish species outside its territory is less aggressive towards its neighbor in future encounters than a male that has had solitary experience outside its territory. Males may respond to territorial intrusions of rivals by increasing androgen production, but treatment with luteinizing hormone alone is not sufficient to increase a male's attack rate. Changes in male behavior resulting from changes in context (on/off territory; distance from next) support the conflict hypothesis, which states that two opposing motivational tendencies, aggression and fear, determine male-male aggression. Overall, this research demonstrates plasticity in the male's behavior, previously thought to be largely innate. This research may help us understand how animals communicate with each other, and how communication processes develop over an individual's lifetime and evolve over generations. |more info| |
| Mark William Bowie M.A. Indiana University 1999 (Biology) Development of a Protocol for Investigating Geotaxis in the Eastern Red-spotted Newt (Notophthalmus viridescens) ABSTRACT: The goal of these experiments was to develop a reliable testing protocol and experimental apparatus to investigate the geotactic orientation of the eastern red-spotted newt, Notophthalmus viridescens. The life history of this animal involves migration to and from ponds in which gravitational cues guiding geotactic orientation, and possible other forms of navigation, may play a role. Newts captured from local ponds and held in an outdoor tank overnight were tested in an orientation arena on slopes of less than 1°. Newts tested on slopes of 0.01° failed to orient relative to slope despite changes to the protocol and the testing arena. Newts tested on slopes of 0.1° oriented bimodally with respect to slope. Results showing that newts can consistently orient on slopes an order of magnitude smaller than orientation responses previously observed in semi-natural conditions suggest that the direction of gravity may be used for functions other than geotaxis. Newts left in the outdoor tank longer than 24 hours prior to testing oriented more consistently to slope than newts left in less than 24 hours. This suggests geotactic orientation is enhanced by holding animals in outdoor tanks more than 24 hours prior to testing. Newts collected from one population (Story 4) failed to exhibit geotactic orientation. Behavioral differences due to time since capture or the Story 4 population being mostly of a different subspecies than other ponds tested were found not to be factors. Future experiments examining possible seasonal shifts in behavior, as well as aspects of the ecology or life history of Story 4 newts may help to explain why these animals failed to exhibit geotactic orientation. |more info| |
| Gabrielle B. Britton Ph.D. Indiana University 2000 (Psychology | Neural Science)
Neuronal Activity in Cerebellar Interpositus Nucleus and Red Nucleus During Conditioned Inhibition of the Eyeblink Response |
| Joseph L. Lipar Ph.D. Indiana University 2000 (Biology) Maternal Investment via Yolk Hormones: Do Female Birds Influence Nestling Competition Through the Differential Allocation of Steroid Hormones? ABSTRACT: Monogamous male birds exhibit a spring peak in plasma testosterone (T) followed by lower levels during the parental phase of the breeding season, while males of polygynous species maintain T at spring levels, court multiple females, and usually provide less parental care. To determine whether T underlies this trade-off between mating and parental effort in dark-eyed juncos (Junco hyemalis), a socially monogamous bird, we placed silastic tubing packed with crystalline T beneath the skin of experimental males (T-males) and compared their annual reproductive success (RS) to that of control males (C-males). T-males had lower apparent annual RS (eggs, nestlings and fledglings) than controls, probably because elevated T reduced parental care. Nevertheless, annual genetic RS of the treatment groups was similar because (1) T-males suffered fewer losses in genetic RS as the result of extra-pair fertilizations (EPFs), and (2) T-males gained more genetic RS through their own EPFs. With respect to male age and treatment, older C-males produced the largest number of fledglings. Older males suffered greater losses to EPFs than did young males, but treatment with T lowered these losses by 50% for both age classes. Older males obtained significantly more RS through EPFs than did young males. Treatment with T enhanced gains for both male age classes. Net annual RS of old males was similar to that of young males, but there was a trend for older males to have higher RS than young males. Because the means of the3 net annual RS for C and T-males were similar, we wondered whether T-males could arise naturally and co-exist in a mixed evolutionarily stable strategy (ESS) with C-male juncos. By examining the RS of C- and T-males living among varying proportions of T-males, we cautiously concluded that when rare, the T-male phenotype would not spread in a population of C-males, and that the C-male phenotype would be a pure ESS. |more info| |
| Richard G. Keen Ph.D. Indiana University 2000 (Psychology)
Relative Numerosity Discrimination in Pigeons |
| Matthew R. Tinsley Ph.D. Indiana University 2000 (Psychology) Systemic and Intra-Accumbral Dopamine Manipulations and Unconditioned Preparatory Behaviors in Rats ABSTRACT: The criteria for identifying incentive properties, the arousing and directing effects of stimuli on behavior, are usually based on the behaviors they are trying to explain. This causes a problem of circular definition and indicates the importance of a behavior-independent definition of incentive. Research on dopamine has led to suggestions that it may serve as a substrate of incentive properties. However, these theories are based on research that used conditioned stimuli, possibly confounding learning and incentive properties and ignoring the incentive properties of unconditioned stimuli. To avoid this problem, I investigated the effect of dopaminergic manipulations on unconditioned incentive stimuli. My results demonstrate similar effects on unconditioned stimuli to those that have been found for conditioned stimuli. These results can be used to refine current theories of dopamine and incentive to make them more compatible with current psychological theories of motivation. |more info| |
| Munire Ozlem Cevik Ph.D. Indiana University 2000 (Psychology)
The Effects of Methamphetamine on Temporal Discrimination |
| Mark W. Harty Defended Ph.D. Indiana University 2000 (Psychology ) Androgen Effects on the Morphology and Electrophysiology of Sexually Dimorphic and Non-Dimorphic Rat Spinal Motoneurons ABSTRACT: -- forthcoming -- |more info| |
| William J. Farrell Ph.D. Indiana University 2000 (Psychology)
Development and Control of Maternal Responsiveness to Infant Rat Ultrasonic Vocalizations |
| W. Anthony (Tony) Frankino Ph.D. Indiana University 2000 (Biology) The Role of Development in the Origin and Evolution of Adaptive Phenotypic Plasticity ABSTRACT: Adaptive phenotypic plasticity is the environment-specific development of variation that enhances relative reproductive success. The occurrence of adaptive plasticity presents the opportunity to study the ecological conditions that favor the evolution and maintenance of phenotypic diversity within species, and provides a unique tool with which to study how developmental or proximate mechanisms shape the evolution of form. Tadpoles of the spadefoot toads Spea bombifrons and S. multiplicatus may dramatically modify their behavior and morphology, changing from their typical omnivorous form into a rapidly developing and growing carnivore. In a series of empirical studies, I identified the conditions that induce these tadpoles to switch between alternative phenotypes, and I studied the effects of these discrete ontogenies on traits that contribute to reproductive success. Of greatest interest is my finding that the probability of developing the carnivore phenotype is highest when tadpoles are food stressed and an alternative food source, anostracan fairy shrimp, is abundant. This means that individual tadpoles assess their own condition and the abundance of alternative resources when responding to the cues that induce development of the carnivore phenotype; low-condition tadpoles become carnivores and increase their relative reproductive success by specializing on the unexploited fairy shrimp. Such environmentally-cued polyphenisms illustrate that the environment in which an individual develops can affect the adult phenotype that is subject to selection. I develop a quantitative genetic model which demonstrates how interactions between the environment and proximate mechanisms regulating development can alter the distribution of phenotypes seen by selection, affecting the course of population evolution in the adaptive landscape. I then review how a research program that integrates the comparative method with quantitative genetics, embryonic manipulations, and molecular genetics has the greatest potential to elucidate how developmental processes affect the evolution of phenotypic plasticity in particular, and biological diversity in general. |more info| |
| Norman C. Pecoraro Ph.D. Indiana University 2001 (Psychology)
Methamphetamine and Circadian Organization |
| Kerry J. Jones M.A. Indiana University 2000 (Biology) Testosterone and Non-Reproductive Components of Avian Life Histories: Effects of Experimentally Testosterone in Non-Breeding Male Dark-Eyed Juncos ABSTRACT: - forthcoming - |more info| |
| Antino Recio Allen Defended M.A. Indiana University 2000 (Biology) An Investigation of the Role of Visual Cues During Host Discrimination by the Jewel Wasp, Nasonia vitripennis ABSTRACT: - forthcoming - |more info| |
| M. Todd Allen Ph.D. Indiana University 2000 (Psychology | Neural Science)
The Role of Cerebellar Cortex and the Hippocampus in the Timing of the Conditioned Response in the Classically Conditioned Rabbit Eyeblink Paradigm |
| Wendy H. Wente Defended Ph.D. Indiana University 2001 (Biology)
Microhabitat Choice in the Pacific Treefrog (Hyla regilla): Characteristics of a Complex Color Polymorphism and Implications for the Development of Assortative Mate Choice Within an Interbreeding Population |