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(1) Hatchery-reared Florida largemouth bass, Micropterus salmoides floridanus, feed on inert pellet food while their wild counterparts capture elusive prey. Differences in levels of prey elusivity often mandate the use of alternate methods of prey capture and are accompanied by a related phenotypic change. (2) This study investigates (a) differences between the prey capture kinematics and strike modes of hatchery and wild juvenile Florida largemouth bass raised on pellets and live prey, and (b) whether elusivity-based variation in prey capture translates to a phenotypic and functional change during skull development. (3) Analysis of high-speed videography demonstrates that wild bass capture live prey with very rapid movements and large excursions. Hatchery bass of the same age, raised and feeding on pellets, however, used slower kinematics with smaller excursions, yielding strikes with a higher degree of suction. (4) Capture events of hatchery bass fed live prey for the first time were characterized by movements that were faster than their wild counterparts, but had smaller excursion measurements and resulted in a decreased level of capture success. After five exposures to elusive mosquito fish, hatchery bass adapted their behaviors to capture prey at the kinematic level of wild bass. (5) The developmental pattern of the skull was conserved between hatchery and wild bass until 80-99mm TL. At this point, wild bass quickly developed morphological changes of the jaw apparatus including a more fusiform head and elongated jaw structures. Natural development in hatchery bass, however, was retarded at this size. Post-release, the skulls of hatchery fish converged towards those of wild bass by 135mm TL. Despite this variation in skull development, no theoretical advantage in food capture was found between these two groups. (6) It is likely that a lack of experience in live prey capture might constrain hatchery bass from utilizing the total functional potential of their specialized morphology, and therefore, exposure to elusive prey should be enforced in rearing-techniques of hatchery fishes in order to improve the low post-stock survival rates of this species.

The elasmobranch fishes possess a remarkable diversity of feeding mechanisms for a group containing relatively few species (~1200). The three most prevalent of these mechanisms involve prey capture during which the predator overtakes its prey (ram), prey is drawn into the mouth of the predator (suction), and relatively stationary consumption of sessile or substrate affixed prey (biting). Biomechanical modeling of cranial force distributions, in situ bite performance trials, and kinematic analysis of prey capture behaviors were employed to identify morphological and behavioral specializations and constraints associated with these feeding mechanisms in lemon Negaprion brevirostris (ram), whitespotted bamboo Chiloscyllium plagiosum (suction), and horn Heterodontus francisci (biting) sharks. Biomechanical modeling of the forces generated by the cranial musculature was used to theoretically estimate the maximum bite force and mechanical loadings occurring throughout the hyostyl ic jaw suspension mechanisms of each species, characterized by suspensory hyomandibular cartilages between the back of the jaws and cranium and anterior ligamentous attachments. To assess the mechanical factors involved in the evolution of elasmobranch jaw suspension mechanisms, the feeding mechanism of the sharpnose sevengill shark Heptranchias perlo was modeled as well. Heptranchias perlo possesses an ancestral amphistylic jaw suspension mechanism including non-suspensory hyomandibular cartilages, a large post-orbital articulation between the jaws and cranium, and anterior ligamentous attachments. Theoretical estimates of maximum bite force were compared to voluntary bite forces measured during in situ bite performance trials. Voluntary bite force measurements allowed the quantification of discrete behavioral attributes of bite force application in each species. To further assess the behavioral specializations associated with these feeding mechanisms, high-speed digital videography w as used to analyze the prey capture cranial kinematics of species. Collectively, these analyses have developed a morphological and behavioral basis from which to understand the functional diversity of the ram, suction, and biting feeding mechanisms in elasmobranchs.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-14T14:31:03Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Luiz Eduardo Alves Bezerra do Nascimento.pdf: 898152 bytes, checksum: 6a9c77c38d08afcb99b849e2f5b50493 (MD5) / Made available in DSpace on 2016-07-14T14:31:03Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Luiz Eduardo Alves Bezerra do Nascimento.pdf: 898152 bytes, checksum: 6a9c77c38d08afcb99b849e2f5b50493 (MD5) Previous issue date: 2015-11-30 / CAPEs / Poecilia vivipara apresenta distribuição ampla na costa brasileira, e sua reprodução por viviparidade viabiliza a utilização de jovens recém-nascidos com 24 horas de vida em estudos ecotoxicológicos para avaliar o potencial de toxicidade de contaminantes ambientais. Este trabalho teve por objetivos avaliar os efeitos letais e subletais nestes estágios iniciais de vida do peixe estuarino Poecilia vivipara após exposição a diferentes concentrações dos HPAs fenantreno e pireno dissolvidos na água. Os jovens recém-nascidos foram obtidos de plantel de reprodutores mantidos em laboratório, expostos ao fenantreno nas concentrações 0, 10, 50, 200 e 500 μg L-1 durante 7 dias, e ao pireno nas concentrações 0, 1, 10, 50 e 100 μg L-1 durante 14 dias. Após a exposição foi avaliada a taxa de mortalidade, e nos sobreviventes foram quantificados os parâmetros subletais atividade da Glutationa S-Transferase (GST), velocidade de natação espontânea, captura de presas e crescimento. Jovens expostos a 500 μg fenantreno L-1 apresentaram 40% de mortalidade, e não foi detectada mortalidade nas demais concentrações. Jovens expostos ao pireno nas concentrações 50 e 100 μg L-1 apresentaram 44% e 33% de mortalidade, respectivamente, e não foi detectada mortalidade nas demais concentrações. Com relação aos parâmetros subletais, a concentração de efeito observado (CEO) para atividade de GST, velocidade média de natação, distância linear nadada e incremento de peso foi igual a 500 μg fenantreno L-1. Já para a exposição ao pireno a (CEO) para atividade de GST foi igual a 10 μg pireno L-1, 50 μg pireno L-1 para velocidade média de natação e distância linear nadada, e 1 μg pireno L-1 para incremento de peso. O aumento da atividade da GST após exposição a 500 μg fenantreno L-1 sugere um aumento dos gastos energéticos com os processos de biotransformação de fase 2, e esta alteração esteve associada a decréscimos na atividade locomotora, na habilidade de capturar presas, e também no crescimento. A exposição ao pireno também apresentou um padrão semelhante, com alterações detectadas em concentrações menores, indicando uma maior potência do pireno comparado ao fenantreno para induzir a GST, gerar hipoatividade locomotora e inibir o crescimento, parâmetro de maior relevância para o recrutamento da espécie. Estes resultados sugerem que o uso de jovens recém-nascidos de Poecilia vivipara como modelos ecotoxicológicos para a compreensão dos efeitos de contaminantes em parâmetros de diferentes níveis de organização biológica relacionados ao recrutamento de peixes é promissor. / Poecilia vivipara has a wide distribution pattern along the Brazilian coast, and its reproduction by viviparity enables the use of newborn in ecotoxicological studies to evaluate the potential toxicity of environmental contaminants. This study aimed to assess the lethal and sublethal effects on these early stages of life of the estuarine fish Poecilia vivipara after exposure to different concentrations of the PAHs phenanthrene and pyrene dissolved in water. The newborn were obtained from a breeding stock kept under controlled conditions, and exposed to phenanthrene concentrations of 10, 50, 200 and 500 μg L-1 and control for 7 days, and pyrene concentrations of 1, 10, 50 and 100 μg L-1 and control for 14 days. After exposure, the mortality rate was calculated, and the survivors were evaluated for the sublethal parameters glutathione S-transferase activity (GST), spontaneous swimming speed, prey capture rate and growth. Young individuals exposed to 500 μg phenanthrene L-1 exhibited 40% mortality, only detected in this concentration. Juveniles exposed to pyrene concentrations of 50 and 100 μg pyrene L-1 exhibited 44% and 33% mortality, respectively, and no mortality was detected in other tested concentrations. Regarding sublethal parameters, the lowest observed effect concentration (LOEC) for GST activity, average swimming speed, linear swimming distance and weight increase was equal to 500 μg phenanthrene L-1. Already for an exposition to pyrene the LOEC for GST activity was equal to 10 μg pyrene L-1, 50 μg pyrene L-1 for average swimming speed, and 1 μg pyrene L-1 for weight increase. The increase in GST activity after exposure to 500 μg phenanthrene L-1 suggests an increase in energy expenditure with the biotransformation processes of phase 2, and this change was associated with decreases in locomotor activity, the ability to catch prey, and also in growth. Exposure to pyrene also exhibited a similar pattern, with changes detected in lower concentrations, indicating a greater pyrene potency compared to phenanthrene to induce GST and to generate locomotor hypoactivity and inhibit growth, the most relevant parameter for the recruitment of the species. These results suggest the potential use of newborn young Poecilia vivipara as ecotoxicological models for understanding the effects of contaminants on parameters of distintic biological organization levels related to the recruitment of fish.

Performance is an organism’s ability to accomplish a particular task or behavior, and morphology can have a major impact on the performance of an organism. Salamanders are ecologically diverse and can feed using a variety of behaviors depending on the environment in which feeding occurs. Feeding is accomplished through the use of the hyobranchial apparatus, which lies along the oropharynx, and this structure can have competing roles; in aquatic environments the apparatus is used for suction feeding and works to depress the floor of the mouth, but during terrestrial feeding this structure projects the tongue forward out of the mouth. Diverse morphologies of the hyobranchial apparatus enable varying degrees of feeding performance, both in aquatic and terrestrial environments. For my dissertation I have investigated the interactions, and possible functional trade-offs, of feeding morphology and performance in salamanders of Family Salamandridae. These salamanders are an ideal system for studying the interactions of morphology and performance across different environments because they have diverse ecology, being either fully aquatic, semi-aquatic, or terrestrial as adults, as well as differences in hyobranchial apparatus morphology. In these studies I have quantified the morphology and performance of seven salamandrid species feeding in aquatic (Chapter 2) and terrestrial (Chapter 3) environments to assess the links between these two parameters, as well as investigated the evolutionary patterns of feeding morphology, performance, and behavior across the Salamandridae (Chapter 4) to better understand the co-evolution of these traits across water-land transitions. During aquatic feeding salamanders use rapid mouth opening and hyobranchial depression to expand the oropharynx and generate negative pressure, and fluid flow, into the mouth. I hypothesized that more robust hyobranchial apparatus would yield increased aquatic feeding performance in salamandrids. When compared to semi-aquatic newts, the fully aquatic species, Paramesotriton labiatus, had greater mineralization of the hyobranchial apparatus, as well as relatively narrower basibranchial and wider ceratobranchial I + II complexes. These morphological differences coincide with greater aquatic feeding performance. Kinematics from high-speed videography revealed that maximum mouth opening velocities and accelerations were approximately two and five times greater, respectively, in Paramesotriton, and hyobranchial depression acceleration was found to be approximately three times greater than in the semi-aquatic species Pleurodeles, Notophthalmus, Triturus, and Cynops. Using digital particle image velocimetry, peak and average fluid velocities generated in Paramesotriton during suction feeding events were found to be 0.5 m s-1 and 0.2 m s-1, respectively, doubling that of all semi-aquatic species. These findings reveal that specialized morphology increases aquatic feeding performance in a fully aquatic newt. Salamanders use the hyobranchial apparatus and its associated musculature for tongue projection during terrestrial feeding. Hyobranchial apparatus composition and morphology vary across species and different morphologies are better suited for feeding in aquatic versus terrestrial environments. I hypothesized that differences in hyobranchial apparatus morphology and function result in functional trade-offs in feeding performance. Specifically I predicted that semi-aquatic and aquatic salamandrids with hyobranchial morphology suited for aquatic feeding would have lower performance, in terms of tongue-projection distance, velocity, acceleration and power, compared to terrestrial salamandrids when feeding in a terrestrial environment. I found that semi-aquatic and aquatic newts had lower tongue projection performance when compared to the terrestrial salamanders Chioglossa lusitanica and Salamandra salamandra. The fully aquatic newt, Paramesotriton labiatus, has a robust, heavily mineralized hyobranchial apparatus and was unable to project its tongue during terrestrial feeding, and instead exhibited suction-feeding movements better suited for aquatic feeding. Conversely, terrestrial species have gracile, cartilaginous hyobranchial apparatus and enlarged tongue pads that coincided with greater tongue-projection distance, velocity, acceleration, and power. Chioglossa exhibited extreme tongue-projection performance, similar to that seen in elastically projecting plethodontid salamanders; muscle-mass-specific power of tongue projection exceeded 2200 W kg-1, more than 350 times that of the next highest performer, Salamandra, which reached 6.3 W kg-1. These findings reveal that two fully terrestrial salamandrids have morphological specializations that yield greater tongue-projection performance compared to species that naturally feed in both aquatic and terrestrial environments. Salamanders of the Salamandridae that feed in both aquatic and terrestrial environments employ different behaviors depending on the environment. Using phylogenetic comparative methods, I assessed the relationships between feeding morphology, kinematics, and performance, and the ecology and feeding behavior of salamandrids. I also examined the co-evolution of feeding morphology and performance within Family Salamandridae. Behavior appears to co-evolve with feeding musculature, velocity of feeding movements, and fluid velocity produced during aquatic feeding. Flow velocity produced during aquatic feeding was related to the cross-sectional area of the rectus cervicis muscles, which rapidly depress the hyobranchial apparatus during suction feeding. Salamandrids with greater cross-sectional area of these depressor muscles generate faster flow velocity in aquatic feeding. Conversely, the evolution of hyobranchial apparatus morphology is more closely linked to ecology than to behavior. These findings indicate that both behavior and ecology are important for understanding the evolution of morphology and feeding performance across Family Salamandridae.

Nitrogen (N) is an essential element to plants for growth, maintenance and reproduction, however most N does not exist in a form that is biologically available to plants. In order to maximise the acquisition and retention of N, plants have evolved a variety of morphological and physiological adaptations and life history strategies, as well as the ability to respond plastically to changes in resource availability in ecological time. Determining the ecophysiological responses of plants to changes in root N availability is crucial to further understanding of the mechanisms underlying competitive interactions between plants, and between plants and other organisms, that ultimately contribute to community structure and ecosystem functioning. Carnivorous plants are ideal systems for investigating ecophysiological responses to N availability as:- (i) they share a unique adaptation for obtaining supplemental N from captured prey, therefore ecological stoichiometry and energetic cost/benefit models may be explored; (ii) the trait of botanical carnivory is widely considered to have independently co-evolved as a response to N-deficient, sunny and wet environments, therefore resource allocation trade-offs between plant investment in N and carbon (C) acquisition may be observed, and (iii) they are extremely sensitive to changes in root N availability in ecological time. In this research, the carnivorous plant Drosera rotundifolia (round-leaved sundew) was used to address several unanswered ecophysiological and evolutionary questions relating to patterns and processes of prey capture and the N nutrition of carnivorous plants. Furthermore, the potential for reducing uncertainty in the calculation of plant reliance on carnivory using a δ15N natural abundance multi-level linear mixing model was explored. A combined approach of in-situ and ex-situ studies was employed, using co-occurring non-carnivorous plants or carnivorous plant species with differing evolutionary lineages or prey capture mechanisms respectively to provide context. Results show that the adaptations of carnivory, high reproductive investment and a relatively short life span enable Drosera rotundifolia to survive and thrive in an extreme, N deficient environment. Phenotypically plastic responses by the plant to light and root N availability provide evidence of resource allocation trade-offs between investment in carnivory for N acquisition and in photosynthesis for C acquisition. Plants invested less heavily in prey capture (measured as the stickiness of leaf mucilage) as N availability increased or light availability decreased. These results show that the energetic costs associated with carnivory are avoided by the plant when less costly sources of N are available for uptake and that the production of carbon-rich mucilage is only made under nutrient-limited and well-lit conditions. Results obtained from the comparison of captured insect prey with background invertebrates of potential prey indicate that Drosera rotundifolia is a dietary generalist, where the quantity of prey captured per plant is positively correlated with leaf stickiness and total leaf area. Plant reliance on prey-derived N decreased with increasing root N availability, providing evidence that carnivory is only of net benefit to the plant in N-deficient and well-lit environments, as the photosynthetic costs of investment in the trait are not exceeded by the energetic gain from prey N uptake in shady or dry habitats. A more accurate and precise method for calculating plant reliance on botanical carnivory is presented which incorporates the insect diet of the plant. This method has wider significance for reducing uncertainty in the calculation of relative source contributions to a mixture for most natural abundance applications using a multi-level linear mixing model. To conclude, results from this research further understanding of the ecophysiological mechanisms underlying plant responses to changes in resource availability and the selective pressures driving the evolution of plant adaptations. These results therefore assist with predicting how plants and plant communities may respond to sustained N deposition inputs and future environmental scenarios.

I characterized dusky dolphin (Lagenorhynchus obscurus) underwater bait-balling behaviors and acoustic signals, and compared data between Argentina and New Zealand (NZ) to investigate the roles of ecology versus social learning. I quantified prey herding and capturing behaviors from video footage, and I analyzed acoustic signals from narrowband recordings. In both locations, I related bait-balling behaviors and acoustic signals to group and prey ball sizes. In NZ, I also related dolphin behaviors to prey ball escape behaviors and acoustic signal parameters to examine proximate functions. Observed herding behaviors typically involved dolphins swimming around or under a prey ball using a side body orientation, while dolphins typically captured fish from the side of a prey ball using a ventral orientation. Coordinated prey-capture behaviors may have made it easier for dolphins to capture fish by trapping fish between dolphins. Signals were categorized as click trains, burst pulses, and combinations due to a bimodal inter-click interval distribution. I observed 3 whistle-like chirp-screams, but no whistles. Sequences of burst pulses also occurred that contained 2-14 burst pulses that aurally and visually appeared closely matched. Similarities between locations suggest that ecological context related to broad behavioral and acoustic parameters, while social learning differences may occur on a finer scale. In NZ, prey balls exhibited horizontal and vertical movements, but the only behavior that preceded escape was “funneling”, the brief formation of a ball shape where the height was at least twice the width. Dolphin behaviors that related to prey balls ascending were type of herding pass, location of prey-capture attempts, and body orientation during attempts. These behavioral parameters may also be used to counter vertical prey escape behaviors. In NZ, all signal categories had a direct or indirect role in capturing prey. Click train-burst pulses were likely used for echolocating on prey, burst pulses and sequences appeared to have communication roles, and the role of click trains was ambiguous. No signal categories appeared to have a herding function, but the sheer number of signals emitted may have caused fish to cluster together more tightly and therefore facilitated capture.

L’environnement dans lequel les espèces animales vivent joue un rôle important dans leur évolution. Les contraintes physiques sont particulièrement intéressantes car elles induisent souvent une pression évolutive qui pousse les espèces, même éloignées, à développer des réponses adaptatives similaires. Les contraintes physiques liées à la vie en milieu aquatique ont un impact important sur les trajectoires évolutives des espèces et notamment sur leur comportement et leur morphologie. De nombreux cas de convergences ont été démontrés, comme l’évolution d’une forme profilée chez les poissons, les mammifères marins et certains oiseaux aquatiques. Ces contraintes, appelées contraintes hydrodynamiques, sont particulièrement présentes lors de la réalisation d’un mouvement. On peut caractériser deux contraintes principales : la trainée et la masse ajoutée. La trainée est la résistance que le fluide oppose au mouvement de l’animal. La masse ajoutée elle, est la masse d’eau déplacée lorsque le corps se met en mouvement donc lors d’une accélération. Ces contraintes sont particulièrement présentes lors de la capture d’une proie dans l’eau. Ainsi, beaucoup d’animaux aquatiques ont développé un système de succion qui leur permet d’aspirer leur proie afin de limiter ces contraintes. Cependant, certains animaux, comme les serpents, ne peuvent pas développer ce type d’adaptation. Pourtant, plus de 200 espèces de serpents attrapent des proies dans l’eau. A travers ce travail, nous nous intéressons aux stratégies adaptatives développées par les serpents aquatiques afin de devenir de performants prédateurs. Deux hypothèses sont explorées : l’adaptation morphologique de la tête des serpents ainsi qu’une adaptation comportementale qui permettraient de réduire les contraintes hydrodynamiques. Des analyses morphologique et comportementale sont réalisées sur plusieurs espèces de serpents aquatiques afin de tester ces hypothèses. Les contraintes associées aux différentes formes de tête et comportements mis en évidence sont caractérisées à l’aide d’expériences d’hydrodynamique. L’interdisciplinarité qui est le cœur de ce manuscrit permet d’apporter un regard nouveau sur ces questions qui intriguent tant les biologistes que les physiciens. / Animal-environment interactions are determinant in driving the evolution of phenotypic variation. Most aquatic animals have developed adaptations to overcome the physical constraints inherent to an aquatic lifestyle and particularly to motion in water. These constraints are the drag and the added mass if an acceleration is involved in the motion, such as during prey capture. The aim of this project is to evaluate the role of water as a potential driver of evolution of aquatic snakes by focusing on morphological and behavioral convergences during underwater prey capture. Snakes are a good model as an aquatic life-style has originated independently in different genera. However, aquatic snakes did not develop a suction feeding system in contrast to most aquatic vertebrates. Prey-capture under water is constrained by the physical properties of the fluid and thus morphological and/or behavioral convergence is expected. By comparing the head shapes and the behavior of different species, we evaluated the impact of water on the evolution of head shape and strike behavior. By using experimental fluid mechanics approaches, we quantified the physical constraints involved in prey capture and evaluated the nature of the evolutionary response in response to these hydrodynamic constraints. This interdisciplinary approach allowed us to bring novel data to our understanding of functional constraints as drivers of phenotypic evolution.

No description available.