Dietary resource use for diamondback terrapins (Malaclemys terrapins) in subtropical mangrove habitats in south Florida creeks and islands was examined to elucidate long-term individual foraging strategies. Fecal analysis revealed seven categories of food items with gastropods, crabs, and bivalves being the most dominant food items respectively. Non-metric multidimensional scaling revealed differences in habitat, but not terrapin size class. Stable isotope analysis confirmed the findings, identifying habitat and site differences in δ13C and δ15N values for both terrapins and their prey. Bi-plots of terrapin and potential prey δ 13C and δ 15N values revealed potential dietary sources previously undetermined by fecal analysis. Comparisons of scute and blood isotope data revealed significant differences in δ13C indicating potential shifts in either food resources and/or habitat use through the time period recorded in the scute tissue. These tissue comparisons represent a powerful tool for estimating long term foraging strategies for a key estuarine species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Pelagic Sargassum was used to determine the effects of habitat architecture for one species of shrimp (Leander tenuicornis) and two species of fish (Stephanolepis hispidus and Histrio histrio). Inter-thallus spacing (low, medium, and high) and depth (shallow versus deep) were manipulated independently to test whether the spatial components of habitat architecture. Two differing habitats (Sargassum versus seagrass species) were tested for the structural component of habitat architecture. There were no significant results for inter-thallus spacing experiments for L. tenuicornis and S. hispidus. H histrio selected habitats with medium inter-thallus spacing in two treatments. Large individual H. histrio contributed mostly to the significant effects. All three species selected habitats with a greater depth aspect. Finally, L. tenuicornis and H. histrio selected habitats with greater structural complexity (i.e., Sargassum). These results demonstrate clearly that habitat architecture of Sargassum influences habitat selection by these shrimp and fishes. / by Chelsea O. Bennice. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Masking or decorator crabs, conceal themselves partially through camouflage, by selecting or indiscriminately attaching materials from their environment to their exoskeleton. Functional aspects of decorating behavior and morphology in this group have not been documented. Using Microphrys bicornutus as a model species, this dissertation demonstrates clearly that decorating is an advantageous phenotype that has evolved to serve several functions. Decorating is a complex behavior that begins when a crab approaches an algal substrate and results in the attachment of algae to hooked setae on the exoskeleton. Once decorated, crabs remain motionless on the substrate until disturbed or until another behavior is initiated. This was confirmed for M. bicornutus, as crabs spent a significant amount of time feeding, remaining motionless, picking, and walking when compared to decorating. Crabs displayed agonistic behaviors during encounters with conspecifics conspecifics. These included both active aggressive behavior and display behavior. Crabs showed a decrease in motility during these encounters, helping maintain dispersed distributions, thereby decreasing intrsapecific encounters in the field. Trials were done to determine the effect of conspecifics, predators and feeding preferences on algal utilization. M. bicornutus showed a significant decrease in the amount of algae used for decoration in the highest density trials (i.e., 4 and 8 crabs). Agonistic displays and aggressive behavior between these crabs likely affected the time available for decorating. Decorated crabs isolated from an algal substrate were more likely to survive in the presence of either of two sympatric fish predators. Thus, being protected by the algal decoration on their exoskeletons. Trials also showed a parallel between algal consumption and algal materials used for decoration. In addition to its protective function, algae used by M. bicornutus for decoration simultaneously serve as short term food supplies for the crabs. Eleven morphologically complex structures were identified and mapped on the exoskeleton. Hooked setae were the primary structures used to attach algae to the crab’s body. Ten additional setal structures were present, including two novel types of setae. On the basis of location and morphological variation exhibited among these latter structures, a primary sensory function may be inferred. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2013.

A fragmentação florestal altera a estrutura das paisagens e as relações dos organismos com esta, sendo a movimentação um dos comportamentos mais afetado. Os indivíduos que se deparam com uma paisagem heterogênea, com áreas de habitat e de não-habitat (i.e., matriz), precisam cruzar as matrizes na procura por recursos. A opção de movimento é feita, então, através de uma avaliação dos custos e benefícios que cada área proporciona ao animal. Entre os maiores custos está o risco de predação, que pode variar conforme a estrutura de cada matriz (e.g. cobertura vegetal) e as características de cada espécie (e.g. capacidade de movimentação). Objetivando analisar o efeito de diferentes matrizes (pasto, milho e Eucaliptus) em relação ao risco de predação para a espécie Pyriglena leucoptera (Tamnophillidae) (1) verificamos se há diferenças entre as matrizes na quantidade de um dos principais predadores dessa ave, as aves de rapina, e (2) inferimos a percepção do risco de predação por meio da análise dos padrões de movimentação, realizando experimentos de translocação e monitoramento por radiotelemetria. Os resultados indicaram haver gradação de predadores nas matrizes estudadas: (milho=pasto)> Eucaliptus. O sucesso das aves em alcançar a mata foi mais alto no Eucaliptus, seguido pelo pasto e pelo milho. Os tempos médios de permanência nas matrizes também foram diferentes: (milho=Eucaliptus)>pasto. Os movimentos foram mais retilíneos no pasto e mais tortuosos no milho, enquanto o Eucaliptus mostrou uma situação intermediária. O milho provavelmente é a matriz mais arriscada para a Pyriglena leucoptera, tendo a maior densidade de aves de rapina, menor sucesso de chegada à mata e maior tortuosidade com maior tempo de permanência na matriz dos indivíduos (i.e. maior tempo de exposição ao risco). O pasto parece ser a matriz de risco intermediário, pois apresenta grande quantidade de aves de rapina, mas com animais menos tempo expostos, fazendo trajetos mais retilíneos, e o sucesso foi maior do que no milho. O Eucaliptus é a matriz de menor risco, teve a menor densidade de aves de rapina e o maior sucesso em chegar à mata. O maior tempo de permanência nessa matriz juntamente com a tortuosidade variada, e o maior sucesso de chegada à floresta, podem significar aproveitamento de recursos. Esses resultados ressaltam a importância dos estudos sobre os efeitos de diferentes matrizes no deslocamento das espécies por paisagens fragmentadas, o que afeta processos ecológicos essenciais ligados à permanência das espécies nestas condições. O manejo adequado das matrizes aparece como uma prioridade em projetos de conservação e restauração da biodiversidade nestas paisagens / Forest fragmentation alters landscape structure and its relationship with organisms, and movement is one of the most affected behaviors. Individuals who are faced with an heterogeneous landscape, composed of habitat and non-habitat areas (i.e., matrix), need to cross the non-habitat matrix in the search for resources. The choice of motion is then made by an evaluation of the costs and benefits that each area provides to the animal. Among major costs while moving through the matrix is the risk of predation, which may vary with the structure of each matrix (e.g., vegetation cover) and the behavioral characteristics of each species (e.g. movement capacity). Aiming to analyze the effect of different matrices (pasture, corn and Eucalyptus) in relation to risk of predation for the species Pyriglena leucoptera (Tamnophillidae) we (1) determined if there were differences between matrices in the density of one of the main predators of the bird, birds of prey, and (2) inferred the perceived risk of predation by performing translocation experiments with radiotelemetry monitoring to describe and analyze movement patterns in the matrix. Our results suggested a predation risk gradient in the studied matrices (corn = pasture)> Eucalyptus. The time birds spent in the matrix until reaching a forest patch was also different among matrices (corn = Eucalyptus) > pasture. Movements were straighter over the pasture matrix and more tortuous in the corn matrix, while in the Eucalyptus matrix movment showed an intermediate pattern. The success of birds to reach a forest patch was higher in the Eucalyptus matrix, followed by the pasture and corn matrix. Corn is probably the riskiest matrix for Pyriglena leucoptera, having the highest density of birds of prey, with most tortuous movement patterns and longest time spent in the matrix (i.e., longer exposure to risk) which resulted in less successful arrival to forest patches. The pasture seems to be the matrix of intermediate risk, because despite a large density of birds of prey, birds spent less time exposed to the risk, making more straight paths, which resulted in a higher success of reaching the forest than in the corn matrix. Eucalyptus was the matrix of lowest risk, had the lowest density of birds of prey and the greatest success in reaching the habitat. In this case, however, tortuosity of movement and the long time spent in this matrix did not result in decrease success of reaching a forest patch, this suggests that birds may be using resources (i.e. foraging) while moving through this less-risky matrix. This project highlights the importance of studies that quantify the effects of matrix type on the movement of organisms through fragmented landscapes, which affects essential ecological processes linked to the persistence of species in these conditions. The proper management of matrices appears as a priority for conservation and restoration of biodiversity in these human-modified landscapes

Estudos sobre seleção de presas podem apresentar resultados bastante diferentes dependendo do predador analisado. Predadores com diferentes técnicas de caça, como as aves de rapina e os mamíferos carnívoros, podem selecionar diferentes tipos de presas. Estudos sistemáticos sobre esse tema ainda são escassos no Brasil. Por esse motivo, o objetivo deste trabalho foi a análise da seletividade na dieta de três predadores quanto ao consumo de pequenos mamíferos na Estação Ecológica de Itirapina, SP. Para a suindara (Tyto alba), a seletividade de presas foi avaliada nos níveis de: espécie, tamanho, idade e sexo. A coruja-buraqueira (Athene cunicularia) foi estudada quanto ao consumo diferenciado nos níveis de espécie, tamanho e idade das presas. Para o lobo guará (Chrysocyon brachyurus), apenas a seleção de espécies foi possível. Foram utilizados restos de ossos (mandíbulas e cinturas pélvicas) das presas encontradas nas pelotas e fezes desses predadores para identificação da espécie e do sexo dos indivíduos, e para a quantificação do número de indivíduos consumidos. A análise de seleção de espécie foi feita por meio de comparações entre a proporção das mesmas encontradas nas dietas e no ambiente. Para isto, foram utilizados o teste G e o intervalo de confiança de Bonferroni. O consumo preferencial por um determinado sexo foi avaliado pelo teste G ou pelo teste exato de Fisher. O tamanho dos pequenos mamíferos na dieta foi calculado por meio de equações de regressão desenvolvidas para cada espécie dessas presas. O Teste de Mann-Whitney foi utilizado para comparações entre o tamanho das presas nas dietas e no ambiente. As idades dos roedores encontrados nas dietas e nos ambientes foram comparadas utilizando-se o teste G. A suindara foi mais seletiva do que a buraqueira no consumo de espécies de pequenos mamíferos, embora ambas incluam as mesmas espécies nas suas dietas. Calomys tener e Oligoryzomys nigripes foram os roedores mais predados pelas corujas. A seleção de indivíduos menores e de juvenis de C. tener pela suindara e de sub-adultos dessa presa pela buraqueira poderia ser entendido pelo modo de forrageamento de cada coruja e características biológicas da presa. Por outro lado, por ser um animal de maior porte, era esperado por parte do lobo-guará o consumo de presas maiores, como Clyomys bishopi. A seleção por indivíduos menores de C. tener pelas duas corujas indica predação de indivíduos mais vulneráveis. Assim a predação diferencial por roedores pequenos pode não ser devido a predação seletiva por parte das corujas, mas sim devido à alta vulnerabilidade dos mesmos, devido a sua inexperiência e por serem errantes. Pode-se perceber por meio deste estudo que, dependendo da localidade e das diferentes composições/abundancia de presas, os predadores parecem adotar diferentes estratégias. Dentro de uma mesma localidade esse recurso é utilizado de forma diferenciada pelos três predadores, pelo menos em termos de proporções, tamanho e idade. Estudos mais amplos e detalhados com utilização de metodologia padronizada, englobando todos os componentes de uma guilda trófica, além de se levar em conta as muitas variáveis ambientais, torne possível entender o papel de cada espécie na comunidade. / Prey selection studies may result in different conclusions depending on the analysed forager. Predators with different foraging modes, such as raptors and carnivorous mammals, may select different prey types. This kind of study is still scarce in Brazil. So, the goal of this research is the analysis of small mammal selection in the diet of three predators at Itirapina Ecological Station, SP. Analysis of prey selection by the Barn Owl (Tyto alba) was conducted in relation to species, size, age and sex. The Burrowing Owl (Athene cunicularia) was studied in relation to the consumption of small mammal species, size and age. The Maned Wolf (Chrysocyon brachyurus) was only evaluated concerning prey species selection. Remains of bones (mandibles and pelvic girdles) found in pellets and faeces of predators were utilized to identify prey species, sex and to quantify number of consumed individuals. Analysis of prey species selection was conducted by comparisons between proportion of prey found in the diet and in environment, applying G test and Bonferroni confidence intervals. Differential sex consumption was evaluated by G test and Fisher exact test. Mann-Whitney test was employed to compare prey size in the diet and in the environment. Rodent ages found in pellets/ faeces and in the field were compared by G test. The Barn Owl was more selective than the Burrowing Owl in relation to prey species consumption, though both of them include the same small mammal species in their diets. Calomys tener and Oligoryzomys nigripes were the most preyed on rodents by the two owls. Small-sized and juvenile individuals of C. tener were more consumed by the Barn Owl, whereas sub-adults were more preyed on by the Burrowing Owl. Differences may be due to foraging mode of each owl and biological characteristics of prey. The consumption of larger prey, such as Clyomys bishopi, by the larger predator, the Maned Wolf, was expected. Selection of smaller individuals within species may suggest predation of more vulnerable prey. So small-sized rodent selection may not result from active predation by the owls, but from higher vulnerability of these prey. Based on this study, depending on locality and differences in prey composition/abundance, predators may adopt different strategies. In the same area, resource was utilized in different manner by these predators, at least, in terms of prey proportion in the diet, size and age. Further studies using the same methodology, involving all components of trophic guilds, besides environmental variables, may better illustrate the role of each species in community.

O comportamento materno pode ser definido como a performance comportamental que a mãe expressa durante os momentos que abrangem desde o período imediato do pré-parto até o momento em que a prole é capaz de sobreviver sozinha sem os cuidados e a atenção materna. O estudo e entendimento dos mecanismos que modulam o comportamento materno podem ter focos diferenciados em relação às consequências na mãe, bem como nos filhotes. O entendimento dos mecanismos neuroanatômicos e neuroquímicos proveniente destes estudos em animais validam importantes fundamentos neurobiológicos de importância crucial para a sociedade em geral, em especial mães que sofrem de distúrbios em período perinatal. No ambiente natural, os animais frequentemente deparam com situações de conflito, e devem fazer escolhas entre diversos comportamentos fundamentais para sua manutenção, tais como alimentação, defesa e reprodução. O enriquecimento ambiental pode promover um impacto positivo ou negativo na expressão de determinados comportamentos. Observou-se um grande impacto da presença de maravalha no momento do teste comportamental, influenciando positivamente a expressão do comportamento materno. Entende-se como modulação (ou seleção) comportamental o ato do animal escolher entre dois ou mais tipos de comportamentos. Pesquisas recentes do nosso grupo de estudos sugerem que alterações no tônus opioidérgico decorridas no terço final da gestação podem modular a expressão de padrões comportamentais no pós-parto. O presente estudo sugere que o pré-tratamento com progesterona durante o período gestacional pode modificar a sensibilidade aos opióides e seus efeitos sobre o comportamento maternal e a seleção comportamental durante a lactação, porém em relação ao desafio farmacológico central, o fenômeno torna-se sutil pois não ocorre ação direta tanto da progesterona exógena quando endógena na substância cinzenta periaquedutal rostro-lateral (PAGrl) ao que se refere ao controle desse paradigma de seleção comportamental. A ação da colecistocinina (CCK) na modulação do comportamento materno parece estar associada ao estado reprodutivo da fêmea modulação em sítios neuroanatômicos específicos. O bloqueio inespecífico dos receptores de CCK neste paradigma de modulação comportamental foi eficiente apenas no que diz respeito ao fenômeno que envolve a saciedade das fêmeas, não promovendo prejuízo em parâmetros de comportamento materno. Em relação à experiência reprodutiva, ratas gestantes e lactantes apresentam melhores desempenhos na caça quando comparadas às ratas virgens, independentemente do desafio farmacológico utilizado. Assim como ocorre na maioria das mulheres, ratas também apresentam diminuição nos níveis de comportamento similar à ansiedade no pós-parto quando comparadas às ratas virgens. A diminuição nos níveis deste comportamento pode influenciar diretamente na habilidade materna. Neste estudo, tal efeito foi maior do que o efeito da própria droga na modulação do comportamento materno neste paradigma comportamental, atenuando a ação ansiogênica do peptídeo relacionado ao gene da calcitonina (CGRP). / Maternal behavior can be defined as the behavioral performance that the mother expresses from the immediate pre birth until offspring can survive alone without specific maternal care. The understanding of mechanisms involved in maternal behavior may have different approach related to mothers and the pups. Understanding the neuroanatomical and neurochemical mechanisms from these animal is important for society in general, specially for mothers suffering from psychological and physiological disorders in the perinatal period. In the natural environment, animals often face situations of conflict, and must make choices between different behaviors essential to their maintenance, such as feeding, defense and reproduction. Environmental enrichment can promote positive or negative impacts on the expression of certain behaviors. We observed a huge impact in the presence of pinus flakes at the moment of behavioral testing, positively influencing the expression of maternal behavior. Behavioral modulation (or selection) is when animals have to choose between two or more types of behaviors. Recent research from our group suggest that changes in opioid tone in the end of pregnancy can modulate the expression of behavioral patterns in postpartum. This study suggests that pretreatment with progesterone during pregnancy can change the sensitivity to opioids and its effect on maternal behavior and behavioral selection during lactation, but related central pharmacological challenge, the phenomenon become mild. Cholecystokinin (CCK) modulation of maternal behavior seems to be associated with the reproductive status and modulation of specific neuroanatomical sites. Blockage of specific CCK receptors in this behavioral modulation is only effective in satiation, but not related to maternal behavior parameters. Pregnant and lactating rats show better performances in hunt when compared to virgin rats, with no drug challenge effect. Lactating rats normally show a decrease in levels of anxiety-like behavior in postpartum period when compared to virgin rats. Decrease in anxiety levels can directly influence maternal ability to take care of their litter. In this study, this effect was greater than the effect of the drug itself in modulation of anxiety behavior, attenuating the peptide calcitonin gene-related peptide (CGRP) anxiogenic effect.

Speciation – the process by which new species arise – is of fundamental importance in the biological sciences. The means by which new species arise, and the relationship among living species, has been a topic that has captivated both lay and scientific observers for centuries. In recent years, the study of speciation has enjoyed increased attention, resulting in significant advances in our understanding of how species form. Although our understanding of the processes that contribute to speciation has increased dramatically in recent years, our knowledge of how reproductive barriers accumulate as speciation proceeds is still limited. Thus, studies that evaluate trait divergence and its consequences at early verses late stages of divergence can provide valuable insight into the speciation process. Chapter 1 of my dissertation focuses on the role of animal personality in the speciation process. Animal personality – defined as consistent individual differences in behavioral tendencies – has been identified as a key player in several ecological and evolutionary processes, yet the role of personality in speciation remains unexplored. In this chapter I discuss the ways by which personality can contribute to a suite of reproductive barriers and drive the speciation process. Chapters 2 through 5 provide a case study evaluating how selection acts on traits at early and late stages of speciation, using the Neotropical Livebearing fish genus Brachyrhaphis as a model system. Brachyrhaphis is ideally suited for this research because several species pairs and population pairs within species occur in similarly divergent selective regimes. I first present results from a field demographic study that shows that the strength of divergent selection acting on life-history traits in populations from divergent predation environments diminishes as speciation proceeds. I then show that population pairs at different stages of divergence are evolving similar morphological patterns along parallel trajectories. At both early and late stages of divergence, populations from environments with dense predator populations have a body shape that appears to be optimized for burst-speed swimming, and important component of predator escape. In contrast, populations from environments lacking predators have a body shape optimized for endurance swimming ability, which is important in environments where competition for foods and mates is high. Next, I show that populations from divergent predation environments do indeed differ in their swimming abilities according to our predictions, reflecting a population level trade-off between burst and endurance swimming ability. Although population level trade-offs were strong, I found no evidence of within population level trade-offs, suggesting that populations have arrived at novel solutions to between population trade-offs that were not present within ancestral populations. Finally, I show that these specialized swimming modes are locally adaptive, and that divergent ecology selects against immigrants, effectively reducing gene flow between populations from divergent environments. Together, these studies provide a valuable glimpse into the repeatability and predictability of trait divergence at different stages of speciation.

The safety of migrating salmon, especially salmonids, in the Pacific Northwest has been a concern for decades. With the advent of fish bypass systems, and safer turbines the focus of salmon safety has turned to total dissolved gases. Produced by entrainment of air into tailrace waters, total dissolved gases (TDG) can cause gas bubble disease, a harmful and potential lethal disease in fish. Avian predators are another danger for migrating salmon. In some areas of the world birds common in the Pacific Northwest can account for as much as 65% of salmon smolt losses. The goal of this thesis is to determine the effects of changing operational conditions at McNary dam on fish exposure to predator habitats and TDG. Computational fluid dynamic models were implemented to predict the hydrodynamics, TDG distribution and inert particle trajectories in the tailrace of McNary dam for varying operational conditions. A 3D volume of fluid (VOF) model was used first to capture the free surface shape in the tailrace. A rigid-lid model was then used to simulate the hydrodynamics and TDG distribution within the tailrace using the free surface shape from the VOF model. This 3D two phase model utilized an anisotropic Reynolds Stress turbulence model. All grids were generated using the commercial Gridgen software. A lagrangian particle tracking model that followed Newton's laws of motion were used to track inert particles throughout the domain. Validation of the model was performed. A grid refinement study with four different refinement levels was performed. Velocities for each grid type were compared against field data taken in 2004, and TDG was compared amongst the four grids. It was determined the medium level of refinement could accurately predict the velocities, and the TDG was relatively independent of grid density; TDG averages at the grid outlets were within 1.435% of one another. The TDG distribution was then compared, using the grid of medium refinement against field data measured in 1997and were between 1.5 and 3% of error depending on the transect. After validation of the model 16 predictive simulations were run with varying levels of total river flow and operational conditions. Tailrace hydrodynamics along with TDG production and distribution were compared for simulations with comparable total river flow rates. Fish trajectories were tracked using the particle tracking model. Inert particles were injected into the domain and properties such as velocity, distance to the shore and depth about each were recorded. Statistics were then generated for the particles based on criteria that defined dangerous predation zones within the tailrace. After completion of the simulations, it was determined that existing operations consistentlyproduced higher levels of TDG due to increased entrainment of the powerhouse flows into the spillway regions. It was also found that with increasing total river flows, TDG levels increased. On average, summer operations had lower TDG than spring due to the lower total river flows. Predation zones were similar for all simulations, but particle statistics varied depending on operational conditions. In general, particles were safer for higher flowrates as fewer low velocity eddies where particles could be trapped formed in simulations with high flowrates.

Fish are one of the most imperiled groups of vertebrates worldwide. Threats to fish fall into one of four general categories: physical habitat loss or degradation, chemical pollution, overfishing, and nonnative species introductions. Nonnative predatory fish often have a devastating impact on native prey, especially with endemic fish, whose restricted distribution and often limited evolutionary history with predators make them particularly susceptible to nonnative predators. One reason nonnative fish are often so efficient predators is that the native fish do not recognize the predator as a threat. Although many studies have examined the role of predator odor recognition, no fish have been shown to possess an innate recognition of the odor of predators unless they share a close co-evolutionary history. Many fish learn to identify novel predators through exposure to a predator's odor in conjunction with a conspecific alarm cue. Alarm cues are substances that are stored in the epidermis of many fish and are released when skin cells are broken. Exposure to novel predator odor in conjunction with alarm cue does not necessarily require a fish to survive a close encounter with a predator to be able to learn to recognize the predator. Here I show that it is possible to train hatchery-raised fish (June sucker, Chasmistes liorus) to recognize a nonnative predator odor (largemouth bass, Micropterus salmoides) through exposure to the odor of a predator that has eaten June sucker. I also show that this training can translate into higher survival in subsequent encounters with predators. I propose that training hatchery-raised fish prior to stocking may increase survival of hatchery-raised fish through anti-predator behavior.

Tetrodotoxin (TTX) is a potent neurotoxin that acts by blocking the pore region of voltage-gated sodium channels in nerve and muscle tissue. This causes paralysis, and often death due to asphyxiation. Interestingly, TTX is found in an array of organisms ranging from bacterial species to vertebrates. Further, TTX is found in both aquatic and terrestrial environments. This range of taxa and environments has led to three common lines of study for ecological research on this toxin: production, predation, and identification of novel TTX bearing taxa. I began my research by also refining a Competitive Inhibition Enzymatic Immunoassay technique for fast, easy, and inexpensive quantification of TTX. I then focused on the three previously mentioned areas of research. Female newts (Taricha granulosa) are known to endow their eggs with TTX in order to protect them from predation. I looked at whether females allocated TTX to their eggs evenly over three years in captivity and compared those levels to TTX levels in eggs directly after capture. I found that eggs had lower levels of TTX following initial capture, but those levels did not change over the next three years. This provides evidence that TTX is endogenously produced in this species. Because of the high levels of TTX in newts, there are few known predators. I observed river otters feeding on newts in a high elevation lake in Oregon. I found that these newts have very low levels of TTX, and that in general high elevation populations in Oregon have low levels of TTX relative to low elevation populations. Finally, I documented TTX in two species of terrestrial flatworm (Bipalium adventitium and Bipalium kewense). Tetrodotoxin has never before been identified in a terrestrial invertebrate species. Further, I found evidence that suggests that TTX is used for both defense and prey capture in these worms. These studies add to our understanding of the evolution of TTX and how it influences interactions between organisms and their biotic and abiotic environments.