Bodies are often made of repeated units, or serial homologs, that develop using the same core gene regulatory network. Local inputs and modifications to this network allow serial homologs to evolve different morphologies, but currently we do not understand which modifications allow these repeated traits to evolve different levels of...
Cattle grazing and invasion by non-native plant species are globally-ubiquitous changes occurring to plant communities that are likely to reverberate through whole food webs. We used a manipulative field experiment to quantify how arthropod community structure differed in native and non-native California grassland communities in the presence and absence of...
Management of marine ecosystems increasingly demands comprehensive and quantitative assessments of ocean health, but lacks a tool to do so. We applied the recently developed Ocean Health Index to assess ocean health in the relatively data-rich US west coast region. The overall region scored 71 out of 100, with sub-regions...
The tropical sea anemone, Aiptasia sp., is a model organism within the phylum cnidaria, a group that includes globally threatened corals which are the bio-engineers of coral reefs.
Aiptasia reproduce both sexually, in a process known as spawning, and asexually, mainly through a process known as pedal laceration. During spawning,...
Most wild animals are concurrently infected with multiple parasite species for most of their lives. These parasite species assemble into rich and diverse communities, with parasites using host tissues for growth and reproduction as well as evolving strategies to evade the host immune system. The net effect of these ecological...
The influence of the physical environment on organisms has long been a subject of ecological research. But, the complex drivers of environmental variation, and the multiple scales at which this can occur, make studying this topic a difficult challenge. In rocky intertidal habitats, oceanographic- and climate-scale variability influence benthic communities...
Successful cell division requires proper chromosome movement, including accurate congression to the metaphase plate and proper segregation to spindle poles. Errors that occur in either event can cause chromosome aneuploidy in daughter cells, which may lead to cell death, genetic diseases and cancers (Matson and Stukenberg,2012, Compton, 2000). The force...
Although it is generally assumed that the intensifying abiotic environment is the primary effect of drought on aquatic organisms, drought-induced top predator extinctions may be an important underlying mechanism. I used manipulative experiments to disentangle the impacts of drying and top predator extinctions on arid-land aquatic invertebrate communities. I then...
For ethical and logistical reasons, population-genetic studies of parasites often rely on the non-invasive sampling of offspring shed from their definitive hosts. However, if the sampled offspring are naturally derived from a small number of parents, then the strong family structure can result in biased population-level estimates of genetic parameters,...
Schistosomiasis afflicts 200 million people and is responsible for 200,000 deaths per year. The infection is caused by a digenean trematode in the genus Schistosoma. The parasite must cycle through both a vertebrate (human) and invertebrate (snail) host to complete the life cycle. My dissertation focuses on the genetic mechanisms...
Disturbance has both direct and indirect ramifications that can influence species abundance, distribution, and ultimately the diversity found within a community. As a result, we might expect disturbance to play a particularly important role in the ability of non-native species to proliferate outside of their native range. In practice, disturbance...
Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system...
Background: In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU[superscript M]) within the
developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent
evidence has shown that specific subsets of FRU[superscript M] neurons are necessary for particular steps of courtship...
The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease...
Emerging infectious diseases are increasing globally and are a threat to human, wildlife, and ecosystem health. The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), or amphibian chytrid fungus, is associated with worldwide amphibian population declines and extinctions. Bd has been found on every continent where amphibians exist and has been documented...
Several taxonomic issues in the moth families Erebidae and Noctuidae are addressed for Northwestern North America. Drasteria parallela Crabo & Mustelin and Cycnia oregonensis tristis Crabo in the Erebidae and Eudryas brevipennis bonneville Shepard & Crabo, Resapamea diluvius Crabo, Resapamea angelika Crabo, Resapamea mammuthus Crabo, Fishia nigrescens Hammond & Crabo,...
Based on regional-scale studies, aboveground production and litter decomposition are thought to positively covary, because they are driven by shared biotic and climatic factors. Until now we have been unable to test whether production and decomposition are generally coupled across climatically dissimilar regions, because we lacked replicated data collected within...
Remains of parasites in vertebrates are rare from the Mesozoic and Paleozoic. Once most parasites that live in - or pass through - the gastrointestinal tract of vertebrates, fossil feces (coprolites) or even intestinal contents (enterolites) can eventually preserve their remains. Here we announce the discovery of a spiral shark...
Species composition within ecological assemblages can drive disease dynamics including pathogen invasion, spread, and persistence. In multi-host pathogen systems, interspecific variation in responses to infection creates important context dependency when predicting the outcome of disease. Here, we examine the responses of three sympatric host species to a single fungal pathogen,...
We live in an exciting time for biology. Technological advances have made data collection easier and cheaper than we could ever have imagined just 10 years ago. We can now synthesize and analyze large data sets containing genomes, transcriptomes, proteomes, and multivariate phenotypes. At the same time, society's need for...
Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have...
A new species of ground beetle, Bembidion ricei, is described from the Andes mountains of Ecuador east of Quito. It belongs to the georgeballi species group of subgenus Ecuadion, and is most similar to Bembidion georgeballi. A key to the species of the group is provided.
Postcopulatory sexual selection—sperm competition and cryptic female choice—has become a major area of research over the past 40 years. Within this field there are many outstanding questions at every level of analysis, from proximate to ultimate. The fitness consequences for both sexes in the period after copulation and before fertilization...
Circadian clocks generate daily rhythms in neuronal, physiological, and metabolic functions. Previous studies in mammals reported daily fluctuations in levels of the major endogenous antioxidant, glutathione (GSH), but the molecular mechanisms that govern such fluctuations remained unknown. To address this question, we used the model species Drosophila, which has a...
Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the...
Most climate change predictions focus on the response of individual species to changing local conditions and ignore species interactions, largely due to the lack of a sound theoretical foundation for how interactions are expected to change with climate and how to incorporate them into climate change models. Much of the...
Whether microevolutionary processes can explain macroevolutionary patterns has long been a matter of contentious debate. The debate has persisted largely because of the challenging task of connecting microevolutionary theory, which examines population-level phenomena on the generation scale, to data collected across larger spatial and temporal scales. My dissertation research broadly...
Background: The harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is native to central and eastern Asia and was purposely introduced into Europe to control aphids. While it proved to be a good biological control agent, its rapid spread and buildup of large populations made it a nuisance, since it overwinters...
In We have analyzed natural variation in mitochondrial form and function among a set of Caenorhabditis briggsae isolates known to harbor mitochondrial DNA structural variation in the form of a heteroplasmic nad5 gene deletion (nad5 Delta) that correlates negatively with organismal fitness. We performed in vivo quantification of 24 mitochondrial...
Selfish DNA poses a significant challenge to genome stability and organismal fitness in diverse eukaryotic lineages. Although selfish mitochondrial DNA (mtDNA) has known associations with cytoplasmic male sterility in numerous gynodioecious plant species and is manifested as petite mutants in experimental yeast lab populations, examples of selfish mtDNA in animals...
Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In...
Resistance of the snail Biomphalaria glabrata to the trematode Schistosoma mansoni is correlated with allelic variation at copper-zinc superoxide dismutase (sod1). We tested whether there is a fitness cost associated with carrying the most resistant allele in three outbred laboratory populations of snails. These three populations were derived from the...
Vegetation at the aquatic–terrestrial interface can alter landscape features through its growth and interactions with sediment and fluids. Even similar species may impart different effects due to variation in their interactions and feedbacks with the environment. Consequently, replacement of one engineering species by another can cause significant change in the...
Sexual selection can influence the mating system of an organism through multiple mechanisms. These mechanisms result in variation in reproductive success among individuals, and include scramble competition, endurance rivalries, contests, mate choice and cryptic choice, and sperm competition. Understanding the mating system of a species requires the identification of which...
To examine the influence of forest management on wildlife immunity, the innate immune system of wild deer mice (Peromyscus maniculatus) inhabiting forest plots of different management intensities in the Oregon coast range was measured by bactericidal assay. Bactericidal activity was compared across three management levels, including 40-50 year old forest...
Four new species of fossil mermithids (Nematoda: Mermithidae) are described from amber: Heydenius arachnius n. sp. from a spider (Arachnida: Araneae) in Dominican amber, Heydenius phasmatophilus n. sp., from a walking stick (Phasmatodea: Phasmatidae) in Baltic amber, Heydenius podenasae n. sp. from a moth (Lepidoptera) in Baltic amber and Heydenius...
Molluscan internal defenses rely heavily on circulating hemocytes. In most cases, encounters with large foreign bodies result in recognition by hemocytes followed by spreading of these defense cells over the object’s surface. The resulting encapsulation concentrates the force of the hemocytes’ assault on the foreign object.
B. glabrata snail lines...
Circadian clocks generate rhythms in molecular, cellular, physiological, and behavioral processes. Recent studies suggest that disruption of the clock mechanism accelerates organismal senescence and age-related pathologies in mammals. Impaired circadian rhythms are observed in many neurological diseases; however, it is not clear whether loss of rhythms is the cause or...
Background: Both sexes of bat flies in the families Nycteribiidae and Streblidae (Diptera: Hippoboscoidea) reside in the hair or on the wing membranes of bats and feed on blood. Members of the Nycteribiidae transmit bat malaria globally however extant streblids have never been implemented as vectors of bat malaria. The...
The high productivity of Eastern Boundary Upwelling Ecosystems (EBUE), some of the most productive ecosystems in the globe, is attributed to the nutrient rich waters brought up through upwelling. Climate change scenarios for coastal upwelling systems, predict an intensification of coastal upwelling winds. Associated with intensification in upwelling are biogeochemical...
A new species of Bembidion (Trichoplataphus Netolitzky) from the Ozark Plateau of Missouri and Arkansas is described (Bembidion ozarkense Maddison and Hildebrandt). It is distinguishable from the closely related species, Bembidion rolandi Fall, by characteristics of the male genitalia, and sequences of the genes cytochrome oxidase I and 28S ribosomal...
Recruitment of larvae from the plankton is an important determinant of
community structure in marine systems. In populations of many marine species,
recruitment determines the basic demographic parameters of immigration, emigration,
and reproduction. Moreover, the effect of recruitment as an "ecological subsidy" can
determine the strength of interactions among species...
Predatory lionfishes (Pterois volitans and P. miles) were introduced to Florida waters during the mid to late 1980s, and eventually established self-sustaining breeding populations in the tropical western Atlantic. These invasive species are now widespread along the southeastern seaboard of the United States, across the Caribbean Sea, and in the...
This dissertation investigates the context-dependency of species interactions between seagrass and macroalgae in upwelling-influenced estuaries. In all coastal systems, nutrient loading is multidirectional, resulting from mostly freshwater and marine inputs. The directionality of nutrient inputs may affect the rate of supply of organic matter to the system. In systems where...
Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to...
Floods are major disturbance events for riverine ecosystems, directly and indirectly impacting organisms and their habitat. In this study I investigated the role of riverine floods and flow alteration in regulating aquatic macroinvertebrate population and community structure. I examined this problem using a variety of methods: a meta-analytic review of...
Darwin devised the evolutionary theory of sexual selection to account for the manifold extravagances of courtship behaviors and displays. Mating interactions represent a major evolutionary process driving the elaboration, vibrancy, and peculiarity of these courtship traits. For my dissertation research, I strived to elucidate the dynamics that constitute the complex...
Humans are increasing the scale and frequency of many natural disturbances, as well as adding novel disturbances to ecosystems. This thesis uses the arthropod community as a metric to examine the multi-trophic responses to disturbances in California grasslands. Chapter 2 explores how the long-term exclusion of native vertebrate herbivores has...
Biological invasions pose one of the greatest threats to global biodiversity, but many naturalized invaders coexist with the native community. Community ecology theory provides a framework for understanding the mechanisms by which invaders might coexist with native species or exclude them from the community, thus informing management practices to maximize...
Acceptance of marine protected areas (MPAs) as fishery and conservation tools has been hampered by lack of direct evidence that MPAs successfully seed unprotected areas with larvae of targeted species. For the first time, we present direct evidence of large-scale population connectivity within an existing and effective network of MPAs....
Foundation species are important components of ecosystems because they provide habitat and ameliorate stressful conditions for residents. This thesis considers the role of surfgrasses (Phyllospadix spp.) as dynamic foundation species on the coast of Oregon in two studies. Chapter 2, which presents an observational survey of two Phyllospadix congeners, investigates...
Like other species interactions in ecological systems, host-pathogen interactions are influenced by environmental factors, landscape characteristics and the broader community context. My thesis explores the potential influences of food-web interactions (Chapter 2), climate change (Chapter 3), landscape structure and host movement patterns (Chapter 4), and the combined influences of local...
This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary...
The intracellular mutualism between cnidarians and photosynthetic dinoflagellates (genus Symbiodinium) is responsible for the physical and trophic structure of diverse coral reef ecosystems. This relationship, based on nutrient exchange, allows for high productivity in tropical waters, which are generally nutrient-poor environments. Numerous environmental stressors currently threaten the health of corals,...
Vertebrates communicate with one another and coordinate intraspecific reproduction by using a variety of sexually dimorphic signals, such as plumage, ornaments, sounds, and/or scents. These sexual dimorphisms are maintained by physiological factors, typically sex-specific hormones (though see Chapter 3 for an exception). The purpose of the research in this dissertation...
Little, if any, quantifications have been made on the contribution of the vertebral column during jumping in quadrupedal mammals. Previous studies of jumpers have focused on the morphological and physiological specializations of the hindlimbs. In this study, such specialization was measured during the supramaximal jumps of the Pacific jumping mouse...
My thesis explored the effects of environmental variability on population
dynamics and community composition of aquatic insects. Environmental variability in
the form of flow regime in streams can limit the distribution and life-history traits of
aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically
different flow...
The respiratory and metabolic biology of dinosaurs is poorly, if at all, reflected in the fossil record. By comparing anatomical features of modern taxa that are functionally linked to specific biology with the remains of theropod dinosaurs (Archosauria: Theropoda) and early birds, we may reasonably infer the physiology of long...
Ecosystems are facing increasing threats from human related activities, such as overfishing, pollution, habitat destruction, species invasions, and diseases, among others. While oceanic islands provide natural laboratories to understand ecological and evolutionary process, they are also particularly vulnerable to these impacts, given their usual isolation from the mainland and the...
Many marine fish populations are severely declining due to over-fishing, loss of both juvenile and adult habitats, and accelerating environmental degradation. Fisheries management and the implementation of marine protected areas (MPAs) and other conservation tools are currently hindered by large gaps in knowledge about larval dispersal and its subsequent effects...
Many species have complex life cycles in which a dispersive larval stage is
followed by a relatively sedentary adult stage. For such species, reproductive output
is often high and large variation in survivorship throughout early life-history phases
(eggs and larvae) can lead to dramatic fluctuations in recruitment which may in...
Chemoreception is one of the dominant sensory modalities for many species of salamanders (reviewed in Chapter 2). At least seven of the ten currently recognized salamander families are known to respond to some sort of chemical cue. These responses are as varied as delaying hatching, seeking refuge, or initiating aggressive...
In this dissertation I study evolutionary patterns at genes encoding antimicrobial peptides (AMPs) in frogs. AMPs are short, amphipathic, cationic, secreted proteins that kill bacteria and other pathogens through a non-catalytic mechanism that involves
binding to and disrupting the microbial cell membrane. In many animal taxa, positive selection is much...
There is little, if any, direct fossil evidence of the cardiovascular, respiratory, reproductive or digestive biology of dinosaurs. However, a variety of data can be used to draw reasonable inferences about the physiology of the carnivorous theropod dinosaurs (Archosauria: Theropoda). Extant archosaurs, birds and crocodilians, possess regionally differentiated, vascularized and...
Contemporary environmental change encompasses massive biodiversity loss and
increasing numbers of emerging diseases worldwide. As part of a global biodiversity
crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium
dendrobatidis is an emerging infectious pathogen prominently associated with many
declines. Chapter 1 reviews the past decade of research on this system...
Mutualistic associations between cnidarians, such as corals, and photosynthetic
dinoflagellate algae provide the trophic and structural foundation of coral reef
ecosystems. In many cases, this intracellular mutualism is highly specific and must be
established anew for each generation of host corals. The ability to maintain partner
specificity across generations implies...
Ultraviolet-B radiation (UVB) is an abiotic stressor in both terrestrial and aquatic systems. The stratospheric ozone layer, depleted due to anthropogenic activities and the cause of elevated UVB at earth's surface over the last four decades, is predicted to recover by 2065. However, UVB levels in aquatic systems may continue...
The earth is undergoing a “biodiversity crisis” characterized by loss of populations, species, genetic diversity, and ecosystem services. Part of this crisis consists of population declines, extinctions, and increased incidence of deformities in amphibians. It is unknown whether deformities contribute to these declines. Many cases of population declines in amphibians...
How complex traits evolve continues to be a major focus of evolutionary
investigation. A current topic of debate is the hypothesis that the phenotypic
integration of complex traits gives rise to evolutionary constraints. I studied two color
traits in the common garter snake, Thamnophis sirtalis, that show a high level...
The phantom midges (Diptera: Chaoboridae) are a relatively small fly family composed of 50 extant species in six genera. Larvae are of interest to limnologists and ecologists because of their tolerance to toxicants, predatory avoidance strategies, and the role chaoborids play in zooplankton community dynamics. Relative to mosquitoes, systematists have...
An ancient pheromonal signal is found in aquatic courting salamandrids and terrestrial courting plethodontids, two highly divergent salamander families. In the aquatic courting salamandrids Cynops pyrrhogaster and C. ensicauda, the decapeptide sodefrin is cleaved from a larger 189 amino acid Sodefrin Precursor Factor (SPF) protein and released from a gland...
Predators are fundamentally important for regulating and driving prey population dynamics as well as structuring ecological communities. Over-exploitation of marine resources has caused dramatic depletions of predatory fish species and shifts in marine community composition, with attendant declines in productivity and diversity of marine ecosystems. Despite the important ramifications of...
My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB...
Environmental stress can negatively affect the ability of organisms to reproduce. Energetic trade-offs exist in all organisms, and under stress, energy may be allocated away from reproduction and towards physiological defense and repair mechanisms. The rocky intertidal environment is ideal for investigating the influence of environmental stress, as organisms are...
While there are many more species of reptiles in the tropics than in temperate
latitudes, relatively little is known about the natural history of tropical species of
snakes. Even basic information, such as reproductive ecology and behavior, is lacking. Patterns of reproduction in tropical species differ from patterns in temperate...
Accurate chromosome segregation and cell cleavage are critical to maintaining genomic integrity. Both events involve the spindle apparatus, but the exact mechanics is as puzzling as the contradicting models proposed in the last two centuries. In this dissertation, current prevailing models of chromosome segregation and cell cleavage are tested using...
Cnidarians, such as anemones and corals, engage in an intracellular symbiosis with
photosynthetic dinoflagellates. Corals form both the trophic and structural foundation of
reef ecosystems. Despite their environmental importance, little is known about the
molecular basis of this symbiosis. In this dissertation we explored the cnidariandinoflagellate symbiosis from two perspectives:...
Many members of the Phylum Cnidaria are mutualistic with unicellular dinoflagellates belonging to the genus Symbiodinium. Corals are the most widely recognized example of these associations due to their key ecological importance in coral reef ecosystems where they serve as the structural and trophic foundation of these rich ecosystems. Coral...
This dissertation focuses on the importance of pelagic subsidies in the Northeast Pacific to rocky shore community regulation. My results document the patterns of pelagic subsidy supply, determine if those subsidies are correlated with community structure, and examine if community regulation differs between areas of high- and low-subsidies. Understanding how...
Over 150 years ago, C. Bergmann observed a within-species pattern of increasing body size as elevation and latitude increased. Bergmann’s data came from numerous endothermic taxa, but the pattern has since been documented among numerous poikilotherms and invertebrates. The ferocious waterbug Abedus herberti Hidalgo (Hemiptera: Belostomatidae) lives in isolated populations...
Interface habitats are considered valuable natural systems, tightly linked to adjacent habitats through the flow of matter and energy. However, there is limited research on mechanisms of connectivity such as movement of organisms and particulate matter and ways in which anthropogenic disturbance to interface habitats may affect immediate and adjacent...
Animal signaling systems frequently utilize multiple traits to produce and transmit a signal. These system elements may span multiple levels of organization. Functional integration of these traits may be expected to generate concordance in evolutionary pattern among system elements, such that evolutionary change in one system component is correlated with...
Previous attempts to understand the factors affecting the energetic cost of locomotion have found a direct link between the energetic cost and the mechanical work done during periods when the limb is in contact with the ground. However, when the limb is not in contact with the ground during the...
Most vertebrates exhibit seasonality in many life history traits. Such seasonal rhythms are temporally organized via the transduction of environmental cues (e.g., photoperiod, temperature) into appropriate endocrine signals. However, among ectothermic vertebrates that undergo continuous winter dormancy, temperature is the only environmental cue available for synchronizing seasonal rhythms. Most intriguing...
Two of the most powerful ways in which humans have altered ecosystems are by increasing productivity and changing the densities of important consumers. The bottom-up effects of productivity and the top-down effects of consumers have been identified as primary determinants of biological diversity, though the links between them remain unclear....
This study investigated whether a device commonly used to measure settlement of mussel larvae for ecological studies, the Tuffy™, functions uniformly whether placed in a bed of filamentous algae or on bare rock. During the summers of 2004 and 2005, the number of mussel larvae settling on Tuffys in patches...
Previous observations of light levels and phytoplankton abundances along the Oregon coast demonstrated that phytoplankton attenuated light sufficiently to potentially limit the growth of intertidal macrophytes and therefore structure local intertidal communities. Inspired by this observation, in spring 2004, I initiated a study to quantify the direct and indirect benthic...
Careful analysis and thoughtful synthesis will be necessary for expanding the envelope of
ecological understanding. This work is my attempt at communicating both of these, in relation
to three questions about our understanding of the structure and dynamics of biological diversity.
These questions focus on a) advancing our understanding of...
My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male...
Population genetic structure is widespread in many organisms and can be found at small spatial scales. Fine-scale differentiation is the result of ecological and evolutionary processes working together to produce an overall pattern, but the relative importance of these factors in population differentiation is poorly understood. The goals of my...
The neurohypophysial peptide system is involved in modulating a
variety of physiological, neurological, and behavioral responses in
vertebrates. The principal forms of these peptides in non-mammalian
tetrapods are vasotocin (VT) and mesotocin (MT). The studies described
in this thesis used pharmacological, molecular, and biochemical
techniques, along with phylogenetic analyses, to...
Scleractinian corals, like many other cnidarians, engage in intracellular symbiosis with
dinoflagellates belonging to the genus Symbiodinium. This association makes
invaluable structural and energetic contributions to the marine environment and to the
coral reef ecosystem in particular. While many aspects of the cnidarian-dinoflagellate
relationship have been well studied, nothing is...
The purpose of this study was to identify any ostelogical features which might prevent
paradoxical movement (=lateral collapse) of the abdominal air sacs in birds during inhalation.
A combination of 26 fresh and frozen adult bird carcasses representing 10 avian orders were
procured from local sources. Dissections of each specimen...
In nature, animals survive threats by responding physiologically and behaviorally in ways that are appropriate to the situation. Which responses are appropriate depend on the animals' surroundings and current physiological and behavioral state. This dissertation investigated the neuroendocrine mechanisms that control context-dependent behavioral responses to stress by focusing on the...
My dissertation focuses on the evolutionary forces that have shaped the chemical signaling system of plethodontid salamanders. Pheromones mediate two phases of plethodontid reproduction: mate attraction prior to courtship and female persuasion during courtship. Substrate-borne chemical signals are believed to play an important role in mate attraction for these animals....
This dissertation focuses on science relevant to the design and implementation of marine reserves. The chapters explore a range of topics related to among-site variation in population, community, and ecosystem dynamics. My results demonstrate the value and feasibility of integrating this knowledge into more comprehensive conservation and management approaches. While...
The majority of female animals are polyandrous: offspring within a single reproductive event are sired by more than one male. However, we lack a clear understanding of the ultimate causes of polyandry, and of the male reproductive strategies which have evolved in response to selection occurring after insemination. I addressed...
The benefits of reproduction are clear, but there are also costs. Much is known about the costs of reproduction in females, but only recently have male costs been investigated in any depth. These costs of reproduction may be minimized by appropriately modifying behavior, but there has been little research on...
A primary goal of population genetics is to identify the role of
microevolutionary forces in producing observed patterns of molecular and phenotypic
variation. I conducted four studies in the northern leopard frog, Rana pipiens, to
determine just how mutation, migration, genetic drift, and selection influenced,
genetic structure of mitochondrial DNA...
Understanding the dynamics of open marine populations is difficult. Ecological processes may vary with the spatial structure of the habitat, and this variation may subsequently affect demographic rates. In a series of observational and experimental studies in the Bahamas, I examined the roles of emigration, mortality, and predation in the...