Mechanisms of adaptation in coral snake mimicry

In Batesian mimicry, an undefended prey species (the mimic) evolves to resemble a defended one (the model) because of the selective advantage of this resemblance in deterring predation. Although Batesian mimicry is one of the oldest known examples of natural selection's power to produce adaptation, many unanswered questions remain about its evolution, including how mimetic signals coevolve with the perceptual abilities of predators, how mimetic signals are produced, how important shared evolutionary history with a model species is for mimics, and if mimicry can evolve over rough adaptive landscapes. My thesis attempts to address these knowledge gaps by examining the venomous coral snake Micrurus fulvius and its nonvenomous mimic, the scarlet kingsnake Lampropeltis elapsoides. In addition to my empirical studies, I have produced two reviews: one is a general review of mimicry in the form of an annotated bibliography, and the other a review of the hypotheses for imperfect mimicry. In a field experiment, I asked whether or not predators were sensitive to differences between models and mimics in phenotype, that is to say, imperfect mimicry. My results revealed that imperfect mimicry was tolerated in some dimensions but not others, and that predators' cognitive biases play a role in perpetuating imperfect mimicry. Two analytical studies of snake pigmentation revealed that coral snakes, their mimics, and several nonmimetic snakes use the same structures and pigments to produce their coloration. The spectral properties of colors produced by those pigments produce similar perceptual experiences for likely agents of selection in coral snake mimicry. This suggests that sharing developmental systems may facilitate the evolution of mimicry. In another field experiment I tested the assumption that the adaptive landscape between mimicry and crypsis (from which mimicry is thought to evolve) is always rough, featuring an adaptive valley of selection against intermediate phenotypes. Under ecological conditions that produce strong selection for precise mimicry, intermediate phenotypes were selected against; however, this was not the case when selection for mimicry was less intense. Therefore, the assumption that the evolution of mimicry always involves a transition through maladaptive intermediate phenotypes may be unwarranted.Doctor of Philosoph

Signal categorization by foraging animals depends on ecological diversity

Warning signals displayed by defended prey are mimicked by both mutualistic (Mullerian) and parasitic (Batesian) species. Yet mimicry is often imperfect: why does selection not improve mimicry? Predators create selection on warning signals, so predator psychology is crucial to understanding mimicry. We conducted experiments where humans acted as predators in a virtual ecosystem to ask how prey diversity affects the way that predators categorize prey phenotypes as profitable or unprofitable. The phenotypic diversity of prey communities strongly affected predator categorization. Higher diversity increased the likelihood that predators would use a 'key' trait to form broad categories, even if it meant committing errors. Broad categorization favors the evolution of mimicry. Both species richness and evenness contributed significantly to this effect. This lets us view the behavioral and evolutionary processes leading to mimicry in light of classical community ecology. Broad categorization by receivers is also likely to affect other forms of signaling.National Institutes of Health [K12GM000708]; Natural Sciences and Engineering Research Council of CanadaOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Spin Resonance of SnO2:V and the Vanadium 3d Electron Orbital

The ESR spectrum of SnO2 containing about 0.5% vanadium observed in K band at liquid‐nitrogen temperature shows two sets of shfs. Relative intensity measurements show that the large shfs (168 G) is due to the two tins located along the c axis and the small shfs (28 G) due to the four tins lying in a diagonal plane of the unit cell containing four oxygens. The large shfs is largely isotropic, with an axial maximum along the c axis. This suggests that the ground electron level is 3d(x2−y2). The next level is 3d(xz). This is deduced from the g values (gxx = 1.939,gyy = 1.903,and gzz = 1.943)(gxx=1.939,gyy=1.903,andgzz=1.943).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71160/2/JCPSA6-42-1-181-1.pd

Erratum: Functional apparent moduli as predictors of oral implant osseointegration dynamics

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78226/1/31720_ftp.pd

Community structure of Pleistocene coral reefs of Curaçao, Netherlands Antilles

The Quaternary fossil record of living coral reefs is fundamental for understanding modern ecological patterns. Living reefs generally accumulate in place, so fossil reefs record a history of their former biological inhabitants and physical environments. Reef corals record their ecological history especially well because they form large, resistant skeletons, which can be identified to species. Thus, presence-absence and relative abundance data can be obtained with a high degree of confidence. Moreover, potential effects of humans on reef ecology were absent or insignificant on most reefs until the last few hundred years, so that it is possible to analyze "natural" distribution patterns before intense human disturbance began. We characterized Pleistocene reef coral assemblages from Curacao, Netherlands Antilles, Caribbean Sea, focusing on predictability in species abundance patterns from different reef environments over broad spatial scales. Our data set is composed of >2 km of surveyed Quaternary reef. Taxonomic composition showed consistent differences between environments and along secondary environmental gradients within environments. Within environments, taxonomic composition of communities was markedly similar indicating nonrandom species associations and communities composed of species occurring in characteristic abundances. This community similarity was maintained with little change over a 40-km distance. The nonrandom patterns in species abundances were similar to those found in the Caribbean before the effects of extensive anthropogenic degradation of reefs in the late 1970s and early 1980s. The high degree of order observed in species abundance patterns of fossil reef coral communities on a scale of tens of kilometers contrasts markedly with patterns observed in previous small-scale studies of modern reefs. Dominance of Acropora palmata in the reef crest zone and patterns of overlap and nonoverlap of species in the Montastraea ''annularis'' sibling species complex highlight the tendency for distribution and abundance patterns of Pleistocene corals to reflect environmental preferences at multiple spatial scales. Wave energy is probably the most important physical environmental variable structuring these coral communities. The strong similarity between ancient and pre-1980s Caribbean reefs and the nonrandom distribution of coral species in space and time indicate that recent variability noted at much smaller time scales may be due to either unprecedented anthropogenic influences on reefs or fundamentally different patterns at varying spatio-temporal scales

Auditory artificial grammar learning in macaque and marmoset monkeys.

Artificial grammars (AG) are designed to emulate aspects of the structure of language, and AG learning (AGL) paradigms can be used to study the extent of nonhuman animals' structure-learning capabilities. However, different AG structures have been used with nonhuman animals and are difficult to compare across studies and species. We developed a simple quantitative parameter space, which we used to summarize previous nonhuman animal AGL results. This was used to highlight an under-studied AG with a forward-branching structure, designed to model certain aspects of the nondeterministic nature of word transitions in natural language and animal song. We tested whether two monkey species could learn aspects of this auditory AG. After habituating the monkeys to the AG, analysis of video recordings showed that common marmosets (New World monkeys) differentiated between well formed, correct testing sequences and those violating the AG structure based primarily on simple learning strategies. By comparison, Rhesus macaques (Old World monkeys) showed evidence for deeper levels of AGL. A novel eye-tracking approach confirmed this result in the macaques and demonstrated evidence for more complex AGL. This study provides evidence for a previously unknown level of AGL complexity in Old World monkeys that seems less evident in New World monkeys, which are more distant evolutionary relatives to humans. The findings allow for the development of both marmosets and macaques as neurobiological model systems to study different aspects of AGL at the neuronal level

Auditory sequence processing reveals evolutionarily conserved regions of frontal cortex in macaques and humans.

An evolutionary account of human language as a neurobiological system must distinguish between human-unique neurocognitive processes supporting language and evolutionarily conserved, domain-general processes that can be traced back to our primate ancestors. Neuroimaging studies across species may determine whether candidate neural processes are supported by homologous, functionally conserved brain areas or by different neurobiological substrates. Here we use functional magnetic resonance imaging in Rhesus macaques and humans to examine the brain regions involved in processing the ordering relationships between auditory nonsense words in rule-based sequences. We find that key regions in the human ventral frontal and opercular cortex have functional counterparts in the monkey brain. These regions are also known to be associated with initial stages of human syntactic processing. This study raises the possibility that certain ventral frontal neural systems, which play a significant role in language function in modern humans, originally evolved to support domain-general abilities involved in sequence processing

PhOTO Zebrafish: A Transgenic Resource for In Vivo Lineage Tracing during Development and Regeneration

Background: Elucidating the complex cell dynamics (divisions, movement, morphological changes, etc.) underlying embryonic development and adult tissue regeneration requires an efficient means to track cells with high fidelity in space and time. To satisfy this criterion, we developed a transgenic zebrafish line, called PhOTO, that allows photoconvertible optical tracking of nuclear and membrane dynamics in vivo. Methodology: PhOTO zebrafish ubiquitously express targeted blue fluorescent protein (FP) Cerulean and photoconvertible FP Dendra2 fusions, allowing for instantaneous, precise targeting and tracking of any number of cells using Dendra2 photoconversion while simultaneously monitoring global cell behavior and morphology. Expression persists through adulthood, making the PhOTO zebrafish an excellent tool for studying tissue regeneration: after tail fin amputation and photoconversion of a ~100µm stripe along the cut area, marked differences seen in how cells contribute to the new tissue give detailed insight into the dynamic process of regeneration. Photoconverted cells that contributed to the regenerate were separated into three distinct populations corresponding to the extent of cell division 7 days after amputation, and a subset of cells that divided the least were organized into an evenly spaced, linear orientation along the length of the newly regenerating fin. Conclusions/Significance: PhOTO zebrafish have wide applicability for lineage tracing at the systems-level in the early embryo as well as in the adult, making them ideal candidate tools for future research in development, traumatic injury and regeneration, cancer progression, and stem cell behavior

Mechanisms of Pacific Summer Water variability in the Arctic's Central Canada Basin

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 7523–7548, doi:10.1002/2014JC010273.Pacific Water flows northward through Bering Strait and penetrates the Arctic Ocean halocline throughout the Canadian Basin sector of the Arctic. In summer, Pacific Summer Water (PSW) is modified by surface buoyancy fluxes and mixing as it crosses the shallow Chukchi Sea before entering the deep ocean. Measurements from Ice-Tethered Profilers, moorings, and hydrographic surveys between 2003 and 2013 reveal spatial and temporal variability in the PSW component of the halocline in the Central Canada Basin with increasing trends in integrated heat and freshwater content, a consequence of PSW layer thickening as well as layer freshening and warming. It is shown here how properties in the Chukchi Sea in summer control the temperature-salinity properties of PSW in the interior by subduction at isopycnals that outcrop in the Chukchi Sea. Results of an ocean model, forced by idealized winds, provide support to the mechanism of surface ocean Ekman transport convergence maintaining PSW ventilation of the halocline.Funding was provided by the National Science Foundation Division of Polar Programs under award 1107623, 1313614, 1107412, 1107277, 1303644, and 0938137 and by Yale University. ICMMG model development was supported by the Russian Fund for Basic Research (14-05-00730A)

Arctic Ocean Acidification: Results from GRENE and JOIS

第6回極域科学シンポジウム分野横断セッション：[IB1] 海氷域における生物地球化学的研究11月17日（火）　統計数理研究所 セミナー室1（D305