ABSTRACT
Significant advances have been made in species delimitation and numerous methods can test precisely defined models of speciation, though the synthesis of phylogeography and taxonomy is still sometimes incomplete. Emerging consensus treats distinct genealogical clusters in genome-scale data as strong initial evidence of speciation in most cases, a hypothesis that must therefore be falsified under an explicit evolutionary model. We can now test speciation hypotheses linking trait differentiation to specific mechanisms of divergence with increasingly large data sets. Integrative taxonomy can, therefore, reflect an understanding of how each axis of variation relates to underlying speciation processes, with nomenclature for distinct evolutionary lineages. We illustrate this approach here with Seal Salamanders (Desmognathus monticola) and introduce a new unsupervised machine-learning approach for species delimitation. Plethodontid salamanders are renowned for their morphological conservatism despite extensive phylogeographic divergence. We discover 2 geographic genetic clusters, for which demographic and spatial models of ecology and gene flow provide robust support for ecogeographic speciation despite limited phenotypic divergence. These data are integrated under evolutionary mechanisms (e.g., spatially localized gene flow with reduced migration) and reflected in emergent properties expected under models of reinforcement (e.g., ethological isolation and selection against hybrids). Their genetic divergence is prima facie evidence for species-level distinctiveness, supported by speciation models and divergence along axes such as behavior, geography, and climate that suggest an ecological basis with subsequent reinforcement through prezygotic isolation. As data sets grow more comprehensive, species-delimitation models can be tested, rejected, or corroborated as explicit speciation hypotheses, providing for reciprocal illumination of evolutionary processes and integrative taxonomies. [Desmognathus; integrative taxonomy; machine learning; species delimitation.].
Subject(s)
Genetic Speciation , Urodela , Animals , Phylogeography , Phylogeny , Urodela/genetics , Biological EvolutionABSTRACT
What factors hinder the reduction of meat and/or dairy intake? In this study, we explored the perceived barriers that meat and/or dairy reducers experienced when shifting their diets. We particularly focused on how meat and/or dairy reducers were affected by their beliefs about how omnivores stereotype vegans (i.e., meta-stereotypes), as meta-stereotypes have not been previously explored in this context. Through open-ended questions in an online survey, we explored the experiences and perceived barriers among female meat and/or dairy reducers (n = 272), as well as their perceptions of vegans (i.e., stereotypes and meta-stereotypes), and how these perceptions affected their lived experiences. We analysed the data using reflexive thematic analysis and generated six themes. We highlighted perceptions of cost (Theme 1) and perceptions of health concerns (Theme 2) as the most dominant barriers to the reduction of meat and/or dairy intake. Regarding (meta) stereotypes, participants' perceptions of vegans were shaped by personal experiences and encounters with vegans (Theme 3), and how participants related to vegans was sometimes reflected in the language they used to describe vegans (Theme 4). Participants felt that they, or reducers more generally, were occasionally judged as vegans (Theme 5), which might influence participants' choices and conformity to eating norms (Theme 6). Meta-stereotypes may play a role in polarised dietary group perceptions, and we discuss how they are shaped by social identity processes as well as by aspects of Western food systems.
Subject(s)
Stereotyping , Humans , Female , Adult , Middle Aged , Young Adult , Meat , Surveys and Questionnaires , Diet, Vegetarian/psychology , Diet/psychology , Dairy Products , Diet, Healthy/psychology , Aged , Health Knowledge, Attitudes, Practice , Feeding Behavior/psychologyABSTRACT
PREMISE: Spatial variation in selective pressures can lead to intraspecific variation in life history, favoring some life histories and constraining others depending on the vulnerability of life stages. We examined how spatial variation in herbivory and climate influences flowering size and the occurrence of semelparity (reproducing once) versus iteroparity (reproducing multiple times) in the introduced range of an invasive plant, houndstongue (Cynoglossum officinale). Houndstongue is a short-lived, semelparous perennial in its native range. In its introduced range, we previously documented increased rates of iteroparity and a higher median threshold flowering size compared to the native range. We hypothesized that the recent introduction of a specialist biocontrol insect (a root-boring weevil, Mogulones crucifer) would decrease threshold flowering size and reduce the proportion of iteroparous plants because M. crucifer preferentially attacks large individuals and may reduce overwinter survival. METHODS: We surveyed 24 sites across the northwestern United States to quantify the frequency of semelparity versus iteroparity and to estimate weevil abundance and used demographic data collected from six sites to estimate median threshold flowering size. RESULTS: We found that sites with greater winter precipitation and no weevils had a greater proportion of iteroparous plants. Sites with higher weevil attack had a lower median threshold flowering size. CONCLUSIONS: The variation in frequency of flowering and threshold flowering size that we documented in North American houndstongue populations, and the relationships between this variation and herbivory and climate, provide evidence for how selective pressures covary with the life histories of invasive plants.
Subject(s)
Boraginaceae , Life History Traits , Weevils , Animals , Herbivory , Northwestern United StatesABSTRACT
Introduction: The human capacity to engage with fictional worlds raises important psychological questions about the mechanisms that make this possible. Of particular interest is whether people respond differently to fictional stories compared to factual ones in terms of how immersed they become and how they view the characters involved and their actions. It has been suggested that fiction provides us with a 'fictive pass' that allows us to evaluate in a more balanced, detached way the morality of a character's behaviour. Methods: We use a randomised controlled experimental design to test this. Results and discussion: We show that, although knowing whether a substantial film clip is fact or fiction does not affect how engaged with ('transported' by) a troubling story an observer becomes, it does grant them a 'fictive pass' to empathise with a moral transgressor. However, a fictive pass does not override the capacity to judge the causes of a character's moral transgression (at least as indexed by a causal attribution task).
ABSTRACT
INTRODUCTION: Head and neck cancer (HNC) patients are at risk of weight change, due to inadequate nutrition intake or dehydration, when receiving radiotherapy (RT). This study aimed to develop methodology to measure water content changes on magnetic resonance imaging (MRI) scans of the head and neck region over the course of RT. METHODS: Retrospective datasets of 54 patients were analysed. Eligible patients had been treated for HNC with cisplatin chemoradiation (CRT) or RT alone and underwent a minimum of 2 MRI scans from weeks 0, 3 and 6 of their treatment. Anatomical regions consisting of ≥90% water, on T2-weighted DIXON MRI sequences, were contoured. Water volume changes of all patients were evaluated, within an anatomically standardised external volume, by comparing the absolute water fraction volume (cc) (VEx90WF) and relative water fraction volume (%) (RelVEx90WF) at weeks 0 and 6 of RT. RESULTS: There was a statistically significant difference between the RelVEx90WF at weeks 0 and 6 (P = 0.005). However, no statistically significant difference was identified between weeks 0 and 6 VEx90WF (P = 0.064). There were no statistically significant differences identified between patients who received CRT versus RT alone. CONCLUSION: This study developed a novel method for measuring changes in water fraction volumes over time, using T2-weighted DIXON MRIs. The methodology created in this study requires further validation through phantom imaging, with known fat and water values.
Subject(s)
Dehydration , Head and Neck Neoplasms , Humans , Retrospective Studies , Head and Neck Neoplasms/diagnostic imaging , Head and Neck Neoplasms/radiotherapy , Magnetic Resonance Imaging/methods , WaterABSTRACT
Fiction, whether in the form of storytelling or plays, has a particular attraction for us: we repeatedly return to it and are willing to invest money and time in doing so. Why this is so is an evolutionary enigma that has been surprisingly underexplored. We hypothesize that emotionally arousing drama, in particular, triggers the same neurobiological mechanism (the endorphin system, reflected in increased pain thresholds) that underpins anthropoid primate and human social bonding. We show that, compared to subjects who watch an emotionally neutral film, subjects who watch an emotionally arousing film have increased pain thresholds and an increased sense of group bonding.