RESUMEN
Catastrophic flank collapses are recognized as important drivers of insular biodiversity dynamics, through the disruption of species ranges and subsequent allopatric divergence. However, little empirical data supports this conjecture, with their evolutionary consequences remaining poorly understood. Using genome-wide data within a population genomics and phylogenomics framework, we evaluate how mega-landslides have impacted evolutionary and demographic history within a species complex of weevils (Curculionidae) within the Canary Island of Tenerife. We reveal a complex genomic landscape, within which individuals of single ancestry were sampled in areas characterized by long-term geological stability, relative to the timing of flank collapses. In contrast, individuals of admixed ancestry were almost exclusively sampled within the boundaries of flank collapses. Estimated divergence times among ancestral populations aligned with the timings of mega-landslide events. Our results provide first evidence for a cyclical dynamic of range fragmentation and secondary contact across flank collapse landscapes, with support for a model where this dynamic is mediated by Quaternary climate oscillations. The context within which we reveal climate and topography to interact cyclically through time to shape the geographic structure of genetic variation, together with related recent work, highlights the importance of topoclimatic phenomena as an agent of diversification within insular invertebrates.
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Genética de Población , Islas , Filogenia , Animales , Gorgojos/genética , Gorgojos/clasificación , BiodiversidadRESUMEN
Since Darwin put forward his opposing hypotheses to explain the successful establishment of species in areas outside their native ranges, the preadaptation and competition-relatedness hypotheses, known as Darwin's naturalization conundrum, numerous studies have sought to understand the relative importance of each. Here, we take advantage of well-characterized beetle communities across laurel forests of the Canary Islands for a first evaluation of the relative support for Darwin's two hypotheses within arthropods. We generated a mitogenome backbone tree comprising nearly half of the beetle genera recorded within the Canary Islands for the phylogenetic placement of native and introduced species sampled in laurel forests, using cytochrome c oxidase I (COI) sequences. For comparative purposes, we also assembled and phylogenetically placed a data set of COI sequences for introduced beetle species that were not sampled within laurel forests. Our results suggest a stronger effect of species preadaptation over resource competition, while also revealing an underappreciated shortfall in arthropod biodiversity data-knowledge of species as being native or introduced. We name this the Humboldtean shortfall and suggest that similar studies using arthropods should incorporate DNA barcode sequencing to mitigate this problem.
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Artrópodos , Escarabajos , Animales , Filogenia , Escarabajos/genética , Biodiversidad , Bosques , Especies IntroducidasRESUMEN
Soils harbour a rich arthropod fauna, but many species are still not formally described (Linnaean shortfall) and the distribution of those already described is poorly understood (Wallacean shortfall). Metabarcoding holds much promise to fill this gap, however, nuclear copies of mitochondrial genes, and other artefacts lead to taxonomic inflation, which compromise the reliability of biodiversity inventories. Here, we explore the potential of a bioinformatic approach to jointly "denoise" and filter nonauthentic mitochondrial sequences from metabarcode reads to obtain reliable soil beetle inventories and address open questions in soil biodiversity research, such as the scale of dispersal constraints in different soil layers. We sampled cloud forest arthropod communities from 49 sites in the Anaga peninsula of Tenerife (Canary Islands). We performed whole organism community DNA (wocDNA) metabarcoding, and built a local reference database with COI barcode sequences of 310 species of Coleoptera for filtering reads and the identification of metabarcoded species. This resulted in reliable haplotype data after considerably reducing nuclear mitochondrial copies and other artefacts. Comparing our results with previous beetle inventories, we found: (i) new species records, potentially representing undescribed species; (ii) new distribution records, and (iii) validated phylogeographic structure when compared with traditional sequencing approaches. Analyses also revealed evidence for higher dispersal constraint within deeper soil beetle communities, compared to those closer to the surface. The combined power of barcoding and metabarcoding contribute to mitigate the important shortfalls associated with soil arthropod diversity data, and thus address unresolved questions for this vast biodiversity fraction.
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Artrópodos , Escarabajos , Animales , Escarabajos/genética , Reproducibilidad de los Resultados , Código de Barras del ADN Taxonómico/métodos , Biodiversidad , Bosques , Artrópodos/genética , SueloRESUMEN
Most of our understanding of island diversity comes from the study of aboveground systems, while the patterns and processes of diversification and community assembly for belowground biotas remain poorly understood. Here, we take advantage of a relatively young and dynamic oceanic island to advance our understanding of ecoevolutionary processes driving community assembly within soil mesofauna. Using whole organism community DNA (wocDNA) metabarcoding and the recently developed metaMATE pipeline, we have generated spatially explicit and reliable haplotype-level DNA sequence data for soil mesofaunal assemblages sampled across the four main habitats within the island of Tenerife. Community ecological and metaphylogeographic analyses have been performed at multiple levels of genetic similarity, from haplotypes to species and supraspecific groupings. Broadly consistent patterns of local-scale species richness across different insular habitats have been found, whereas local insular richness is lower than in continental settings. Our results reveal an important role for niche conservatism as a driver of insular community assembly of soil mesofauna, with only limited evidence for habitat shifts promoting diversification. Furthermore, support is found for a fundamental role of habitat in the assembly of soil mesofauna, where habitat specialism is mainly due to colonization and the establishment of preadapted species. Hierarchical patterns of distance decay at the community level and metaphylogeographical analyses support a pattern of geographic structuring over limited spatial scales, from the level of haplotypes through to species and lineages, as expected for taxa with strong dispersal limitations. Our results demonstrate the potential for wocDNA metabarcoding to advance our understanding of biodiversity.
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Código de Barras del ADN Taxonómico , Suelo , Biodiversidad , ADN , Ecosistema , Haplotipos/genéticaRESUMEN
Dispersal limitation has been recurrently suggested to shape both macroecological patterns and microevolutionary processes within invertebrates. However, because of potential interactions among biological, environmental, temporal, and spatial variables, causal links among flight-related traits, diversification and spatial patterns of community assembly remain elusive. Integrating genetic variation within species across whole insect assemblages, within a simplified spatial and environmental framework, can be used to reduce the impact of these potentially confounding variables. Here, we used standardized sampling and mitochondrial DNA sequencing for a whole-community characterization of the beetle fauna inhabiting a singular forested habitat (laurel forest) within an oceanic archipelago setting (Canary Islands). The spatial structure of species assemblages together with species-level genetic diversity was compared at the archipelago and island scales for 104 winged and 110 wingless beetle lineages. We found that wingless beetle lineages have: (i) smaller range sizes at the archipelago scale, (ii) lower representation in younger island communities, (iii) stronger population genetic structure, and (iv) greater spatial structuring of species assemblages between and within islands. Our results reveal that dispersal limitation is a fundamental trait driving diversity patterns at multiple hierarchical levels by promoting spatial diversification and affecting the spatial configuration of entire assemblages at both island and archipelago scales.
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Biodiversidad , Ecosistema , Animales , Insectos/genética , Islas , Océanos y Mares , EspañaRESUMEN
Geographic isolation substantially contributes to species endemism on oceanic islands when speciation involves the colonisation of a new island. However, less is understood about the drivers of speciation within islands. What is lacking is a general understanding of the geographic scale of gene flow limitation within islands, and thus the spatial scale and drivers of geographical speciation within insular contexts. Using a community of beetle species, we show that when dispersal ability and climate tolerance are restricted, microclimatic variation over distances of only a few kilometres can maintain strong geographic isolation extending back several millions of years. Further to this, we demonstrate congruent diversification with gene flow across species, mediated by Quaternary climate oscillations that have facilitated a dynamic of isolation and secondary contact. The unprecedented scale of parallel species responses to a common environmental driver for evolutionary change has profound consequences for understanding past and future species responses to climate variation.
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Evolución Biológica , Clima , Flujo Génico , Especiación Genética , Geografía , Islas , Océanos y Mares , FilogeniaRESUMEN
Using a series of standardized sampling plots within forest ecosystems in remote oceanic islands, we reveal fundamental differences between the structuring of aboveground and belowground arthropod biodiversity that are likely due to large-scale species introductions by humans. Species of beetle and spider were sampled almost exclusively from single islands, while soil-dwelling Collembola exhibited more than tenfold higher species sharing among islands. Comparison of Collembola mitochondrial metagenomic data to a database of more than 80 000 Collembola barcode sequences revealed almost 30% of sampled island species are genetically identical, or near identical, to individuals sampled from often very distant geographic regions of the world. Patterns of mtDNA relatedness among Collembola implicate human-mediated species introductions, with minimum estimates for the proportion of introduced species on the sampled islands ranging from 45% to 88%. Our results call for more attention to soil mesofauna to understand the global extent and ecological consequences of species introductions.
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Artrópodos/clasificación , Biodiversidad , ADN Mitocondrial/genética , Especies Introducidas , Metagenómica , Animales , Bosques , IslasRESUMEN
Planthopper family Nogodinidae is recorded for the first time from the Canary Islands after a new species, Morsina gomerae sp. nov., described from the dry landscapes of La Gomera island. Mikewilsonia Holzinger, 2019 is placed in synonymy under Morsina Melichar, 1902. Mikewilsonia kunzi Holzinger, 2019 is transferred to Morsina with a new combination proposed-Morsina kunzi (Holzinger, 2019), comb. nov.
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Hemípteros , Animales , EspañaRESUMEN
Insects show remarkable phenotypic plasticity in response to changing environmental conditions. The abiotic factors that determine their phenotypes often vary in time and space, and oceanic islands harbour ideal environments for testing predictions on this matter. The ubiquitous beetle Pimelia laevigata costipennis Wollaston, 1864 (Tenebrionidae) is distributed over the entire altitudinal gradient of the island El Hierro (Canary archipelago), from 0 to 1501 m above sea level. Here, we examine how environmental factors (i.e., rainfall and temperature), associated with the altitudinal gradient, affect the body size, reproductive phenology, clutch size and egg volume, and population dynamics of this ectothermic flightless insect. Pimelia l. costipennis populations inhabiting upland localities, typified by lower temperatures, and greater precipitation and vegetation cover, were larger in body size and laid larger clutches with smaller eggs than those in the lowlands. Moreover, reproduction occurred earlier in the year at lower sites and later at higher sites, whereas activity density was highest in the uplands where it increases with temperature. This study first explores the changes in life history patterns along a whole insular altitudinal gradient, and finds interpopulation plasticity. It confirms that environmental factors associated with species spatial distribution act additively as drivers of phenological and phenotypic expression.
RESUMEN
Metabarcoding of Metazoa using mitochondrial genes may be confounded by both the accumulation of PCR and sequencing artefacts and the co-amplification of nuclear mitochondrial pseudogenes (NUMTs). The application of read abundance thresholds and denoising methods is efficient in reducing noise accompanying authentic mitochondrial amplicon sequence variants (ASVs). However, these procedures do not fully account for the complex nature of concomitant sequences and the highly variable DNA contribution of specimens in a metabarcoding sample. We propose, as a complement to denoising, the metabarcoding Multidimensional Abundance Threshold Evaluation (metaMATE) framework, a novel approach that allows comprehensive examination of multiple dimensions of abundance filtering and the evaluation of the prevalence of unwanted concomitant sequences in denoised metabarcoding datasets. metaMATE requires a denoised set of ASVs as input, and designates a subset of ASVs as being either authentic (mitochondrial DNA haplotypes) or nonauthentic ASVs (NUMTs and erroneous sequences) by comparison to external reference data and by analysing nucleotide substitution patterns. metaMATE (i) facilitates the application of read abundance filtering strategies, which are structured with regard to sequence library and phylogeny and applied for a range of increasing abundance threshold values, and (ii) evaluates their performance by quantifying the prevalence of nonauthentic ASVs and the collateral effects on the removal of authentic ASVs. The output from metaMATE facilitates decision-making about required filtering stringency and can be used to improve the reliability of intraspecific genetic information derived from metabarcode data. The framework is implemented in the metaMATE software (available at https://github.com/tjcreedy/metamate).
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Artefactos , Código de Barras del ADN Taxonómico , ADN Mitocondrial , Seudogenes , Animales , ADN Mitocondrial/genética , Filogenia , Reproducibilidad de los Resultados , Análisis de Secuencia de ADNRESUMEN
We administered a standardized 41-item questionnaire to a convenience sample of graduates of five residency programs with formal global health pathways and compared findings to a national cohort of practicing physicians to evaluate the comparative effectiveness of an overarching global health pathway on residency program graduates. Compared with the national cohort database, global health pathway graduates self-reported that they felt better prepared to treat immigrants, refugees, patients with limited English proficiency (LEP), racial/ethnic minorities, those with non-Western health beliefs, international travelers, and military veterans (P < 0.05). They were more likely to report using best practices when working with lesbian, gay, bisexual, transgender, queer/questioning patients, immigrant and refugee patients, patients with non-Western health beliefs, patients with LEP, and patients communicating via American Sign Language (P < 0.05). They also reported being more familiar with 11 of 14 high-impact or common infections encountered in travelers, immigrants, and military personnel (P < 0.05). Our findings suggest that formal postgraduate training focused on global health improves knowledge, attitudes, and self-reported medical practices when caring for diverse and marginalized populations in the United States.
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Competencia Clínica , Salud Global/educación , Internado y Residencia , Calidad de la Atención de Salud , Humanos , Encuestas y Cuestionarios , Estados UnidosRESUMEN
Obtaining fundamental biodiversity metrics such as alpha, beta and gamma diversity for arthropods is often complicated by a lack of prior taxonomic information and/or taxonomic expertise, which can result in unreliable morphologically based estimates. We provide a set of standardized ecological and molecular sampling protocols that can be employed by researchers whose taxonomic skills may be limited, and where there may be a lack of robust a priori information regarding the regional pool of species. These protocols combine mass sampling of arthropods, classification of samples into parataxonomic units (PUs) and selective sampling of individuals for mtDNA sequencing to infer biological species. We sampled ten lowland rainforest plots located on the volcanic oceanic island of Réunion (Mascarene archipelago) for spiders, a group with limited taxonomic and distributional data for this region. We classified adults and juveniles into PUs and then demonstrated the reconciliation of these units with presumed biological species using mtDNA sequence data, ecological data and distributional data. Because our species assignment protocol is not reliant upon prior taxonomic information, or taxonomic expertise, it minimizes the problem of the Linnean shortfall to yield diversity estimates that can be directly compared across independent studies. Field sampling can be extended to other arthropod groups and habitats by adapting our field sampling protocol accordingly.
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Artrópodos/clasificación , Biodiversidad , Bosques , Animales , ReuniónRESUMEN
The weevil Oromia thoracica n. sp. from Gran Canaria (Canary Islands) is described and compared to its closest allies. It can easily be distinguished by less sculptured elytra, its differently shaped antennal scrobe, and by the pronotum not constricted anteriorly and expanded over the head. Some ecological data are also provided, and considerations on the fauna occurring in the mesovoid shallow substratum (MSS) from the locality of this new species are made. Additional records and comments on other Oromia species as well as an identification key to the species of the genus are given.
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Gorgojos/clasificación , Animales , Femenino , Masculino , España , Gorgojos/anatomía & histologíaRESUMEN
El síndrome de Albright-McCune Sternberg (SAMS) es un desorden raro que se origina de una mutación del gen GNAS1. Se caracteriza por presentar un fenotipo típico, el cual incluye fibrodisplasia (FD) poliostótica, pubertad precoz (PP), pigmentaciones café au lait (café con leche) junto con otras endocrinopatías. La presente investigación trata de una paciente femenina de 22 años de edad con SAMS la cual presenta algunos signos y síntomas del síndrome tales como: FD poliostótica, pigmentaciones color café con leche en la piel, PP e hipotiroidismo. Acudió por dolor a nivel de las encías inferiores producto de un aumento óseo bimaxilar, inicia su enfermedad actual en mayo de 2013 presentando dolor a nivel de mucosa gingival inferior, localizado, punzante, de intensidad moderada, el cual se agrava ante la masticación y dura hasta el cese del estimulo. La FD fue diagnosticada posterior a la realización de una biopsia de tejido óseo y estudios radiográficos, la paciente presentó metrorragia a los nueve meses de edad el cual se repitió a los cinco años y persistió de manera intermitente hasta los veinte años de edad donde fue diagnosticada con ovarios poliquísticos por lo cual se le prescribió etinilestradiol y acetato de ciproterona. Aunque el SAMS generalmente cursa con una hiperfunción endocrina la paciente tiene un diagnóstico de hipotiroidismo por lo cual está bajo tratamiento con levotiroxina.
The Albright-McCune Sternberg syndrome (AMSS) is a rare disorder that arises from a mutation of the GNAS1 gene. It is characterized by a typical phenotype, which includes polyostotic fibrous dysplasia (FD), precocious puberty (PP), cafe-au-lait pigmentations and other endocrinopathies. The following research is about a 22 year old female patient with SAMS which presents some signs and symptoms of the syndrome such as polyostotic FD, pigmentation of the skin, PP and hypothyroidism. She attended by pain in the lower gum product of increased bimaxillary volume it began in may 2013 having pain in lower gingiva localized, throbbing, of moderate intensity, which is exacerbated by chewing and lasts until the cessation of the stimulus. The FD was diagnosed after performing a bone biopsy and radiographic studies, the patient had metrorrhagia at nine months of age which was repeated at five years and persisted intermittently until twenty years where he was diagnosed with polycystic ovaries so was prescribed ethinylestradiol and cyproterone acetate. Although the AMSS usually occurs with endocrine hyperfunction the patient has a diagnosis of hypothyroidism which is treated with levothyroxine.