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19,493 results for “Populism”
Sexually-selected male weapon increases the risk of population extinction under environmental change: An experimental evidence
<p><span>Exaggerated sexually-selected traits, occurring more commonly in males, help individuals to increase reproductive success, but are costly to produce and maintain. These costs on the one hand may improve population fitness by intensifying selection against maladapted males, but on the other hand may increase the risk of extinction under environmental challenge. However, the impact of sexually selected traits on extinction risk have not been investigated experimentally. We used replicate populations of a male-dimorphic mite, <em>Rhizoglyphus robini</em>, to test if prevalence of a sexually-selected weapon affected the risk of extinction under gradual temperature increase (20C per generation). In two independent experiments that utilized either inbred lines or lines mass selected for or against the weapon to establish experimental replicate populations differing in the prevalence of the weapon, we found that populations with high weapon prevalence were more likely to go extinct. Extinctions occurred despite partial suppression of the weapon expression at increased temperature and were not explained by increased male mortality. Our results provide the first, to our knowledge, experimental evidence demonstrating dramatic effect of elaborated sexual traits on the risk of extinction under environmental challenge.</span></p>
Data from: Philopatry influences the genetic population structure of the blacktip shark (Carcharhinus limbatus) at multiple spatial scales
<p>Understanding how interactions among microevolutionary forces generate genetic population structure of exploited species is vital to the implementation of management policies that facilitate population persistence. Philopatry displayed by many coastal shark species can impact gene flow and facilitate selection, and thus has direct implications for the spatial scales of management plans. Here, genetic structure of the blacktip shark (Carcharhinus limbatus) was examined using a mixed-marker approach based on mitochondrial control region sequences and 4,339 SNP-containing loci generated using ddRAD-Seq. Genetic variation was assessed among young-of-the-year sampled in 11 sites in waters of the United States in the western North Atlantic Ocean, including the Gulf of Mexico. Spatial and environmental analyses detected 68 nuclear loci putatively under selection, enabling separate assessments of neutral and adaptive genetic structure. Both mitochondrial and neutral SNP data indicated three genetically distinct units – the Atlantic, eastern Gulf, and western Gulf – that align with regional stocks and suggest regional philopatry by males and females. Heterogeneity at loci putatively under selection, associated with temperature and salinity, was observed among sites within Gulf units, suggesting local adaptation. Furthermore, five pairs of siblings were identified in the same site across timescales corresponding with female reproductive cycles. This indicates that females re-used a site for parturition, which has the potential to facilitate the sorting of adaptive variation among neighboring sites. The results demonstrate differential impacts of microevolutionary forces at varying spatial scales and highlight the importance of conserving essential habitats to maintain sources of adaptive variation that may buffer species against environmental change.</p>
Fitness, risk taking, and spatial behavior covary with boldness in experimental vole populations
<p>Individuals of a population may vary along a pace-of-life syndrome from highly fecund, short-lived, bold, dispersive 'fast' types at one end of the spectrum to less fecund, long-lived, shy, plastic 'slow' types at the other end. Risk-taking behaviour might mediate the underlying life-history trade-off but empirical evidence supporting this hypothesis is still ambiguous. Using experimentally created populations of common voles (<em>Microtus arvalis</em>) - a species with distinct seasonal life-history trajectories - we aimed to test whether individual differences in boldness behaviour co-vary with risk-taking, space use, and fitness<span>. </span>We quantified risk taking, space use (via automated tracking), survival and reproductive success (via genetic parentage analysis) in 8 to 14 experimental, mixed-sex populations of 113 common voles of known boldness type in large grassland enclosures over a significant part of their adult life span and two reproductive events. Populations were assorted to contain extreme boldness types (bold or shy) of both sexes. Bolder individuals took more risks than shyer ones, which did not affect survival. Bolder males but not females produced more offspring than shy conspecifics. Daily home range and core area sizes, based on 95% and 50% Kernel density estimates (20 ± 10 per individual, n = 54 individuals), were highly repeatable over time. Individual space use unfolded differently for sex-boldness type combinations over the course of the experiment. While day ranges decreased for shy females, they increased for bold females and all males. Space use trajectories may, hence, indicate differences in coping styles when confronted with a novel social and physical environment. Thus, inter-individual differences in boldness predict risk taking under near natural conditions and have consequences for fitness in males, which have a higher reproductive potential than females. Given extreme inter- and intra-annual fluctuations in population density in the study species and its short life span, density-dependent fluctuating selection operating differently on the sexes might maintain (co)variation in boldness, risk taking and pace-of-life.</p>
Data from: Phylogenetic, population structure, and population demographic analyses reveal that Vicia sepium in Japan is native and not introduced
<p><span><em>Vicia</em> <em>sepium</em></span><span> (bush vetch) is a perennial legume widely distributed throughout the Eurasian continent. However, its distribution in Japan is limited to Mt. Ibuki and small parts of central and southern Hokkaido. Therefore, each Japanese <em>V. sepium</em> lineage has been considered to have been introduced separately from Europe. Here, we examined whether the species was introduced or not on the basis of cpDNA sequences and genome-wide SNPs from Japanese and overseas samples. Both the cpDNA haplotype network and the nuclear DNA phylogenetic tree showed that Japanese <em>V. sepium</em> is monophyletic. Furthermore, although the nuclear DNA phylogenetic tree also showed that each lineage is clearly monophyletic, genetic admixture of the genetic cluster dominated in the Hokkaido lineage was also detected in the Mt. Ibuki lineage. Population divergence analysis showed that the two lineages diverged during the last glacial period. The Mt. Ibuki lineage showed a sudden population decline 300–400 years ago, indicating that some anthropogenic activity might be involved, while the Hokkaido lineage showed a gradual population decline from 5,000 years ago. Consequently, these two lineages show low current genetic diversity compared with overseas lineages. These results show that the Japanese <em>V. sepium</em> is not introduced but is native.</span></p>
Dataset for: Utilizing high-resolution genetic markers to track population-level exposure of migratory birds to renewable energy development
<p class="MsoNormal"><span>With new motivation to increase the proportion of energy demands met by zero-carbon sources, there is a greater focus on efforts to assess and mitigate the impacts of renewable energy development on sensitive ecosystems and wildlife, of which birds are of particular interest. One challenge for researchers, due in part to a lack of appropriate tools, has been estimating the effects from such development on individual breeding populations of migratory birds. To help address this, we utilize a newly developed, high-resolution genetic tagging method to rapidly identify the breeding population of origin of carcasses recovered from renewable energy facilities and combine them with maps of genetic variation across geographic space (called 'genoscapes') for five species of migratory birds known to be exposed to energy development, to assess the extent of population-level effects on migratory birds. We demonstrate that most avian remains collected were from the largest populations of a given species. In contrast, those remains from smaller, declining populations made up a smaller percentage of the total number of birds assayed. Results suggest that application of this genetic tagging method can successfully define population-level exposure to renewable energy development and may be a powerful tool to inform future siting and mitigation activities associated with renewable energy programs.</span></p>
Data from: Past population control biases interpretations of contemporary genetic data: implications for future invasive Sitka black-tailed deer management in Haida Gwaii
<p>Invasive species management practices often include genetic analyses to better inform decision-making and resource allocation. Yet, past management actions may artificially bias recovered patterns of genetic variation; for example, a population bottleneck caused by contemporary culling may mirror some patterns associated with historical isolation. Here, we aimed to disentangle the impacts of past management activities from natural processes for Sitka black-tailed deer (<em>Odocoileus</em> <em>hemionus</em> <em>sitkensis</em>), an invasive species that has been repeatedly culled on two islands, SGang Gwaay and Reef, within the Haida Gwaii archipelago (Canada). We applied a recently developed Genotyping-in-Thousands by sequencing panel to contemporary (e.g., blood, serum, tissue, muscle, feces) and archived deer samples, the latter collected prior to management activity within the system (c. 1997–1998), which allowed us to contextualize conflicting patterns of isolation and connectivity previously observed on SGang Gwaay and Reef. Successful genotyping (92.6%) and population genetic analysis of 292 individuals at 236 SNPs revealed signals of historical isolation on SGang Gwaay and Reef, provided evidence of a founder effect during initial colonization, and indicated an absence of ongoing gene flow. Furthermore, our spatiotemporal analyses consistently supported a priori predictions associated with bottlenecks within post-cull populations, such as within-island loss of genetic variation, elevated within-island kinship, and increased levels of among-island genetic differentiation. These findings are promising for future management of deer on SGang Gwaay and Reef, suggesting that eradications on these islands may be durable. More broadly, our work highlights the importance of understanding management history before interpreting contemporary population genetic data.</p>
Population dynamics and seasonal migration patterns of Spodoptera exigua in northern China based on 11 years of monitoring data
<p>The beet armyworm, <em>Spodoptera exigua </em>(Hübner) is an important migratory pest worldwide that has caused serious economic losses in the main crop-producing areas of China. To effectively monitor and control this pest, it is necessary to investigate its interannual and seasonal migration patterns in northern China. In this study, we weekly monitored the population dynamics of <em>S. exigua</em> using sex pheromone traps in Shenyang, Liaoning Province from 2012 to 2022 and simulated the migration trajectories using the HYSPLIT model. Overall, the migration numbers varied significantly among years, with large migrations in 2018 and 2020 that resulted in a total catch of more than 2000 individuals. </p>
Data for: A novel cricket morph has diverged in song and wing morphology across island populations
<p class="MsoNormal"><span>Divergence of sexual signals between populations can lead to speciation, yet opportunities to study the immediate aftermath of novel signal evolution are rare. The recent emergence and spread of a new mating song, purring, in Hawaiian populations of the Pacific field cricket (<em>Teleogryllus oceanicus</em>) allows us to investigate population divergence soon after the origin of a new signal. Male crickets produce songs with specialized wing structures to attract mates from afar (calling) and entice them to mate when found (courtship). However, in Hawaii, these songs also attract an eavesdropping parasitoid fly (<em>Ormia ochracea</em>) that kills singing males. The novel purring song, produced with heavily modified wing morphology, attracts female crickets but not the parasitoid fly, acting as a solution to this conflict between natural and sexual selection. We've since observed increasing numbers of purring males across Hawaii. In this integrative field study, we investigated the distribution of purring and the proportion of purring males relative to other morphs in six populations on four islands and compared a suite of phenotypic traits (wing morphology, calling song, and courtship song) that make up this novel signal across populations of purring males. We show that purring is found in varying proportions across five, and is locally dominant in four, Hawaiian populations. We also show that calling songs, courtship songs, and wing morphology of purring males differ geographically. Our findings demonstrate the rapid pace of evolution in island populations and provide insights into the emergence and divergence of new sexual signals over time.</span></p>
Low-coverage whole genome sequencing for highly accurate population assignment: Mapping migratory connectivity in the American Redstart (Setophaga ruticilla)
<p>Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing methods, such as low-coverage whole genome sequencing (lcWGS), provides new opportunities for improved estimates of migratory connectivity. Here, we use lcWGS to identify fine-scale population structure in a widespread songbird, the American Redstart (<em>Setophaga</em> <em>ruticilla</em>), and accurately assign individuals to genetically distinct breeding populations. Assignment of individuals from the nonbreeding range reveals population-specific patterns of varying migratory connectivity. By combining migratory connectivity results with demographic analysis of population abundance and trends, we consider full annual cycle conservation strategies for preserving numbers of individuals and genetic diversity. Notably, we highlight the importance of the Northern Temperate-Greater Antilles migratory population as containing the largest proportion of individuals in the species. Finally, we highlight valuable considerations for other population assignment studies aimed at using lcWGS. Our results have broad implications for improving our understanding of the ecology and evolution of migratory species through conservation genomics approaches.</p>
Preservation of genetic diversity in a highly fragmented population of the gray-sided vole Myodes rufocanus in an intensive farming region
<p class="MsoNormal"><span>Individual dispersal plays an important role in preserving genetic diversity in density-fluctuating populations of arvicoline rodents. When habitats are fragmented and dispersal between habitats is severely constrained, genetic diversity can be lost. Here, I investigated whether genetic diversity in the gray-sided vole <em>Myodes rufocanus </em>was preserved in an intensive farming region in Japan, where voles inhabited isolated windbreak forests along the borders of plowed lands. Genetic structure was examined in 673 vole samples (330 in spring and 343 in fall) collected at 34 windbreak forests located 0.35–20 km apart. A part of the control region (425 bp) of mitochondrial DNA (mtDNA) was sequenced in 673 voles, yielding 76 haplotypes. Genetic differentiation of maternally inherited mtDNA among trapping sites was markedly lower in males than in females in both seasons, indicating strong male-biased dispersal. Genotypes at six microsatellite DNA loci were determined in 494 voles (245 in spring and 249 in fall) from 18 trapping sites, and loci harbored 16–24 alleles. The mean number of alleles per locus (allelic diversity) at trapping sites was positively correlated with the number of examined individuals (density) in both seasons, and the relationship was very similar to that of a previous study performed in much less fragmented populations. Genetic differentiation of microsatellite DNA among trapping sites decreased considerably from spring to fall. In a STRUCTURE analysis with a most probable cluster number of two, closer trapping sites showed more similar mean values of cluster admixture proportions. The present findings indicate that gene flow among isolated windbreak forests, which occurred mainly by dispersal of males, was not restrained in this intensive farming region. Furthermore, the results suggest that genetic diversity in the study population was preserved as well as in less fragmented populations.</span></p>
Abundance and population growth estimates for bare-nosed wombats
<p><span>Wildlife managers often rely on population estimates, but estimates can be challenging to obtain for geographically widespread species. Spotlight surveys provide abundance data for many species and, when conducted over wide spatial scales, have the potential to provide population estimates of geographically widespread species. The bare-nosed wombat (<em>Vombatus</em> <em>ursinus</em>) has a broad geographic range and is subject to spotlight surveys. We used 19 years (2002–2020) of annual spotlight surveys to provide the first estimates of population abundance for two of the three extant bare-nosed wombat subspecies: <em>V. u. ursinus</em> on Flinders Island; and <em>V. u. tasmaniensis</em> on the Tasmanian mainland. Using distance sampling methods, we estimated annual rates of change and 2020 population sizes for both sub-species. Tasmanian mainland surveys included habitat data, which allowed us to also look for evidence of habitat associations for <em>V. u. tasmaniensis</em>. The average wombat density estimate was higher on Flinders Island (0.42 ha<sup>-1</sup>, 95% CrI = 0.25 – 0.79) than on the Tasmanian mainland (0.11 ha<sup>-1</sup>, CrI = 0.07 – 0.19) and both wombat subspecies increased over the 19-year survey period with an estimated annual growth rate of 2.90% (CrI = -1.7 – 7.3) on Flinders Island and 1.20% (CrI = -1.1 – 2.9) on mainland Tasmania. Habitat associations for <em>V. u. tasmaniensis</em> were weak, possibly owing to survey design; however, we detected regional variation in density for this subspecies. We estimated the population size of <em>V. u. ursinus </em>to be 71,826 (CrI = 43,913 – 136,761) on Flinders Island, which when combined with a previously published estimate of 2,599 (CI = 2,254 – 2,858) from Maria Island, where the subspecies was introduced, provides a total population estimate. We also estimated 840,665 (CrI = 531,104 – 1,201,547) <em>V. u. tasmaniensis </em>on mainland Tasmania. These estimates may be conservative, owing to individual heterogeneity in when wombats emerge from burrows. Although these two sub-species are not currently threatened, our population estimates provide an important reference when assessing their population status in the future, and demonstrate how spotlight surveys can be valuable to inform management of geographically widespread species.</span></p>
Data from: Maximum stem diameter predicts liana population demography
<p>Determining population demographic rates is fundamental to understanding differences in species life-history strategies and their capacity to coexist. Calculating demographic rates, however, is challenging and requires long-term, large-scale censuses. Body size may serve as a simple predictor of demographic rate; can it act as a proxy for demographic rate when those data are unavailable? We tested the hypothesis that maximum body size predicts species' demographic rate using repeated censuses of the 77 most common liana species on the Barro Colorado Island, Panama (BCI) 50-ha plot. We found that maximum stem diameter does predict species' population turnover and demography. We also found that lianas on BCI can grow to the enormous diameter of 635 mm, indicating that they can store large amounts of carbon and compete intensely with tropical canopy trees. This study is the first to show that maximum stem diameter can predict plant species' demographic rates and that lianas can attain extremely large diameters. Understanding liana demography is particularly timely because lianas are increasing rapidly in many tropical forests, yet their species-level population dynamics remain chronically understudied. Determining per-species maximum liana diameters in additional forests will enable systematic comparative analyses of liana demography and potential influence across forest types.</p>
Temporal matches between monarch butterfly and milkweed population changes over the past 25,000 years
<p>In intimate ecological interactions, the interdependency of species may result in correlated demographic histories. For species of conservation concern, understanding the long-term dynamics of such interactions may shed light on the drivers of population decline. Here we address the demographic history of the monarch butterfly, <em>Danaus</em> <em>plexippus</em>, and its dominant host plant, the common milkweed, <em>Asclepias</em> <em>syriaca</em>, using broad-scale sampling and genomic inference. Because genetic resources for milkweed have lagged behind those for monarchs, we first release a chromosome-level genome assembly and annotation for common milkweed. Next, we show that despite its enormous geographic range across eastern North America, <em>A. syriaca</em> is best characterized as a single, roughly panmictic population. Using Approximate Bayesian Computation via Random Forests (ABC-RF), a machine learning method for reconstructing demographic histories, we show that both monarchs and milkweed experienced population expansion during the most recent recession of North American glaciers 10,000–20,000 years ago. Our data also identify concurrent population expansions in both species during the large-scale clearing of eastern forests (~200 years ago). Finally, we find no evidence that either species experienced a reduction in effective population size over the past 75 years. Thus, the well-documented decline of monarch abundance over the past 40 years is not visible in our genomic dataset, reflecting a possible mismatch of the overwintering census population to effective population size in this species.</p>
Data from: Arriving late and lean at a stopover site is selected against in a declining migratory bird population
<p>Loss and/or deterioration of refuelling habitats have caused population declines in many migratory bird species, but whether this results from unequal mortality among individuals varying in migration traits remains to be shown. Based on 13 years of body mass and size data of great knots (<em>Calidris tenuirostris</em>) at a stopover site of the Yellow Sea, combined with resightings of individuals marked at this stopover site along the East Asian-Australasian Flyway, we assessed year to year changes in annual apparent survival rates, and how apparent survival differed between migration phenotypes (their i.e. migration timing and fuel stores). The measurements occurred over a period of habitat loss and/or deterioration in this flyway. We found that the annual apparent survival rates of great knots rapidly declined from 2006 to 2018, late-arriving individuals with small fuel stores exhibiting the lowest apparent survival rate. There was an advancement in mean arrival date and an increase in the mean fuel load of stopping birds over the study period. Our results suggest that late-arriving individuals with small fuel loads were selected against. Thus, habitat loss and/or deterioration at staging sites may cause changes in the composition of migratory phenotypes at the population-level.</p>
Dataset for: Estimating pregnancy rate from blubber progesterone levels of a blindly biopsied beluga population poses methodological, analytical and statistical challenges
<p class="MsoBodyText"><span>Beluga (<em>Delphinapterus leucas</em>) from the St. Lawrence Estuary, Canada, have been declining since the early 2000s, suggesting recruitment issues as a result of low fecundity, abnormal abortion rates or poor calf or juvenile survival. Pregnancy is difficult to observe in cetaceans, making the ground-truthing of pregnancy estimates in wild individuals challenging. Blubber progesterone concentrations were contrasted among 62 SLE beluga with a known reproductive state (i.e., pregnant, resting, parturient, and lactating females), that were found dead in 1997–2019. The suitability of a threshold obtained from decaying carcasses to assess reproductive state and pregnancy rate of freshly-dead or free-ranging and blindly-sampled beluga was examined using three statistical approaches and two datasets (135 freshly-harvested carcasses in Nunavik, and 65 biopsy-sampled SLE beluga). Progesterone concentrations in decaying carcasses were considerably higher in known-pregnant (mean </span><span>±</span><span> sd: </span><span>365 </span><span>±</span><span> 244 ng g<sup>-1</sup> of tissue) </span><span>than resting (</span><span>3.1 </span><span>±</span><span> 4.5 ng g<sup>-1</sup> of tissue</span><span>) or lactating (</span><span>38.4 </span><span>±</span><span> 100 ng g<sup>-1</sup> of tissue</span><span>) females. An approach based on statistical mixtures of distributions and a logistic regression was compared to the commonly-used, fixed threshold approach (here, 100 ng g<sup>-1</sup>) for discriminating pregnant from non-pregnant females. The error rate for classifying individuals of known reproductive status was the lowest for the fixed threshold and logistic regression approaches, but the mixture approach required limited <em>a priori</em> knowledge for clustering individuals of unknown pregnancy status. Mismatches in assignations occurred at lipid content <10% of sample weight. Our results emphasize the importance of reporting lipid contents and progesterone concentrations in both units (ng g<sup>-1 </sup>of tissue and ng g<sup>-1</sup> of lipid) when sample mass is low. By highlighting ways to circumvent potential biases in field sampling associated with capturability of different segments of a population, this study also enhances the usefulness of the technique for estimating pregnancy rate of free-ranging population. </span></p>
Trait value of Stipa krylovii populations in control and drought treatments
<p><span>Understanding patterns of intraspecific trait variation can help us understand plant adaptability to environmental changes. To explore the underlying adaptation mechanisms of zonal plant species, we selected seven populations of <em>Stipa</em> <em>krylovii</em>, a dominant species in the Inner Mongolia Steppe of China, and evaluated</span> <span>the effects of phenotypic plasticity and genetic differentiation, the effects of climate variables on population trait differentiation, and traits coordinated patterns under each soil moisture treatment. We selected seeds from seven populations of <em>S. krylovii </em>in the Inner Mongolia Steppe, China, and carried out a soil moisture (2) × population origin (7) common garden experiment at Tianjin City, China, and measured ten plant traits of <em>S. krylovii</em>. General linear analyses were used to analyze how soil moisture and population origin affect each trait variation, Mantel tests were used to analyze population trait differentiation - geographic distance (or climatic difference) relationships, regression analyses were used to evaluate the trait-climatic variable relationships, and plant trait networks (PTNs) were used to evaluate the traits coordinated patterns. Both soil moisture and population origin showed significant effects on most of the traits. Aboveground biomass, root-shoot ratio, leaf width, specific leaf area, and leaf nitrogen (N) content were significantly correlated with climate variables under the control condition. Specific leaf area and leaf N content were significantly correlated with climate variables under drought conditions. By PTNs, the hub trait(s) was plant height under the control treatment and were aboveground biomass, root length, and specific leaf area under drought conditions. This study indicates that both phenotypic plasticity and genetic differentiation can significantly affect the adaptability of <em>S. krylovii</em>. In addition, soil moisture treatments show significant effects on trait-climate relationships and trait-coordinated patterns. These findings provide new insights into the adaptive mechanisms of zonal species in the semi-arid grassland region.</span></p>
Comparative transmission genetics of introgressed chromatin in reciprocal advanced backcross populations in Gossypium (cotton) polyploids
<p>Introgression is a potential source of valuable genetic variation and interspecific introgression lines are important resources for plant breeders to access novel alleles. Experimental advanced-generation backcross populations contain individuals with genomic compositions similar to those resulting from natural interspecific hybridization and provide opportunities to study the nature and transmission pattern of donor chromatin in recipient genomes. Here, we analyze transmission of donor chromatin in reciprocal backcrosses between <em>G. hirsutum</em> and <em>G. barbadense</em>. Across the genome, recurrent backcrossing in both backgrounds yielded donor chromatin at slightly higher frequencies than the Mendelian expectation in BC<sub>5</sub>F<sub>1</sub> plants, while the average frequency of donor alleles in BC<sub>5</sub>F<sub>2</sub> segregating families was less than expected. In the two subgenomes of polyploid cotton, the rate of donor chromatin introgression was similar. Although donor chromatin was tolerated over much of the recipient genomes, 21 regions recalcitrant to donor alleles were identified. Only limited correspondence is observed between the recalcitrant regions in the two backgrounds, suggesting the effect of species background on introgression of donor segments. Genetic breakdown was progressive, with floral abscission and seed inviability ongoing during backcrossing cycles. Regions of either high or low introgression tended to be in terminal chromosomal regions that are generally rich in both genes and crossover events, with long stretches around the centromere having limited crossover activity resulting in relatively constant low introgression frequencies. Constraints on fixation and selection of donor alleles highlights the challenges of utilizing introgression breeding in crop improvement.</p>
The dynamic matrix predicts population response to long-term experimental forest fragmentation
<div><strong>Context</strong></div> <div> </div> <div>Earth's forests are fragmented. Species' long-term persistence depends on their conservation in fragmented landscapes with remnants embedded in a matrix of human land use. This matrix influences species' persistence in fragments by determining their degree of isolation and the extent to which edge effects alter habitat. Matrix habitat is often dynamic, so its impact on persistence of remnant species changes over time.</div> <div> </div> <div><strong>Objectives</strong></div> <div> </div> <div>Previous research showed that the abundance response of predatory beetle species to matrix habitat predicted their response in fragments with a log-response ratio of about 0.5. When abundance declined in the matrix, there was a smaller but predictable decline in fragments. However, the predictive utility of a fragment:matrix log-response ratio needs testing with functionally different species, more detailed data, and a focus on mechanism.</div> <div> </div> <div><strong>Methods</strong></div> <div> </div> <div>In the Wog Wog habitat fragmentation experiment, we follow a detritivorous amphipod 27 years after forest fragmentation.</div> <div> </div> <div><strong>Results</strong></div> <div> </div> <div>The amphipod's response in habitat fragments was predicted by its response in the matrix with a log-response ratio of about 0.5, similar to predatory beetles. The amphipod's response was explained by its abiotic niche. The amphipod's short-term response did not predict its long-term response.</div> <div> </div> <div><strong>Conclusions</strong></div> <div> </div> <div>The log-response ratio might generalize across the invertebrate food web. For two groups within the Wog Wog experiment, a species' dynamic response in matrix habitat predicted its persistence in fragments. Future work should explore the generality of this finding. With knowledge of projected land use of matrix habitat, a species' matrix response could be used for management planning.</div>
High prevalence of lipopolysaccharide mutants and R2-Pyocin susceptible variants in Pseudomonas aeruginosa populations sourced from cystic fibrosis lung infections
<p>Chronic, highly antibiotic-resistant infections in cystic fibrosis (CF) lungs contribute to increasing morbidity and mortality. <em>Pseudomonas</em> <em>aeruginosa</em>, a common CF pathogen, exhibits resistance to multiple antibiotics, contributing to antimicrobial resistance (AMR). These bacterial populations display genetic and phenotypic diversity, but it is unclear how this diversity affects susceptibility to bacteriocins. R-pyocins, i.e. bacteriocins produced by <em>P. aeruginosa</em>, are phage-tail-like antimicrobials. R-pyocins have potential as antimicrobials, however, recent research suggests the diversity of <em>P. aeruginosa</em> variants within CF lung infections leads to varying susceptibility to R-pyocins. This variation may be linked to changes in lipopolysaccharide (LPS), acting as the R-pyocin receptor. Currently, it is unknown how frequently R-pyocin-susceptible strains are in chronic CF lung infection, particularly when considering the heterogeneity within these strains. In this study, we tested R2-pyocin susceptibility of 139 <em>P. aeruginosa</em> variants from 17 sputum samples of seven CF patients and analyzed LPS phenotypes. We found that 83% of sputum samples did not have R2-pyocin-resistant variants, while nearly all samples contained susceptible variants. There was no correlation between LPS phenotype and R2-pyocin susceptibility, though we estimate that about 76% of sputum-derived variants lack an O-specific antigen, 40% lack a common antigen, and 24% have altered LPS cores. The absence of a correlation between LPS phenotype and R-pyocin susceptibility suggests LPS packing density may play a significant role in R-pyocin susceptibility among CF variants. Our research supports the potential of R-pyocins as therapeutic agents, as many infectious CF variants are susceptible to R2-pyocins, even within diverse bacterial populations.</p>
Microsatellite genotypes of Japanese abies species: Insights from population genetics and SDM
<p><span>Range shifts during the Pleistocene shaped the unique phylogeographical structures of many species. Pleistocene range shifts gave currently allopatric species opportunities to occur in sympatry, likely resulting in ancient introgressions between related taxa. In our study, we investigate the range shifts and introgression patterns of three Japanese <em>Abies </em>species (<em>A. firma, A. homolepis, and A. veitchii</em>) by employing an extensive survey of 43 populations. This survey includes comprehensive analysis of both mitochondrial (mtDNA) and nuclear (18 microsatellites) genomes, in combination with species distribution modeling (SDM). It is important to note that these two types of markers provide distinct and complementary information, as they have different modes of inheritance and mutation rates. Bayesian clustering analysis indicates that the three species were clearly separated, with the exception of the <em>A. homolepis </em>var. <em>umbellata</em> population, which is considered a natural hybrid between <em>A. homolepis</em> and <em>A. firma</em>. However, mtDNA haplotypes of the four northern populations of <em>A. firma</em> were entirely replaced by two major haplotypes of <em>A. homolepis </em>and <em>A. veitchii.</em> The results of Neighbor-net, NewHybrids, STRUCTURE analyses, and SDM suggest that historical introgression between species occurred in each geographic region, with mtDNA capture being the likely mechanism. However, contrary to these findings, the ABC coalescent analysis did not support an ancient introgression. Therefore, further validation with genome-wide level data is needed to clarify this issue. Our conclusion is that climate-induced range shifts during the Pleistocene/Holocene likely played a crucial role in the observed patterns of introgression in these species.</span></p>
ScienceDex guides
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.