筛选
科学数据
统计数据
共检索到31834条 ,权限内显示50条;
Data from: Evolution of heterophil/lymphocyte ratios in response to ecological and life-history traits: a comparative analysis across the avian tree of life
- 负责人：
- DOI：
- doi:10.5061/dryad.s3cc172
- 摘要：
- 1. Lymphocytes and heterophils are the two most abundant leukocyte types, which play a major role in adaptive and innate immune defence, respectively. The ratio of heterophils to lymphocytes (H/L ratio) may reflect a readiness to cope with infection through injury (via heterophils) rather than with a communicable disease (via lymphocytes). Since elevated H/L ratio constitutes a corticosterone-mediated response to external stressors, this trait is generally acknowledged as the robust measure of physiological stress in vertebrates. 2. Here, I hypothesized that baseline H/L ratios of birds (as measured under normal physiological function) could be an important evolutionary trait shaped by species’ ecology and life-history. I predicted that H/L ratios should be determined by traits related to pathogen exposure (migratoriness, sociality, breeding latitude) and trade-offs between investment in reproduction (clutch size) and self-maintenance (longevity). 3. I compiled published data on leukocyte profiles for nearly 250 bird species representing over half of all extant avian orders and nearly 30% of all extant avian families. Phylogenetically-informed comparative methods were used to assess evolutionary associations of H/L ratios with ecological and life-history traits across the avian tree of life. 4. Relatively strong phylogenetic signal and phylogenetic autocorrelation in avian H/L ratios indicated that most diversification in this trait occurred relatively early in bird radiation. Fluctuating selection and drift were identified as the major forces responsible for the evolution of H/L ratios in birds, while low H/L ratios were identified as an ancestral state in birds. Finally, phylogenetically-informed Bayesian models showed that H/L ratios correlated negatively with longevity and positively with sociality and breeding latitude. 5. This study was the first to describe the patterns of avian H/L ratio evolution in a broad phylogenetic framework. The results indicate that H/L ratios should not be merely recognized as a proxy for the intra-specific variation in physiological stress, but also as an important evolutionary trait which probably have adaptive significance visible in a wider phylogenetic perspective.
Data from: Ecologically relevant dispersal of corals on isolated reefs: implications for managing resilience
- 负责人：
- DOI：
- doi:10.5061/dryad.s3r4hn4p
- 摘要：
- Coral reefs are in decline worldwide, and marine reserve networks have been advocated as a powerful management tool for maximizing the resilience of coral communities to an increasing variety, number, and severity of disturbances. However, the effective design of reserves must account for the spatial scales of larval dispersal that affect the demography of communities over ecological time frames. Ecologically relevant distances of dispersal were inferred from DNA microsatellite data in a broadcast-spawning (Acropora tenuis) and a brooding (Seriatopora hystrix) coral at isolated reef systems off northwest Australia. Congruent with expectations based on life histories, levels of genetic subdivision among populations were markedly higher in the brooder than in the broadcast spawner. Additionally, significant subdivision for both species between systems (>100 km), and between (>10 km) or within reefs (<10 km) within systems, indicated that many reefs or reef patches are demographically independent. There was also a clear distinction in the scale of genetic structure between the different systems; at the more geographically complex of the systems, a much finer scale structure was detected in both species. This suggested that the hydrodynamics associated with these complex reefs restrict distances regularly traveled by larvae. The primary implication is that short-term recovery of these coral communities after severe disturbance requires the input of larvae from viable communities kilometers to a few tens of kilometers away. Therefore, to be self-sustaining, we suggest that coral reef protected areas need to be large enough to encompass these routine dispersal distances. Further, to facilitate recovery from severe disturbances, protected areas need to be replicated over these spatial scales. However, specific designs also need to account for size, complexity, and isolation of reefs, which will either restrict or enhance dispersal within this range.
Data from: Role of sex and migration in adaptation to sink environments
- 负责人：
- DOI：
- doi:10.5061/dryad.s42n1
- 摘要：
- Understanding the effects of sex and migration on adaptation to novel environments remains a key problem in evolutionary biology. Using a single-cell alga Chlamydomonas reinhardtii, we investigated how sex and migration affected rates of evolutionary rescue in a sink environment, and subsequent changes in fitness following evolutionary rescue. We show that sex and migration affect both the rate of evolutionary rescue and subsequent adaptation. However, their combined effects change as the populations adapt to a sink habitat. Both sex and migration independently increased rates of evolutionary rescue, but the effect of sex on subsequent fitness improvements, following initial rescue, changed with migration, as sex was beneficial in the absence of migration but constraining adaptation when combined with migration. These results suggest that sex and migration are beneficial during the initial stages of adaptation, but can become detrimental as the population adapts to its environment.
Data from: The effect of depressive symptoms on cognition in patients with fibromyalgia
- 负责人：
- DOI：
- doi:10.5061/dryad.s47rq
- 摘要：
- Background: Fibromyalgia (FM) patients frequently complain of cognitive problems, but it remains unclear whether these cognitive complaints can be attributed to a dysfunction of the central nervous system or if they can be explained by other factors associated with the disease, such as depression, anxiety and sleep dysfunction. Methods: One hundred and ten patients with FM were compared with thirty-three patients diagnosed with a depressive disorder (DD) and fifty healthy controls (HC). Several measures of attention and executive functions were used to make these comparisons and the patients were also asked to complete questionnaires on depression, anxiety and sleep quality. Univariate analyses of covariance (ANCOVA) were performed to identify and control confounders and multiple linear models were used to examine the effects of fibromyalgia and depression on cognitive measures. Results: FM and HC differed significantly with respect to depression, anxiety and sleep dysfunction, whereas FM and DD did not differ in terms of symptoms of depression and anxiety. However, FM was associated with a worse quality of sleep than DD. Comparisons of cognitive performance between groups showed that short-term and working memory and inattention measures were only associated with symptoms of depression, whereas selective attention was associated with both depression and fibromyalgia, and processing speed, cognitive flexibility and inhibitory control showed a significant interaction between depression and fibromyalgia. Moreover, cognitive flexibility and inhibition abilities were specifically associated with FM. Conclusion: FM patients show a cluster of cognitive impairment in the attentional and executive domains, although some of the symptoms observed could be explained by the severity of the symptoms of depression, while others seem to depend on the effects of fibromyalgia. Implications of the findings for the understanding and management of cognitive impairment of FM patients are discussed.
Data from: Simultaneous estimation of occupancy and detection probabilities an illustration using Cincinnatian brachiopods
- 负责人：
- DOI：
- doi:10.5061/dryad.s4h53
- 摘要：
- Preservation in the fossil record is never perfect in the sense that we cannot sample all individuals of a given population in time and space. Incomplete detection (i.e., preservation and modern-day sampling of fossils) often affects estimates of other paleobiological parameters of interest, such as occupancy and turnover. Here, I simultaneously model the occupancy and detection probability of taxa, teasing apart the zeros in data that reflect true absences and those that imply non-detection of taxa that were actually present in the space and time of interest. Occupancy modeling, an approach first developed in population ecology, can easily incorporate covariates of interest, such as sampling effort and habitat variables. I use a data set of brachiopod taxa from the Paleozoic to illustrate the utility of this approach for paleontological questions. I demonstrate a range of models, including those that allow colonization between time intervals and those that incorporate facies as site covariates. I also suggest how future data collection can be improved so that process- and sampling-oriented approaches such as occupancy modeling can be applied with ease to paleobiological settings to answer important paleoecological and evolutionary questions.
Data from: Transgenerational effects and the cost of ant tending in aphids
- 负责人：
- DOI：
- doi:10.5061/dryad.s4s2b
- 摘要：
- In mutualistic interactions, partners obtain a net benefit, but there may also be costs associated with the provision of benefits for a partner. The question of whether aphids suffer such costs when attended by ants has been raised in previous work. Transgenerational effects, where offspring phenotypes are adjusted based on maternal influences, could be important in the mutualistic interaction between aphids and ants, in particular because aphids have telescoping generations where two offspring generations can be present in a mature aphid. We investigated the immediate and transgenerational influence of ant tending on aphid life history and reproduction by observing the interaction between the facultative myrmecophile Aphis fabae and the ant Lasius niger over 13 aphid generations in the laboratory. We found that the effect of ant tending changes dynamically over successive aphid generations after the start of tending. Initially, total aphid colony weight, aphid adult weight and aphid embryo size decreased compared with untended aphids, consistent with a cost of ant association, but these differences disappeared within four generations of interaction. We conclude that transgenerational effects are important in the aphid–ant interactions and that the costs for aphids of being tended by ants can vary over generations.
Data from: Bats (Chiroptera: Noctilionoidea) challenge a recent origin of extant neotropical diversity
- 负责人：
- DOI：
- doi:10.5061/dryad.s533p
- 摘要：
- The mechanisms underlying the high extant biodiversity in the Neotropics have been controversial since the 19th century. Support for the influence of period-specific changes on diversification often rests on detecting more speciation events during a particular period. The timing of speciation events may reflect the influence of incomplete taxon sampling, protracted speciation, and null processes of lineage accumulation. Here we assess the influence of these factors on the timing of speciation with new multilocus data for New World noctilionoid bats (Chiroptera: Noctilionoidea). Biogeographic analyses revealed the importance of the Neotropics in noctilionoid diversification, and the critical role of dispersal. We detected no shift in speciation rate associated with the Quaternary or pre-Quaternary periods, and instead found an increase in speciation linked to the evolution of the subfamily Stenodermatinae (?18 Ma). Simulations modeling constant speciation and extinction rates for the phylogeny systematically showed more speciation events in the Quaternary. Since recording more divergence events in the Quaternary can result from lineage accumulation, the age of extant sister species cannot be interpreted as supporting higher speciation rates during this period. Instead, analyzing the factors that influence speciation requires modeling lineage-specific traits and environmental, spatial, and ecological drivers of speciation.
Data from: Incorporating animal spatial memory in step selection functions
- 负责人：
- 关键词：
- animal movement Biased Brownian Bridge kernel estimation cognitive maps GPS-tracking habitat selection spatial memory
- DOI：
- doi:10.5061/dryad.s5812
- 摘要：
- Memory is among the most important and neglected forces that shapes animal movement patterns. Research on the movement-memory interface is crucial to understand how animals use spatial learning to navigate across space because memory-biased navigation is directly linked to animals’ space use and home range behaviour; however, because memory cannot be measured directly, it is difficult to account for. Here, we incorporated spatial memory into Step Selection Functions (SSF) to understand how resource selection and spatial memory affect space use of feral hogs (Sus scrofa). We used Biased Random Bridge kernel estimates linked to residence time as a surrogate for memory and tested four conceptually different dynamic maps of spatial memory. We applied this memory-based SSF to a data set of hog relocations to evaluate the importance of land cover type, time of day, and spatial memory on the animals’ space use. Our approach has shown how the incorporation of spatial memory into animal movement models can improve estimates of habitat selection. Memory-based SSF provided a feasible way to gain insight into how animals use spatial learning to guide their movement decisions. We found that while hogs selected forested areas and water bodies and avoided grasslands during the day (primarily at noon), they had a strong tendency to select previously visited areas, mainly those held in recent memory. Beyond actively updating their memory with recent experiences, hogs were able to discriminate among spatial memories encoded at different circadian phases of their activity. Even though hogs are thought to have long memory retention, they likely relied on recent experiences because the local food resources are quickly depleted and slowly renewed, yielding an uncertain spatial distribution of resources.
Data from: Agonist-specific voltage-dependent gating of lysosomal Two-Pore Na + Channels
- 负责人：
- DOI：
- doi:10.5061/dryad.s5f6j9h
- 摘要：
- Mammalian Two-Pore-Channels (TPC1, 2; TPCN1, TPCN2) are ubiquitously-expressed cation channels in the endosomes and lysosomes that regulate luminal pH homeostasis, membrane trafficking, and Ebola viral infection. Lysosomal patch-clamp studies and high-resolution structural determinations have demonstrated that TPCs are Na+-selective channels activated by lysosome-localized PI(3,5)P2. Whereas the channel activity of TPC1 is strongly dependent on membrane voltage, TPC2 lacks such voltage dependence despite the presence of several positively-charged amino acid (AA) residues in the presumed “S4 voltage-sensing” domains. By performing a Ca2+-imaging-based high-throughput screening followed by lysosomal electrophysiology, here we identified a class of tri-cyclic anti-depressants (TCAs) as small-molecule agonists of TPC channels. TCAs activate both TPC1 and TPC2 in a voltage-dependent manner, so we refer to them as Lysosomal Na+ channel Voltage-dependent Activators (LyNa-VAs). We also identified another compound which, like PI(3,5)P2, activates TPC2 independent of voltage, suggesting the existence of agonist-specific gating mechanisms. Our identification of small-molecule TPC agonists should facilitate the studies of the cell biological roles of TPCs, and can also readily explain the reported effects of TCAs in the modulation of autophagy and lysosomal function.
Data from: Nutrient regulation strategies differ between cricket morphs that trade-off dispersal and reproduction
- 负责人：
- DOI：
- doi:10.5061/dryad.rt950
- 摘要：
- 1. Nutrient regulation should covary with life history, but actual demonstrations of this connection are rare. 2. Here we use a wing-polymorphic cricket, Gryllus firmus, that trades-off dispersal and reproduction; the long-winged morph with functional flight muscles (LW(f)) is adapted for dispersal at the expense of egg production, while the short-winged (SW) morph is adapted for egg production at the expense of flight. We explore the extent to which these two morphs differentially regulate macronutrient intake to best match their life history strategy. 3. In a “choice” experiment, we offered female crickets of each morph (LW(f) and SW) two nutritionally complementary foods varying in protein and digestible carbohydrate content. In a second “no-choice” experiment, we confined crickets to one of five foods, each with a different protein-carbohydrate-ratio. In both experiments, and for both morphs, we measured food intake, mass gain, and lipid concentration. 4. In the “choice” experiments, LW(f) females selected a more carbohydrate-biased diet than SW females. The two morphs gained similar total mass, but the LW morph had higher lipid concentration. 5. In the no-choice experiment, the two morphs practiced different nutrient “consumption rules.” SW females ate similar total nutrient amounts (protein plus carbohydrate) across diets, while LW(f) females decreased intake as the protein-carbohydrate ratio of the available food became increasingly imbalanced. Overall mass gain was marginally higher in the SW morph, and lowest on the diets that were extremely carbohydrate-biased. LW(f) and SW females had similar lipid concentrations across the diets, even though LW(f) crickets ate less carbohydrate on the two carbohydrate-biased diets. Our data suggest that for LW(f) females there are costs of overeating nutrients in excess of requirements, but they are efficient at utilizing ingested nutrients. 6. Our results shed new light on how the nutritional environment interacts with the direct trade-off between dispersal and reproduction occurring in adult G. firmus crickets. Dispersal is linked to heightened diet selectivity and an emphasis on nutrients promoting flight fuel (lipid) storage over protein acquisition for egg-laying, such that nutritional regulation complements the metabolic mechanisms that generate this trade-off.
