Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
12,683
datasets available to search
ShareScore release 0.9.0
Dataset results
12,683 results for “tolerability”
Data from: Overyielding in young tree plantations is driven by local complementarity and selection effects related to shade tolerance
1. Overyielding in mixed-species forests has been demonstrated in a vast body of literature, and the focus of functional biodiversity research is now shifting towards a mechanistic understanding of these observations. 2. We explored diversity-productivity relationships (DPRs) at two sites of a large-scale tree diversity experiment, with benign (Zed) and harsh (Ged) environmental conditions for plantation establishment. Additive partitioning methodologies were adopted to detect phenomenological patterns in the productivity data, and the trait structure of mixed communities was used to advance insights into compositional effects. 3. After six years of plantation development, biomass productivity was significantly higher in mixtures compared to the monocultures of component species. We observed that processes operated through direct tree-tree interactions, since the diversity signal disappeared where trees in mixed stands were surrounded by conspecific neighbors only. This result is particularly relevant for mixed-species planation systems, as trees are commonly planted in monospecific patches to simplify the management. Partitioning unveiled strong selection effects at both plantation sites. However, at the Ged-site this was caused by competitive dominance of species with fast young growth whereas at the Zed-site, species with slow young growth improved their performances but not at the expense of others (i.e. trait-dependent complementarity). Species tolerance to shading is an influential trait to predict biodiversity effects, with community-weighted means in shade tolerance mediating dominance effects (Ged) and functional diversity in shade tolerance mediating (trait-dependent) complementarity effects (Zed). 4. Synthesis. This study highlights that biodiversity effects in young tree plantations could be explained by the functional composition of mixed communities, with a key role for species levels of shade tolerance. As contrasting results between plantation sites were observed, future research should target the context-dependency of DPRs.
Data from: Elucidating the role of genetic drift and natural selection in cork oak differentiation regarding drought tolerance
Drought is the main selection agent in Mediterranean ecosystems and it is been suggested as an important evolutionary force responsible for population diversification in these environments. However, population divergence in quantitative traits can be driven by either directional natural selection, genetic drift or both. To investigate the roles of these forces on among-population divergence in ecophysiological traits related to drought tolerance (Δ13C, SLA, leaf size, Nmass), we compared molecular and quantitative genetic differentiation among thirteen cork oak (Quercus suber L.) populations spanning over a gradient of rainfall and temperature. Population differentiation for height, specific leaf area and leaf nitrogen content far exceeded the molecular differentiation measured by six nuclear microsatellites and was associated with the climatic gradient in among-year rainfall variation. These results suggest (1) these traits are subjected to directional selection and (2) the genetic differences among populations are partly due to adaptation to the rainfall unpredictability at the place of origin. By contrast, the low among population divergence found in stem diameter, annual growth and carbon isotopic discrimination (a surrogate for water use efficiency) and the weak association with the environmental gradient suggest low or no directional selection on these traits under dry conditions. Among-population differentiation for neutral markers was not a good predictor for differentiation regarding the quantitative traits studied here, but for leaf size. The observed correlation between the genetic differentiation for leaf size and that for molecular markers was exclusively due to the association between leaf size and microsatellite QpZAG46, which suggests a possible linkage between microsatellite QpZAG46 and genes encoding for leaf size.
Data from: Hotter nests produce hatchling lizards with lower thermal tolerance
In many regions, the frequency and duration of summer heatwaves is predicted to increase in future. Hotter summers could result in higher temperatures inside lizard nests, potentially exposing embryos to thermally stressful conditions during development. Potentially, developmentally plastic shifts in thermal tolerance could allow lizards to adapt to climate warming. To determine how higher nest temperatures affect the thermal tolerance of hatchling geckos, we incubated eggs of the rock-dwelling velvet gecko, Amalosia lesueurii, at two fluctuating temperature regimes to mimic current nest temperatures (mean 23.2°C, range 10–33°C, 'cold') and future nest temperatures (mean 27.0°C, range 14–37°C, 'hot'). Hatchlings from the hot incubation group hatched 27 days earlier and had a lower critical thermal maximum (CTmax 38.7°C) and a higher critical thermal minimum (CTmin 6.2°C) than hatchlings from cold incubation group (40.2 and 5.7°C, respectively). In the field, hatchlings typically settle under rocks near communal nests. During the hatching period, rock temperatures ranged from 13 to 59°C, and regularly exceeded the CTmax of both hot- and cold-incubated hatchlings. Because rock temperatures were so high, the heat tolerance of lizards had little effect on their ability to exploit rocks as retreat sites. Instead, the timing of hatching dictated whether lizards could exploit rocks as retreat sites; that is, cold-incubated lizards that hatched later encountered less thermally stressful environments than earlier hatching hot-incubated lizards. In conclusion, we found no evidence that CTmax can shift upwards in response to higher incubation temperatures, suggesting that hotter summers may increase the vulnerability of lizards to climate warming.
Data from: Individual variation in whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance in a marine teleost
Hypoxia is a pervasive problem in coastal environments and is predicted to have enduring impacts on aquatic ecosystems. Intraspecific variation in hypoxia tolerance is well documented in fish; however, the factors underlying this variation remain unknown. Here, we investigate the role of the heart in individual hypoxia tolerance of the European sea bass (Dicentrarchus labrax). We found individual whole-animal hypoxia tolerance is a stable trait in sea bass for more than 18 months (duration of study). We next examined in vitro cardiac performance and found myocardial muscle from hypoxia-tolerant individuals generated greater force, with higher rates of contraction and relaxation, than hypoxic-sensitive individuals during hypoxic exposure. Thus, whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance. As the occurrence of aquatic hypoxia is expected to increase in marine ecosystems, our experimental data suggest that cardiac performance may influence fish survival and distribution.
Data from: Tolerance and overcompensation to infection by Phytophthora infestans in the wild perennial climber Solanum dulcamara
Studies of infection by Phytophthora infestans—the causal agent of potato late blight—in wild species can provide novel insights into plant defense responses, and indicate how wild plants might be influenced by recurrent epidemics in agricultural fields. In the present study, our aim was to investigate if different clones of Solanum dulcamara (a relative of potato) collected in the wild differ in resistance and tolerance to infection by a common European isolate of P. infestans. We performed infection experiments with six S. dulcamara genotypes (clones) both in the laboratory and in the field and measured the degree of infection and plant performance traits. In the laboratory, the six evaluated genotypes varied from resistant to susceptible, as measured by degree of infection 20 days post infection. Two of the four genotypes susceptible to infection showed a quadratic (concave downward) relationship between the degree of infection and shoot length, with maximum shoot length at intermediate values of infection. This result suggests overcompensation, that is, an increase in growth in infected individuals. The number of leaves decreased with increasing degree of infection, but at different rates in the four susceptible genotypes, indicating genetic variation for tolerance. In the field, the inoculated genotypes did not show any disease symptoms, but plant biomass at the end of the growing season was higher for inoculated plants than for controls, in‐line with the overcompensation detected in the laboratory. We conclude that in S. dulcamara there are indications of genetic variation for both resistance and tolerance to P. infestans infection. Moreover, some genotypes displayed overcompensation. Learning about plant tolerance and overcompensation to infection by pathogens can help broaden our understanding of plant defense in natural populations and help develop more sustainable plant protection strategies for economically important crop diseases.
Data from: A conifer–angiosperm divergence in the growth vs shade tolerance trade-off underlies the dynamics of a New Zealand warm-temperate rain forest
1. A central tenet of forest ecology is that succession and regeneration dynamics are driven by an interspecific trade-off between juvenile growth rates in high light and shade tolerance. There is evidence, however, that a single trade-off axis may fail to explain the dynamics of mixed conifer-angiosperm rainforests in the southern hemisphere, especially in New Zealand. 2. We tested for growth vs shade tolerance trade-offs by measuring juvenile growth of five podocarps and five broadleaved canopy angiosperms across a wide range of light environments in a New Zealand warm-temperate rainforest. The light compensation point of growth was used as a measure of species light requirements, which we then compared with height growth in 10% light, approximating the environments encountered beneath small tree-fall gaps. 3. Despite considerable overlap between the ranges of both growth rates and compensation points found in the two lineages, major axis tests showed that the growth vs shade tolerance trade-off differed significantly between podocarp and angiosperm species. At a common compensation point, angiosperms were faster-growing than podocarps in 10% light. However, juveniles of these angiosperm species were notably scarce in the more open environments associated with forest margins. 4. Synthesis. A conifer–angiosperm divergence in the growth vs shade tolerance trade-off may explain long-standing problems of the dynamics of these forests. Although juveniles of most lowland podocarps can tolerate considerable shade, the more vigorous response of broadleaved angiosperms to small canopy openings enables them to out-compete podocarps in old-growth stands. The greater abundance of podocarp juveniles on forest margins cannot be attributed to them outcompeting angiosperm species where light is abundant, and is likely to reflect superior resistance to frost and/or drought. The drivers of the dynamics of New Zealand's podocarp–broadleaved forests therefore differ appreciably from those ascribed to tropical and north-temperate forests.
Data from: Costs and tradeoffs of resistance and tolerance to belowground herbivory in potato
1. The success of sustainable crop production depends on our ability to select or create varieties that can allocate resources to both growth and defence. However, breeding efforts have emphasized increases in yields but have partially neglected defence traits against pests. Estimating the costs of multiple defences against tuber herbivores and the tradeoffs among them, as well as understanding the relationship between yield and multiple defences is still unknown but relevant to both basic and applied ecology. 2. Using twenty commercial potato varieties available in Colombia and the tuber herbivore Tecia solanivora, we tested whether high yielding varieties show a reduction in three types of defence: constitutive and induced resistance, as well as tolerance. Specifically, we determined (1) the costs in terms of yield of all three defences, (2) the possible tradeoffs among them, and (3) if oviposition preference was related to the expression of these defences. 3. We detected no costs in terms of yield of constitutive and induced resistance to tuber damage. We did, however, find evidence of costs of being able to tolerate tuber herbivory. While we found no tradeoffs among any of the estimated defences, there was a positive correlation between aboveground compensatory growth and tolerance in terms of tuber production, suggesting that after damage there are no shifts in the allocation of resources from aboveground to belowground biomass. Finally, we found that females laid more eggs on those varieties with the lowest level of constitutive resistance. 4. Synthesis and applications. Our findings suggest that in potatoes, breeding for higher yields has not caused any reduction in constitutive or induced resistance to tuber damage. This is not the case for tolerance where those varieties with higher yields are also less likely to tolerate tuber damage. Given the high incidence of tuber pests in Colombia, selecting for higher tolerance could allow for high productivity in the presence of herbivores. Finding mechanisms to decouple the tolerance response from yield should be a new priority in potato breeding in Colombia to guarantee a higher yield in both the presence and absence of herbivores.
Data from: Competitive reversal between plant species is driven by species-specific tolerance to flooding stress and nutrient acquisition during early marsh succession
1. Understanding plant species interactions along successional trajectories are critical for managing and restoring ecosystems, as both resource availability and abiotic stresses change over time to affect competitive outcomes and species distributions. Newly created ecosystems experience a succession of plants species and rapid changes in resource availability, which may influence the outcome of biotic interactions. How these biotic interactions vary along abiotic gradients in early successional systems is not well understood. 2. Here, we tested the hypothesis that species-specific tolerances to flooding would influence their relative ability to capture resources (i.e., nutrients) and affect competition intensity between pioneer and secondary successional species in an early successional created tidal marsh. We transplanted a competitively dominant higher marsh species, Spartina patens, across an elevation gradient within and outside of clones of a pioneer stress-tolerant low marsh species, Spartina alterniflora. 3. Within six months, Spartina alterniflora had suppressed the stature and growth of S. patens; however, the magnitude of this competitive effect increased at lower marsh elevations where S. alterniflora was more efficient at capturing available nitrogen (N). In unvegetated areas, where S. patens vigor was high, the amount of available N was approximately 40 times greater than within S. alterniflora clones. 4. Synthesis and applications. Our results demonstrate that competition intensity of the stress-tolerant species over the competitive species depended on relative resource capture in response to abiotic stress. Managing for specific vegetation communities in marsh restoration, therefore, requires insight into these relationships and interactions. Specifically, marsh restoration in high nutrient environments will limit the succession to high density competitive species due to competition with stress-tolerant pioneer species, particularly at lower elevations.
Data from: Annual environmental variation influences host tolerance to parasites
When confronted with a parasite or pathogen, hosts can defend themselves by resisting or tolerating the attack. While resistance can be diminished when resources are limited, it is unclear how robust tolerance is to changes in environmental conditions. Here we investigate the sensitivity of tolerance in a single host population living in a highly variable environment. We manipulated the abundance of an invasive parasitic fly, Philornis downsi, in nests of Galápagos mockingbirds (Mimus parvulus) over four field seasons and measured host fitness in response to parasitism. Mockingbird tolerance to P. downsi varied significantly among years and decreased when rainfall was limited. Video observations indicate that parental provisioning of nestlings appears key to tolerance: in drought years, mockingbirds likely do not have sufficient resources to compensate for the effects of P. downsi. These results indicate that host tolerance is a labile trait and suggest that environmental variation plays a major role in mediating the consequences of host-parasite interactions.
Data from: Parental environmental effects due to contrasting watering adapt competitive ability, but not drought tolerance, in offspring of a semi-arid annual Brassicaceae
1. Parental effects (PE) can be adaptive and improve offspring performance when parents and offspring experience similar environmental conditions. However, it is unknown whether adaptive PE exist also in habitats where such similarity is unlikely due to strong temporal variation. In particular, we do not know whether PE can adapt offspring to fluctuating levels of neighbour competition in such habitats. 2. Here, we tested for adaptive PE in terms of two key environmental factors in a semi-arid annual system, competition and drought. While rainfall was stochastic in the study site, the competitive environment was partly predictable: higher plant densities followed after favourable (rainy) years due to high seed production. We therefore expected PE to adapt the offspring's competitive ability to these (predictable) fluctuations in plant densities, rather than to adapt the offspring's drought tolerance to the (unpredictable) occurrence of intensified drought. 3. Parental plants of Biscutella didyma, an annual Brassicaceae, were raised under favourable watering and under drought conditions. Offspring performance was then tested under a full-factorial combination of two neighbour regimes and six watering levels in the glasshouse. 4. Offspring of parents grown under favourable conditions were stronger competitors. This was associated with a small shift in phenology but not with higher parental seed provisioning. Offspring from parents grown under drought showed no improved drought tolerance. Moreover, no PE were detectable when offspring were grown without neighbours. 5. Our results suggest a novel path of adaptive PE: higher competitive ability was induced in offspring that were more likely to experience high neighbour densities. Together with the lack of adaptive PE towards drought tolerance, this emphasizes that a correlation between parental and offspring environment is crucial for adaptive PE to evolve. Our results also call for the inclusion of competitive effects in future PE studies. 6. Synthesis. This study demonstrates the important role of adaptive PE for plant fitness (regarding competition) but also their limits (regarding drought) in temporally variable environments, based on the predictability of the respective environmental factor.
Data from: Potential fitness tradeoffs for thermal tolerance in the intertidal copepod Tigriopus californicus
Thermal adaptation to spatially varying environmental conditions occurs in a wide range of species, but what is less clear is the nature of fitness trade-offs associated with this temperature adaptation. Here, populations of the intertidal copepod Tigriopus californicus are examined at both local and latitudinal scales to determine whether these populations have evolved differences in their survival under high temperature stress. A clear pattern of increasing high temperature stress tolerance is seen with decreasing latitude, consistent with temperature adaptation. Additionally, there is also evidence for significant variation in thermal tolerance on a smaller scale. The competitive fitness of pairs of northern and southern copepod populations were also examined under a series of lower, more moderate temperatures. These fitness assays show that the southern populations that have the best survival under extreme high temperatures have lowered competitive fitness at the lower temperatures tested, whereas the fitness of the southern populations exceeded that of the northern populations at the highest temperatures tested. Combined, these results suggest that there may be evolutionary trade-offs between performance at high and stressful temperatures and fitness at moderate temperatures in this species.
Data from: Evolution of thermal tolerance and its fitness consequences: parallel and non-parallel responses to urban heat islands across three cities
The question of parallel evolution—what causes it, and how common it is—has long captured the interest of evolutionary biologists. Widespread urban development over the last century has driven rapid evolutionary responses on contemporary timescales, presenting a unique opportunity to test the predictability and parallelism of evolutionary change. Here we examine rapid urban evolution in an acorn-dwelling ant species, focusing on the urban heat island signal and the ant's tolerance of these altered urban temperature regimes. Using a common-garden experimental design with acorn ant colonies collected from urban and rural populations in three cities and reared under five temperature treatments in the laboratory, we assessed plastic and evolutionary shifts in the heat and cold tolerance of F1 offspring worker ants. In two of three cities, we found evolved losses of cold tolerance, and compression of thermal tolerance breadth. Results for heat tolerance were more complex: in one city, we found evidence of simple evolved shifts in heat tolerance in urban populations, though in another, the difference in urban and rural population heat tolerance depended on laboratory rearing temperature, and only became weakly apparent at the warmest rearing temperatures. The shifts in tolerance appeared to be adaptive, as our analysis of the fitness consequences of warming revealed that while urban populations produced more sexual reproductives under warmer laboratory rearing temperatures, rural populations produced fewer. Patterns of natural selection on thermal tolerances supported our findings of fitness tradeoffs and local adaptation across urban and rural acorn ant populations, as selection on thermal tolerance acted in opposite directions between the warmest and coldest rearing temperatures. Our study provides mixed support for parallel evolution of thermal tolerance under urban temperature rise.
Data from: Oligocene niche shift, Miocene diversification - cold tolerance and accelerated speciation rates in the St. John's Worts (Hypericum, Hypericaceae)
Background: Our aim is to understand the evolution of species-rich plant groups that shifted from tropical into cold/temperate biomes. It is well known that climate affects evolutionary processes, such as how fast species diversify, species range shifts, and species distributions. Many plant lineages may have gone extinct in the Northern Hemisphere due to Late Eocene climate cooling, while some tropical lineages may have adapted to temperate conditions and radiated; the hyper-diverse and geographically widespread genus Hypericum is one of these. Results:To investigate the effect of macroecological niche shifts on evolutionary success we combine historical biogeography with analyses of diversification dynamics and climatic niche shifts in a phylogenetic framework. Hypericum evolved cold tolerance c. 30 million years ago, and successfully colonized all ice-free continents, where today ~500 species exist. The other members of Hypericaceae stayed in their tropical habitats and evolved into ~120 species. We identified a 15–20 million year lag between the initial change in temperature preference in Hypericum and subsequent diversification rate shifts in the Miocene. Conclusions:Contrary to the dramatic niche shift early in the evolution of Hypericum most extant species occur in temperate climates including high elevations in the tropics. These cold/temperate niches are a distinctive characteristic of Hypericum. We conclude that the initial release from an evolutionary constraint (from tropical to temperate climates) is an important novelty in Hypericum. However, the initial shift in the adaptive landscape into colder climates appears to be a precondition, and may not be directly related to increased diversification rates. Instead, subsequent events of mountain formation and further climate cooling may better explain distribution patterns and species-richness in Hypericum. These findings exemplify important macroevolutionary patterns of plant diversification during large-scale global climate change.
Data from: Temporally autocorrelated environmental fluctuations inhibit the evolution of stress tolerance
As global environmental conditions continue to change at an unprecedented rate many species will experience increases in natural and anthropogenic stress. Generally speaking, selection is expected to favor adaptations that reduce the negative impact of environmental stress (i.e., stress tolerance). However, natural environmental variables typically fluctuate, exhibiting various degrees of temporal autocorrelation, known as environmental 'colors,' which may complicate evolutionary responses to stress. Here we combine experiments and theory to show that temporal environmental autocorrelation can determine long-term evolutionary responses to stress, without affecting the total amount of stress experienced over time. Experimental evolution of RNA virus lineages in differing environmental autocorrelation treatments agreed closely with predictions from our theoretical models that stress tolerance is favored in less autocorrelated (whiter) environments but disfavored in more autocorrelated ('redder)ned' environments. This is explained by an interaction between environmental color autocorrelation and a phenotypic tradeoff between stress tolerance and reproductive ability. The degree to which environmental color autocorrelation influences evolutionary trajectories depends on the shape of this tradeoff as well as the relative level of tolerance exhibited by novel mutants. These results suggest that long-term evolutionary dynamics depend not only on the overall strength of selection, but also on the way that selection is distributed over time.
Data from: Maternal allocation of carotenoids increases tolerance to bacterial infection in brown trout
Life-history theory predicts that iteroparous females allocate their resources differently among different breeding seasons depending on their residual reproductive value. In iteroparous salmonids there is typically much variation in egg size, egg number, and in the compounds that females allocate to their clutch. These compounds include various carotenoids whose functions are not sufficiently understood yet. We sampled 37 female and 35 male brown trout from natural streams, collected their gametes for in vitro fertilizations, experimentally produced 185 families in 7 full-factorial breeding blocks, raised the developing embryos singly (n = 2960), and either sham-treated or infected them with Pseudomonas fluorescens. We used female redness (as a measure of carotenoids stored in the skin) and their allocation of carotenoids to clutches to infer maternal strategies. Astaxanthin contents largely determined egg colour. Neither egg weight nor female size was correlated with the content of this carotenoid. However, astaxanthin content was positively correlated with larval growth and with tolerance against P. fluorescens. There was a negative correlation between female skin redness and the carotenoid content of their eggs. Although higher astaxanthin contents in the eggs were associated with an improvement of early fitness-related traits, some females appeared not to maximally support their current offspring as revealed by the negative correlation between female red skin colouration and egg carotenoid content. This correlation was not explained by female size and supports the prediction of a maternal trade-off between current and future reproduction.
Data from: Experimental evaluation of the robustness of the growth-stress tolerance trade-off within the perennial grass Dactylis glomerata
1. A core tenet of functional ecology is that the vast phenotypic diversity observed in the plant kingdom could be partly generated by a trade- off between the ability of plants to grow quickly and acquire resources in rich environments vs. the ability to conserve resources and avoid mortality under stress. However, experimental demonstrations remain scarce and potentially blurred by phylogenetic constraints in cross-species analyses. Here we experimentally decoupled growth potential and stress survival by applying an off-season stress on contrasting populations of the perennial grass Dactylis glomerata exhibiting a range of seasonal dormancy. 2. Seventeen populations of D. glomerata, originating from a latitudinal gradient from Norway to Morocco, were subjected to three types of dehydration stress: winter frost in Norway, summer drought, and early spring (off-season) drought stress in the south of France. Growth rate, and two leaf traits (leaf width and leaf dry matter content) suspected to be involved in the adaptation to dehydration stress, were monitored under optimal conditions. We quantified plant dehydration survival as the amount of plant recovery after a severe stress. 3. Nordic populations were found to be winter dormant. Winter and summer dormant populations better survived frost and summer drought, respectively. However, no trade-off between growth potential and dehydration survival was detected in non-dormant plants in early spring when dehydration occurred unseasonably for all populations. Furthermore, Mediterranean populations better survived an early spring drought. 4. Our results highlight the importance of assessing plant growth potential as a response to seasonal environmental cues. They suggest that growth potential and stress survival trade-off when plants exhibit seasonal dormancy but can be functionally independent at other seasons. Consequently, the growth-stress survival relationship could be better described as a dynamic linkage rather than a constant and general trade-off. Moreover, leaf trait values, such as thinner and more lignified leaves reflecting drought adaptation, may have contributed to the improved drought-stress survival without resulting in a cost to growth. 5. Further exploration of the growth-stress survival relationship should permit deciphering the suite of plant traits and trait covariations involved in plants' responses to increasing stress.
Data from: Thermal tolerance patterns across latitude and elevation
Linking variation in species' traits to large-scale environmental gradients can lend insight into the evolutionary processes that have shaped functional diversity and future responses to environmental change. Here, we ask how heat and cold tolerance vary as a function of latitude, elevation and climate extremes, using an extensive global dataset of ectotherm and endotherm thermal tolerance limits, while accounting for methodological variation in acclimation temperature, ramping rate and duration of exposure among studies. We show that previously reported relationships between thermal limits and latitude in ectotherms are robust to variation in methods. Heat tolerance of terrestrial ectotherms declined marginally towards higher latitudes and did not vary with elevation, whereas heat tolerance of freshwater and marine ectotherms declined more steeply with latitude. By contrast, cold tolerance limits declined steeply with latitude in marine, intertidal, freshwater and terrestrial ectotherms, and towards higher elevations on land. In all realms, both upper and lower thermal tolerance limits increased with extreme daily temperature, suggesting that different experienced climate extremes across realms explain the patterns, as predicted under the Climate Extremes Hypothesis. Statistically accounting for methodological variation in acclimation temperature, ramping rate and exposure duration improved model fits, and increased slopes with extreme ambient temperature. Our results suggest that fundamentally different patterns of thermal limits found among the earth's realms may be largely explained by differences in episodic thermal extremes among realms, updating global macrophysiological 'rules'.
Data from: Population structure, genetic variation and linkage disequilibrium in perennial ryegrass populations divergently selected for freezing tolerance
Low temperature is one of the abiotic stresses seriously affecting the growth of perennial ryegrass (Lolium perenne L. Understanding the genetic control of freezing tolerance would aid in the development of cultivars of perennial ryegrass with improved adaptation to frost. A total number of 80 individuals (24 of High frost [HF]; 29 of Low frost [LF] and 27 of Unselected [US]) from the second generation of the two divergently selected populations and an unselected control population were genotyped using 278 genome-wide SNPs derived from Lolium perenne L. transcriptome sequence. Our studies showed that the HF and LF populations are very divergent after selection for freezing tolerance, whereas the HF and US populations are more similar. Linkage disequilibrium (LD) decay varied across the seven chromosomes and the conspicuous pattern of LD between the HF and LF population confirmed their divergence in freezing tolerance. Furthermore, two Fst outlier methods; finite island model (fdist) by LOSITAN and hierarchical structure model using ARLEQUIN detected six loci under directional selection. These outlier loci are most probably linked to genes involved in freezing tolerance, cold adaptation and abiotic stress and might be the potential marker resources for breeding perennial ryegrass cultivars with improved freezing tolerance.
Data from: Adaptive differences in gene expression associated with heavy metal tolerance in the soil arthropod Orchesella cincta
Field-selected tolerance to heavy metals has been reported for Orchesella cincta (Arthropoda: Collembola) populations occurring at metal-contaminated mining sites. This tolerance is correlated with heritable increase of metal excretion efficiency; less pronounced cadmium (Cd) induced growth reduction and, over-expression of the metallothionein gene. We applied transcriptomics to determine differential gene expression caused by this abiotic stress in reference and Cd tolerant populations. Many cDNAs responded to Cd exposure in the reference population. Significantly fewer clones were Cd responsive in tolerant animals. Analysis of variance revealed transcripts that interact between Cd exposure and population. Hierarchical cluster analysis of these clones identified two major groups. The first one contained cDNAs that were up regulated by Cd in the reference culture, but non-responsive or down regulated in tolerant animals. This cluster was also characterized by elevated constitutive expression in the tolerant population. Gene ontology analysis revealed that these cDNAs were involved in structural integrity of the cuticle, anti-microbial defense, calcium-channel blocking, sulfur assimilation and chromatin remodeling. The second group consisted of cDNAs down regulated in reference animals but not responding or slightly up regulated in tolerant animals. Their functions involved carbohydrate metabolic processes, Ca2+ dependent stress signaling, redox state, proteolysis and digestion. The reference population showed a strong signature of stress-induced genome-wide perturbation of gene expression, whereas the tolerant animals maintained normal gene expression upon Cd exposure. We confirmed the micro-evolutionary processes occurring in soil arthropod populations and suggest a major contribution of gene regulation to the evolution of a stress-adapted phenotype.
Using aerobic exercise to evaluate sub-lethal tolerance of acute warming in fishes
<p>We investigated whether fatigue from sustained aerobic swimming provides a sublethal endpoint to define tolerance of acute warming in fishes, as an alternative to loss of equilibrium (LOE) during a critical thermal maximum protocol (CT<sub>max</sub>). Two species were studied, Nile tilapia <i>Oreochromis niloticus</i> and pacu <i>Piaractus mesopotamicus</i>. Each fish underwent an incremental swim test to determine gait transition speed (U<sub>GT</sub>), where it first engaged the unsteady anaerobic swimming mode that preceded fatigue. After suitable recovery each fish was swum at 85% of their own U<sub>GT</sub> and warmed 1°C every 30 min, to identify the temperature at which they fatigued, denoted as CT<sub>swim</sub>. Fish were also submitted to a standard CT<sub>max</sub>, warming at the same rate as CT<sub>swim, </sub>under static conditions until LOE. All individuals fatigued in CT<sub>swim</sub>, at a mean temperature approximately 2°C lower than their CT<sub>max</sub>. Therefore, if exposed to acute warming in the wild, the ability to perform aerobic metabolic work would be constrained at temperatures significantly below those that directly threatened survival. The collapse in performance at CT<sub>swim</sub> was preceded by a gait transition qualitatively indistinguishable from that during the incremental swim test. This suggests that fatigue in CT<sub>swim</sub> was linked to an inability to meet the tissue oxygen demands of exercise plus warming. This is consistent with the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis, regarding the mechanism underlying tolerance of warming in fishes. Overall, fatigue at CT<sub>swim</sub> provides an ecologically relevant sub-lethal threshold that is more sensitive to extreme events than LOE at CT<sub>max</sub>.</p>
ScienceDex guides
Understand access before you commit
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.