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4,157 results for “Survival.”
A salivary chitinase of Varroa destructor influences host immunity and mite's survival
<p>This dataset represents raw data underlying the findings (and the figures) reported in the manuscript "<strong>A salivary chitinase of <em>Varroa destructor</em> influences host immunity and mite’s survival</strong>".</p> <p> </p> <p><strong>Fig 2A.</strong> <strong>Salivary gland expression of putative host regulation factors present found in the predicted secretome of <em>Varroa destructor</em>.</strong> (A)<strong> </strong>Relative expression data of 3 selected candidates are presented as mean fold changes of 3-4 independent biological replicates. Each replicate consisted of a pool of 5-10 mites and comprised , from which the RNA was extracted from,two samples: salivary glands (SG), and from the rest of the whole body, deprived of salivary glands (Whole Body – SG). Values on Y-axis are reported in Log<sub>10</sub> scale. Error bars represent standard error of the meandeviation (SD). Statistically significant differences are denoted with an asterisk (P < 0.005).</p> <p> </p> <p> </p> <p><strong>Fig 4.</strong> <strong>Survival of <em>Varroa. destructor</em> as affected by RNAi-mediated silencing of the gene encoding VdCHIsal. </strong>(A) Relative expression of <em>Vd-CHIsal</em> after mite soaking in a dsRNA solution. qRT-PCR data are presented as mean fold changes of 2-67 independent biological replicates. Each replicate consisted in a pool of 2-3 mites. Each time point was separately analyzed and the 0.9% NaCl 0.9% control sample was used as calibrator. Mean dCt values within each time point were compared by Student’s t-testone-way ANOVA followed by Tukey’s post-hoc test. Mean values denoted with different letters are significantly different. Error bars represent standard deviation (the standard error of the meanSD). Mean values denoted with asterisks are significantly different (*p<0.05; ** p<0.01). (B) Kaplan-Meier survival curves of mites soaked in a solution of dsRNA targeting <em>Vd-CHIsal</em>. Saline controls (0.9% NaCl), GFP dsRNA and Vd-CHIsal dsRNA soaked mites (blue rhombus, green circles and orange squares, respectively) were individually maintained on the same host pupa throughout the whole duration of the assayP. Subjects at risk were 18, 30 and 45 for 0.9% NaCl, GFP dsRNA and Vd-CHIsal dsRNA treatments, respectively. Survival curve of dsVd-CHIsal was significantly different from dsGFP (log rank test: <em>X</em><sub>2</sub>= 6.086; P=0.0136) and from NaCl 0.9 (log rank test: <em>X</em><sub>2</sub>=6.611; P=0.0101), while no difference was observed between dsGFP and NaCl 0.9% (log rank test: <em>X</em><sub>2</sub>= 0.46; P=0.49). Statistical significance was set at 0.016 (Bonferroni correction). aIn a separateconcurrent set of trials, host pupae were replaced every 24 h for both saline controls (0.9% NaCl) and Vd-CHIsal dsRNA soaked mites (violet down-pointing and red up-pointing triangles, respectively). Subjects at risk were 29 and 22 for 0.9% NaCl and Vd-CHIsal dsRNA, respectively. Host pupae were maintained throughout the feeding or replaced every 24 h. Survival curve of dsVd-CHIsal was significantly different from (log rank test: <em>X</em><sub>2</sub>= 18.21; P<0.0001), Statistical significance was set at 0.05.Statistical details are in the text. Error bars represent the standard error of the mean.</p> <p> </p> <p> </p> <p><strong>Fig 5.</strong> <strong>Differentially expressed genes in honey bee pupae artificially infested with mites delivering saliva with the full repertoire of proteins or lacking Vd-CHIsal.</strong> (A) Differential expression of 13 honey bee genes, as affected by presence of Vd-CHIsal in the saliva (KD/WS). DESeq2 adjusted <em>P</em> was < 0.05 and FDR was set at 5%. Log transformed mean FPKM values are reported on Y axis. For each Each group representsexperimental condition 3 individually analyzedseparate pupae were analyzed. Error bars represent SEMSD. Summary tables data sheets of differential expression analysis are presented in S2 and S3 Tables. (B) Relative expression of immune-related genes in honey bee pupae as affected by <em>Vd-CHIsal</em> expression in <em>Varroa destructor</em> infesting mites. Each groupmean value representsis obtained on 7-10 individually analyzed pupae, individually analyzed. Results of qRT-PCR are presented as mean fold changes relative to non-infested pupae used as calibrator. Values on Y axis are reported in Log<sub>10</sub> scale. Error bars represent standard deviation (the standard error of the meanSD). Mean values were compared by one-way ANOVA, followed by Tukey post-hoc test, and values statistically different are denoted with different letters (P<0.05). Detailed resultsDetails of statistical analyses are presented in S4 Table. NP: non-parasitized controls; WS: pupae infested with mites soaked in saline solution; KD: pupae infested with mites soaked in a solution of <em>dsRNA </em><em>Vd-CHIsal</em> dsRNA dsRNA solution.</p> <p> </p> <p><strong>S1 File. </strong>Table resulting from Trinotate in-house annotation of the putatively secreted components of<em> Varroa destructor </em>predicted proteome. The annotation was performed following the protocol described in Materials and Methods section. Content of columns is hereafter described. A: GenBank accession number of the original transcript of <em>V. destructor</em>; B: GenBank accession number of the matching protein in <em>V. destructor</em>; C: ID name assigned by Transdecoder software; D: coordinates of the translation; E: top BLASTp hits in Swiss-Prot db; F: top BLASTp hits in the database of Hymenoptera venom; G: top BLASTp hits in the database of Acarina saliva; H: Pfam hits; I,: SignalP results indicating the presence of the signal peptide; J: TMHMM results indicating the presence of transmembrane domains; K: eggnog db hits; L: Kegg db hits; M: gene ontology retrieved from BLASTp; N: gene ontology retrieved from Pfam.</p>
Data from: Mountain Plover habitat selection and nest survival in relation to weather variability and spatial attributes of Black-tailed Prairie Dog disturbance
<p>Habitat loss and altered disturbance regimes have led to declines in many species of grassland and sagebrush birds, including the imperiled Mountain Plover (<i>Charadrius montanus</i>). In certain parts of their range Mountain Plovers rely almost exclusively on Black-Tailed Prairie Dog (<i>Cynomys ludovicianus</i>) colonies as nesting habitat. Previous studies have examined Mountain Plover nest and brood survival on prairie dog colonies, but little is known about how colony size and shape influence these vital rates or patterns of habitat selection. We examined how 1) adult habitat utilization, 2) nest-site selection, and 3) nest success responded to a suite of local- and site-level variables on large prairie dog colony complexes in northeastern Wyoming. Abundance of adult Mountain Plovers was highest on points within older, "medium"-sized (100–500 ha) colonies with high cover of annual forbs and bare ground (5.8 birds/km<sup>2</sup>), but lower on extremely large (>2000 ha) colonies (2.1 birds/km<sup>2</sup>). Nest sites were characterized by high proportions of annual forbs and bare ground and low cactus cover and vegetation height. Nest survival was higher for older nests, and nests with lower cactus cover, and decreased with increasing temperatures. Uncertainty was high for models of daily nest survival, potentially because of two competing sources of nest failure: nest depredation and nest abandonment or inviability of eggs. Drivers of these two sources of nest failure differed, with inclement weather and higher temperatures associated with nest abandonment or egg inviability. We highlight how prairie dogs alter vegetation structure and bare ground heterogeneously across the landscape, and how this in turn influences bird abundance and nest distribution at different temporal and spatial scales. Furthermore, our work reveals how partitioning the causes of nest failure during nest survival analyses enhances understanding of survival rate covariates.</p>
Survival and home ranges of woodland birds in restoration plantings
<p>Woodland birds are a species assemblage of conservation concern, and their persistence in fragmented agricultural landscapes is dependent on both the preservation of existing woodland remnants and the implementation of restoration plantings. However, little is known about the habitat-use and persistence of birds in fragmented agricultural landscapes. We present a detailed, population-oriented study of woodland birds in temperate eucalypt woodland restoration plantings and remnant woodland patches in the South-west Slopes bioregion of New South Wales, Australia. First, we undertook a three-year mark-recapture project to assess annual survival and site fidelity in restoration plantings and woodland remnants. We supplemented our recapture efforts with resightings of colour-banded individuals. Second, we tracked individual birds of two species – superb fairywren (<i>Malurus cyaneus</i>) and willie wagtail (<i>Rhipidura leucophrys</i>) – and documented snapshots of their home ranges and movement patterns during the breeding season. Annual survival in the woodland bird assemblage was lower than expected (51%). Home ranges of the superb fairywren were positively correlated with patch size, and were constrained by patch edges in linear sites. Superb fairywrens and willie wagtails were more likely to travel longer distances between substrates while foraging in linear sites. Willie wagtails engaged in significant gap-crossing (up to 400 m) between adjacent habitat patches. Our findings indicate that 1) patch isolation and certain patch configurations place resident birds at an energetic disadvantage, and 2) in our study area, woodland bird populations are continuing to decline. We recommend landscape-scale restoration programs aim to address ongoing population declines. Studies such as ours conducted over longer time periods would provide a deeper understanding of habitat-use and population processes of woodland birds in fragmented agricultural landscapes.</p>
A negative association between horn length and survival in a weakly dimorphic ungulate
<p><span>While all models of sexual selection assume that the development and expression of enlarged secondary sexual traits are costly, males with larger ornaments or weapons generally show greater survival or longevity. These studies have mostly been performed in species with high sexual size dimorphism, subject to intense sexual selection. Here we examined the relationships between horn growth and several survival metrics in the weakly dimorphic Pyrenean chamois (<i>Rupicapra pyrenaica</i>). In this unhunted population living at high density, males and females were able to grow long horns without any apparent costs in terms of longevity. However, we found a negative relationship between horn growth and survival during prime age in males. This association reduces the potential evolutionary consequences of trophy hunting in male chamois. We also found that <span>females with long horns tended to have lower survival at old ages. Our results illustrate the </span>contrasting conclusions that may be drawn when different survival metrics are used in analyses. The ability to detect trade-off between the expression of male secondary sexual traits and survival may depend more on environmental conditions experienced by the population than on the strength of sexual selection.</span></p>
Influence of biological and environmental conditions on winter mortality risk of a northern ungulate: evidence for a late-winter survival bottleneck
<p><b>1.</b> A relationship between winter weather and survival of northern ungulates has long been established, yet the possible roles of biological (e.g., nutritional status) and environmental (e.g., weather) conditions make it important to determine which potential limiting factors are most influential.</p> <p><b>2</b>. Our objective was to examine the potential effects of individual (body mass and age) and extrinsic (winter severity and snow melt conditions) factors on the magnitude and timing of mortality for adult (>2.5 years old) female white-tailed deer (<i>Odocoileus virginianus </i>[Zimmerman, 1780] during February–May in the Upper Peninsula of Michigan, USA.</p> <p><b>3</b>. One hundred and fifty deer were captured and monitored during 2009–2015 in two areas with varying snowfall. February–May survival ranged from 0.24–0.89 (mean = 0.69) across years. Mortality risk increased 1.9% with each unit increase of cumulative winter severity index, decreased 8.2% with each cumulative snow free day, and decreased 4.3% with each kg increase in body mass. Age and weekly snow depth did not influence weekly deer survival. Predation, primarily from coyote (<i>Canis latrans </i>[Say, 1823]) and wolves (<i>Canis lupus </i>[L., 1758]), accounted for 78% of known-cause mortalities.</p> <p><b>4</b>. Our results suggest that cumulative winter severity, and possibly to a lesser degree deer condition entering winter, impacted deer winter survival. However, the timing of spring snow melt appeared to be the most influential factor determining late winter mortality of deer in our study. This supports the hypothesis that nutrition and energetic demands from weather conditions are both important to northern ungulate winter ecology. Under this model, a delay of several weeks in the timing of spring snow melt could exert a large influence on deer survival, resulting in a survival bottleneck.</p>
Data from: Greater sage-grouse survival varies with breeding season events in West Nile virus non-outbreak years
<p>Greater Sage-Grouse (Centrocercus urophasianus) are a species of conservation concern and are highly susceptible to mortality from West Nile virus (WNV). Culex tarsalis, a mosquito species, is the suspected primary vector for transmitting WNV to sage-grouse. We captured, radio-tagged, and monitored female sage-grouse to estimate breeding season (April 15‒September 15) survival 2016-2017. Deceased sage-grouse were tested for active WNV; live captured and hunter harvested sage-grouse were tested for WNV antibody titers. Additionally, we trapped mosquitoes with CO2 baited traps 4 nights per week (542 trap nights) to estimate WNV minimum infection rate (MIR). Eight sage-grouse mortalities occurred during the WNV seasons of 2016 and 2017; 5 had recoverable tissue, and one of 5 tested positive for WNV infection. Survival varied temporally with sage-grouse biological seasons, not WNV seasonality. Survival was 0.68 (95% CI= 0.56–0.78; n=74) during the reproductive season (April 1−September 15). Mammalian predators were the leading suspected cause of mortality (40%), followed by unknown cause (25%), avian predation (15%), unknown predation (15%), and WNV (5%). These results indicate WNV was not a significant driver of adult sage-grouse survival during this study. Three sage-grouse (1.9%; 95% CI=0.5−5.9%) contained WNV antibodies. We captured 12,472 mosquitoes of which 3,933 (32%) were Culex tarsalis. Estimated WNV MIR of Culex tarsalis during 2016 and 2017 was 3.3 and 1.6, respectively. Our results suggest sage-grouse in South Dakota have limited exposure to WNV, and WNV was not a significant source of sage-grouse mortality in South Dakota during 2016 and 2017. Based on our finding that a majority of sage-grouse in South Dakota are susceptible to WNV infection, WNV could potentially have an impact on the population during an epizootic event; however, when WNV is at or near endemic levels, it appears to have little impact on sage-grouse<br> survival. </p>
Caterpillar survival in the city: Attack rates on model lepidopteran larvae along an urban-rural gradient show no increase in predation with increasing urban intensity (Raw Data)
<p><span><span><span><span><span><span><span><span><span><span><span>Growing native plants in urban gardens is often promoted as a possible means of increasing lepidopteran populations. However, the efficacy of such efforts has not been well studied. Lepidopterans vary widely in their ability to survive in cities, and the few previous studies of caterpillar abundance or biomass across an urban-rural gradient have yielded mixed results. We placed clay caterpillar models in native plant gardens to assess whether the attack rate on these models varied with degree of urbanization (percent impervious surface within 1 km radius of each garden), and whether responses differed across predator taxa. We also examined how garden characteristics (plant biovolume density, plant species richness) affected probability of attack. Overall, attack rates on these models decreased with increasing impervious surface, although predator taxa varied in their sometimes complex responses. For parasitoid wasps, which accounted for 47% of all attacks, increasing biovolume density increased attack probability at impervious surface levels below 35%, but decreased the probability of attack at higher levels of impervious surface. In contrast, probabilities of attack by both predatory wasps and vertebrates decreased with increasing percent impervious surface, but did not vary with impervious surface for ants and spiders. Predation on caterpillars in urban gardens may be lower than in rural ones; however, this potential increase in survival may be a result of declines in some predator taxa, such as predatory wasps and insectivorous birds. More studies across an urban gradient are needed to measure factors other than predation that influence caterpillar survival in gardens.</span></span></span></span></span></span></span></span></span></span></span></p>
Habitat-specific survival of golden-winged warblers (Vermivora chrysoptera) during the non-breeding season in an agricultural landscape
<p>Nearctic-Neotropical migratory birds are considered priority species for conservation because they are subject to threats at distinct breeding, migratory and stopover locations throughout their annual cycle, and many species have undergone severe population declines. Research during the non-breeding season has focused on identifying the locations and habitats that migrants use, but wintering migrants are known to occupy habitats of both high and low quality, especially when the best sites are saturated by conspecifics. Thus, the presence or abundance of a species may not be a reliable indicator of winter habitat quality. The habitat associations of the golden-winged warbler <i>Vermivora chrysoptera</i>, a Nearctic-Neotropical migrant bird species of elevated conservation concern, are relatively well studied, yet conservation efforts are hindered by lack of information about basic demographic rates. In particular, no published estimates exist for non-breeding season survival, which can be a key vital rate affecting population viability, nor how survival rates vary among habitats, which is important to designing conservation programs to support populations during the winter period. We studied a color-banded population of golden-winged warblers in Costa Rica over a 3-year period and estimated overall survival rates, and the effects of habitat characteristics on survival. We found that monthly survival of juveniles (0.881) was lower than adult birds (0.978). Monthly survival during the non-breeding season (0.967) was higher than monthly survival during the rest of the annual cycle (0.930). Survival was negatively related to canopy height, and we observed a significant quadratic effect where survival peaked at intermediate levels of vine tangles and dead hanging leaves, which corresponds to habitat features associated with abundance in prior studies at this same site. Our findings contribute to our existing knowledge about the potential impacts of winter-season events on Nearctic-Neotropical migratory bird populations, and also informs potential conservation strategies for wintering golden-winged warblers.</p>
Data from: Extreme prescribed fire during drought reduces survival and density of woody resprouters
Management intervention in ecosystems with degraded environmental services requires innovative resource management strategies that go beyond conventional restoration and conservation practices. We established a unique study that experimentally targeted extreme fire conditions during drought in humid subtropical and semiarid ecoregions. In the southern Great Plains of North America, conventional restoration and conservation practices have been either historically ineffective or economically cost prohibitive at restoring grass-dominated ecosystems following conversion to resprouting shrublands. Our aim was to assess the potential for extreme fire during drought to force the system along an alternate ecological trajectory from its current progression toward closed-canopy resprouting shrubland, something conventional fire prescriptions have been unable to accomplish. We first tested the potential for high intensity fires exhibiting extreme behaviour to disrupt the progression from grassland to shrubland. In both ecoregions, significant levels of mortality were observed for mature woody resprouters. As a result, densities were either maintained or reduced three years following extreme fire treatments, whereas resprouter densities continued to increase in areas that were not burned. A second interventionist approach involving extreme fire and herbicide treatment combinations was not supported. Interactions between prescribed extreme fire and herbicide did not significantly reduce resprouter densities more than using herbicide alone at either site. Synthesis and applications: Extreme fires during drought resulted in exceptionally high levels of mortality across all sizes of woody resprouters and limited recruitment, resulting in 35–55% lower densities of resprouters than in areas not burned. These findings counter prevailing scientific and management expectations, which are based largely on studies that impose tight controls over prescribed fire conditions and avoid extreme fire behaviour. Future interventions for controlling woody resprouters with fire may require rethinking the present ideology that extreme fire behaviour has no place in modern social-ecological landscapes.
Data from: Sexual dimorphism explains residual variance around the survival-reproduction tradeoff in lizards: implications for sexual conflict over life-history evolution
The tradeoff between survival and reproduction is a central feature of life-history variation, but few studies have sought to explain why females of some species exhibit relatively lower survival than expected for a given level of reproductive effort. Intralocus sexual conflict theory proposes that sex differences in selection on survival and reproductive effort may, by virtue of shared genes underlying these components of fitness, prevent females from optimizing this life-history tradeoff. To test this hypothesis, we used a phylogenetically based comparative analysis of published estimates for mean annual survival and reproductive effort from females of 82 lizard species to (1) characterize the tradeoff between survival and reproduction, and (2) test whether variation around this tradeoff is explained by sexual size dimorphism (SSD), a potential proxy for sexual conflict over life-history traits. Across species, we found a strong negative correlation between mean annual survival and reproductive effort, confirming this classic life-history tradeoff. Although residual variance around this tradeoff is unrelated to the absolute magnitude of SSD, it is strongly related to the direction of SSD. Specifically, we found that females have lower survival than expected for a given level of reproductive effort in female-larger species, whereas they have higher survival than expected in male-larger species. Given that female-larger SSD is thought to reflect selection for increased fecundity, our results suggest that intralocus sexual conflict may be particularly likely to constrain female life-history evolution in situations where increased reproductive effort is favored, but the phenotypes that facilitate this increase (e.g., body size) are constrained by antagonistic selection on males.
Data from: Pleistocene survival on central Alpine nunataks: genetic evidence from the jumping bristletail Machilis pallida
Mechanisms of survival during the Pleistocene glaciation periods have been studied for more than a century. Until now, molecular studies that confirmed animal survival on Alpine nunataks, i.e., ice-free summits surrounded by glaciers, were restricted to peripheral areas. Here, we search for molecular signatures of inner-Alpine survival of the narrow-endemic and putatively parthenogenetic Alpine jumping bristletail Machilis pallida combining mitochondrial and AFLP data from its three known populations. The mitochondrial data indicate survival on both peripheral and central nunataks, the latter suggesting that refugia in the centre of the Alpine main ridge were more widespread than previously recognised. Incongruences between mitochondrial and AFLP patterns suggest a complex evolutionary history of the species and may be explained via parallel fixation of parthenogenesis of different origins during the Last Glacial Maximum. We suggest that the inferred parthenogenesis may have been essential for central-nunatak survival, but may pose a serious threat for M. pallida in consideration of the present climatic changes.
Data from: Immunosenescence and the ability to survive bacterial infection in the red flour beetle Tribolium castaneum
1. In most animals, ageing is associated with a decline in immune function (immune senescence). However, different components of the immune system seem to age differentially, and many studies do not measure the ultimate fitness consequences of immune function after infection. Previous work shows that immune function may be traded off with other fitness components such as reproduction. It is possible that age alters the nature of these trade-offs, particularly in conjunction with factors such as gender and mating that can also affect investment in immune function. 2. We tested the impact of age, sex and mating on post-infection survivorship in Tribolium castaneum flour beetles, as well as the components of baseline constitutive innate immunity and external (secreted) immune function in uninfected individuals. We also tested whether the reproductive ability of uninfected females is traded off with immune function (baseline innate and external immunity) and post-infection survivorship across age groups. 3. We found that age, sex and mating significantly affected immune components and infection outcome, although the magnitude and nature of the impact varied in each case. We found that older beetles were more susceptible to infection by the pathogen Bacillus thuringiensis even though major components of the constitutive innate immune defence (antibacterial and phenoloxidase activity) remained unchanged or improved with age. Thus, these aspects of innate immunity cannot explain the observed decline in post-infection survival of older beetles. We did not find trade-offs between the reproductive ability of uninfected females and their immune function. In contrast to innate immunity, external immunity showed an overall decline with age but was also affected by sex and mating. Finally, we show that bacterial infection alters external immunity via complex interactions between age, sex and mating status. 4. Our work uncovers novel interactions between age, sex and mating that can determine the evolution and outcome of immunosenescence by affecting the time course of relative investment in different immune and fitness components.
Data from: Survival costs of within‐ and between‐season mate change in the European Blackbird (Turdus merula)
Many studies of socially monogamous birds discuss the adaptive role of between-season partner change, but only a handful of them refer to the benefits of pair fidelity in terms of increased survival. Moreover, there are no studies describing the benefits of within-season mate retention. Our data relating to an urban population of European Blackbirds (Turdus merula) enabled us to test the dependence of survival on pair faithfulness. Because Blackbirds divorce within and between seasons, we were able to test the influence of pair faithfulness on their within- and between-season survival and mate fidelity. For this purpose, we used a multievent capture-mark-recapture (MECMR) statistical model, which is based on recapture rates and different pair states (faithful to mate, paired with new partner, or dead). Our study indicated that between- and within-season survival depends on pair states: pair-bond duration increases survival to the next capture occasion in both sexes. We found that the pair-bond duration to the current partner increased the chances of being with the same partner during the next breeding occasion, although we failed to find any within-season pair-bond influence for females. Our results showed sex differences in mating at the end of the season: females had a much smaller chance of breeding with the current new partner in the next year. This study has demonstrated that within- and between-season survival is dependent on mate retention, and we discuss this in the context of how searching for a new partner could affect the birds' survival.
Data from: Preference for outbred host plants and positive effects of inbreeding on egg survival in a specialist herbivore
Inbreeding can profoundly affect the interactions of plants with herbivores as well as with the natural enemies of the herbivores. We studied how plant inbreeding affects herbivore oviposition preference, and whether inbreeding of both plants and herbivores alters the probability of predation or parasitism of herbivore eggs. In a laboratory preference test with the specialist herbivore moth Abrostola asclepiadis and inbred and outbred Vincetoxicum hirundinaria plants, we discovered that herbivores preferred to oviposit on outbred plants. A field experiment with inbred and outbred plants that bore inbred or outbred herbivore eggs revealed that the eggs of the outbred herbivores were more likely to be lost by predation, parasitism or plant hypersensitive responses than inbred eggs. This difference did not lead to differences in the realized fecundity as the number of hatched larvae did not differ between inbred and outbred herbivores. Thus, the strength of inbreeding depression in herbivores decreases when their natural enemies are involved. Plant inbreeding did not alter the attraction of natural enemies of the eggs. We conclude that inbreeding can significantly alter the interactions of plants and herbivores at different life-history stages, and that some of these alterations are mediated by the natural enemies of the herbivores.
Data from: The quick are the dead: pheasants that are slow to reverse a learned association survive for longer in the wild
Cognitive abilities likely evolve through natural selection if they provide individuals with fitness benefits. A growing number of studies demonstrate a positive relationship between performance in psychometric tasks and (proxy) measures of fitness. We assayed the performance of 154 Common Pheasant Phasianus colchicus chicks on tests of acquisition and reversal learning, using a different set of chicks and different set of cue types (spatial location and colour) in each of two years and then followed their fates after release into the wild. Across all birds, individuals that were slow to reverse previously learned associations were more likely to survive to four months old. For heavy birds, individuals that rapidly acquired an association had improved survival to four months, whereas for light birds, slow acquirers were more likely to be alive. Slow reversers also exhibited less exploratory behaviour in assays when five weeks old. Fast acquirers visited more artificial feeders after release. By contrast to most other studies, we showed that apparently 'poor' cognitive performance (slow reversal speed suggesting low behavioural flexibility) correlates with fitness benefits in at least some circumstances. This correlation suggests a novel mechanism by which continued exaggeration of cognitive abilities may be constrained.
Data from: Population density and climate shape early-life survival and recruitment in a long-lived pelagic seabird
1. Our understanding of demographic processes is mainly based on analyses of traits from the adult component of populations. Early-life demographic traits are poorly known mainly for methodological reasons. Yet, survival of juvenile and immature individuals is critical for the recruitment into the population and thus for the whole population dynamic, especially for long-lived species. This bias currently restrains our ability to fully understand population dynamics of long-lived species and life-history theory. 2. The goal of this study was to estimate the early-life demographic parameters of a long-lived species with a long immature period (9–10 years), to test for sex and age effects on these parameters and to identify the environmental factors encountered during the period of immaturity that may influence survival and recruitment. 3. Using capture–mark–recapture multievent models allowing us to deal with uncertain and unobservable individual states, we analysed a long-term data set of wandering albatrosses to estimate both age- and sex-specific early-life survival and recruitment. We investigated environmental factors potentially driving these demographic traits using climatic and fisheries covariates and tested for density dependence. 4. Our study provides for the first time an estimate of annual survival during the first 2 years at sea for an albatross species (0·801 ± 0·014). Both age and sex affected early-life survival and recruitment processes of this long-lived seabird species. Early-life survival and recruitment were highly variable across years although the sensitivity of young birds to environmental variability decreased with age. Early-life survival was negatively associated with sea surface temperature, and recruitment rate was positively related to both Southern Annular Mode and sea surface temperature. We found strong evidence for density-dependent mortality of juveniles. Population size explained 41% of the variation of this parameter over the study period. 5. These results indicate that early-life survival and recruitment were strongly age and sex dependent in a dimorphic long-lived species. In addition, early-life demographic parameters were affected by natal environmental conditions and by environmental conditions faced during the period of immaturity. Finally, our results constitute one of the first demonstrations of density dependence on juvenile survival in seabirds, with major consequences for our understanding of population dynamics in seabirds.
Data from: The costs of parental care: a meta-analysis of the trade-off between parental effort and survival in birds
A fundamental premise of life-history theory is that organisms that increase current reproductive investment suffer increased mortality. Possibly the most studied life-history phenotypic relationship is the trade-off between parental effort and survival. However, evidence supporting this trade-off is equivocal. Here, we conducted a meta-analysis to test the generality of this tenet. Using experimental studies that manipulated parental effort in birds we show that: 1) the effect of parental effort on survival was similar across species regardless of phylogeny, 2) individuals that experienced reduced parental effort had similar survival probabilities than control individuals, regardless of sex, and 3) males that experienced increased parental effort were less likely to survive than control males, whereas females that experienced increased effort were just as likely to survive as control females. Our results suggest that the trade-off between parental effort and survival is more complex than previously assumed. Finally, our study provides recommendations of unexplored avenues of future research into life-history trade-offs.
Data from: A novel nonparametric measure of explained variation for survival data with an easy graphical interpretation
Introduction: For survival data the coefficient of determination cannot be used to describe how good a model fits to the data. Therefore, several measures of explained variation for survival data have been proposed in recent years. Methods: We analyse an existing measure of explained variation with regard to minimisation aspects and demonstrate that these are not fulfilled for the measure. Results: In analogy to the least squares method from linear regression analysis we develop a novel measure for categorical covariates which is based only on the Kaplan-Meier estimator. Hence, the novel measure is a completely nonparametric measure with an easy graphical interpretation. For the novel measure different weighting possibilities are available and a statistical test of significance can be performed. Eventually, we apply the novel measure and further measures of explained variation to a dataset comprising persons with a histopathological papillary thyroid carcinoma. Conclusion: We propose a novel measure of explained variation with a comprehensible derivation as well as a graphical interpretation, which may be used in further analyses with survival data.
Data from: Flexibility in the duration of parental care: female leopards prioritise cub survival over reproductive output
1.Deciding when to terminate care of offspring is a key consideration for parents. Prolonging care may increase fitness of current offspring, but it can also reduce opportunities for future reproduction. Despite its evolutionary importance, few studies have explored the optimal duration of parental care, particularly among large carnivores. 2.We used a 40-year dataset to assess the trade-offs associated with the length of maternal care in leopards in the Sabi Sand Game Reserve, South Africa. We compared the costs imposed by care on the survival and residual reproductive value of leopard mothers against the benefits derived from maternal care in terms of increased offspring survival, recruitment and reproduction. We also examined the demographic and ecological factors affecting the duration of care in light of five explanatory hypotheses: litter-size, sex-allocation, resource-limitation, timing-of-independence, and terminal-investment. 3.Duration of care exhibited by female leopards varied markedly, from 9–35 months. Mothers did not appear to suffer any short- or long-term survival costs from caring for cubs, but extending care reduced the number of litters that mothers could produce during their lifetimes. Interestingly, the duration of care did not appear to affect the post-independence survival or reproductive success of offspring (although it may have indirectly affected offspring survival by influencing dispersal distance). However, results from generalised linear mixed models showed that mothers prolonged care during periods of prey scarcity, supporting the resource-limitation hypothesis. Female leopards also cared for sons longer than daughters, in line with the sex-allocation hypothesis. 4.Cub survival is an important determinant of the lifetime reproductive success in leopards. By buffering offspring against environmental perturbation without jeopardizing their own survivorship, female leopards apparently 'hedge their bets' with current offspring rather than gamble on future offspring which have a small probability of surviving. 5.In many species, parents put their own needs before that of their offspring. Leopard mothers appear sensitive to their offspring's demands, and adjust levels of care accordingly.
Data from: Increased survival of experimentally evolved antimicrobial peptide-resistant Staphylococcus aureus in an animal host
Antimicrobial peptides (AMPs) have been proposed as new class of antimicrobial drugs, following the increasing prevalence of bacteria resistant to antibiotics. Synthetic AMPs are functional analogues of highly evolutionarily conserved immune effectors in animals and plants, produced in response to microbial infection. Therefore, the proposed therapeutic use of AMPs bears the risk of 'arming the enemy': bacteria that evolve resistance to AMPs may be cross-resistant to immune effectors (AMPs) in their hosts. We used a panel of populations of Staphylococcus aureus that were experimentally selected for resistance to a suite of individual AMPs and antibiotics to investigate the 'arming the enemy' hypothesis. We tested whether the selected strains showed higher survival in an insect model (Tenebrio molitor) and cross-resistance against other antimicrobials in vitro. A population selected for resistance to the antimicrobial peptide iseganan showed increased in vivo survival, but was not more virulent. We suggest that increased survival of AMP-resistant bacteria almost certainly poses problems to immune-compromised hosts.
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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.