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opencc-by-4.0May 2010View details →

Figure 1 in Avifaunal Responses to Warm Climate: The Message from Last Interglacial Faunas

Figure 1. Sites with Last Interglacial avifaunas in North America.

opencc-zeroAug 2021View details →

Bud traits and post-fire responses of Cerrado woody species, Southeastern Brazil

1) Species growing in fire-prone savannas usually persist by resprouting from their buds. In this study, we evaluated how various persistence traits allow bud protection for improved survival in fire-prone ecosystems. 2) Using an integrative morphological and macroanatomical approach, we analyzed how woody plants protect their buds. We tested bud protection at the community level and evaluated: a) how bud protection changes along a fire frequency gradient, b) if it differs between shrubs and trees and c) whether the level of bud protection is related to post-fire responses of 28 woody savanna species. 3) A mix of traits involving bud protection may enable woody species persistence in fire-prone ecosystems. Savanna species better protected their buds than forest species by developing bark and trichomes that allowed resprouting after fire. Regarding growth forms, shrub species capable of resprouting aboveground had their buds better protected than trees. 4) Bud protection is not only linked with their position to the bark, but also with the presence of trichomes. Profuse trichomes covering buds were related to savanna species. Some species with no bud protection by bark but with trichomes covering their buds were able to resprout after fire. The presence of accessory buds is also a trait more related to savannas, possibly influencing the resprouting after fire as they are better protected and increase the bud bank. Finally, different persistence traits interact with one another to better protect the buds, requiring a detailed screening of the traits to assess species responses to fire. 5) Synthesis. During fire, species have their aerial biomass consumed by the flames. To be able to resprout new branches and persist in the environment, they must have well-protected buds. In this study, we evaluated different ways that woody species protect their buds and related them with their resprouting strategy after fire. We investigated the protection by the bark, presence of trichomes and accessory buds. By studying the woody community in a gradient of savannas and forests we found that buds can be protected by bark, trichomes, or soil. Species can present a mix of these traits and strategies, which enhances their resprouting after fire.

opencc-zeroAug 2021View details →

Plasticity of the gastrocnemius elastic system in response to decreased work and power demand during growth

Elastic energy storage and release can enhance performance that would otherwise be limited by the force-velocity constraints of muscle. While functional influence of a biological spring depends on tuning between components of an elastic system (the muscle, spring, driven mass, and lever system), we do not know whether elastic systems systematically adapt to functional demand. To test whether altering work and power generation during maturation alters the morphology of an elastic system, we prevented growing guinea fowl (Numida Meleagris) from jumping. At maturity, we compared the jump performance of our treatment group to that of controls and measured the morphology of the gastrocnemius elastic system. We found that restricted birds jumped with lower jump power and work, yet there were no significant between-group differences in the components of the elastic system. Further, subject-specific models revealed no difference in energy storage capacity between groups, though energy storage was most sensitive to variations in muscle properties (most significantly operating length and least dependent on tendon stiffness). We conclude that the gastrocnemius elastic system in the guinea fowl displays little to no plastic response to decreased demand during growth and hypothesize that neural plasticity may explain performance variation.

FIGURE 6 in Olfactory Responses Of Phytoseiulus Persimilis To Rose Plants With Or Without Prey Or Competitors

FIGURE 6: In the Y-tube olfactometer, Phytoseiulus persimilis were offered a choice between odours from clean air in one arm vs odours from clean rose plants in the other (a,c) and between clean rose plants in one arm vs odours from both Phytoseiulus persimilis and Tetranychus urticae in the other (b, d). The population of Phytoseiulus persimilis used had been exposed to rose plants with T. urticae for 24h (a – b) or during 6 months (c – d). P values of the G test for each replicate are given next to each bar; overall P values are given in Table 1.

FIGURE 1 in Olfactory Responses Of Phytoseiulus Persimilis To Rose Plants With Or Without Prey Or Competitors

FIGURE 1: In the Y-tube olfactometer, Phytoseiulus persimilis were offered a choice between odours from clean air in one arm vs odours from clean plants in the other. a – rose plants; b –bean plants; c – cucumber plants. P values of the G test for each replicate are given next to each bar; overall P values are given in Table 1.

FIGURE 3 in Olfactory Responses Of Phytoseiulus Persimilis To Rose Plants With Or Without Prey Or Competitors

FIGURE 3: In the Y-tube olfactometer, Phytoseiulus persimilis were offered a choice between odours from clean plants in one arm vs odours from plants infested with Tetranychus urticae in the other. a – rose plants; b – bean plants; c – cucumber plants. P values of the G test for each replicate are given next to each bar; overall P values are given in Table 1.

FIGURE 5 in Olfactory Responses Of Phytoseiulus Persimilis To Rose Plants With Or Without Prey Or Competitors

FIGURE 5: In the Y-tube olfactometer, Tetranychus urticae were offered a choice between odours from clean air in one arm vs odours from clean plants in the other. a – rose plants; b – bean plants; c – cucumber plants. P values of the G test for each replicate are given next to each bar; overall P values are given in Table 1.

FIGURE 4 in Olfactory Responses Of Phytoseiulus Persimilis To Rose Plants With Or Without Prey Or Competitors

FIGURE 4: In the Y-tube olfactometer, Phytoseiulus persimilis were offered a choice between odours from clean rose plants in one arm vs odours from both Phytoseiulus persimilis and Tetranychus urticae in the other. a – rose plants; b – bean plants; c – cucumber plants. P values of the G test for each replicate are given next to each bar; overall P values are given in Table 1.

Inferred ancestry of scytonemin biosynthesis proteins in cyanobacteria indicates a response to Paleoproterozoic oxygenation

Protection from radiation damage is an important adaptation for phototrophic microbes. In the case of cyanobacteria, surface, shallow water, and peritidal environments are especially exposed to long- wavelength ultraviolet (UVA) radiation. Several groups of cyanobacteria within these environments are protected from UVA damage by the production of the pigment scytonemin. Paleontological evidence of cyanobacteria in UVA-exposed environments from the Proterozoic, and possibly as early as the Archaean, suggests a long evolutionary history of radiation protection within this group. We show that phylogenetic analyses of enzymes in the scytonemin biosynthesis pathway support this hypothesis, and reveal a deep history of vertical inheritance of this pathway within extant cyanobacterial diversity. Referencing this phylogeny to cyanobacterial molecular clocks suggests that scytonemin production likely appeared during the early Proterozoic, soon after the Great Oxygenation Event. This timing is consistent with an adaptive scenario for the evolution of scytonemin production, wherein the threat of UVA-generated reactive oxygen species becomes significantly greater once molecular oxygen was more pervasive across photosynthetic environments.

Pied tamarins go multimodal in response to anthropogenic noise

Sounds produced by human activities are often loud and may mask acoustic signals used by other species for communication. To circumvent this, animals may use various strategies, including shifting modality completely or complementing acoustic information by also using another modality of communication. Here we tested the overlooked multimodal shift hypothesis using pied tamarins (Saguinus bicolor) as models. We predicted that in noisier areas the species would exhibit more scent marking behaviour (i.e., olfactory communication), while reducing the emission of long calls (i.e., acoustic communication). We collected information on vocal and scent marking behaviour in nine groups of wild pied tamarins in Manaus, Brazil. We found that scent marking occurrence increased with noise amplitude, though the number of long calls did not change. Thus, our results do not suggest a shift between channels but complementation of information, where scent marking may counteract against the compromising of the acoustic channel by the urban environment. This is an interesting result from a conservation perspective and supports ongoing efforts to create ecological corridors in Manaus, Brazil; once habitat connection is established, pied tamarins may be capable of coping with city noise to communicate with conspecifics, a key tenet of species survival.

Spatial and temporal variation in phenotypes and fitness in response to developmental thermal environments

1) Phenotypic variation within populations is influenced by the environment via plasticity and natural selection. How phenotypes respond to the environment can vary among traits, populations, and life stages in ways that can influence fitness. 2) Plastic responses during early development are particularly important because they can affect components of fitness throughout an individual's life. Consequently, how natural selection shapes developmental plasticity could be influenced by fitness consequences across different life stages. Moreover, spatial variation in selection pressures could generate differences in plastic responses among populations. 3) To gain insight into sources of variation in phenotypes and survival, we used a laboratory egg incubation experiment using brown anole lizards (Anolis sagrei) from mainland (ancestral) and island (descendent) populations, combined with a mark-release-recapture experiment in the field. Our study was designed to (i) quantify the effects developmental temperature on embryo development and offspring morphology, (ii) assess how developmental temperature influences offspring survival across different life stages, and (iii) quantify how thermal reaction norms vary among ancestral and descendant populations. 4) Developmental temperature influenced offspring morphology, but thermal reaction norms of embryos showed little variation among populations. Developmental temperature influenced offspring survival, but the patterns differed between embryo and hatchling stages; the optimal temperature for embryos was about 5ºC lower than that for hatchlings. High temperatures were thermally stressful to embryos, but they reduced incubation duration and led to early hatching. In turn, earlier hatching increased the probability of survival to adulthood. Moreover, the effect of temperature on hatchling survival was most pronounced for offspring that hatched late in the season. 5) The difference in optimal developmental temperatures between life stages may be driven by physiological tolerance for embryos and by ecological factors for hatchlings. Moreover, the fitness consequences of the developmental environment depend upon the phenology of hatching. Overall, these results highlight how the developmental environment can differentially effect fitness across life stages and show that temporal thermal heterogeneity can influence survival of embryos, but the consequences on post-hatching stages may vary at different times of the season.

Data from: Rapid microgeographic evolution in response to climate change

Environmental change is predicted to accelerate into the future and will exert strong selection pressure on biota. While many species may be fated to extinction, others may survive through their capacity to evolve rapidly at highly localized (i.e. microgeographic) scales. Yet, even as new examples have been discovered, the limits to such evolutionary responses have not often been evaluated. One of the first examples of microgeographic variation involved pond populations of wood frogs (Rana sylvatica). Although separated by just tens to hundreds of meters, these populations exhibited countergradient variation in intrinsic embryonic development rates when reared in a common garden. We repeated this experiment 17 years (approx. 6-9 generations) later and found that microgeographic variation persists in contemporary populations. Furthermore, we found that contemporary embryos have evolved to develop 14% to 19% faster than those in 2001. Structural equation models indicate that the predominant cause for this response is likely due to changes in climate over the intervening 17 years. Despite potential for rapid and fine-scale evolution, demographic declines in populations experiencing the greatest changes in climate and habitat imply a limit to the species' ability to mitigate extreme environmental change.

Increased epigenetic diversity and transient epigenetic memory in response to salinity stress in Thlaspi arvense

Epigenetic diversity could play an important role in adaptive evolution of organisms, especially for plant species occurring in new and stressful environments. Thlaspi arvense (pennycress), a valuable oilseed crop, is widespread in temperate regions of the northern hemisphere. In this study, we investigated the effect of salinity stress on the epigenetic variation of DNA methylation and epigenetic stress memory in pennycress using methylation-sensitive amplification polymorphism (MSAP) markers. We examined how the status of DNA methylation changes across individuals in response to salinity stress and whether such an effect of maternal stress could be transferred to offspring for one or two generations in non-stressed environments. Our results based on 306 epiloci indicated no consistent change of DNA methylation status in specific epiloci across individuals within the same conditions. In contrast, we found that the epigenetic diversity at population level increased significantly in response to the stimulation of salinity stress; and this "stimulation effect" could be transferred partially in the form of stress memory to at least two generations of offspring in non-stressed environments. In addition, we observed a parallel change in functionally important traits, i.e. phenotypic variation was significantly higher in plants grown under salinity stress compared with those of control groups. Taken together, our results provide novel clues for the increased spontaneous epimutation rate in response to stress in plants, of potential adaptive significance.

Optimizing parameters for using the parallel auditory brainstem response (pABR) to quickly estimate hearing thresholds

Objectives: Timely assessments are critical to providing early intervention and better hearing and spoken language outcomes for children with hearing loss. To facilitate faster diagnostic hearing assessments in infants, the authors developed the parallel auditory brainstem response (pABR), which presents randomly timed trains of tone pips at five frequencies to each ear simultaneously. The pABR yields high-quality waveforms that are similar to the standard, single-frequency serial ABR but in a fraction of the recording time. While well-documented for standard ABRs, it is yet unknown how presentation rate and level interact to affect responses collected in parallel. Furthermore, the stimuli are yet to be calibrated to perceptual thresholds. Therefore, this study aimed to determine the optimal range of parameters for the pABR and to establish the normative stimulus level correction values for the ABR stimuli. Design: Two experiments were completed, each with a group of 20 adults (18 – 35 years old) with normal hearing thresholds (≤ 20 dB HL) from 250 to 8000 Hz. First, pABR electroencephalographic (EEG) responses were recorded for six stimulation rates and two intensities. The changes in component wave V amplitude and latency were analyzed, as well as the time required for all responses to reach a criterion signal-to-noise ratio of 0 dB. Second, behavioral thresholds were measured for pure tones and for the pABR stimuli at each rate to determine the correction factors that relate the stimulus level in dB peSPL to perceptual thresholds in dB nHL. Results: The pABR showed some adaptation with increased stimulation rate. A wide range of rates yielded robust responses in under 15 minutes, but 40 Hz was the optimal singular presentation rate. Extending the analysis window to include later components of the response offered further time-saving advantages for the temporally broader responses to low frequency tone pips. The perceptual thresholds to pABR stimuli changed subtly with rate, giving a relatively similar set of correction factors to convert the level of the pABR stimuli from dB peSPL to dB nHL. Conclusions: The optimal stimulation rate for the pABR is 40 Hz, but using multiple rates may prove useful. Perceptual thresholds that subtly change across rate allow for a testing paradigm that easily transitions between rates, which may be useful for quickly estimating thresholds for different configurations of hearing loss. These optimized parameters facilitate expediency and effectiveness of the pABR to estimate hearing thresholds in a clinical setting.

opencc-by-4.0Sep 2021View details →

Data of "Poor repeatability of cortisol responses to adrenocorticotropic hormone (ACTH) in beef heifers: is the ACTH challenge a suitable measure for stress research in cattle?"

Data for article "Poor repeatability of cortisol responses to adrenocorticotropic hormone (ACTH) in beef heifers: is the ACTH challenge a suitable measure for stress research in cattle?" Dataset of 64 crossbred beef heifers which were subjected to three ACTH challenges. Both experimental independent variables (animal id, horn status, replicate, time of day of the ACTH challenge, ACTH challenge number) and post-ACTH salivary cortisol concentrations (at the seven sampling timepoints and area under the curve values) are presented.

opencc-by-4.0Sep 2021View details →

Dataset for "Constraining the response factors of an extractive electrospray ionization mass spectrometer for near-molecular aerosol speciation"

Online characterization of aerosol composition at the near-molecular level is key to understanding chemical reaction mechanisms, kinetics, and sources under various atmospheric conditions. The recently developed extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) is capable of detecting a wide range of organic oxidation products in the particle phase in real time with minimal fragmentation. Quantification can sometimes be hindered by a lack of available commercial standards for aerosol constituents, however. Good correlations between the EESI-TOF and other aerosol speciation techniques have been reported, though no attempts have yet been made to parameterize the EESI-TOF response factor for different chemical species. Here, we report the first parameterization of the EESI-TOF response factor for secondary organic aerosol (SOA) at the near-molecular level based on their elemental composition. SOA was formed by ozonolysis of monoterpenes or OH-oxidation of aromatics inside an oxidation flow reactor (OFR) using ammonium nitrate as seed particles. A Vocus proton-transfer reaction mass spectrometer (Vocus-PTR) and a high-resolution aerosol mass spectrometer (AMS) were used to determine the gas phase molecular composition and the particle phase bulk chemical composition, respectively. The EESI response factors towards bulk SOA coating and the inorganic seed particle core were constrained by intercomparison with the AMS. The highest bulk EESI response factor was observed for SOA produced from 1,3,5-trimethylbenzene, followed by those produced from d-limonene and o-cresol, consistent with previous findings. The near-molecular EESI response factors were derived from intercomparisons with Vocus-PTR measurements, and were found to vary from 103 to 106 ions s-1 ppb-1, mostly within ±1 order of magnitude of their geometric mean of 104.6 ions s-1 ppb-1. For aromatic SOA components, the EESI response factors correlated with molecular weight and oxygen content, and inversely correlated with volatility. The near-molecular response factors mostly agreed within a factor of 20 for isomers observed across the aromatics and biogenic systems. Parameterization of the near-molecular response factors based on the measured elemental formulae could reproduce the empirically determined response factor for a single VOC system to within a factor of 5 for the configuration of our mass spectrometers. The results demonstrate that standard-free quantification using EESI-TOF is possible.

opencc-zeroOct 2021View details →

Diversity mediates the responses of invertebrate density to duration and frequency of rivers' annual drying regime

Predicting the impacts of global change on highly dynamic ecosystems requires a better understanding of how communities respond to disturbance duration, frequency and timing. Intermittent rivers and ephemeral streams are dynamic ecosystems that are recognized as the most common fluvial ecosystem globally. The complexity of the drying process can give rise to different annual and antecedent hydrological conditions, but their effect on aquatic communities remains unclear. Here, using aquatic invertebrates from 33 streams across a flow-intermittence gradient, we assessed how annual (drying duration and frequency) and recent drying characteristics (duration of the last dry period and flowing duration since the last rewetting) affect the density and diversity metrics of communities and trophic groups while controlling for other key abiotic factors (dissolved oxygen and altitude). We characterized invertebrate communities using taxonomy and functional traits to capture biological features that increase vulnerability to drying. In addition, using structural equation modelling (SEM), we evaluated pathways by which drying characteristics directly impact invertebrate density and whether diversity indirectly mediates such relationships. We show that drying frequency drove reductions in diversity at the community level and within trophic groups, whereas both the drying duration and frequency had a negative influence on density metrics. Reductions in taxonomic richness were linked to increased annual drying duration, whereas functional diversity declined in response to annual drying frequency. Filterer, predator and shredder trophic groups exhibited the strongest negative responses to drying. Recent drying characteristics had a minor effect on density and diversity metrics. Our SEM results demonstrated that diversity mediates the negative impacts of annual drying duration and frequency on invertebrate density through reductions in their taxonomic richness and functional diversity. Our results underscore the importance of considering multiple drying characteristics together with the interdependence of density and diversity to better anticipate drying responses in freshwater ecosystems.

opencc-zeroOct 2021View details →

Alternative developmental and transcriptomic responses to host plant water limitation in a butterfly metapopulation

The dataset is from a study examining the effects of host plant water stress on the developmental and transcriptomic responses of its specialist Lepidopteran herbivore. The study combines host plant metabolic profiling with development assays and full-transcriptome sequencing of herbivore larvae. First, we profiled metabolic differences between well-watered and water-limited ribwort plantain (Plantago lanceolata) using proton nuclear magnetic resonance spectroscopy (1H-NMR). Second, we tested how performance of developing Glanville fritillary (Melitaea cinxia) larvae was affected by host plant water limitation experienced at different larval developmental stages. Third, we examined larval gene regulatory responses to water limited host plants by sequencing full transcriptomes of 77 female larvae (RNA seq). Finally, to examine intrapopulation variation in the responses of the larvae, we compared the phenotypic and transcriptomic responses across full-sib families originating from different parts of the metapopulation. In this dataset, we provide data for the P. lanceolata metabolite responses to water limitation and developmental responses of the M. cinxia larvae to feeding on water limited P. lanceolata. The transcriptomic data are available from NCBI's Gene Expression Omnibus, with the accession number GSE159376.

opencc-zeroOct 2021View details →

Response diversity in corals: hidden differences in bleaching mortality among cryptic Pocillopora species

Variation among functionally similar species in their response to environmental stress buffers ecosystems from changing states. Functionally similar species may often be cryptic species representing evolutionarily distinct genetic lineages that are morphologically indistinguishable. However, the extent to which cryptic species differ in their response to stress, and could therefore provide a source of response diversity, remains unclear because they are often not identified or are assumed to be ecologically equivalent. Here, we uncover differences in the bleaching response between sympatric cryptic species of the common Indo-Pacific coral, Pocillopora. In April 2019, prolonged ocean heating occurred at Moorea, French Polynesia. 72% of pocilloporid colonies bleached after 22 days of severe heating (>8°C-days) at 10 m depth on the north shore fore reef. Colony mortality ranged from 11% to 42% around the island four months after heating subsided. The majority (86%) of pocilloporids that died from bleaching belonged to a single haplotype, despite twelve haplotypes, representing at least five species, being sampled. Mitochondrial (open reading frame) sequence variation was greater between the haplotypes that experienced mortality versus haplotypes that all survived than it was between nominal species that all survived. Colonies >30 cm in diameter were identified as the haplotype experiencing the most mortality, and in 1125 colonies that were not genetically identified, bleaching and mortality increased with colony size. Mortality did not increase with colony size within the haplotype suffering the highest mortality, suggesting that size-dependent bleaching and mortality at the genus level was caused instead by differences among cryptic species. The relative abundance of haplotypes shifted between February and August, driven by declines in the same common haplotype for which mortality was estimated directly, at sites where heat accumulation was greatest, and where larger colony sizes occurred. The identification of morphologically indistinguishable species that differ in their response to thermal stress, but share a similar ecological function in terms of maintaining a coral-dominated state, has important consequences for uncovering response diversity that drives resilience, especially in systems with low or declining functional diversity.