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Biodiversity‐oriented urban management and planning require information on the drivers of wildlife composition and ecosystem function within cities. Urban landscapes impose environmental gradients along which species may be filtered away, or respond by showing adaptive variation in functional trait values. Such trait variation may in turn be due to a species' phenotypic plasticity, or a consequence of microevolution leading to local adaptation. This study investigates three possible plant responses to urban environmental gradients, with different evolutionary consequences: extinction, plasticity and adaptation. We assessed whether individual functional traits (LMA—leaf mass per area, plant height and flower length), population performance traits (seed mass and germination rate), as well as species frequency in the plant community, responded to gradients in mowing frequency, soil fertility and structure, temperature and surrounding mean building height, among four herbaceous plant species present in the metropolitan area of Strasbourg. Using a common garden experiment, we tested whether the observed trait variation was hereditary, and may thus constitute evidence for local adaptation. Our results detected the three types of expected responses. Plantago lanceolata is plastic to urban gradients, and Trifolium pratense showed both plastic and hereditary responses. Dactylis glomerata and Medicago lupulina showed all three responses: they both declined under increasing mowing frequency, were plastic to surrounding mean building height, and showed hereditary responses to different urban gradients. Urban management and planning therefore impact on the evolutionary capabilities of plants in cities. In the case of management this is highlighted by the detected trends in species' traits and frequency in response to mowing. The consequences of urban planning are evidenced by mean building height eliciting most often plastic and adaptive responses. Synthesis. Herbaceous plants often change their morphology in response to urban conditions: grass cutting, altered soils, warmer temperatures and being surrounded by tightly packed buildings. These changes are sometimes hereditary, which suggests that city management and planning affect the ability of plants to survive and evolve in urban environments. [ABSTRACT FROM AUTHOR]

Plants synthesize a broad array of specialized chemical compounds that mediate their interactions with the surrounding environment. Some of this chemical diversity is functional and subject to natural selection, but the factors underlying chemical evolution at the intraspecific level remain largely unknown. Here, we combined chemical, environmental and genetic data to investigate the effect of aridity on the expression of chemotypes in the invasive shrub Senecio pterophorus. We studied the variation in pyrrolizidine alkaloids (PAs), a group of specialized metabolites widespread across the families Boraginaceae, Asteraceae and Fabaceae, from native populations spanning a cline of aridity and from three cross‐continental introductions, under natural and common garden conditions. We examined whether the relationship between chemistry and aridity was compatible with a process of adaptive differentiation using a method that partitions the variance and covariance by controlling for the population neutral genetic structure. We found a consistent shift from retrorsine‐like to seneciphylline‐like compounds under increasing aridity in both natural and controlled conditions in coherence with the biosynthetic pathways. This pattern was independent of the neutral genetic structure and occurred along the environmental gradient in the native range and in a convergent manner in all nonnative regions, which suggests adaptive differentiation in response to aridity. Our findings show that the diversity of PAs in S. pterophorus has been partially shaped by aridity. Investigating how abiotic factors influence chemical evolution is key to elucidating the plant responses in future climate scenarios and the cascading effects on other trophic levels. [ABSTRACT FROM AUTHOR]

Leaf area varies within and between species, and previous work has linked this variation to environment and evolutionary history. However, many previous studies fail to examine both these factors and often are data‐limited.To address this, our study developed a new workflow using machine learning to automate the extraction of leaf area from herbarium collections of Australian eucalypts (Eucalyptus, Angophora and Corymbia). This dataset included 136,599 measurements, expanding existing data on this taxon's leaf area by roughly 50‐fold. Our methods were validated using field standard metrics of accuracy, and comparisons to manual measurements both from the present study and existing datasets.With this dataset for the eucalypt clade, we observed positive relationships between leaf area and mean annual temperature and precipitation similar to those reported for the global flora. However, these relationships were not consistently observed within species, potentially due to gene flow suppressing local adaptation. When we examined these relationships at different phylogenetic levels, the slope of trait–climate associations within lineages converged towards the overall eucalypt slope at shallow phylogenetic scales (5–12 MY), suggesting that effects of gene flow relax just above the species level.The strengthening of trait–climate correlations at evolutionary scales just beyond the intraspecific level may represent a widespread phenomenon across various traits and taxa. Future studies can unveil these relationships with the larger sample sizes of new trait datasets generated through machine learning.Synthesis. Using machine learning, researchers are able to confirm current positive global relationships between leaf area and mean annual temperature and precipitation. Additionally, they were able to take this a step further and examine how it changes across time. Here they saw that at roughly 5–12 million years ago in the phylogenetic tree, the trait–climate slope begins to show significantly less variation. Overall, the study shows the potential of machine learning in ecology, with exciting new potential findings with its use. [ABSTRACT FROM AUTHOR]

There is evidence of bacteriophages driving microbial community composition from natural examples, such as cholera outbreaks, during phage therapy, experiments, and mathematical models. However, many studies suggest little or no role of phages in shaping community dynamics, suggesting that viruses may instead follow microbial population dynamics. Evidence from coevolutionary studies suggests that phages may have a greater role in shaping composition at the strain rather than the species level (where evolutionary mechanisms predominate). Phages are most likely to affect community composition when encounter rates with susceptible hosts is high, over short timescales with novel phage, and in relatively simple communities. The ubiquity of bacteriophages (phages) and the major evolutionary and ecological impacts they can have on their microbial hosts has resulted in phages often cited as key drivers shaping microbial community composition (the relative abundances of species). However, the evidence for the importance of phages is mixed. Here, we critically review the theory and data exploring the role of phages in communities, identifying the conditions when phages are likely to be important drivers of community composition. At ecological scales, we conclude that phages are often followers rather than drivers of microbial population and community dynamics. While phages can affect strain diversity within species, there is yet to be strong evidence suggesting that fluctuations in species' strains affects community composition. [ABSTRACT FROM AUTHOR]

Abstract Background Snake venoms can exhibit remarkable inter- and intraspecific variation. While diverse ecological and environmental factors are theorised to explain this variation, only a handful of studies have attempted to unravel their precise roles. This knowledge gap not only impedes our understanding of venom evolution but may also have dire consequences on snakebite treatment. To address this shortcoming, we investigated the evolutionary ecology of venoms of Russell’s viper (Daboia russelii) and spectacled cobra (Naja naja), India’s two clinically most important snakes responsible for an alarming number of human deaths and disabilities. Methodology Several individuals (n = 226) of D. russelii and N. naja belonging to multiple clutches (n = 9) and their mothers were maintained in captivity to source ontogenetic stage-specific venoms. Using various in vitro and in vivo assays, we assessed the significance of prey, ontogeny and sex in driving venom composition, function, and potency. Results Considerable ontogenetic shifts in venom profiles were observed in D. russelii, with the venoms of newborns being many times as potent as juveniles and adults against mammalian (2.3–2.5 ×) and reptilian (2–10 ×) prey. This is the first documentation of the ontogenetic shift in viperine snakes. In stark contrast, N. naja, which shares a biogeographic distribution similar to D. russelii, deployed identical biochemical cocktails across development. Furthermore, the binding kinetics of cobra venom toxins against synthetic target receptors from various prey and predators shed light on the evolutionary arms race. Conclusions Our findings, therefore, provide fascinating insights into the roles of ecology and life history traits in shaping snake venoms.

Considerable morphological and ecological diversity has been found in extinct and extant members of the bear genus, Ursus, and appears to be key in explaining how they have thrived across vast ecological gradients. One example is the cave bear Ursus spelaeus. We applied 2D geometric morphometric techniques to describe morphological changes in the mandibles of extant Ursus species to further interpret the palaeoecology of U. spelaeus. Ursus species were discriminated using their mandibular morphology, which showed intra and interspecific shape variation that was indirectly linked to climatic adaptations through dietary variation. Mandibles of bears that inhabit colder, drier and more seasonal environments were generally slender with large diastema and a dorsoventrally smaller ramus. In contrast, species from warmer environments with higher levels of precipitation were found to have a dorsoventrally taller ramus (relative to the corpus). Discriminant function analyses of the morphology of U. spelaeus suggested adaptations to a series of fluctuating environments through time, helping to assess previously proposed Marine Isotope Stages for sedimentary deposits in Scladina Cave. Our geometric morphometrics analyses of bear mandibular ecomorphology demonstrates how geometric morphometrics provides a valuable tool to enhance paleoenvironmental reconstructions within deposits of the same fossil site. [ABSTRACT FROM AUTHOR]

Interspecific variation in body size is one of the most popular topics in comparative studies. Despite recent advances, little is known about the patterns and processes behind the evolution of body size in insects. Here, we used a robust data set comprising all geometrid moth species occurring in Northern Europe to examine the evolutionary associations involving body size and several life-history traits under an explicitly phylogenetic framework. We provided new insights into the interactive effects of life-history traits on body size and evidence of correlated evolution. We further established the sequence of trait evolution linking body size with the life-history traits correlated with it. We found that most (but not all) of the studied life-history traits, to some extent, influenced interspecific variation in body size, but interactive effects were uncommon. Both bi- and multivariate phylogenetic analyses indicated that larger species tend to be nocturnal flyers, overwinter in the larval stage, feed on the foliage of trees rather than herbs, and have a generalist feeding behaviour. We found evidence of correlated evolution involving body size with overwintering stage, host-plant growth form, and dietary specialization. The examination of evolutionary transitions within the correlated evolution models signalled that overwintering as larvae commonly preceded the evolution of large sizes, as did feeding on tree foliage and the generalist feeding behaviour. By showing that both body size and all life-history traits correlated with it evolve at very slow rates, we caution against uncritical attempts to propose causal explanations for respective associations based on contemporary ecological settings. Graphical Abstract [ABSTRACT FROM AUTHOR]

Background: Snake venoms can exhibit remarkable inter- and intraspecific variation. While diverse ecological and environmental factors are theorised to explain this variation, only a handful of studies have attempted to unravel their precise roles. This knowledge gap not only impedes our understanding of venom evolution but may also have dire consequences on snakebite treatment. To address this shortcoming, we investigated the evolutionary ecology of venoms of Russell's viper (Daboia russelii) and spectacled cobra (Naja naja), India's two clinically most important snakes responsible for an alarming number of human deaths and disabilities. Methodology: Several individuals (n = 226) of D. russelii and N. naja belonging to multiple clutches (n = 9) and their mothers were maintained in captivity to source ontogenetic stage-specific venoms. Using various in vitro and in vivo assays, we assessed the significance of prey, ontogeny and sex in driving venom composition, function, and potency. Results: Considerable ontogenetic shifts in venom profiles were observed in D. russelii, with the venoms of newborns being many times as potent as juveniles and adults against mammalian (2.3–2.5 ×) and reptilian (2–10 ×) prey. This is the first documentation of the ontogenetic shift in viperine snakes. In stark contrast, N. naja, which shares a biogeographic distribution similar to D. russelii, deployed identical biochemical cocktails across development. Furthermore, the binding kinetics of cobra venom toxins against synthetic target receptors from various prey and predators shed light on the evolutionary arms race. Conclusions: Our findings, therefore, provide fascinating insights into the roles of ecology and life history traits in shaping snake venoms. [ABSTRACT FROM AUTHOR]

Ongoing climate change poses an increasing threat to biodiversity. To avoid decline or extinction, species need to either adjust or adapt to new environmental conditions or track their climatic niches across space. In sessile organisms such as plants, phenotypic plasticity can help maintain fitness in variable and even novel environmental conditions and is therefore likely to play an important role in allowing them to survive climate change, particularly in the short term. Understanding a species' response to rising temperature is crucial for planning well‐targeted and cost‐effective conservation measures. We sampled seeds of three Hypericum species (H. maculatum, H. montanum, and H. perforatum), from a total of 23 populations originating from different parts of their native distribution areas in Europe. We grew them under four different temperature regimes in a greenhouse to simulate current and predicted future climatic conditions in the distribution areas. We measured flowering start, flower count, and subsequent seed weight, allowing us to study variations in the thermal plasticity of flowering phenology and its relation to fitness. Our results show that individuals flowered earlier with increasing temperature, while the degree of phenological plasticity varied among species. More specifically, the plasticity of H. maculatum varied depending on population origin, with individuals from the leading range edge being less plastic. Importantly, we show a positive relationship between higher plasticity and increased flower production, indicating adaptive phenological plasticity. The observed connection between plasticity and fitness supports the idea that plasticity may be adaptive. This study underlines the need for information on plasticity for predicting species' potential to thrive under global change and the need for studies on whether higher phenotypic plasticity is currently being selected as natural populations experience a rapidly changing climate. [ABSTRACT FROM AUTHOR]

Quantifying assemblage variation across environmental gradients provides insight into the ecological and evolutionary mechanisms that differentiate assemblages locally within a larger climate regime. We assessed how vascular plant functional composition and diversity varied across microenvironment to identify ecological differences in assemblages in a mountainous fieldsite in northeastern Utah, USA. Then, we looked at how life‐history strategies and information about phylogenetic differences affect the relationship between functional metrics and environment. We found less functionally dispersed assemblages that were shorter and more resource‐conservative on south‐facing slopes where intra‐annual soil temperature was hotter and more variable. In contrast, we found more functionally dispersed assemblages, that were taller and more resource‐acquisitive on north‐facing slopes where intra‐annual temperature was cooler and less variable. Herbaceous and woody perennials drove these trends. Additionally, including information about phylogenetic differences in a dispersion metric indicated that phylogeny accounts for traits we did not measure. At this fieldsite, soil temperature acts as an environmental filter across aspect. If soil temperature increases and becomes more variable, intra‐annually, the function of north‐ versus south‐facing assemblages may be at risk for contrasting reasons. On south‐facing slopes, assemblages may not have the variance in functional diversity needed to respond to more intense, stressful conditions. Conversely, assemblages on north‐facing slopes may not have the resource‐conservative strategies needed to persist if temperatures become hotter and more variable intra‐annually. Given these results, we advocate for the inclusion of aspect differentiation in studies seeking to understand species and assemblage shifts in response to changing climate conditions. [ABSTRACT FROM AUTHOR]

The NC10 phylum links anaerobic methane oxidation to nitrite denitrification through a unique O2‐producing intra‐aerobic methanotrophic pathway. Although numerous amplicon‐based studies revealed the distribution of this phylum, comprehensive genomic insights and niche characterization in deep‐sea environments were still largely unknown. In this study, we extensively surveyed the NC10 bacteria across diverse deep‐sea environments, including waters, sediments, cold seeps, biofilms, rocky substrates, and subseafloor aquifers. We then reconstructed and analysed 38 metagenome‐assembled genomes (MAGs), and revealed the extensive distribution of NC10 bacteria and their intense selective pressure in these harsh environments. Isotopic analyses combined with gene expression profiling confirmed that active nitrite‐dependent anaerobic methane oxidation (n‐DAMO) occurs within deep‐sea sediments. In addition, the identification of the Wood–Ljungdahl (WL) and 3‐hydroxypropionate/4‐hydroxybutyrat (3HB/4HP) pathways in these MAGs suggests their capability for carbon fixation as chemoautotrophs in these deep‐sea environments. Indeed, we found that for their survival in the oligotrophic deep‐sea biosphere, NC10 bacteria encode two branches of the WL pathway, utilizing acetyl‐CoA from the carbonyl branch for citric acid cycle‐based energy production and methane from the methyl branch for n‐DAMO. The observed low ratios of non‐synonymous substitutions to synonymous substitutions (pN/pS) in n‐DAMO‐related genes across these habitats suggest a pronounced purifying selection that is critical for the survival of NC10 bacteria in oligotrophic deep‐sea environments. These findings not only advance our understanding of the evolutionary adaptations of NC10 bacteria but also underscore the intricate coupling between the carbon and nitrogen cycles within deep‐sea ecosystems, driven by this bacterial phylum. [ABSTRACT FROM AUTHOR]

Plant dwarfism, a syndrome characterised by a significant reduction in plant height and organ size, is a widely observed pattern of stress‐tolerant life‐form evolution that results from local adaptation to harsh environmental conditions. The drivers of assemblage‐level dwarfism have primarily been attributed to abiotic factors, such as low temperature, aridity, poor soil fertility or frequent fires. While biotic factors such as grazing pressure from herbivores can contribute to the establishment of plant dwarfism, these factors have rarely been tested at assemblage levels.Focusing on a dwarf plant assemblage comprising over 80 taxa on a small continental island in Japan with a high deer density, we hypothesised that historical deer grazing could also be a factor contributing to the large‐scale convergent evolution of dwarfism.To test this hypothesis, we measured the size of 1908 individual plants of 40 taxa pairs, comprising both palatable and unpalatable pairs from the island and their counterpart taxa from neighbouring regions, and sought to assess which factors (i.e. low solar radiation, estimated divergence time, low nutrient conditions and grazing pressure from deer) may have contributed to the formation of the dwarf plant assemblage on the island. We also performed genetic analysis to infer the time frames for the establishment of dwarf taxa.Statistical analyses revealed that plant size was significantly reduced mainly among the palatable taxa growing on the island, with preferential grazing by deer being identified as the most significant factor influencing plant size. Furthermore, genetic analyses revealed that dwarf ecotypes may have evolved over tens of thousands of years.Synthesis: To the best of our knowledge, this study is the first to demonstrate that interactions with herbivores can shape the assemblage‐level convergence of plant dwarfism. These findings enhance our current understanding of the formation of plant functional diversity. [ABSTRACT FROM AUTHOR]

Camouflage and warning signals are different antipredator strategies, which offer an excellent opportunity to study the evolutionary forces acting on prey appearance. Edible prey often escape detection via camouflage, which usually leads to apostatic selection favoring rare morphs. By contrast, defended prey often display conspicuous coloration acting as warning signals to predators, which usually leads to positive frequency dependence and signal uniformity. However, when two morphs of the same species vary greatly in conspicuousness, the maintenance of both cryptic and conspicuous forms in profitable prey populations remains enigmatic. Using the white and melanic morphs of the invasive box tree moth (Cydalima perspectalis) presented at three different frequencies, we investigate (a) the palatability of caterpillars and adult moths to birds, (b) predation rates on the less conspicuous melanic morph, and (c) the role of frequency dependence in balancing morph frequencies. Our results show that caterpillars are distasteful for birds but not adult moths that are fully palatable. We found that the less conspicuous, melanic morph, benefits from reduced predation due to its lower detectability. The more conspicuous, white morph, instead, is more predated and is best off when common, suggesting positive frequency dependence. These results offer new insights into the evolution of color polymorphism and prey defenses in a polymorphic moth species. Further investigation is required to understand the role of different predation regimes on the maintenance of the polymorphism in this species and test whether additional selection pressures operate in natural populations. [ABSTRACT FROM AUTHOR]

Ecological disturbance has been proposed to have a variety of effects on biodiversity. These mechanisms are well studied over shorter timescales through experimental manipulation of ecosystems, but the effect of disturbance on longer timescales, where evolutionary processes operate, is less well understood. This is at least in part because evolutionary processes are too slow to observe in experimental manipulations of ecosystems. Here, we use the Rapid Evolutionary Simulator system (REvoSim) to solve this problem. REvoSim is a spatially explicit, agent-based simulation tool that models both ecological and evolutionary processes and is capable of simulating many thousands of generations of evolution per hour in a population of up to 1 million organisms. We use REvoSim to evaluate the biological cropping hypothesis, which predicts that the non-selective culling of organisms from populations ("cropping") can enhance diversity in those populations over long timescales by reducing the homogenising effects of competitive exclusion. Our experiments demonstrate that cropping alone can increase diversity within populations under certain circumstances: those where it has the net effect of reducing the selection pressure acting on those populations. However, intense cropping pressure may increase the selection pressure on organisms to reproduce rapidly, potentially offsetting the effects of reduced competitive exclusion on diversity. We also show that cropping alone is not sufficient to result in reproductive isolation within populations. This implies that, while cropping can maintain a high species diversity within an ecosystem, additional mechanisms must be invoked to generate that high diversity in the first instance. [ABSTRACT FROM AUTHOR]

Phenotypic change plays diverse roles in species' colonization, but most invasion studies target single species. To compare ecomorphological changes among co-invading species with overlapping niches, we examined three lizards on the island of O'ahu (Anolis carolinensis, A. sagrei, Phelsuma laticauda). Using specimens from three decades of unfolding invasions obtained through museum collections and contemporary field work, we quantified shifts in three traits: snout vent length (SVL), forelimb-, and hindlimb-length (limb lengths relative to SVL). We hypothesized that competition among these three species has led to ecological shifts that will be detectable through morphological change. Overall, we found that unique patterns of phenotypic change were both species-specific and sex-specific within species: (1) male A. sagrei, female A. carolinensis, and male P. laticauda increased in SVL and (2) relative hindlimb length increased in female A. carolinensis since the 1980s. The observed changes involve traits that may be consequential to invasion dynamics. This study illustrates how museum- and field-based research can be integrated to document nuanced temporal patterns in the phenotypes of co-invading species that share similar niches in native ranges, raising questions about the underlying process(es) driving species- and sex-specific change in co-invaded systems. [ABSTRACT FROM AUTHOR]

Locomotory performance is an important determinant of fitness in most animals, including flying insects. Strong selective pressures on wing morphology are therefore expected. Previous studies on wing shape in Lepidoptera have found some support for hypotheses relating wing shape to environment-specific selective pressures on aerodynamic performance. Here, we present a phylogenetic comparative study on wing shape in the lepidopteran family Geometridae, covering 374 species of the northern European fauna. We focused on 11 wing traits including aspect ratio, wing roundness, and the pointedness of the apex, as well as the ratio of forewing and hindwing areas. All measures were taken from images available on the internet, using a combination of tools available in Fiji software and R. We found that wing shape demonstrates a phylogenetically conservative pattern of evolution in Geometridae, showing similar or stronger phylogenetic signal than many of its potential predictors. Several wing traits showed statistically significant associations with predictors such as body size, phenology, and preference for forest habitats. Overall, however, all of these associations remained notably weak, with no wing shape being excluded for any value of the predictors, including body size. We conclude that, in geometrids, wing traits do not readily respond to selective pressures optimizing aerodynamic performance of the moths in different environments. Selection on wing shape may nevertheless operate through other functions of the wings, with the effectiveness of crypsis at rest being a promising candidate for further studies. [ABSTRACT FROM AUTHOR]

In alpine ecosystems, elevation broadly functions as a steep thermal gradient, with plant communities exposed to regular fluctuations in hot and cold temperatures. These conditions lead to selective filtering, potentially contributing to species-level variation in thermal tolerance and population-level genetic divergence. Few studies have explored the breadth of alpine plant thermal tolerances across a thermal gradient or the underlying genetic variation thereof. We measured photosystem heat (Tcrit-hot) and cold (Tcrit-cold) thresholds of ten Australian alpine species across elevation gradients and characterised their neutral genetic variation. To reveal the biogeographical drivers of present-day genetic signatures, we also reconstructed temporal changes in habitat suitability across potential distributional ranges. We found intraspecific variation in thermal thresholds, but this was not associated with elevation, nor underpinned by genetic differentiation on a local scale. Instead, regional population differentiation and considerable homozygosity within populations may, in part, be driven by distributional contractions, long-term persistence, and migrations following habitat suitability. Our habitat suitability models suggest that cool-climate-distributed alpine plants may be threatened by a warming climate. Yet, the observed wide thermal tolerances did not reflect this vulnerability. Conservation efforts should seek to understand variations in species-level thermal tolerance across alpine microclimates. [ABSTRACT FROM AUTHOR]

In seasonal environments, organisms must synchronize their life cycles to conditions favorable for growth and reproduction. Because season length varies geographically, local adaptation should arise in traits that regulate phenological responses. Geographic photoperiodism clines are well known, but comparable studies on thermal performance are equivocal and often overlook nonlinear responses. Therefore, we examined local adaptation in plastic responses to both photoperiod and temperature along a 752‐km latitudinal cline, by comparing four Swedish populations of the butterfly Pieris napi. Using a common garden design, we estimated (1) photoperiod response curves for diapause induction and (2) thermal performance curves for development and growth rates. We show that differences in photoperiodism follow the expected geographical pattern, where diapause is induced at longer daylengths in northern populations (where growth seasons are short and summer days long). However, population differences in thermal performance curves were small and seemingly idiosyncratic, without clear clinal patterns. Photoperiodic responses appear to evolve more readily than thermal responses, highlighting photoperiodism as a key driver of local life cycle synchronization. [ABSTRACT FROM AUTHOR]

We give a series of numerical examples of competitive evolution in the predation system, showing in some cases how the choice is made to increase the efficiency of the predation mechanism (or other significant parameters) to the detriment of populations (both of prey and predators). We then develop the mathematical theory that enables us to understand the causality involved, and we identify a trend towards the emergence of the functional predation mechanism as such (and not of populations of the species involved). The realization of this trend only takes place when the conditions for it are offered by the hazards proposed to successive competitive choices. The logical structure of this trend is similar to that of the "tendency of rate of profit to fall" in certain economic models. [ABSTRACT FROM AUTHOR]

Software for realistically simulating complex population genomic processes is revolutionizing our understanding of evolutionary processes, and providing novel opportunities for integrating empirical data with simulations. However, the integration between standalone simulation software and R is currently not well developed. Here, we present slimr, an R package designed to create a seamless link between standalone software SLiM >3.0, one of the most powerful population genomic simulation frameworks, and the R development environment, with its powerful data manipulation and analysis tools. We show how slimr facilitates smooth integration between genetic data, ecological data and simulation in a single environment. The package enables pipelines that begin with data reading, cleaning and manipulation, proceed to constructing empirically based parameters and initial conditions for simulations, then to running numerical simulations and finally to retrieving simulation results in a format suitable for comparisons with empirical data – aided by advanced analysis and visualization tools provided by R. We demonstrate the use of slimr with an example from our own work on the landscape population genomics of desert mammals, highlighting the advantage of having a single integrated tool for both data analysis and simulation. slimr makes the powerful simulation ability of SLiM directly accessible to R users, allowing integrated simulation projects that incorporate empirical data without the need to switch between software environments. This should provide more opportunities for evolutionary biologists and ecologists to use realistic simulations to better understand the interplay between ecological and evolutionary processes. [ABSTRACT FROM AUTHOR]

The net outcomes of mutualisms are mediated by the trade-offs between the costs and benefits provided by both partners. Our review proposes the existence of a trade-off in ant protection mutualisms between the benefits generated by the ants' protection against the attack of herbivores and the losses caused by the disruption of pollination processes, which are commonly not quantified. This trade-off has important implications for understanding the evolution of extrafloral nectaries (EFNs), an adaptation that has repeatedly evolved throughout the flowering plant clade. We propose that the outcome of this trade-off is contingent on the specific traits of the organisms involved. We provide evidence that the protective mutualisms between ants and plants mediated by EFNs have optimal protective ant partners, represented by the optimum point of the balance between positive effects on plant protection and negative effects on pollination process. Our review also provides important details about a potential synergism of EFN functionality; that is, these structures can attract ants to protect against herbivores and/or distract them from flowers so as not to disrupt pollination processes. Finally, we argue that generalizations regarding how ants impact plants should be made with caution since ants' effects on plants vary with the identity of the ant species in their overall net outcome. [ABSTRACT FROM AUTHOR]

Summary: The phytoplankton Phaeocystis globosa plays an important role in sulfur cycling and climate control, and can develop harmful algal blooms (HABs). Here we report a chromosome-scale reference genome assembly of P. globosa, which enable in-depth analysis of molecular underpinnings of important ecological characteristics. Comparative genomic analyses detected two-rounds of genome duplications that may have fueled evolutionary innovations. The genome duplication may have resulted in the formation of dual HiDP and LoDP dimethylsulphoniopropionate (DMSP) biosynthesis pathways in P. globosa. Selective gene family expansions may have strengthened biological pathways critical for colonial formation that is often associated with the development of algal blooms. The copy numbers of rhodopsin genes are variable in different strains, suggesting that rhodopsin genes may play a role in strain-specific adaptation to ecological factors. The successful reconstruction of the P. globosa genome sets up an excellent platform that facilitates in-depth research on bloom development and DMSP metabolism.

Summary: Learning, memorizing, and recalling of potential ovipositing sites can influence oviposition preference. Classical conditioning experiments have shown that vinegar flies can learn the association of olfactory, gustatory, or visual stimuli with either positive or negative unconditioned stimuli. However, less is known about whether similar associations are formed in an ecologically more relevant context like during oviposition. Our experiments reveal that Drosophila melanogaster females increase their preference for substrates they have already experienced. However, this change of preference requires that the flies not only smelled or touched the substrates but also oviposited on them. We furthermore show that such an experience results in long-term memory lasting for at least 4 days, i.e., a duration that so far was shown only for aversive conditioning. Our study thus reveals a different form of associative learning in D. melanogaster that might be highly relevant for settling novel ecological niches.

Abstract Ongoing climate change poses an increasing threat to biodiversity. To avoid decline or extinction, species need to either adjust or adapt to new environmental conditions or track their climatic niches across space. In sessile organisms such as plants, phenotypic plasticity can help maintain fitness in variable and even novel environmental conditions and is therefore likely to play an important role in allowing them to survive climate change, particularly in the short term. Understanding a species' response to rising temperature is crucial for planning well‐targeted and cost‐effective conservation measures. We sampled seeds of three Hypericum species (H. maculatum, H. montanum, and H. perforatum), from a total of 23 populations originating from different parts of their native distribution areas in Europe. We grew them under four different temperature regimes in a greenhouse to simulate current and predicted future climatic conditions in the distribution areas. We measured flowering start, flower count, and subsequent seed weight, allowing us to study variations in the thermal plasticity of flowering phenology and its relation to fitness. Our results show that individuals flowered earlier with increasing temperature, while the degree of phenological plasticity varied among species. More specifically, the plasticity of H. maculatum varied depending on population origin, with individuals from the leading range edge being less plastic. Importantly, we show a positive relationship between higher plasticity and increased flower production, indicating adaptive phenological plasticity. The observed connection between plasticity and fitness supports the idea that plasticity may be adaptive. This study underlines the need for information on plasticity for predicting species' potential to thrive under global change and the need for studies on whether higher phenotypic plasticity is currently being selected as natural populations experience a rapidly changing climate.

Abstract Quantifying assemblage variation across environmental gradients provides insight into the ecological and evolutionary mechanisms that differentiate assemblages locally within a larger climate regime. We assessed how vascular plant functional composition and diversity varied across microenvironment to identify ecological differences in assemblages in a mountainous fieldsite in northeastern Utah, USA. Then, we looked at how life‐history strategies and information about phylogenetic differences affect the relationship between functional metrics and environment. We found less functionally dispersed assemblages that were shorter and more resource‐conservative on south‐facing slopes where intra‐annual soil temperature was hotter and more variable. In contrast, we found more functionally dispersed assemblages, that were taller and more resource‐acquisitive on north‐facing slopes where intra‐annual temperature was cooler and less variable. Herbaceous and woody perennials drove these trends. Additionally, including information about phylogenetic differences in a dispersion metric indicated that phylogeny accounts for traits we did not measure. At this fieldsite, soil temperature acts as an environmental filter across aspect. If soil temperature increases and becomes more variable, intra‐annually, the function of north‐ versus south‐facing assemblages may be at risk for contrasting reasons. On south‐facing slopes, assemblages may not have the variance in functional diversity needed to respond to more intense, stressful conditions. Conversely, assemblages on north‐facing slopes may not have the resource‐conservative strategies needed to persist if temperatures become hotter and more variable intra‐annually. Given these results, we advocate for the inclusion of aspect differentiation in studies seeking to understand species and assemblage shifts in response to changing climate conditions.

Summary: The hemoglobinless Antarctic icefish develop large hearts to compensate for reduced oxygen-carrying capacity, which serves as a naturally occurred model to explore the factors regulating cardiogenesis. Through miRNAome and microRNAome comparisons between an icefish (Chionodraco hamatus) and two red-blooded notothenioids, we discovered significant upregulation of factors in the BMP signaling pathways and altered expression of many miRNAs, including downregulation of 14 miRNAs in the icefish heart. Through knocking down of these miRNAs, we identified two of them, miR-458-3p and miR-144-5p, involved in enlarged heart development. The two miRNAs were found to regulate cardiomyocyte proliferation by targeting bone morphogenetic protein-2 (bmp2). We further validated that activation of the miRNA-bmp2 signaling in the fish heart could be triggered by hypoxic exposure. Our study suggested that a few miRNAs play important roles in the hypoxia-induced cardiac remodeling of the icefish which shed new light on the mechanisms regulating cardiomyocyte proliferation in heart.

Summary: Biological diversity often arises as organisms adapt to new ecological conditions (i.e., ecological opportunities) or colonize suitable areas (i.e., spatial opportunities). Cases of geographical expansion followed by local ecological divergence are well described; they result in clades comprising ecologically heterogeneous subclades. Here, we show that the desert ant genus Cataglyphis likely originated in open grassland habitats in the Middle East ∼18 million years ago and became a taxon of diverse species specializing in prey of different masses. The genus then colonized the Mediterranean Basin around 9 million years ago. The result was the rapid accumulation of species, and the appearance of local assemblages containing species from different lineages that still displayed ancestral foraging specialties. These findings highlight that, in Cataglyphis, ecological diversification preceded geographical expansion, resulting in a clade composed of ecologically homogeneous subclades.

Conservation strategies for huemul (Hippocamelus bisulcus), listed as an endangered cervid by IUCN, have not helped to reverse its declining population trends. Recent evaluations of historical data revealed that they also inhabited lower valleys and grasslands as residents or only during winter. However, the dogma persists that huemuls do not need such habitats. To determine if more solid evidence exists to back up or refute our hypothesis that huemuls once inhabited lower valleys and grasslands, we researched the literature and discovered additional relevant historical sources on this species. These new findings substantiate that huemuls also occupied unforested areas, reaching the Atlantic coast, and resided on various islands including Tierra del Fuego, and that their co-occurrence with guanaco was frequent. Their extreme naivety towards humans resulted in their extirpation on winter ranges settled by humans, resulting in refugee huemuls year-round on remote mountain summer ranges. The ease by which indigenous people could kill them for subsistence and commercial export of hides to Europe, followed by the lowlands becoming modified by settlers and their exotic species facilitated the huemuls’ extirpation. The hypothesis of a dramatic modification of the original biogeographical distribution of huemuls is supported by anatomical and ecological features along with historical accounts. Sedentariness on only rugged summer ranges makes long-term survival of this species crucially challenging and requires sound conservation strategies that incorporate geographical areas of their former distribution.

Variations in plant characteristics in response to habitat heterogeneity can provide valuable insights into the mechanisms governing plant responses to environmental conditions. In this study, we investigated the role of environmental factors associated with arid conditions in shaping the phenotypic responses of an arid annual plant, Anastatica hierochuntica, across several populations found along an aridity gradient and across multiple spatial scales. Utilizing both field surveys and a net house experiment, we assessed the effects of environmental factors on trait variability within and between populations. The results indicated a significant convergence in plant height due to site aridity, reflecting growth potential based on abiotic resources. Convergence was also observed in the plant's electrolyte leakage with aridity and in plant height concerning soil salinity at specific sites. Phenotypic plasticity was pivotal in maintaining trait variability, with plant height plasticity increasing with soil salinity, SLA plasticity decreasing with aridity, and leaf number plasticity rising with aridity. In conclusion, our findings underscore the adaptive significance of phenotypic variability, especially plasticity, in arid conditions. Notably, trait variability and plasticity did not consistently diminish in stressful settings, emphasizing the adaptive value of flexible responses in such environments. [ABSTRACT FROM AUTHOR]

The tropical eastern Pacific (TEP) has been divided into several biogeographic provinces separated by two types of habitat gaps: stretches of sandy shoreline that separate rocky reefs on the mainland (Sinaloan and Central American gaps) and expanses of deep ocean between offshore TEP islands and the mainland. Those gaps are known to influence the distribution and evolution of TEP reef fishes by acting as barriers to gene flow. We investigated potential effects of those gaps on the genetic structure and connectivity of populations of five widely distributed TEP reef-fish species that have different modes of life, habitat preferences and reproductive strategies: Caranx caballus, Rypticus bicolor, Hypsoblennius brevipinnis, Plagiotremus azaleus and Stegastes flavilatus. We used the coxI mitochondrial DNA marker to make phylogeographic, population genetics, and coalescent analyses of geographic patterns of genetic variation in these species. Those analyses showed high variation in levels of genetic diversity. We found no geographic genetic differentiation relating to mainland gaps in any species. Such genetic homogeneity may relate to factors such as migratory behavior, high pelagic dispersal potential and wide environmental tolerance. In two species, differentiation across oceanic gaps separating oceanic islands from the mainland may reflect differences between insular and mainland environments. Historical population expansions that occurred between 400 and 100 thousand years ago in different species may have shaped by patterns of Pleistocene climatic dynamics. The lack of polymorphism of coxI in the damselfish Stegastes flavilatus may relate to the effects of a historical population collapse, although we were not able to detect that genetically. [ABSTRACT FROM AUTHOR]

Aim: Understanding the global distribution of biodiversity and the factors that influence it are among the central goals of biogeography. How abiotic and biotic factors limit species' ranges has been investigated across a variety of environments and taxonomic groups. However, such investigations across oceanic depths remain underrepresented, particularly for chemosynthetic environments such as hydrocarbon seeps. The depth differentiation (DD) hypothesis suggests that steep environmental gradients in the upper depths of the ocean may limit species' ranges over relatively short vertical distances. The present study aims to investigate the evidence for the DD hypothesis at hydrocarbon seep sites along the Pacific Costa Rica Margin (CRM) by investigating the biogeographic distributions of gastropods sampled there and the factors that influence them. Location: Costa Rica. Taxon: Mollusca, Gastropoda, Provannidae, Genus: Provanna (Dall, 1918). Methods: 1813 Provanna snails were collected across 1300 metres (m) of depth from Costa Rican hydrocarbon seeps. To test the DD hypothesis, species partitioning across the depth range was investigated. In addition to gradients in oceanographic conditions, such as temperature, oxygen, and salinity, other factors potentially responsible for filtering species were also considered as alternative hypotheses, including the availability of biogenic substrate, the availability of and reliance on chemosynthetic fluids, and specific preferences for certain environmental conditions. Results and Main Conclusions: Three species of Provanna were identified from the CRM and exhibited partitioning across depth. For the two dominant species (P. laevis and P. goniata), the data suggest that depth‐associated oceanographic conditions are more likely than any other factor investigated to explain their observed partitioning across depth, supporting the DD hypothesis. This study also presents novel evidence that such partitioning may be unilaterally determined, wherein species with narrower depth ranges may limit the local depth ranges of others. This study represents an extension of biogeographic range limit literature into chemosynthetic habitats and across oceanic depths. [ABSTRACT FROM AUTHOR]

Conservation strategies for huemul (Hippocamelus bisulcus), listed as an endangered cervid by IUCN, have not helped to reverse its declining population trends. Recent evaluations of historical data revealed that they also inhabited lower valleys and grasslands as residents or only during winter. However, the dogma persists that huemuls do not need such habitats. To determine if more solid evidence exists to back up or refute our hypothesis that huemuls once inhabited lower valleys and grasslands, we researched the literature and discovered additional relevant historical sources on this species. These new findings substantiate that huemuls also occupied unforested areas, reaching the Atlantic coast, and resided on various islands including Tierra del Fuego, and that their co-occurrence with guanaco was frequent. Their extreme naivety towards humans resulted in their extirpation on winter ranges settled by humans, resulting in refugee huemuls year-round on remote mountain summer ranges. The ease by which indigenous people could kill them for subsistence and commercial export of hides to Europe, followed by the lowlands becoming modified by settlers and their exotic species facilitated the huemuls' extirpation. The hypothesis of a dramatic modification of the original biogeographical distribution of huemuls is supported by anatomical and ecological features along with historical accounts. Sedentariness on only rugged summer ranges makes long-term survival of this species crucially challenging and requires sound conservation strategies that incorporate geographical areas of their former distribution. [ABSTRACT FROM AUTHOR]

Laterality, the tendency of animals to use the structures on one side of the body more frequently or efficiently than the other side, can reflect the evolutionary history of species, their ecological characteristics, and cognitive abilities. Using anurans as a model system, it has been hypothesized that the strength of laterality (measured as the percentage of right-handed individuals) is higher in terrestrial and arboreal species, which exhibit asynchronous locomotion type (e.g., walking, climbing), than in aquatic species where synchronous locomotion type (e.g., swimming) predominates. We tested these predictions, including body size as an additional factor, in 19 Neotropical anuran species. For this, we obtained data on forelimb use preference for individuals of such species. We then combined these data with published data for another 14 anuran species obtained through a systematic review of the literature. The combined dataset was used to perform a phylogenetic comparative analysis to verify the strength of laterality in the species. We found that four out of the 19 tested species show a percentage of right-handed individuals that was higher or lower than expected by chance. Individuals of these four species exhibit asynchronous movements of forelimbs during displacements, foraging behaviors, sexual displays, or agonistic interactions. Results of a phyloANOVA and a phyloANCOVA indicated that the strength of laterality was higher in species with asynchronous movements, but this was unrelated to microhabitat and body size. Asynchronous (i.e., non-simultaneous) movements of limbs imply alternating muscle contractions and a higher neural asymmetry than synchronous (i.e., simultaneous) movements of limbs. Therefore, species with an asynchronous locomotion type could be reflecting such complexity and neural asymmetry in higher levels of forelimb laterality. Our results mostly support the predictions based on models that cover the expected relationship between the strength of laterality and the evolutionary ecology of vertebrates. [ABSTRACT FROM AUTHOR]

Abstract In seasonal environments, organisms must synchronize their life cycles to conditions favorable for growth and reproduction. Because season length varies geographically, local adaptation should arise in traits that regulate phenological responses. Geographic photoperiodism clines are well known, but comparable studies on thermal performance are equivocal and often overlook nonlinear responses. Therefore, we examined local adaptation in plastic responses to both photoperiod and temperature along a 752‐km latitudinal cline, by comparing four Swedish populations of the butterfly Pieris napi. Using a common garden design, we estimated (1) photoperiod response curves for diapause induction and (2) thermal performance curves for development and growth rates. We show that differences in photoperiodism follow the expected geographical pattern, where diapause is induced at longer daylengths in northern populations (where growth seasons are short and summer days long). However, population differences in thermal performance curves were small and seemingly idiosyncratic, without clear clinal patterns. Photoperiodic responses appear to evolve more readily than thermal responses, highlighting photoperiodism as a key driver of local life cycle synchronization.

Organisms continuously modify their environment, often impacting the fitness of future conspecifics due to ecological inheritance. When this inheritance is biased toward kin, selection favors modifications that increase the fitness of downstream individuals. How such selection shapes trait variation within populations remains poorly understood. Using mathematical modelling, we investigate the coevolution of multiple traits in a group-structured population when these traits affect the group environment, which is then bequeathed to future generations. We examine when such coevolution favors polymorphism as well as the resulting associations among traits. We find in particular that two traits become associated when one trait affects the environment while the other influences the likelihood that future kin experience this environment. To illustrate this, we model the coevolution of (a) the attack rate on a local renewable resource, which deteriorates environmental conditions, with (b) dispersal between groups, which reduces the likelihood that kin suffers from such deterioration. We show this often leads to the emergence of two highly differentiated morphs: one that readily disperses and depletes local resources, and another that maintains these resources and tends to remain philopatric. More broadly, we suggest that ecological inheritance can contribute to phenotypic diversity and lead to complex polymorphism. [ABSTRACT FROM AUTHOR]

As plant-microbe interactions are both ubiquitous and critical in shaping plant fitness, patterns of plant adaptation to their local environment may be influenced by these interactions. Identifying the contribution of soil microbes to plant adaptation may provide insight into the evolution of plant traits and their microbial symbioses. To this end, we assessed the contribution of soil microbes to plant salinity adaptation by growing 10 populations of Bromus tectorum , collected from habitats differing in their salinity, in the greenhouse under either high-salinity or nonsaline conditions and with or without soil microbial partners. Across two live soil inoculum treatments, we found evidence for adaptation of these populations to their home salinity environment. However, when grown in sterile soils, plants were slightly maladapted to their home salinity environment. As plants were on average more fit in sterile soils, pathogenic microbes may have been significant drivers of plant fitness herein. Consequently, we hypothesized that the plant fitness advantage in their home salinity may have been due to increased plant resistance to pathogenic attack in those salinity environments. Our results highlight that plant-microbe interactions may partially mediate patterns of plant adaptation as well as be important selective agents in plant evolution. [ABSTRACT FROM AUTHOR]

Studies of eco‐evolutionary dynamics have integrated evolution with ecological processes at multiple scales (populations, communities and ecosystems) and with multiple interspecific interactions (antagonistic, mutualistic and competitive). However, evolution has often been conceptualised as a simple process: short‐term directional adaptation that increases population growth. Here we argue that diverse other evolutionary processes, well studied in population genetics and evolutionary ecology, should also be considered to explore the full spectrum of feedback between ecological and evolutionary processes. Relevant but underappreciated processes include (1) drift and mutation, (2) disruptive selection causing lineage diversification or speciation reversal and (3) evolution driven by relative fitness differences that may decrease population growth. Because eco‐evolutionary dynamics have often been studied by population and community ecologists, it will be important to incorporate a variety of concepts in population genetics and evolutionary ecology to better understand and predict eco‐evolutionary dynamics in nature. [ABSTRACT FROM AUTHOR]

Prosopanche is a poorly known genus of parasitic plants from South and Central America. Growing almost entirely underground with a complete lack of leaves, plants of Prosopanche bear more resemblance to fungi than plants and have many remarkable aspects to their life history and ecology that require further investigation. Here, we provide an up‐to‐date revision of the current state of understanding of Prosopanche, including taxonomy, biogeography, plant‐pollinator ecology and host‐parasite interactions. We discuss the untapped research potential of this group of plants and recommend the Prosopanche as an ideal candidate for exploring the evolutionary origins of parasitism among flowering plants.

In alpine ecosystems, elevation broadly functions as a steep thermal gradient, with plant communities exposed to regular fluctuations in hot and cold temperatures. These conditions lead to selective filtering, potentially contributing to species-level variation in thermal tolerance and population-level genetic divergence. Few studies have explored the breadth of alpine plant thermal tolerances across a thermal gradient or the underlying genetic variation thereof. We measured photosystem heat (Tcrit-hot) and cold (Tcrit-cold) thresholds of ten Australian alpine species across elevation gradients and characterised their neutral genetic variation. To reveal the biogeographical drivers of present-day genetic signatures, we also reconstructed temporal changes in habitat suitability across potential distributional ranges. We found intraspecific variation in thermal thresholds, but this was not associated with elevation, nor underpinned by genetic differentiation on a local scale. Instead, regional population differentiation and considerable homozygosity within populations may, in part, be driven by distributional contractions, long-term persistence, and migrations following habitat suitability. Our habitat suitability models suggest that cool-climate-distributed alpine plants may be threatened by a warming climate. Yet, the observed wide thermal tolerances did not reflect this vulnerability. Conservation efforts should seek to understand variations in species-level thermal tolerance across alpine microclimates.

We give a series of numerical examples of competitive evolution in the predation system, showing in some cases how the choice is made to increase the efficiency of the predation mechanism (or other significant parameters) to the detriment of populations (both of prey and predators). We then develop the mathematical theory that enables us to understand the causality involved, and we identify a trend towards the emergence of the functional predation mechanism as such (and not of populations of the species involved). The realization of this trend only takes place when the conditions for it are offered by the hazards proposed to successive competitive choices. The logical structure of this trend is similar to that of the “tendency of rate of profit to fall” in certain economic models.

Summary: A major objective of microbial ecology is to identify how the composition of microbial taxa shapes host phenotypes. However, most studies focus on pairwise interactions and ignore the potentially significant effects of higher-order microbial interactions.Here, we quantify the effects of higher-order interactions among taxa on host infection risk. We apply our approach to an in silico dataset that is built to resemble a population of insect hosts with gut-associated microbial communities at risk of infection from an intestinal parasite across a breadth of nutrient environmental contexts.We find that the effect of higher-order interactions is considerable and can change appreciably across environmental contexts. Furthermore, we show that higher-order interactions can stabilize community structure thereby reducing host susceptibility to parasite invasion.Our approach illustrates how incorporating the effects of higher-order interactions among gut microbiota across environments can be essential for understanding their effects on host phenotypes.

Summary: Sex pheromones impart maximal attraction when their components are present at optimal ratios that confer balanced olfactory inputs in potential mates. Altering ratios or adding pheromone analogs to optimal mixtures may disrupt balanced olfactory antagonism and result in reduced attraction, however, tests in natural populations are lacking. We tested this hypothesis in sea lamprey (Petromyzon marinus), a fish whose male sex pheromone attracts females when two critical components, 3-keto petromyzonol sulfate (3kPZS) and petromyzonol sulfate (PZS), are present at certain ratios. Here, we report a pheromone analog, petromyzonol tetrasulfate (3sPZS), reduced female attraction to 3kPZS but not to PZS. 3sPZS mixed with additional PZS synergistically disrupted female attraction to the male pheromone and reduced spawning by 97% in a high-density population. Our results provide evidence of balanced olfactory antagonism in a vertebrate and establish a tactic to disrupt spawning of sea lamprey, a destructive invader of the Laurentian Great Lakes.

Heat waves are becoming more frequent and intense with climate change, but the demographic and evolutionary consequences of heat waves are rarely investigated in herbaceous plant species. We examine the consequences of a short but extreme heat wave in Oregon populations of the common yellow monkeyflower (Mimulus guttatus) by leveraging a common garden experiment planted with range‐wide populations and observational studies of 11 local populations. In the common garden, 89% of seedlings died during the heat wave including >96% of seedlings from geographically local populations. Some populations from hotter and drier environments had higher fitness, however, others from comparable environments performed poorly. Observational studies of local natural populations drastically differed in the consequences of the heat wave—one population was completely extirpated and nearly half had a >50% decrease in fitness. However, a few populations had greater fitness during the heat wave year. Differences in mortality corresponded to the impact of the heat wave on soil moisture—retention of soil moisture throughout the heat wave led to greater survivorship. Our results suggest that not all populations experience the same intensity or degree of mortality during extreme events and such heterogeneity could be important for genetic rescue or to facilitate the distribution of adaptive variants throughout the region. [ABSTRACT FROM AUTHOR]

The idea that fire acts as an evolutionary force contributing to shaping species traits started a century ago, but had not been widely recognized until very recently. Among the first to realize this force were E dward B. Poulton, R. D ale Guthrie, and E dwin V. Komarek in animals and W illis L. Jepson, W alter W. Hough, T om M. Harris, P hilip V. Wells, and R obert W. Mutch in plants. They were all ahead of their time in their evolutionary thinking. Since then, evolutionary fire ecology has percolated very slowly into the mainstream ecology and evolutionary biology; in fact, this topic is still seldom mentioned in textbooks of ecology or evolution. Currently, there is plenty of evidence suggesting that we cannot understand the biodiversity of our planet without considering the key evolutionary role of fire. But there is still research to be done in order to fully understand fire's contribution to species evolution and to predicting species responses to rapid global changes. [ABSTRACT FROM AUTHOR]

Orchid mycorrhiza forms unique symbiotic associations between members of the Orchidaceae and multiple ecological guilds of fungi. Because orchids associate with a wide variety of fungi with different ecological functions, they represent an ideal study system to address fundamental questions about the evolution and ecophysiology of mycorrhizal symbiosis. Although it is well established that shifts in mycorrhizal associations are linked to transitions in plant trophic mode, it remains unclear what ecological drivers promote these evolutionary changes.Here, we investigated mycorrhizal communities and isotope signatures across six populations of the terrestrial orchid Neottia ovata growing under contrasting light conditions in temperate Europe. We hypothesized that plants growing in forests would associate with different mycorrhizal fungi than plants occurring in grasslands and that the limited light availability in forests leads to a higher contribution of fungi to the carbon budget of orchids.Our results showed that N. ovata predominantly associated with rhizoctonia fungi of the family Serendipitaceae in both habitats, but plants in forests also recruited ectomycorrhizal fungi. Root communities highly resembled soil communities and variation in root communities was significantly related to habitat type and edaphic factors. In contrast, isotope signatures (13C, 15N, 2H and 18O) and N concentration showed no significant relationship with habitat type. In addition, both 13C and 2H were not significantly correlated to habitat's light availability.Although it has been suggested that the presence of a wide variety of ectomycorrhizal fungi in root communities of orchids can serve as a precursor for evolutionary shifts to partial mycoheterotrophy (mixotrophy), the presence or absence of ectomycorrhizal fungi did not substantially influence the isotope signatures of N. ovata. These results indicate that rhizoctonia fungi played the major functional role in C and nutrient supply and that ectomycorrhizal fungi did not substantially contribute to the carbon budget of the plants. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

From genes to communities, understanding how diversity is maintained remains a fundamental question in biology. One challenging to identify, yet potentially ubiquitous, mechanism for the maintenance of diversity is negative frequency dependent selection (NFDS), which occurs when entities (e.g., genotypes, life history strategies, species) experience a per capita reduction in fitness with increases in relative abundance. Because NFDS allows rare entities to increase in frequency while preventing abundant entities from excluding others, we posit that negative frequency dependent selection plays a central role in the maintenance of diversity. In this review, we relate NFDS to coexistence, identify mechanisms of NFDS (e.g., mutualism, predation, parasitism), review strategies for identifying NFDS, and distinguish NFDS from other mechanisms of coexistence (e.g., storage effects, fluctuating selection). We also emphasize that NFDS is a key place where ecology and evolution intersect. Specifically, there are many examples of frequency dependent processes in ecology, but fewer cases that link this process to selection. Similarly, there are many examples of selection in evolution, but fewer cases that link changes in trait values to negative frequency dependence. Bridging these two well‐developed fields of ecology and evolution will allow for mechanistic insights into the maintenance of diversity at multiple levels. [ABSTRACT FROM AUTHOR]

Hybridization between taxa generates new pools of genetic variation that can lead to different environmental responses and demographic trajectories over time than seen in parental lineages. The potential for hybrids to have novel environmental tolerances may be increasingly important in mountainous regions, which are rapidly warming and drying due to climate change. Demographic analysis makes it possible to quantify within‐ and among‐species responses to variation in climate and to predict population growth rates as those conditions change. We estimated vital rates and population growth in 13 natural populations of two cinquefoil taxa (Potentilla hippiana and P. pulcherrima) and their hybrid across elevation gradients in the Southern Rockies. Using three consecutive years of environmental and demographic data, we compared the demographic responses of hybrid and parental taxa to environmental variation across space and time. All three taxa had lower predicted population growth rates under warm, dry conditions. However, the magnitude of these responses varied among taxa and populations. Hybrids had consistently lower predicted population growth rates than P. hippiana. In contrast, hybrid performance relative to P. pulcherrima varied with population and climate, with the hybrid maintaining relatively stable growth rates while populations of P. pulcherrima shrank under warm, dry conditions. Our findings demonstrate that hybrids in this system are neither intrinsically unfit nor universally more vigorous than parents, suggesting that the demographic consequences of hybridization are context‐dependent. Our results also imply that shifts to warmer and drier conditions could have particularly negative repercussions for P. pulcherrima, which is currently the most abundant taxon in the study area, possibly as a legacy of more favorable historical climates. More broadly, the distributions of these long‐lived taxa are lagging behind their demographic trajectories, such that the currently less common P. hippiana could become the most abundant of the Potentilla taxa as this region continues to warm and dry. [ABSTRACT FROM AUTHOR]