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Phenotypic plasticity and rapid evolution are fundamental processes by which organisms can maintain their function and fitness in the face of environmental changes. Here we quantified the plasticity and evolutionary potential of an alpine herb Wahlenbergia ceracea. Utilizing its mixed-mating system, we generated outcrossed and self-pollinated families that were grown in either cool or warm environments, and that had parents that had also been grown in either cool or warm environments. We then analysed the contribution of environmental and genetic factors to variation in a range of phenotypic traits including phenology, leaf mass per area, photosynthetic function, thermal tolerance, and reproductive fitness. The strongest effect was that of current growth temperature, indicating strong phenotypic plasticity. All traits except thermal tolerance were plastic, whereby warm-grown plants flowered earlier, grew larger, and produced more reproductive stems compared with cool-grown plants. Flowering onset and biomass were heritable and under selection, with early flowering and larger plants having higher relative fitness. There was little evidence for transgenerational plasticity, maternal effects, or genotype×environment interactions. Inbreeding delayed flowering and reduced reproductive fitness and biomass. Overall, we found that W. ceracea has the capacity to respond rapidly to climate warming via plasticity, and the potential for evolutionary change. [ABSTRACT FROM AUTHOR]

Summary Climate change is disrupting floral traits that mediate mutualistic and antagonistic species interactions. Plastic responses of these traits to multiple shifting conditions may be adaptive, depending on natural selection in new environments. We manipulated snowmelt date over three seasons (3–11 d earlier) in factorial combination with growing‐season precipitation (normal, halved, or doubled) to measure plastic responses of volatile emissions and other floral traits in Ipomopsis aggregata. We quantified how precipitation and early snowmelt affected selection on traits by seed predators and pollinators. Within years, floral emissions did not respond to precipitation treatments but shifted with snowmelt treatment depending on the year. Across 3 yr, emissions correlated with both precipitation and snowmelt date. These effects were driven by changes in soil moisture. Selection on several traits changed with earlier snowmelt or reduced precipitation, in some cases driven by predispersal seed predation. Floral trait plasticity was not generally adaptive. Floral volatile emissions shifted in the face of two effects of climate change, and the new environments modulated selection imposed by interacting species. The complexity of the responses underscores the need for more studies of how climate change will affect floral volatiles and other floral traits. [ABSTRACT FROM AUTHOR]

Lady beetles (Coleoptera: Coccinellidae) are important biocontrol agents that are considered generalist predators, although some tribes, such as Scymnini, are specialized in predation of sucking pests, such as mealybugs, aphids, and whiteflies. However, prey preference or pre‐imaginal conditioning may occur as coccinellids are subjected to large‐scale rearing. Thus, predator–prey interaction may be an outcome of conditioning to prey stimuli. To evaluate possible pre‐imaginal conditioning, population lines were created for the lady beetles Cryptolaemus montrouzieri Mulsant and Tenuisvalvae notata (Mulsant), each fed for at least eight generations the mealybugs Ferrisia dasylirii (Cockrell) or Planococcus citri Risso (Hemiptera: Pseudococcidae). Next, the behavioral response of these coccinellids was measured in arenas treated with prey volatiles or footprints, regarding walking time, walking speed, walking distance, and residence time. Finally, food preference between prey species was measured in laboratory and semi‐field conditions on infested cotton plants. Conditioned coccinellids responded similarly to volatiles released by either prey species offered. Furthermore, there were no changes in predator behavior towards footprints of either prey species. Both predator species consumed more P. citri in all tests, regardless of rearing prey indicating no pre‐imaginal conditioning. These results suggest that rearing prey may not affect the predator behavior, and both coccinellid species are effective in the biological control of mealybugs. [ABSTRACT FROM AUTHOR]

Adaptive phenotypic plasticity evolves in response to the contrasting selection pressures that arise when organisms face environmental heterogeneity. Despite its importance for understanding how organisms successfully cope with environmental change, adaptive plasticity is often assumed but rarely demonstrated. We study here the adaptive nature of the extreme seasonal within-individual floral polyphenism exhibited by the crucifer Moricandia arvensis , a Mediterranean species that produces two different types of flowers depending on the season of the year. During spring, this species has large, cross-shaped, lilac flowers, while during summer, it develops small, rounded, white flowers. Although floral polyphenism was associated with increased plant fitness, selection moved floral traits away from their local optimum values during the harsh summer. This result strongly suggests that floral polyphenism is not adaptive in M. arvensis. The main factor selecting against floral polyphenism was pollinators, as they select for the same floral morph in all environments. Despite not being adaptive, floral polyphenism occurs throughout the entire distribution range of M. arvensis and has probably been present since the origin of the species. To solve this paradox, we explored the factors causing floral polyphenism, finding that floral polyphenism was triggered by summer flowering. Summer flowering was beneficial because it led to extra seed production and was favored by adaptive plasticity in leaf functional traits. Taken together, our study reveals a complex scenario in which nonadaptive floral polyphenism has been indirectly maintained over M. arvensis evolutionary history by selection operating to favor summer flowering. Our study provides thus strong evidence that nonadaptive plasticity may evolve as a byproduct of colonizing stressful environments. [ABSTRACT FROM AUTHOR]

The Sirtuin (SIRT1-7) family comprises seven evolutionary-conserved enzymes that couple cellular NAD availability with health, nutrition and welfare status in vertebrates. This study re-annotated the sirt3/5 branch in the gilthead sea bream, revealing three paralogues of sirt3 (sirt3.1a/sirt3.1b/sirt3.2) and two of sirt5 (sirt5a/sirt5b) in this Perciform fish. The phylogeny and synteny analyses unveiled that the Sirt3.1/Sirt3.2 dichotomy was retained in teleosts and aquatic-living Sarcopterygian after early vertebrate 2R whole genome duplication (WGD). Additionally, only certain percomorphaceae and gilthead sea bream showed a conserved tandem-duplicated synteny block involving the mammalian-clustered sirt3.1 gene (psmd13-sirt3.1a/b-drd4-cdhr5-ctsd). Conversely, the expansion of the Sirt5 branch was shaped by the teleost-specific 3R WGD. As extensively reviewed in the literature, human-orthologues (sirt3.1/sirt5a) showed a high, conserved expression in skeletal muscle that increased as development advanced. However, recent sirt3.2 and sirt5b suffered an overall muscle transcriptional silencing across life, as well as an enhanced expression on immune-relevant tissues and gills. These findings fill gaps in the ontogeny and differentiation of Sirt genes in the environmentally adaptable gilthead sea bream, becoming a good starting point to advance towards a full understanding of its neo-functionalization. The mechanisms originating from these new paralogs also open new perspectives in the study of cellular energy sensing processes in vertebrates. [ABSTRACT FROM AUTHOR]

The study of natural coenopopulations of the rare medicinal species Rhodiola rosea is of highest relevance for conservation of this valuable plant species. Analysis of the adaptive response of the species growing under different environmental conditions is basically used to elaborate recommendations for its protection and rational use. The aim of this work was to study the anatomical and morphological features of the leaf blades of Rh. rosea growing under different environmental and coenotic conditions of the Altai Mountains. We studied the anatomical features of leaves of Rh. rosea from 7 coenopopulations (in one coenopopulation, both female and male plants were studied) and assessed the adaptive response of plants to different growing conditions by conventional methods. The values of indicators from different coenopopulations were compared by one-way analysis of variance (ANOVA), and the correlation coefficient was calculated to estimate the correlation between different indicators. The study revealed a reserve of adaptive plasticity for Rh. rosea, which allows the species to grow under different light and water conditions. For specimens from one geographic location studied, statistically significant differences in the indicator values were fewer compared with specimens from different areas. Heliophytic and xerophytic adaptations of the studied plants varied depending on coenopopulation. The analysis of male and female Rh. rosea species from the Kurai ridge (CP 3) revealed that the most photosynthetically active layer and vascular tissue are better developed in leaves of females compared to males. It was found that Rh. rosea growing in the mountains bear shorter and thicker leaves; the thickness of integumentary tissue with cuticle increases at higher altitudes, the number of stomata and cells on integumentary tissue per epidermis unit area decreases, and the thickness of photoassimilating tissue grows. Changes in anatomical and morphological characteristics are adaptive responses to increased insolation at higher altitudes and, probably, to decreased partial pressure of carbon dioxide.

The effects of an obesogenic post-weaning diet on the growth and metabolic parameters of adult offspring submitted to a hypocaloric diet in perinatal life were evaluated. Male Wistar rats were divided into two groups according to maternal diet during pregnancy and lactation: Control (C, received normocaloric diet) and hypocaloric diet during pregnancy and lactation (H, received hypocaloric diet). At weaning, half the number of animals in each group was divided into two more groups according to the post-weaning diet: control (CC, n=12), control and subject to the obesogenic diet (CO n=11), hypocaloric diet and control (HC, n=14) and hypocaloric and obesogenic diet (HO, n=9). Maternal body weight, food intake, and energy intake were recorded daily. In the offspring, birth weight, growth rate, and physical characteristics were evaluated. At 120 days, relative food consumption, glucose tolerance test (GTT), biochemical profile, and organ weight were analyzed. Mothers on a low-calorie diet showed no difference in body weight during pregnancy or lactation even with lower energy intake. In offspring, litters from mothers fed a low-calorie diet showed a deficit in physical characteristics (growth restriction and low weight). The effect of an obesogenic diet on visceral fat weight, GTT, and hypercholesterolemia was most pronounced in animals subjected to a perinatal hypocaloric diet followed by a lifelong obesogenic diet. Conclusion: Our observations expand the evidence that social environments with food scarcity and/or obesogenic environments determine greater susceptibility to obesity.

Understanding the evolution of adaptive plasticity is fundamental to our knowledge of how organisms interact with their environments and cope with environmental change. Plasticity in melanin pigmentation is common in response to variable environments, especially thermal environments. Yet, the adaptive significance of melanin plasticity in thermally variable environments is often assumed, but rarely explicitly tested. Furthermore, understanding the role of plasticity when a trait is responsive to multiple environmental stimuli and plays many functional roles remains poorly understood. We test the hypothesis that melanin plasticity is an adaptation for thermally variable environments using Hyles lineata, the white‐lined sphinx moth, which shows plasticity in melanin pigmentation during the larval stage. Melanin pigmentation influences thermal traits in H. lineata, as melanic individuals had higher heating rates and reached higher body temperatures than non‐melanic individuals. Importantly, melanin pigmentation has temperature specific fitness consequences. While melanic individuals had an advantage in cold temperatures, neither phenotype had a clear fitness advantage at warm temperatures. Thus, the costs associated with melanin production may be unrelated to thermal context. Our results highlight the importance of explicitly testing the adaptive role of plasticity and considering all the factors that influence costs and benefits of plastic phenotypes across environments. [ABSTRACT FROM AUTHOR]

Vegetative traits of plants can respond directly to changes in the environment, such as those occurring under climate change. That phenotypic plasticity could be adaptive, maladaptive, or neutral. We manipulated the timing of spring snowmelt and amount of summer precipitation in factorial combination and examined responses of specific leaf area (SLA), trichome density, leaf water content (LWC), photosynthetic rate, stomatal conductance and intrinsic water-use efficiency (iWUE) in the subalpine herb Ipomopsis aggregata. The experiment was repeated in three years differing in natural timing of snowmelt. To examine natural selection, we used survival, relative growth rate, and flowering as fitness indices. A 50% reduction in summer precipitation reduced stomatal conductance and increased iWUE, and doubled precipitation increased LWC. Combining natural and experimental variation, earlier snowmelt reduced soil moisture, photosynthetic rate and stomatal conductance, and increased trichome density and iWUE. Precipitation reduction reversed the mortality selection favoring high stomatal conductance under normal and doubled precipitation, and higher LWC improved growth. Earlier snowmelt is a strong signal of climate change and can change expression of leaf morphology and gas exchange traits, just as reduced precipitation can. Stomatal conductance and SLA showed adaptive plasticity under some conditions.

Despite newly available therapies for acute stroke and innovative prevention strategies, stroke remains the third leading cause of disability-adjusted life-years (DALYs) lost worldwide, mostly because more than half of stroke survivors aged 65 and over exhibit an incomplete functional recovery of the paretic limb. Given that a repeated sensory input is one of the most effective modulators of cortical motor and somatosensory structures, focal muscle vibration (fMV) is gaining growing interest as a safe, well-tolerated, and non-invasive brain stimulation technique to promote motor recovery after stroke with a long-lasting and clinically relevant improvement in strength, step symmetry, gait, and kinematics parameters. In this narrative review, we first summarize the structural (neural plasticity) and functional changes (network relearning) triggered by the stroke lesion and carried out at a brain and spinal cord level in an attempt to recover from the loss of function. Then, we will focus on the fMV’s plasticity-based mechanisms reporting evidence of a possible concurrently acting multisite plasticity induced by fMV. Finally, to understand what the most effective fMV rehabilitation protocol could be, we will report the most recent evidence regarding the different clinical approaches and timing of the fMV treatment, the related open issues, and prospects.

Enhancing cerebellar activity influences motor cortical activity and contributes to motor adaptation, though it is unclear which neurophysiological mechanisms contributing to adaptation are influenced by the cerebellum. Pre-movement beta event-related desynchronization (β-ERD), which reflects a release of inhibitory control in the premotor cortex during movement planning, is one mechanism that may be modulated by the cerebellum through cerebellar-premotor connections. We hypothesized that enhancing cerebellar activity with intermittent theta burst stimulation (iTBS) would improve adaptation rates and increase β-ERD during motor adaptation. Thirty-four participants were randomly assigned to an active (A-iTBS) or sham cerebellar iTBS (S-iTBS) group. Participants performed a visuomotor task, using a joystick to move a cursor to targets, prior to receiving A-iTBS or S-iTBS, following which they completed training with a 45° rotation to the cursor movement. Behavioural adaptation was assessed using the angular error of the cursor path relative to the ideal trajectory. The results showed a greater adaptation rate following A-iTBS and an increase in β-ERD, specific to the high β range (20–30 Hz) during motor planning, compared to S-iTBS, indicative of cerebellar modulation of the motor cortical inhibitory control network. The enhanced release of inhibitory activity persisted throughout training, which suggests that the cerebellar influence over the premotor cortex extends beyond adaptation to other stages of motor learning. The results from this study further understanding of cerebellum-motor connections as they relate to acquiring motor skills and may inform future skill training and rehabilitation protocols. [ABSTRACT FROM AUTHOR]

Organisms construct their own environments and phenotypes through the adaptive processes of habitat choice, habitat construction, and phenotypic plasticity. We examine how these processes affect the dynamics of mean fitness change through the environmental change term of the Price Equation. This tends to be ignored in evolutionary theory, owing to the emphasis on the first term describing the effect of natural selection on mean fitness (the additive genetic variance for fitness of Fisher's Fundamental Theorem). Using population genetic models and the Price Equation, we show how adaptive niche constructing traits favorably alter the distribution of environments that organisms encounter and thereby increase population mean fitness. Because niche‐constructing traits increase the frequency of higher‐fitness environments, selection favors their evolution. Furthermore, their alteration of the actual or experienced environmental distribution creates selective feedback between niche constructing traits and other traits, especially those with genotype‐by‐environment interaction for fitness. By altering the distribution of experienced environments, niche constructing traits can increase the additive genetic variance for such traits. This effect accelerates the process of overall adaption to the niche‐constructed environmental distribution and can contribute to the rapid refinement of alternative phenotypic adaptations to different environments. Our findings suggest that evolutionary biologists revisit and reevaluate the environmental term of the Price Equation: owing to adaptive niche construction, it contributes directly to positive change in mean fitness; its magnitude can be comparable to that of natural selection; and, when there is fitness G × E, it increases the additive genetic variance for fitness, the much‐celebrated first term. [ABSTRACT FROM AUTHOR]

Differential gene expression represents a fundamental cause and manifestation of phenotypic plasticity. Adaptive phenotypic plasticity in gene expression as a trait evolves when alleles that mediate gene regulation serve to increase organismal fitness by improving the alignment of variation in gene expression with variation in circumstances. Among the diverse circumstances that a gene encounters are distinct cell types, developmental stages and sexes, as well as an organism's extrinsic ecological environments. Consequently, adaptive phenotypic plasticity provides a common framework to consider diverse evolutionary problems by considering the shared implications of alleles that produce context-dependent gene expression. From this perspective, adaptive plasticity represents an evolutionary resolution to conflicts of interest that arise from any negatively pleiotropic effects of expression of a gene across ontogeny, among tissues, between the sexes, or across extrinsic environments. This view highlights shared properties within the general relation of fitness, trait expression and context that may nonetheless differ substantively in the grain of selection within and among generations to influence the likelihood of adaptive plasticity as an evolutionary response. Research programmes that historically have focused on these separate issues may use the insights from one another by recognizing their shared dependence on context-dependent gene regulatory evolution. [ABSTRACT FROM AUTHOR]

Summary: Rapid environmental change is forcing populations into environments where plasticity will no longer maintain fitness. When populations are exposed to novel environments, evolutionary theory predicts that genetic variation in fitness will increase and should be associated with genetic differences in plasticity. If true, then genetic variation in plasticity can increase adaptive potential in novel environments, and population persistence via evolutionary rescue is more likely.To test whether genetic variation in fitness increases in novel environments and is associated with plasticity, we transplanted 8149 clones of 314 genotypes of a Sicilian daisy (Senecio chrysanthemifolius) within and outside its native range, and quantified genetic variation in fitness, and plasticity in leaf traits and gene expression.Although mean fitness declined by 87% in the novel environment, genetic variance in fitness increased threefold and was correlated with plasticity in leaf traits. High fitness genotypes showed greater plasticity in gene expression, but lower plasticity in most leaf traits. Interestingly, genotypes with the highest fitness in the novel environment had the lowest fitness at the native site.These results suggest that standing genetic variation in plasticity could help populations to persist and adapt to novel environments, despite remaining hidden in native environments. See also the Commentary on this article by Cross & Thompson, 239: 10–12. [ABSTRACT FROM AUTHOR]

Environmentally induced reductions in fitness components (survival, fecundity) are generally considered as passive, maladaptive responses to stress. However, there is also mounting evidence for active, programmed forms of environmentally induced cell death in unicellular organisms. While conceptual work has questioned how such programmed cell death (PCD) might be maintained by natural selection, few experimental studies have investigated how PCD influences genetic differences in longer-term fitness across environments. Here, we tracked the population dynamics of two closely related strains of the halotolerant microalga Dunaliella salina following transfers across salinities. We showed that after a salinity increase, only one of these strains displayed a massive population decline (−69% in 1 h), largely attenuated by exposure to a PCD inhibitor. However, this decline was followed by a rapid demographic rebound, characterized by faster growth than the nondeclining strain, such that sharper decline was correlated with faster subsequent growth across experiments and conditions. Strikingly, the decline was more pronounced in conditions more favorable to growth (more light, more nutrients, less competition), further suggesting that it was not simply passive. We explored several hypotheses that could explain this decline-rebound pattern, which suggests that successive stresses could select for higher environmentally induced death in this system. [ABSTRACT FROM AUTHOR]

Abstract Background Urban development results in habitat destruction, affecting populations of amphibians, the most fragile group of vertebrates. With changes in the environment, these animals become more exposed to light and predators. To enhance their chances of survival, they display plasticity of body coloration. Aside from adaptive benefits, animals exhibiting background matching meet the energetic costs and restrictions of changing body tones. To study the physiological consequences of Hyla arborea tadpole adaptation to background color, we followed oxidative stress parameters after rearing larvae on a constant background (black/white) and after changing the background color. Results Larvae cultivated for 20 days on constant substrate color exhibited differences in body coloration but without differences in lipid peroxidation (LPO) concentration between dark and pale individuals, suggesting that coloration investment during this period did not induce higher oxidative damage in darker tadpoles. Prolonged exposure of larvae (37 days) to a dark habitat increased antioxidative system defense and LPO concentrations, compared to animals reared permanently in the white surroundings. The positive correlation of oxidative damage with color intensity of individuals points to the physiological consequences of higher investment in the number of pigment cells necessary for dark pigmentation. In individuals faced with non-matching background and change in body coloration, defense system declined and LPO occurred relative to individuals cultivated in white habitat. Conclusion Here, we have pointed to consequences related to background matching and stress that amphibians experienced during chromatic adaptations. Background color change causes a complex physiological response affecting the antioxidative defense parameters. This investigation elucidates the accompanying cost of amphibiansʼ adjustment to an altered environment.

Exploring patterns and causes of intraspecific trait variation is crucial for a better understanding of the effects of climate change on plant populations and ecosystems. However, our current understanding of the intraspecific trait variation is mainly based on structural (morphological) traits, and we have limited knowledge on patterns and causes of variation in biochemical traits (e.g. leaf pigments), which are also crucial for plant adaptation. As a result, we also do not know how similar the climatic effects on structural versus biochemical traits are.Using plant traits from 110 genotypes representing 11 Festuca rubra populations grown in 4 different climates, we studied trait covariation among structural traits (linked to fitness, resource use, gas exchange and reproduction) and biochemical traits (linked to photosynthesis, photoprotection and oxidative stress). We also disentangled the relative role of the climate of origin and the climate of cultivation in the structural versus biochemical traits and tested for adaptive plasticity in the traits.We found that (1) biochemical traits did not covary with structural traits and represent independent 'photoharvesting–photoprotection' strategy dimension of functional variation; (2) interactive effects of climate of origin and cultivation were more pronounced for biochemical than structural traits. (3) Trait plasticity was affected by the climate of origin (precipitation and temperature as well as their interaction); (4) F. rubra showed both adaptive and maladaptive plasticity, and adaptiveness depended upon trait type, cultivation climate and climate of origin.Overall, our results suggest that structural and biochemical plant traits respond differentially to climate and thus the response of one group of traits cannot be predicted from the other. Responses are also strongly determined by interactions between the climate of origin and cultivation. Thus, more studies on variation in biochemical traits, their correspondence to other traits, and their variation with climate are needed. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms of species coexistence has always been a fundamental topic in ecology. Classical theory predicts that interspecific competition may select for traits that stabilize niche differences, although recent work shows that this is not strictly necessary. Here, we ask whether adaptive phenotypic plasticity could allow species coexistence (i.e., some stability at an equilibrium point) without ecological differentiation in habitat use. We used individual-based stochastic simulations defining a landscape composed of spatially uncorrelated or autocorrelated environmental patches, where two species with the same competitive strategies, not able to coexist without some form of phenotypic plasticity, expanded their ranges in the absence of a competition—colonization trade-off (a well-studied mechanism for species diversity). Each patch is characterized by a random environmental value that determines the optimal phenotype of its occupants. In such a scenario, only local adaptation and gene flow (migration) may interact to promote genetic variation and coexistence in the metapopulation. Results show that a competitively inferior species with adaptive phenotypic plasticity can coexist in a same patch with a competitively superior, non-plastic species, provided the migration rates and variances of the patches' environmental values are sufficiently large.

Developmental plasticity is the ability of a genotype to express multiple phenotypes under different environmental conditions and has been shown to facilitate the evolution of novel traits. However, while the associated cost of plasticity, i.e. the loss in fitness due to the ability to express plasticity in response to environmental change, and the cost of phenotype, i.e. the loss of fitness due to expressing a fixed phenotype across environments, have been theoretically predicted, empirically such costs remain poorly documented and little understood. Here, we use a plasticity model system, hermaphroditic nematode Pristionchus pacificus , to experimentally measure these costs in wild isolates under controlled laboratory conditions. P. pacificus can develop either a bacterial feeding or predatory mouth morph in response to different external stimuli, with natural variation of mouth-morph ratios between strains. We first demonstrated the cost of phenotype by analyzing fecundity and developmental speed in relation to mouth morphs across the P. pacificus phylogenetic tree. Then, we exposed P. pacificus strains to two distinct microbial diets that induce strain-specific mouth-form ratios. Our results indicate that the plastic strain does shoulder a cost of plasticity, i.e. the diet-induced predatory mouth morph is associated with reduced fecundity and slower developmental speed. In contrast, the non-plastic strain suffers from the cost of phenotype since its phenotype does not change to match the unfavorable bacterial diet but shows increased fitness and higher developmental speed on the favorable diet. Furthermore, using a stage-structured population model based on empirically derived life history parameters, we show how population structure can alleviate the cost of plasticity in P. pacificus. The results of the model illustrate the extent to which the costs associated with plasticity and its effect on competition depend on ecological factors. This study provides support for costs of plasticity and phenotype based on empirical and modeling approaches. [ABSTRACT FROM AUTHOR]

Background: Urban development results in habitat destruction, affecting populations of amphibians, the most fragile group of vertebrates. With changes in the environment, these animals become more exposed to light and predators. To enhance their chances of survival, they display plasticity of body coloration. Aside from adaptive benefits, animals exhibiting background matching meet the energetic costs and restrictions of changing body tones. To study the physiological consequences of Hyla arborea tadpole adaptation to background color, we followed oxidative stress parameters after rearing larvae on a constant background (black/white) and after changing the background color. Results: Larvae cultivated for 20 days on constant substrate color exhibited differences in body coloration but without differences in lipid peroxidation (LPO) concentration between dark and pale individuals, suggesting that coloration investment during this period did not induce higher oxidative damage in darker tadpoles. Prolonged exposure of larvae (37 days) to a dark habitat increased antioxidative system defense and LPO concentrations, compared to animals reared permanently in the white surroundings. The positive correlation of oxidative damage with color intensity of individuals points to the physiological consequences of higher investment in the number of pigment cells necessary for dark pigmentation. In individuals faced with non-matching background and change in body coloration, defense system declined and LPO occurred relative to individuals cultivated in white habitat. Conclusion: Here, we have pointed to consequences related to background matching and stress that amphibians experienced during chromatic adaptations. Background color change causes a complex physiological response affecting the antioxidative defense parameters. This investigation elucidates the accompanying cost of amphibiansʼ adjustment to an altered environment. [ABSTRACT FROM AUTHOR]

Background and Aims Polyploids are often hypothesized to have increased phenotypic plasticity compared with their diploid progenitors, but recent work suggests that the relationship between whole-genome duplication (WGD) and plasticity is not so straightforward. Impacts of WGD on plasticity are moderated by other evolutionary processes in nature, which has impeded generalizations regarding the effects of WGD alone. We assessed shifts in phenotypic plasticity and mean trait values accompanying WGD, as well as the adaptive consequences of these shifts. Methods To isolate WGD effects, we compared two diploid lineages of Arabidopsis thaliana wiht corresponding autotetraploids grown across different salt and nutrient conditions in a growth chamber. Key Results For the few cases in which diploids and polyploids differed in plasticity, polyploids were more plastic, consistent with hypotheses that WGD increases plasticity. Under stress, increased plasticity was often adaptive (associated with higher total seed mass), but in other cases plasticity was unrelated to fitness. Mean trait values and plasticity were equally likely to be affected by WGD, but the adaptive consequences of these shifts were often context dependent or lineage specific. For example, polyploids had extended life spans, a shift that was adaptive in one polyploid lineage under amenable conditions but was maladaptive in the other lineage under stress. Conclusions Our work shows that increased phenotypic plasticity can result from WGD alone, independent of other evolutionary processes. We find that the effects of WGD can differ depending on the genotype of the progenitor and the environmental context. Though our experiment was limited to two genotypes of a single species, these findings support the idea that WGD can indeed increase plasticity. [ABSTRACT FROM AUTHOR]

Enhancing cerebellar activity influences motor cortical activity and contributes to motor adaptation, though it is unclear which neurophysiological mechanisms contributing to adaptation are influenced by the cerebellum. Pre-movement beta event-related desynchronization (β-ERD), which reflects a release of inhibitory control in the premotor cortex during movement planning, is one mechanism that may be modulated by the cerebellum through cerebellar-premotor connections. We hypothesized that enhancing cerebellar activity with intermittent theta burst stimulation (iTBS) would improve adaptation rates and increase β-ERD during motor adaptation. Thirty-four participants were randomly assigned to an active (A-iTBS) or sham cerebellar iTBS (S-iTBS) group. Participants performed a visuomotor task, using a joystick to move a cursor to targets, prior to receiving A-iTBS or S-iTBS, following which they completed training with a 45° rotation to the cursor movement. Behavioural adaptation was assessed using the angular error of the cursor path relative to the ideal trajectory. The results showed a greater adaptation rate following A-iTBS and an increase in β-ERD, specific to the high β range (20–30 Hz) during motor planning, compared to S-iTBS, indicative of cerebellar modulation of the motor cortical inhibitory control network. The enhanced release of inhibitory activity persisted throughout training, which suggests that the cerebellar influence over the premotor cortex extends beyond adaptation to other stages of motor learning. The results from this study further understanding of cerebellum-motor connections as they relate to acquiring motor skills and may inform future skill training and rehabilitation protocols.

The active skeletal muscle and the maintenance of muscle mass are essential for good health, wellness and disease prevention and treatment. The muscle as an endocrine organ capable of synthesizing myokines, has been documented recently. These peptides are secreted as a response to muscular contractions induced by exercise, and can develop molecular communication with other tissues, improving cardiovascular, metabolic, and mental health. The endocrine function of a muscle continues to be in a constant investigation; however, knowledge up to date urge us to continue promoting physical activity. Additionally, the extended knowledge of myokins is useful to prescribe individualized physical exercise programs to each patient.

Phenotypic variations between populations often correlate with climatic variables. Determining the presence of phenotypic plasticity and local adaptation of a species to different environments over a large spatial scale can provide insight on the persistence of a species across its range. Amphibians, and in particular their larvae, are good models for studies of phenotypic variation as they are especially sensitive to their immediate environment. Few studies have attempted to determine the mechanisms that drive phenotypic variation between populations of a single amphibian species over a large spatial scale especially across contrasting climatic regimes. The African clawed frog, Xenopus laevis, occurs in two regions with contrasting rainfall regimes in southern Africa. We hypothesised that the phenotypic variation of life-history traits of X. laevis tadpoles emerges from a combination of plastic and genetic responses. We predicted that plasticity would allow the development of tadpoles from both regions in each environment. We also predicted that local adaptation of larval traits would drive the differentiation of reaction norms between populations and lower survival in tadpoles reared away from their home environment. We measured growth, time to metamorphosis, and survival in a reciprocal transplant experiment using outdoor mesocosms. Supporting our prediction, we found that the measured variation of all traits was explained by both adaptation and plasticity. However, the reaction norms differed between populations suggesting adaptive and asymmetric plasticity. All tadpoles experienced lower survival when translocated, but only translocated tadpoles from the winter rainfall region matched survival of local tadpoles. This has implications for the dynamics of translocated X. laevis into novel environments, especially from the winter rainfall region. Our discovery of their asymmetric capacity to overcome novel environmental conditions by phenotypic plasticity alone provides insight into their invasion success. [ABSTRACT FROM AUTHOR]

Sensory perception of environmental cues has been shown to trigger plastic responses that can induce important fitness costs, including the dramatic modulation of aging across distant taxa. For example, male Drosophila melanogaster suffer a marked decrease in fitness, characterized by faster reproductive and actuarial aging, if they perceive female cues but fail to mate shortly after (aging via sexual perception). While this has been a breakthrough for our understanding of the mechanisms of aging, it raises the question of why such plastic responses evolved. Here, we used D. melanogaster to ask whether sexual perception costs may be a by-product of adaptive plastic responses to female cues. We found that (a) short-term perception (1 day) of female cues before mating opportunities increases male relative lifetime reproductive success in a competitive environment, (b) medium-term perception (3–7 days) is neutral, and (c) long-term perception (15 days) leads to reproductive costs. We then ran mathematical simulations under a wide range of sociosexual and demographic scenarios to show that such plastic male responses can be adaptive whenever mating rates fluctuate within the range experienced by D. melanogaster and other insects in the wild, suggesting that this may be a widespread strategy in nature. Finally, we show that, because the short-term benefits of plastic responses will be acquired mostly by high-quality males while long-term costs will be paid mostly by low-quality males, sexual perception can significantly magnify sexual selection (15%–27% average increase in the opportunity for selection). [ABSTRACT FROM AUTHOR]

When environmental change is rapid or unpredictable, phenotypic plasticity can facilitate adaptation to new or stressful environments to promote population persistence long enough for adaptive evolution to occur. However, the underlying genetic mechanisms that contribute to plasticity and its role in adaptive evolution are generally unknown. Two main opposing hypotheses dominate-genetic compensation and genetic assimilation. Here, we predominantly find evidence for genetic compensation over assimilation in adapting the freshwater algae Chlamydomonas reinhardtii to 36 g/L salt environments over 500 generations. More canalized genes in the high-salt (HS) lines displayed a pattern of genetic compensation (63%) fixing near or at the ancestral native expression level, rather than genetic assimilation of the salt-induced level, suggesting that compensation was more common during adaptation to salt. Network analysis revealed an enrichment of genes involved in energy production and salt-resistance processes in HS lines, while an increase in DNA repair mechanisms was seen in ancestral strains. In addition, whole-transcriptome similarity among ancestral and HS lines displayed the evolution of a similar plastic response to salt conditions in independently reared HS lines. We also found more cis-acting regions in the HS lines; however, the expression patterns of most genes did not mimic that of their inherited sequence. Thus, the expression changes induced via plasticity offer temporary relief, but downstream changes are required for a sustainable solution during the evolutionary process., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Phenotypic plasticity enables plants to buffer against environmental stresses and match their phenotypes to local conditions. However, consistent conclusive evidence for adaptive plasticity has only been obtained for a few traits. More studies on a wider variety of plant functional traits and environmental factors are still needed to further understand the adaptive significance of plasticity. We grew 21 genotypes of the stoloniferous clonal plant Duchesnea indica under different light and nutrient conditions, and used selection gradient analyses to test the adaptive value (benefits) of morphological and physiological plasticity responding to variation in light and nutrient availability. Plants grown in shade exhibited lower values for fitness measures (fruit number, ramet number and biomass), shortened thinner internode length and decreased adult leaf chlorophyll content, but higher petiole length, specific leaf area and old leaf chlorophyll content, than plants grown without shade. Plants grown in the low nutrient condition had shorter petiole length, thicker and smaller leaf area, lower chlorophyll content, but higher fruit number and root:shoot ratio than plants grown under the high nutrient condition. Selection gradient analyses revealed that plasticity of petiole length and old leaf chlorophyll content in response to light variation was adaptive, and plasticity of old and adult leaf chlorophyll content in response to nutrient variation was adaptive. Therefore, the adaptive value of plasticity in different traits depends on the specific ecological context. Our findings contribute to understanding the adaptive significance of phenotypic plasticity of clonal plants in response to environmental variation. [ABSTRACT FROM AUTHOR]

Better understanding of the mechanistic basis of plant plasticity will enhance efforts to breed crops resilient to predicted climate change. However, complexity in plasticity's conceptualisation and measurement may hinder fruitful crossover of concepts between disciplines that would enable such advances. We argue active adaptive plasticity is particularly important in shaping the fitness of wild plants, representing the first line of a plant's defence to environmental change. Here, we define how this concept may be applied to crop breeding, suggest appropriate approaches to measure it in crops, and propose a refocussing on active adaptive plasticity to enhance crop resilience. We also discuss how the same concept may have wider utility, such as in ex situ plant conservation and reintroductions. Increasing environmental uncertainty is focussing research interest on plant plasticity. But despite calls for plasticity concepts to be adopted in crop breeding, this does not appear to have happened. Plasticity is a broad and multifaceted concept, making it potentially difficult to identify those aspects of previous research most relevant to the crop breeding context. Given the challenges posed by climate change and the different evolutionary contexts in natural and crop systems, we identify active adaptive plasticity as a key issue for further investigation by crop breeders. We outline and illustrate the experimental and statistical analytical approaches necessary to begin to assess active adaptive plasticity, and we highlight benefits that might arise in other fields from a fuller understanding of the role and regulation of this aspect of plasticity. [ABSTRACT FROM AUTHOR]

Spatial covariance between genotypic and environmental influences on phenotypes (CovGE) can result in the nonrandom distribution of genotypes across environmental gradients and is a potentially important factor driving local adaptation. However, a framework to quantify the magnitude and significance of CovGE has been lacking. We develop a novel quantitative/analytical approach to estimate and test the significance of CovGE from reciprocal transplant or common garden experiments, which we validate using simulated data. We demonstrate how power to detect CovGE changes over a range of experimental designs. We confirm an inverse relationship between gene‐by‐environment interactions (GxE) and CovGE, as predicted by first principles, but show how phenotypes can be influenced by both. The metric provides a way to measure how phenotypic plasticity covaries with genetic differentiation and highlights the importance of understanding the dual influences of CovGE and GxE on phenotypes in studies of local adaptation and species' responses to environmental change. [ABSTRACT FROM AUTHOR]

Abstract Urban stressors represent strong selective gradients that can elicit evolutionary change, especially in non‐native species that may harbor substantial within‐population variability. To test whether urban stressors drive phenotypic differentiation and influence local adaptation, we compared stress responses of populations of a ubiquitous invader, reed canary grass (Phalaris arundinacea). Specifically, we quantified responses to salt, copper, and zinc additions by reed canary grass collected from four populations spanning an urbanization gradient (natural, rural, moderate urban, and intense urban). We measured ten phenotypic traits and trait plasticities, because reed canary grass is known to be highly plastic and because plasticity may enhance invasion success. We tested the following hypotheses: (a) Source populations vary systematically in their stress response, with the intense urban population least sensitive and the natural population most sensitive, and (b) plastic responses are adaptive under stressful conditions. We found clear trait variation among populations, with the greatest divergence in traits and trait plasticities between the natural and intense urban populations. The intense urban population showed stress tolerator characteristics for resource acquisition traits including leaf dry matter content and specific root length. Trait plasticity varied among populations for over half the traits measured, highlighting that plasticity differences were as common as trait differences. Plasticity in root mass ratio and specific root length were adaptive in some contexts, suggesting that natural selection by anthropogenic stressors may have contributed to root trait differences. Reed canary grass populations in highly urbanized wetlands may therefore be evolving enhanced tolerance to urban stressors, suggesting a mechanism by which invasive species may proliferate across urban wetland systems generally.

Phenotypic plasticity, or an organism’s capacity to change its phenotype in response to environmental variation, is a pervasive—perhaps even ubiquitous—feature of the biological world. Accordingly, plasticity research suggests serious implications for biological theory, including evolutionary theory. The theoretical implications of plasticity have growing support from empirical literature documenting the range, extent, and adaptiveness of plasticity. However, the empirical evidence for particular instances of plasticity has still not been adequately scrutinized by biologists or philosophers. After reviewing some important conceptual and theoretical background information, this paper synthesizes some past discussions of the methodology of plasticity studies and provides some novel methodological guidance for plasticity researchers. My conclusion is that not all plasticity studies should carry the same weight: there are patterns we can identify in the features of such studies that should contribute to (or detract from) their credibility. In particular, I argue that some types of organisms and some types of plastic phenotypes are more conducive to the empirical study of plasticity than others.

Evidence accumulates that dispersal is correlated with individual behavioural phenotype (dispersal syndrome). The evolutionary causes and consequences of such covariation depend on the degree of plasticity versus inheritance of the traits, which requires challenging experiments to implement in mobile organisms. Here, we combine a forced dispersal experiment, natural colonization and longitudinal data to establish if dispersal and aggression levels are integrated and to test their adaptive nature in pied flycatchers (Ficedula hypoleuca). We found that (forced) dispersers behaved more aggressively in their first breeding year after dispersal and decreased their aggression in following years. Strength of dispersal syndrome and direction of fecundity selection on aggression in newly colonized areas varied between years. We propose that the net benefits of aggression for dispersers increase under harsh conditions (e.g. low food abundance). This hypothesis now warrants further testing. Overall, this study provides unprecedented experimental evidence that dispersal syndromes can be remodelled via adaptive plasticity depending on the individuals' local breeding experience and/or year-specific ecological conditions. It highlights the importance of individual behavioural variation in population dynamics. [ABSTRACT FROM AUTHOR]

Distinguishing between genetic, environmental, and genotype × environment effects is central to understanding geographic variation in phenotypic clines. Two of the best-documented phenotypic clines are Bergmann's rule and Allen's rule, which describe larger body sizes and shortened extremities in colder climates, respectively. Although numerous studies have found inter- and intraspecific evidence for both ecogeographic patterns, we still have a poor understanding of the extent to which these patterns are driven by genetics, environment, or both. Here, we measured the genetic and environmental contributions to Bergmann's rule and Allen's rule across introduced populations of house mice (Mus musculus domesticus) in the Americas. First, we documented clines for body mass, tail length, and ear length in natural populations and found that these conform to both Bergmann's rule and Allen's rule. We then raised descendants of wild-caught mice in the lab and showed that these differences persisted in a common environment and are heritable, indicating that they have a genetic basis. Finally, using a full-sib design, we reared mice under warm and cold conditions. We found very little plasticity associated with body size, suggesting that Bergmann's rule has been shaped by strong directional selection in house mice. However, extremities showed considerable plasticity, as both tails and ears grew shorter in cold environments. These results indicate that adaptive phenotypic plasticity as well as genetic changes underlie major patterns of clinal variation in house mice and likely facilitated their rapid expansion into new environments across the Americas. [ABSTRACT FROM AUTHOR]

Many species are shifting their ranges and being forced to rapidly respond to novel stressful environmental conditions. Colonizing individuals experience strong selective forces that favor the expression of life history traits notably affecting dispersal and reproductive rates in newly invaded habitats. Limited information is currently available on trait variation within the invasive range despite being critical for understanding ecological and evolutionary factors that drive the process of range expansion of invasive species. Here we evaluated life history shifts in the widely introduced Asian clam Corbicula cf. C. fluminea within its invaded range. Through an exhaustive literature search, we obtained data for 17 invasive populations of this clam from different ecosystems worldwide. We tested the relationship between population and individual parameters relevant to the process of range expansion. Our main results are that recently introduced populations of clams were characterized by (a) low density and low rate of population increase, (b) earlier reproduction in slow‐growing populations of clams, and (c) no effect of density on population increase. All populations of the Asian clam analyzed in this study, which are fixed for one genotype (the lineage called Form A/R), experienced different selective environments in the introduced range. These findings support the perspective that adaptive phenotypic plasticity favored the expression of traits that maximize fitness in recently established populations, which faced stronger r‐selective forces relative to long‐established ones. We discuss the role of plasticity in facilitating rapid adaptation and in increasing the likelihood of populations to overcome difficulties associated with low densities and low population increase in newly invaded areas. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity is predicted to evolve in environmentally variable habitats, or those experiencing a high frequency of strong selection. The evolution of plasticity may however be constrained by costs or physiological limitations. In flowers, UV‐absorbing pigmentation ameliorates UV damage to pollen, and is linked with elevated UV exposure. Whether plasticity contributes to this pattern remains unclear. Petals of Argentina anserina have larger UV‐absorbing petal areas at high elevations where they experience higher and more variable UV exposure than low elevations. We measured UV‐induced pigmentation plasticity in high‐ and low‐elevation populations (hereafter, "high," "low"), and selection on pigmentation via male fitness. We dissected UV pigment biochemistry using metabolomics to explore biochemical mechanisms underlying plasticity. High displayed positive UV‐induced pigmentation plasticity but low lacked plasticity. Selection favored elevated pigmentation under UV in high, supporting adaptive plasticity. In high, UV absorption was conferred by flavonoids produced in one flavonoid pathway branch. However, in low, UV absorption was associated with many compounds spanning multiple branches. Elevated plasticity was thus associated with reduced pigment diversity. These results are consistent with adaptive floral pigmentation plasticity in more extreme and variable environments. We discuss how biochemical underpinnings of pigmentation may permit or constrain the evolution of pigmentation plasticity. [ABSTRACT FROM AUTHOR]

Epigenetic inheritance is another piece of the puzzle of nongenetic inheritance, although the prevalence, sources, persistence, and phenotypic consequences of heritable epigenetic marks across taxa remain unclear. We systematically reviewed over 500 studies from the past 5 years to identify trends in the frequency of epigenetic inheritance due to differences in reproductive mode and germline development. Genetic, intrinsic (e.g., disease), and extrinsic (e.g., environmental) factors were identified as sources of epigenetic inheritance, with impacts on phenotype and adaptation depending on environmental predictability. Our review shows that multigenerational persistence of epigenomic patterns is common in both plants and animals, but also highlights many knowledge gaps that remain to be filled. We provide a framework to guide future studies towards understanding the generational persistence and eco-evolutionary significance of epigenomic patterns. Epigenetic mechanisms can alter gene expression and allow species to respond rapidly to their environments by modifying their phenotypes. Reproductive mode (i.e., sexual versus asexual, oviparity versus viviparity in animals) and germline development commonly predict the persistence of epigenetic marks. The consequences of persistent epigenomic variation vary depending on the sources (intrinsic, genetic, extrinsic). Environmental predictability is a key factor for determining the consequences of epigenetic inheritance on phenotype and fitness. We provide a roadmap for future studies to further our understanding of the extent and evolutionary importance of epigenetic inheritance by quantifying: (i) persistence across generations, (ii) contributions to phenotype and fitness, and (iii) cross-taxa comparisons. [ABSTRACT FROM AUTHOR]

Abstract Understanding how tree species will respond to a future climate requires reliable and quantitative estimates of intra‐specific variation under current climate conditions. We studied three 10‐year‐old common garden experiments established across a rainfall and drought gradient planted with nearly 10,000 pedunculate oak (Quercus robur L.) trees from ten provenances with known family structure. We aimed at disentangling adaptive and plastic responses for growth (height and diameter at breast height) as well as for leaf and wood functional traits related to adaptation to dry environments. We used restricted maximum likelihood approaches to assess additive genetic variation expressed as narrow‐sense heritability (h2), quantitative trait differentiation among provenances (QST), and genotype‐by‐environment interactions (GxE). We found strong and significant patterns of local adaptation in growth in all three common gardens, suggesting that transfer of seed material should not exceed a climatic distance of approximately 1°C under current climatic conditions, while transfer along precipitation gradients seems to be less stringent. Moreover, heritability reached 0.64 for tree height and 0.67 for dbh at the dry margin of the testing spectrum, suggesting significant additive genetic variation of potential use for future selection and tree breeding. GxE interactions in growth were significant and explained less phenotypic variation than origin of seed source (4% versus 10%). Functional trait variation among provenances was partly related to drought regimes at provenances origins but had moderate explanatory power for growth. We conclude that directional selection, either naturally or through breeding, is the most likely and feasible outcome for pedunculate oak to adapt to warmer and drier climate conditions in the future.

Abstract Phenotypic responses to a novel or extreme environment are initially plastic, only later to be followed by genetic change. Whether or not environmentally induced phenotypes are sufficiently recurrent and fit to leave a signature in adaptive evolution is debated. Here, we analyze multivariate data from 34 plant reciprocal transplant studies to test: (1) if plasticity is an adaptive source of developmental bias that makes locally adapted populations resemble the environmentally induced phenotypes of ancestors; and (2) if plasticity, standing phenotypic variation and genetic divergence align during local adaptation. Phenotypic variation increased marginally in foreign environments but, as predicted, the direction of ancestral plasticity was generally well aligned with the phenotypic difference between locally adapted populations, making plasticity appear to "take the lead" in adaptive evolution. Plastic responses were sometimes more extreme than the phenotypes of locally adapted plants, which can give the impression that plasticity and evolutionary adaptation oppose each other; however, environmentally induced and locally adapted phenotypes were rarely misaligned. Adaptive fine‐tuning of phenotypes—genetic accommodation—did not fall along the main axis of standing phenotypic variation or the direction of plasticity, and local adaptation did not consistently modify the direction or magnitude of plasticity. These results suggest that plasticity is a persistent source of developmental bias that shapes how plant populations adapt to environmental change, even when plasticity does not constrain how populations respond to selection.

Abstract Background In species with complex life cycles, size at metamorphosis is a key life-history trait which reflects the complex interactions between costs and benefits of life in the aquatic and terrestrial environments. Whereas the effects of a deteriorating larval habitat (e.g. pond desiccation) on triggering an early metamorphosis have been extensively investigated in amphibians, the consequences of the resulting reduced size at metamorphosis on fitness in the post-metamorphic terrestrial stage remain poorly understood. We tested the hypothesis that a smaller size at metamorphosis negatively affects performance and survival in the ensuing terrestrial stage. Using as model a tropical amphibian (Ceratophrys stolzmanni) showing a large phenotypic plasticity in metamorphosing traits, we evaluated the effects of size at metamorphosis on fitness-related trophic and locomotor performance traits, as well as on growth and survival rates. Results Our results support the hypothesis that a larger size at metamorphosis is correlated with better survival and performance. The survival rate of large metamorphosing individuals was 95%, compared to 60% for those completing metamorphosis at a small size. Locomotor performance and gape size were positively correlated with body size, larger animals being more mobile and capable to ingest larger prey. However, smaller individuals achieved higher growth rates, thus reducing the size gap. Conclusions Overall, size at metamorphosis affected profoundly the chances of survival in the short term, but smaller surviving individuals partly compensated their initial disadvantages by increasing growth rates.

Abstract Many theoretical models predict when genetic evolution and phenotypic plasticity allow adaptation to changing environmental conditions. These models generally assume stabilizing selection around some optimal phenotype. We however often ignore how optimal phenotypes change with the environment, which limit our understanding of the adaptive value of phenotypic plasticity. Here, we propose an approach based on our knowledge of the causal relationships between climate, adaptive traits, and fitness to further these questions. This approach relies on a sensitivity analysis of the process‐based model Phenofit, which mathematically formalizes these causal relationships, to predict fitness landscapes and optimal budburst dates along elevation gradients in three major European tree species. Variation in the overall shape of the fitness landscape and resulting directional selection gradients were found to be mainly driven by temperature variation. The optimal budburst date was delayed with elevation, while the range of dates allowing high fitness narrowed and the maximal fitness at the optimum decreased. We also found that the plasticity of the budburst date should allow tracking the spatial variation in the optimal date, but with variable mismatch depending on the species, ranging from negligible mismatch in fir, moderate in beech, to large in oak. Phenotypic plasticity would therefore be more adaptive in fir and beech than in oak. In all species, we predicted stronger directional selection for earlier budburst date at higher elevation. The weak selection on budburst date in fir should result in the evolution of negligible genetic divergence, while beech and oak would evolve counter‐gradient variation, where genetic and environmental effects are in opposite directions. Our study suggests that theoretical models should consider how whole fitness landscapes change with the environment. The approach introduced here has the potential to be developed for other traits and species to explore how populations will adapt to climate change.

Climate warming is predicted to shift species’ ranges as previously uninhabitable environments just beyond the leading range edges become suitable habitat and trailing range edges become increasingly unsuitable. Understanding which aspects of the environment and species traits mediate these range shifts is critical for understanding species’ possible redistributions under global change, yet we have a limited understanding of the ecological and evolutionary responses underlying population spread or extinction at species’ range edges. Within plant populations, shifts in flowering phenology have been one of the strongest and most consistent responses to climate change, and are likely to play an important role in mediating population dynamics within and beyond species’ ranges. However, the role of phenological shifts, and particularly phenological plasticity, in species’ range shifts remains relatively unstudied. Here, we synthesize literature on phenology, plasticity, and adaptation to suggest ways in which phenological responses to climate may vary across species’ ranges and review the empirical evidence for and against these hypotheses. We then outline how phenological plasticity could facilitate or hinder persistence and potential consequences of phenological plasticity in range expansions, including phenological cues, shifts in correlated traits, altered species interactions, and effects on gene flow. Finally, we suggest future avenues for research, such as characterizing reaction norms for phenology across a species’ range and in beyond-the-range transplant experiments. Given the prevalence and magnitude of phenological shifts, future work should carefully dissect its costs and benefits for population persistence, and incorporate phenological plasticity into models predicting species’ persistence and geographic range shifts under climate change.

Urban stressors represent strong selective gradients that can elicit evolutionary change, especially in non‐native species that may harbor substantial within‐population variability. To test whether urban stressors drive phenotypic differentiation and influence local adaptation, we compared stress responses of populations of a ubiquitous invader, reed canary grass (Phalaris arundinacea). Specifically, we quantified responses to salt, copper, and zinc additions by reed canary grass collected from four populations spanning an urbanization gradient (natural, rural, moderate urban, and intense urban). We measured ten phenotypic traits and trait plasticities, because reed canary grass is known to be highly plastic and because plasticity may enhance invasion success. We tested the following hypotheses: (a) Source populations vary systematically in their stress response, with the intense urban population least sensitive and the natural population most sensitive, and (b) plastic responses are adaptive under stressful conditions. We found clear trait variation among populations, with the greatest divergence in traits and trait plasticities between the natural and intense urban populations. The intense urban population showed stress tolerator characteristics for resource acquisition traits including leaf dry matter content and specific root length. Trait plasticity varied among populations for over half the traits measured, highlighting that plasticity differences were as common as trait differences. Plasticity in root mass ratio and specific root length were adaptive in some contexts, suggesting that natural selection by anthropogenic stressors may have contributed to root trait differences. Reed canary grass populations in highly urbanized wetlands may therefore be evolving enhanced tolerance to urban stressors, suggesting a mechanism by which invasive species may proliferate across urban wetland systems generally. [ABSTRACT FROM AUTHOR]

Hydrilla verticillata (Hydrocharitaceae) is a submerged freshwater flowering plant within the monotypic genus. Over the geological periods, fossils of this family and genus have shown distinct diversifications between warm and cool fluctuations with more adaptations occurring in warmer periods and suppressions during severely cold paleoclimate changes. Recently, H. verticillata has shown a wide range of adaptive plasticity, allowing successful proliferation into non‐native regions, whilst also undergoing unexplained disappearance from its native localities, and this phenomenon has stimulated this inquiry. Against this somewhat complex background, particular interest for this investigation has been focussed on an understanding of which aspects of climate change have contributed towards global adaptations and distribution patterns of H. verticillata. Whilst it is recognised that some of these changes are natural, other aggravating impacts are due to anthropogenic influences. Identifying the appropriate combinations of these climatic factors (temperature, rainfall, photoperiod), in concert with environmental (water level, CO2, salinity, eutrophication), geographical (altitude, latitude) and other factors (UV‐B) are necessary precursors for instituting appropriate management strategies. In this respect, control measures are needed in non‐native regions and restoration of this plant in native habitats are essential for its ecologically balanced global distribution. [ABSTRACT FROM AUTHOR]

Interactions with microbial symbionts have yielded great macroevolutionary innovations across the tree of life, like the origins of chloroplasts and the mitochondrial powerhouses of eukaryotic cells. There is also increasing evidence that host‐associated microbiomes influence patterns of microevolutionary adaptation in plants and animals. Here we describe how microbes can facilitate adaptation in plants and how to test for and differentiate between the two main mechanisms by which microbes can produce adaptive responses in higher organisms: microbe‐mediated local adaptation and microbe‐mediated adaptive plasticity. Microbe‐mediated local adaptation is when local plant genotypes have higher fitness than foreign genotypes because of a genotype‐specific affiliation with locally beneficial microbes. Microbe‐mediated adaptive plasticity occurs when local plant phenotypes, elicited by either the microbial community or the non‐microbial environment, have higher fitness than foreign phenotypes as a result of interactions with locally beneficial microbes. These microbial effects on adaptation can be difficult to differentiate from traditional modes of adaptation but may be prevalent. Ignoring microbial effects may lead to erroneous conclusions about the traits and mechanisms underlying adaptation, hindering management decisions in conservation, restoration, and agriculture. [ABSTRACT FROM AUTHOR]

As postulated by life‐history theory, not all life‐history traits can be maximized simultaneously. In ectothermic animals, climate warming is predicted to increase growth rates, but at a cost to overall life span. Maternal effects are expected to mediate this life‐history trade‐off, but such effects have not yet been explicitly elucidated.To understand maternal effects on the life‐history responses to climate warming in lizard offspring, we conducted a manipulative field experiment on a desert‐dwelling viviparous lacertid lizard Eremias multiocellata, using open‐top chambers in a factorial design (maternal warm climate and maternal present climate treatments × offspring warm climate and offspring present climate treatments).We found that the maternal warm climate treatment had little impact on the physiological and life‐history traits of adult females (i.e. metabolic rate, reproductive output, growth and survival). However, the offspring warm climate treatment significantly affected offspring growth, and both maternal and offspring warm climate treatments interacted to affect offspring survival.Offspring from the warm climate treatment grew faster than those from the present climate treatment. However, the offspring warm climate treatment significantly decreased the survival rate of offspring from maternal present climate treatment, but not for those from the maternal warm climate treatment.Our study demonstrates that maternal effects mediate the trade‐off between growth and survival of offspring lizards, allowing them to grow fast without a concurrent cost of low survival rate (short life span). These findings stress the importance of adaptive maternal effects in buffering the impact of climate warming on organisms, which may help us to accurately predict the vulnerability of populations and species to future warming climates. [ABSTRACT FROM AUTHOR]

Cognitive systems face a tension between stability and plasticity. The maintenance of long‐term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short‐term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom‐up acoustic information or top‐down word knowledge is available to disambiguate speech input, there is short‐term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well‐documented, it is not yet known whether bottom‐up and top‐down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom‐up information from the acoustic signal and top‐down information from lexical knowledge in the adaptive plasticity of speech categorization according to short‐term input regularities. The results implicate speech category activation, whether from top‐down or bottom‐up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input. [ABSTRACT FROM AUTHOR]

Objective: Acoustic distortions to the speech signal impair spoken language recognition, but healthy listeners exhibit adaptive plasticity consistent with rapid adjustments in how the distorted speech input maps to speech representations, perhaps through engagement of supervised error-driven learning. This puts adaptive plasticity in speech perception in an interesting position with regard to developmental dyslexia inasmuch as dyslexia impacts speech processing and may involve dysfunction in neurobiological systems hypothesized to be involved in adaptive plasticity. Method: Here, we examined typical young adult listeners (N = 17), and those with dyslexia (N = 16), as they reported the identity of native-language monosyllabic spoken words to which signal processing had been applied to create a systematic acoustic distortion. During training, all participants experienced incremental signal distortion increases to mildly distorted speech along with orthographic and auditory feedback indicating word identity following response across a brief, 250-trial training block. During pretest and posttest phases, no feedback was provided to participants. Results: Word recognition across severely distorted speech was poor at pretest and equivalent across groups. Training led to improved word recognition for the most severely distorted speech at posttest, with evidence that adaptive plasticity generalized to support recognition of new tokens not previously experienced under distortion. However, training-related recognition gains for listeners with dyslexia were significantly less robust than for control listeners. Conclusions: Less efficient adaptive plasticity to speech distortions may impact the ability of individuals with dyslexia to deal with variability arising from sources like acoustic noise and foreign-accented speech. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity, or an organism's capacity to change its phenotype in response to environmental variation, is a pervasive--perhaps even ubiquitous--feature of the biological world. Accordingly, plasticity research suggests serious implications for biological theory, including evolutionary theory. The theoretical implications of plasticity have growing support from empirical literature documenting the range, extent, and adaptiveness of plasticity. However, the empirical evidence for particular instances of plasticity has still not been adequately scrutinized by biologists or philosophers. After reviewing some important conceptual and theoretical background information, this paper synthesizes some past discussions of the methodology of plasticity studies and provides some novel methodological guidance for plasticity researchers. My conclusion is that not all plasticity studies should carry the same weight: there are patterns we can identify in the features of such studies that should contribute to (or detract from) their credibility. In particular, I argue that some types of organisms and some types of plastic phenotypes are more conducive to the empirical study of plasticity than others. [ABSTRACT FROM AUTHOR]