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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.

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., We tested whether populations of a ubiquitous wetland invader, reed canary grass (Phalaris arundinacea), differed phenotypically across an urbanization gradient, suggesting evolutionary responses to common urban stressors. We found clear trait and trait plasticity variation among populations, suggesting reed canary grass may be evolving enhanced tolerance to anthropogenic stressors.

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.

Islands present significant technological and ecological challenges for long-term human settlement, with archaeological investigations of islands globally able to shed light on the adaptive plasticity of cultural groups to changing climatic regimes. The Massim islands of eastern New Guinea significantly reduced in size throughout the Holocene (⩽11.7 kya), providing a unique opportunity to investigate the long-term adaptive capabilities of humans to changing island ecosystems. Here, we report a 2500-2300 year cultural sequence on Nimowa Island in the Louisiade Archipelago of the Massim region which began with the arrival of a late Lapita population during initial beachfront development. Sediment analyses indicate earlier settlement on the island would not have been possible as the coastline was unstable until near-modern sea levels were reached. The island was abandoned from 1290 to 530 cal. BP during a period of unusually dry conditions (‘Medieval Climate Anomaly’) and probable freshwater shortages. Re-settlement coincided with wetter climatic conditions (‘Little Ice Age’), associated with the establishment of large villages, the earliest expression of local pottery traditions and the onset of large-scale regional exchange networks. Import of non-local obsidian reflects two pulses of interaction followed by periods of increased isolation. With the absence of high-quality lithic resources, shell, coral and bone were used as a locally available alternative for tool production. Increased cyclone frequency from ~500 cal. BP greatly increased beach volume in the island and coastal New Guinea, which facilitated the movement of populations onto smaller islands. A late prehistoric shift in settlement patterns had a profound impact on regional social dynamics.

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.

Synedrella nodiflora is an invasive species originated from tropical America and now has spread throughout Indonesia. We analysed the ability of Synedrella nodiflora from the level of HSP70 gene expression at different heat stress in urban tropical lowland landscape Universitas Indonesia. We used the qPCR to quantify the level of HSP70 gene expression and analysed using Pfaffl model. We found the level of HSP70 gene expression got higher related to elevated temperature from 29oC to 39oC with a range of fold from 123.1 to 1676.9. This ability reflects the adaptive plasticity of Synedrella nodiflora in the course of the invasion process.

The Southwestern North America megadrought is an extreme climate event. Artemisia tridentata (big sagebrush) is the dominant, keystone species of sagebrush-steppe ecosystems in arid and semi-arid habitats of western North America. I conducted a genotype-by-environment (GxE) experiment on two putative genotypes (drought-tolerant, G1 and drought-sensitive, G2) and two cytotypes, diploid (2x) and tetraploid (4x), to determine the phenotypic responses of big sagebrush seedlings to drought. For three chlorophyll fluorescence parameters, my results indicate a complex set of factors influence sagebrush responses to drought, including canalization, adaptive phenotypic plasticity, cryptic genetic diversity, and GxE interactions. Variation in leaf temperature profiles of sagebrush seedlings is exclusively driven by treatment effects, suggesting that variation for this trait is determined by non-adaptive phenotypic plasticity. I did not detect significant treatment effects for root to shoot (R:S) length ratios for 2x and 4x families exposed to drought, although I did detect significant differences among G1 and G2 genotypes of both cytotypes. Tetraploid seedlings significantly outperformed 2x seedlings for R:S length ratios across all three watering treatments. My results indicate that sagebrush populations differ in their capacity to respond to megadrought; thus, proper sourcing of seeds for restoration efforts should account for the genotypes and cytotypes of populations.

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.

Aims Cultivar mixtures can increase productivity through complementarity in resource use, but reported results are often conflicting and the role of plasticity in shaping plant-plant interactions is poorly understood. We aim to determine if individual cultivars show different phenotypic responses when grown in a mixture, whether these responses depend on the neighboring cultivar identity, and how they contribute to variations in productivity and nitrogen (N) use. Methods Five spring barley cultivars were field-grown in pure stands and in mixtures during 2 years. Plant traits related to development, growth, N use, and reproduction were measured to identify temporal patterns of plastic responses to neighboring plants. Results Plants in mixtures were shorter and developed slower early in the season, but later on they grew faster and produced more grain than the corresponding pure stands. Some cultivars showed complementary N accumulation only when grown together with specific neighbors. Mechanisms of improved productivity differed between the individual mixtures. Conclusions Plastic plant-plant interaction between cultivars is an important driver behind the variability in mixing effects. Results contribute to a better understanding of how productivity in cultivar mixtures is affected by plastic adaptation and differentiation of plant traits, depending on the environment created by neighboring genotypes.

In the Asian citrus psyllid (Diaphorina citri Kuwayama), learning facilitates host recognition and mate preference; however, it is unclear whether induced female oviposition preference occurs in this species. We investigated the influence of natal host experience on adult oviposition preference when reared on either 'Valencia' orange (Citrus x sinesis) or orange jasmine (Murraya paniculata). Psyllids reared on 'Valencia' orange preferred 'Valencia' orange as an oviposition host compared with orange jasmine, whereas there was no difference in oviposition between the two hosts in orange jasmine reared psyllids. Nymphs transferred from 'Valencia' orange to orange jasmine were smaller in adult size and required more time for development. These findings were reversed in orange jasmine reared psyllids, which increased in size and displayed shorter development times when transferred from orange jasmine to 'Valencia' orange. However, mortality increased in nymphs transferred to the non-natal host species in both treatment groups compared with nymphs transferred to the same host. These results indicate an association between host plant preference and performance in this species. Maternal host experience appeared to influence the oviposition preference in this species. Juvenile psyllid performance appeared negatively affected by orange jasmine plants such that fitness was reduced, suggesting benefits for maternal host fidelity in those insects not acclimated to feeding on orange jasmine. Induced oviposition preference may provide an important mechanism of adaptive plasticity in D. citri reproductive strategies, allowing females to discriminate among potential host species in favor of those to which her offspring are best adapted.

Genotypes can persist in unpredictable environments by ‘hedging their bets’ and producing diverse phenotypes. Theoretical studies have shown that the phenotypic variability needed for a bet-hedging strategy can be generated by factors either inside or outside an organism. However, sensing the environment and bet hedging are frequently treated as distinct evolutionary strategies. Furthermore, nearly all empirical studies of the molecular underpinnings of bet-hedging strategies to date have focused on internal sources of variability. We took a synthetic approach and constructed an experimental system where a phenotypic trade-off is mediated by actively sensing a cue present in the environment. We show that active sensing can generate a diversified bet-hedging strategy. Mutations affecting the norm of reaction to the cue alter the diversification strategy, indicating that bet hedging by active sensing is evolvable. Our results indicate that a broader class of biological systems should be considered as potential examples of bet-hedging strategies, and that research into the structure of environmental variability is needed to distinguish bet-hedging strategies from adaptive plasticity. This article is protected by copyright. All rights reserved

Effect of increased temperature during egg maturation on the mass of single eggs produced by the offspring was investigated experimentally in Atlantic salmon Salmo salar. Mass of eggs produced by next-generation females was larger when their mothers experienced warmer water during the last two months of egg maturation, relative to those that experienced unheated river water. There was no similar trans-generational paternal effect on offspring egg mass.

Healthy humans are characterized by a fine physiological weather sensitivity. Normally, it is expressed as brain and behavior responses to ordinary geophysical factors, such as wind conditions, temperature, atmospheric pressure, and relative humidity. According to comparative evolutionary assessment, behavioral weather sensitivity grows with its phylogenetic complication within a species, which has been demonstrated in rats (Rattus norvegicus) and humans. The behavioral response of rats is more acute than in men. In men, correlations between electroencephalogram rhythms (EEG) and weather fluctuations become stronger, as “Δ-θ-α-β” cerebral rhythms speed up. This dependence progresses throughout the ontogenesis of a healthy man, i.e., as one matures and advances in age. The number of correlations between weather and REG or EEG parameters increases nonlinearly within an ontogenetic series from 3 to 72 years of age. Physiological weather sensitivity forms a diversity of reactions to environmental changes enlarging the arsenal of the adaptive plasticity of a whole body.

Plants can detect the presence of competitors through the change the spectral quality of light induced by potentially competing plants. This change in spectral quality can induce shade avoidance plasticity to maximise light acquisition. We examined how simulated competition as seedlings impact performance when plants are exposed to real competition later in life. We predicted that individuals experiencing simulated competition as seedlings will perform better under competition later in life. We grew seedlings of six short-lived herbaceous species under simulated competition and no competition treatments early in life and real competition and no competition later in life. Seedlings in the real competition treatment were grown in pots with grass competitors. Competitors were prevented from interacting with seedlings early in the experiment using above ground by pinning back competitor plants, and below ground through root exclusion pots. We ended the simulated competition treatment and started the real competition treatment (by removing the barriers) when seedlings reached a threshold size. We found that plants in the simulated competition treatment did not express shade-avoidance plasticity. No species performed better under competition when exposed to simulated competition as seedlings. Three of the six species performed significantly worse under competition when exposed to simulated competition as seedlings. Plants are often capable of detecting and responding to their enemies. However, none of the species in our study demonstrated either the capacity to detect the presence of competitors, or increased performance under competition when exposed to the cues for future competition early in life. In some instances, plants respond passively to competitors and adaptive responses to the presence of enemies can be limited.

Crassostrea hongkongensis, a commercially valuable aquaculture species dwelling in estuaries along the coast of the South China Sea, is remarkable for its eurysalinity traits that enable its successful colonization of diverse osmotic niches ranging from near freshwater to seawater. In order to elucidate how this oyster copes with coastal waters with immense salinity differences, we performed in situ transcriptomic analysis (RNA-seq) to characterize the global expression patterns of oysters distributed across naturally formed salinity gradients in Zhenhai Bay along the northern coast of the South China Sea. Principal component analysis reveals distinct expression profiles of oysters living in the extreme conditions of hypo-salinity and hyper-salinity. Compared with the situation of optimal salinity for oyster growth, hypo-salinity mainly regulated expression of genes involved in FoxO and oxytocin signaling, tight junction and several immune pathways, while hyper-salinity altered gene expression implicated in amino acid metabolism, AMPK and PI3K-AKt signaling pathways, demonstrating the complexity and plasticity of transcriptomic expression underpinning oyster eurysalinity. Furthermore, the expression patterns of several genes correlated with salinity gradients reveals the fine-tuned coordination of molecular networks necessary for adaptive homeostasis in C. hongkongensis. In conclusion, a striking capacity and distinct patterns of transcriptomic expression contribute to eurysalinity adaptation in C. hongkongensis, which provides new mechanistic insights into the adaptive plasticity and resilience of marine mollusks.

Sensory drive predicts that the conditions under which signaling takes place have large effects on signals, sensory systems, and behavior. The coupling of an ecological genetics approach with sensory drive has been fruitful. An ecological genetics approach compares populations that experience different environments and asks whether population differences are adaptive and are the result of genetic and/or environmental variation. The multi-faceted effects of signaling environments are well-exemplified by the bluefin killifish. In this system, males with blue anal fins are abundant in tannin-stained swamps that lack UV/blue light but are absent in clear springs where UV/blue light is abundant. Past work indicates that lighting environments shape genetic and environmental variation in color patterns, visual systems, and behavior. Less is known about the selective forces creating the across population correlations between UV/blue light and the abundance of blue males. Here, we present three new experiments that investigate the roles of lighting environments on male competition, female mate choice, and predation. We found strong effects of lighting environments on male competition where blue males were more likely to emerge as dominant in tea-stained water than in clear water. Our preliminary study on predation indicated that blue males may be less susceptible to predation in tea-stained water than in clear water. However, there was little evidence for female preferences favoring blue males. The resulting pattern is one where the effects of lighting environments on genetic variation and phenotypic plasticity match the direction of selection and favor the expression of blue males in swamps.

We analyzed the blood lipid spectra in four closely related sculpin (Cottoidei) species endemic to Lake Baikal. These data characterize the Baikal sculpins as a set of model organisms for studying the adaptive plasticity of cholesterol metabolism and also mechanisms of resistance to the development of dyslipidemia and atherosclerosis.

Communication via substrate-borne vibrations is the most widespread form of acoustic communication in arthropods. However, remarkably little is known about physiological sources of selection on vibrational communication systems, in particular those underlying mate choice and male competition. Here, we studied the energetic cost of vibrational signalling in the leafhopper Aphrodes makarovi (Hemiptera: Cicadellidae). We measured O2 consumption of a single male for 15–30 min using the closed-bottle method and a lifetime-based optode, while we recorded emitted vibrational signals with a laser vibrometer. Males were emitting three types of vibrational signals (advertisement calls, masking signals and pulse signals), and the respiration rate was significantly positively correlated with the cumulative signalling time. Our results showed that vibrational signalling was around 12.4 times energetically more demanding than resting. Furthermore, production of masking signals emitted in rivalry situations was as energetically demanding as production of advertisement calls used in sexual communication between partners. We also assessed the effect of calling effort on male survival. We determined calling effort by playback experiments once every week of male’s adult life until death. The average male longevity was 50 days, and survival was negatively correlated with the number of emitted advertisement calls, calling rate and calling time in early life. Considering that in mating systems based on vibrational signals, communication occurs in a changing social environment, more detailed studies on indirect costs of signalling in such systems may provide new insights into mechanisms that lead to adaptive plasticity in male sexual behaviour.

In marine benthic communities, phenotypic responses to contact competition are well resolved, but the causes and consequences of non-contact competition remain unclear. Here, we used the arborescent bryozoan Bugula neritina to firstly identify whether colonies change their phenotype as a result of non-contact competition, and then understand the mechanism behind the changes. Secondly, we determined the phenotypes that change in response to non-contact competition, with focus on changes in the feeding structure, viz. the lophophore. Lastly, we used a reciprocal transplant design to test whether phenotypic responses to non-contact competition reduce its negative effects. We found that phenotypic responses to non-contact competition were mediated by the biological effects of conspecific neighbours, but were also determined by the physical effects associated with increased density. Further, we found that colonies grown in high conspecific density environments were smaller (though more elongated for their size) and had smaller lophophores than colonies from low conspecific density treatments. However, we found no evidence that such phenotypic responses constituted adaptive plasticity; instead, individuals that experienced non-contact competition always performed worse than individuals that had not, and the effects of exposure to non-contact competition were additive. Our study suggests that non-contact competition is an important and persistent process in benthic marine communities, but that phenotypic plasticity, though present, does not buffer individuals from the negative effects of this process.

1. Interannual variability in climatic conditions should be taken into account in climate change studies in semi-arid ecosystems. It may determine differentiation in phenotypic plasticity among populations, with populations experiencing higher environmental heterogeneity showing higher levels of plasticity., 2. The ability of populations to evolve key functional traits and plasticity may determine the survival of plant populations under the drier and more variable climate expected for semi-arid ecosystems., 3. Working with populations of the semi-arid Chilean shrub Senna candolleana along its entire distribution range, we assessed inter- and intra-population variation in functional traits as well as in their plasticity in response to water availability. We measured morphological and physiological traits related to drought resistance in both field conditions and in a greenhouse experiment, where drought response was evaluated under two water availability treatments., 4. All populations responded plastically, but higher precipitation heterogeneity in dry-edge populations seemed to have selected for more plastic genotypes compared to populations growing at mesic sites and with more homogeneous environmental conditions., 5. Synthesis. Our results suggest adaptive plasticity since higher levels of phenotypic plasticity were positively associated with plant performance. However, we did not find evidence for genetic variation for plasticity within populations. To the extent that phenotypic plasticity may play a key role in future persistence, populations at mesic sites may be more vulnerable to climate change due to their lower plasticity and their current limitations to evolve novel norms of reaction. Conversely, although Senna candolleana populations at the dry edge are exposed to higher levels of stress, they may be less susceptible to climate change in view of their greater plasticity. We highlight the need to consider population differentiation in both mean traits and their plasticity to model realistic scenarios of species distribution under climate change., Funding was provided by the Spanish Ministry for Innovation and Science with the grants Consolider Montes (CSD2008_00040) and VULGLO (CGL2010-22180-C03-03).

Under natural conditions, many aspects of the abiotic and biotic environment vary with time of day, season or even era, while these conditions are typically kept constant in laboratory settings. The timing information contained within the environment serves as critical timing cues for the internal biological timing system, but how this system drives daily rhythms in behaviour and physiology may also depend on the internal state of the animal. The disparity between timing of these cues in natural and laboratory conditions can result in substantial differences in the scheduling of behaviour and physiology under these conditions. In nature, temporal coordination of biological processes is critical to maximize fitness because they optimize the balance between reproduction, foraging and predation risk. Here we focus on the role of peripheral circadian clocks, and the rhythms that they drive, in enabling adaptive phenotypes. We discuss how reproduction, endocrine activity and metabolism interact with peripheral clocks, and outline the complex phenotypes arising from changes in this system. We conclude that peripheral timing is critical to adaptive plasticity of circadian organization in the field, and that we must abandon standard laboratory conditions to understand the mechanisms that underlie this plasticity which maximizes fitness under natural conditions. This article is part of the themed issue ‘Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals’.

Research on parasite-altered feeding behavior in insects is contributing to an emerging literature that considers possible adaptive consequences of altered feeding behavior for the host or the parasite. Several recent ecoimmunological studies show that insects can adaptively alter their foraging behavior in response to parasitism. Another body of recent work shows that infection by parasites can change the behavior of insect hosts to benefit the parasite; manipulations of host feeding behavior may be part of this phenomenon. Here, we address both the functional and the underlying physiological frontiers of parasite-altered feeding behavior in order to spur research that better integrates the two. Functional categories of parasite-altered behavior that are adaptive for the host include prophylaxis, therapy and compensation, while host manipulation is adaptive for the parasite. To better understand and distinguish prophylaxis, therapy and compensation, further study of physiological feedbacks affecting host sensory systems is especially needed. For host manipulation in particular, research on mechanisms by which parasites control host feedbacks will be important to integrate with functional approaches. We see this integration as critical to advancing the field of parasite-altered feeding behavior, which may be common in insects and consequential for human and environmental health.

Animals will continue to encounter increasingly warm environments, including more frequent and intense heat waves. Yet the physiological consequences of heat waves remain equivocal, potentially because of variation in adaptive plasticity (reversible acclimation) and/or aspects of experimental design. Thus, we measured a suite of physiological variables in the corn snake (Pantherophis guttatus) after exposure to field-parameterized, fluctuating temperature regimes (moderate temperature and heat wave treatments) to address two hypotheses: (1) a heat wave causes physiological stress, and (2) thermal performance of immune function exhibits adaptive plasticity in response to a heat wave. We found little support for our first hypothesis because a simulated heat wave had a negative effect on body mass, but it also reduced oxidative damage and did not affect peak performance of three immune metrics. Likewise, we found only partial support for our second hypothesis. After exposure to a simulated heat wave, P. guttatus exhibited greater performance breadth and reduced temperature specialization (the standardized difference between peak performance and performance breadth) for only one of three immune metrics and did so in a sex-dependent manner. Further, a simulated heat wave did not elicit greater performance of any immune metric at higher temperatures. Yet a heat wave likely reduced innate immune function in P. guttatus because each metric of innate immune performance in this species (as in most vertebrates) was lower at elevated temperatures. Together with previous research, our study indicates that a heat wave may have complex, modest, and even positive physiological effects in some taxa.

Adaptation of natural populations to variable environmental conditions may occur by changes in trait means and/or in the levels of plasticity. Theory predicts that environmental heterogeneity favors plasticity of adaptive traits. Here we investigated the performance in several traits of three sympatric Drosophila species freshly collected in two environments that differ in the heterogeneity of environmental conditions. Differences in trait means within species were found in several traits, indicating that populations differed in their evolutionary response to the environmental conditions of their origin. Different species showed distinct adaptation with a very different role of plasticity across species for coping with environmental changes. However, geographically distinct populations of the same species generally displayed the same levels of plasticity as induced by fluctuating thermal regimes. This indicates a weak and trait‐specific effect of environmental heterogeneity on plasticity. Furthermore, similar levels of plasticity were found in a laboratory‐adapted population of Drosophila melanogaster with a common geographic origin but adapted to the laboratory conditions for more than 100 generations. Thus, this study does not confirm theoretical predictions on the degree of adaptive plasticity among populations in relation to environmental heterogeneity but shows a very distinct role of species‐specific plasticity.

Global stressors, such as ocean acidification, constitute a rapidly emerging and significant problem for marine organisms, ecosystem functioning and services. The coastal ecosystems of the Humboldt Current System (HCS) off Chile harbour a broad physical-chemical latitudinal and temporal gradient with considerable patchiness in local oceanographic conditions. This heterogeneity may, in turn, modulate the specific tolerances of organisms to climate stress in species with populations distributed along this environmental gradient. Negative response ratios are observed in species models (mussels, gastropods and planktonic copepods) exposed to changes in the partial pressure of CO

Calling behaviour is an essential component of gaining access to mates, and calling site selection may be an important component of effective communication. Environmental factors like microclimate, or the presence of competitors and predators often show seasonal or spatial variation, and behavioural plasticity that allows the caller to adjust to this variation may be adaptive. Prompted by the observation of across-season variation in elevated calling site use in our grey treefrog population, we formulated three hypotheses about their calling site choice and tested them using field observations and behavioural trials in the lab. We found that calling site selection is largely determined by local temperature regimes, and suggest that this temperature-based plasticity in calling site selection is adaptive because it allows males to increase their metabolic efficiency and mate attraction effectiveness. The mere presence of heterospecific competitors and predators did not affect calling site selection at the pond, but close proximity to a predator during behavioural trials did reduce calling activity. This suggests that grey treefrog males attend to the presence of predators, that they can assess the degree of risk associated with predator proximity, and that they can adjust calling behaviour adaptively to reduce the chances of being detected by a predator.

Plant and animal parents may respond to environmental conditions such as resource stress by altering traits of their offspring via heritable non-genetic effects. While such transgenerational plasticity can result in progeny phenotypes that are functionally pre-adapted to the inducing environment, it is unclear whether such parental effects measurably enhance the adult competitive success and lifetime reproductive output of progeny, and whether they may also adversely affect fitness if offspring encounter contrasting conditions. In glasshouse experiments with inbred genotypes of the annual plant Polygonum persicaria , we tested the effects of parental shade versus sun on (a) competitive performance of progeny in shade, and (b) lifetime reproductive fitness of progeny in three contrasting treatments. Shaded parents produced offspring with increased fitness in shade despite competition, as well as greater competitive impact on plant neighbours. Inherited effects of parental light conditions also significantly altered lifetime fitness: parental shade increased reproductive output for progeny in neighbour and understorey shade, but decreased fitness for progeny in sunny, dry conditions. Along with these substantial adaptive and maladaptive transgenerational effects, results show complex interactions between genotypes, parent environment and progeny conditions that underscore the role of environmental variability and change in shaping future adaptive potential. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.

Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually "indestructible". With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs.

11 páginas, 1 figura, 4 tablas.-- El pdf es la versión post-print.-- Laboratorio Internacional de Cambio Global LINC-Global, Museo Nacional de Ciencias Naturales-CSIC., Functional traits, their plasticity and their integration in a phenotype have profound impacts on plant performance. We developed structural equation models (SEMs) to evaluate their relative contribution to promote invasiveness in plants along resource gradients. We compared 20 invasive–native phylogenetically and ecologically related pairs. SEMs included one morphological (root-to-shoot ratio (R/S)) and one physiological (photosynthesis nitrogen-use efficiency (PNUE)) trait, their plasticities in response to nutrient and light variation, and phenotypic integration among 31 traits. Additionally, these components were related to two fitness estimators, biomass and survival. The relative contributions of traits, plasticity and integration were similar in invasive and native species. Trait means were more important than plasticity and integration for fitness. Invasive species showed higher fitness than natives because: they had lower R/S and higher PNUE values across gradients; their higher PNUE plasticity positively influenced biomass and thus survival; and they offset more the cases where plasticity and integration had a negative direct effect on fitness. Our results suggest that invasiveness is promoted by higher values in the fitness hierarchy -- trait means are more important than trait plasticity, and plasticity is similar to integration -- rather than by a specific combination of the three components of the functional strategy., O.G. acknowledges financial support from the Spanish Ministry for Education and Science and Fulbright Commission. Funding was provided by the Spanish Ministry for Innovation and Science through grants CGL2010-16388 ⁄ BOS, Consolider Montes (CSD2008_00040) and VULGLO (CGL2010-22180-C03-03), by the Community of Castilla-La Mancha (POII10-0179-4700) and by the Community of Madrid, grant REMEDINAL 2 (CM-S2009 ⁄ AMB-1783).

Poison frogs in the genus Dendrobates (sensu Grant et al. 2006) are known to lay black pigmented eggs. During a field study in May 2010 in central Panama, a captive pair of wild-caught adult Dendrobates auratus laid a clutch of whitish eggs. The eggs developed and metamorphic froglets were similar in size and color to that of age-matched normal-colored tadpoles produced by different parents and reared in exactly the same conditions. The observation of a pale pigmented tadpole in the wild suggests that polymorphism in the degree of melanism is not simply an artifact of laboratory rearing. Our study is the first to report the production of viable whitish eggs by any species in the genus Dendrobates. Whether this coloration arises due to constraint or is a polymorphism that has adaptive significance awaits further study.

Despite the apparent advantages of adaptive plasticity, it is not common. We examined the effects of variation and uncertainty on selection for plasticity using an individual-based computer simulation model. In the model, the environment consisted of a linear gradient of 50 demes with dispersal occurring either before or after selection. Individuals consisted of multiple loci whose phenotypic expression either are affected (plastic) or are not affected (nonplastic) by the environment. Typically, evolution occurred first as genetic differentiation, which was then replaced by the evolution of adaptive plasticity, opposite to the evolutionary trend that is often assumed. Increasing dispersal rates selected for plasticity, if selection occurred before dispersal. If selection occurred after dispersal, the highest plasticity was at intermediate dispersal rates. Temporal variation in the environment occurring after development, but before selection, favored the evolution of plasticity. With dispersal before selection, such temporal variation resulted in hyperplasticity, with a reaction norm much steeper than the optimum. This effect was enhanced with negative temporal autocorrelation and can be interpreted as representing a form of bet hedging. As the number of nonplastic loci increased, plasticity was disfavored due to an increase in the uncertainty of the genomic environment. This effect was reversed with temporal variation. Thus, variation and uncertainty affect whether or not plasticity is favored with different sources of variation—arising from the amount and timing of dispersal, from temporal variation, and even from the genetic architecture underlying the phenotype—having contrasting, interacting, and at times unexpected effects.

Phenotypic plasticity is a widespread phenomenon in which one genotype produces different phenotypes under different environmental conditions. Whether plasticity is adaptive or not depends on the optimal phenotypic value in each environment (Via 1993). Adaptive plasticity is expected to align with the direction of selective gradients, moving traits closer to the optima (Fig. 1A). Likewise, if the optimal values are similar in both environments, plasticity may be non-adaptive, opposing the directions of selective gradients (Fig. 1B). Plasticity as a trait is also subject to selective pressures and can itself evolve. This article is protected by copyright. All rights reserved

Most ectotherms follow the temperature-size rule meaning that individuals growing up under cool conditions are larger as adults than those growing up in warm conditions. This pattern is difficult to explain because growth is usually slower in the cold meaning it takes longer to reach a larger adult size. One potential explanation for this pattern is that the typical increase in fecundity with body size is steeper in cool environments than it is in warm environments. As such, the relative gain in fecundity for being larger in the cold would compensate for the extra time it takes to grow to that size. We present the first empirical test of this model using the water strider Aquarius remigis. Individuals were reared at either 20° or 25°C with subsampling at each instar to estimate growth trajectories. At adult eclosion, half were switched to the alternate temperature and all females isolated, mated, and reproductive output measured for 3 weeks. We found that A. remigis does follow the temperature-size rule but that fecundity was highly plastic with respect to laying temperature such that the slightly greater fecundity of those reared at 20°C was due to their larger size. Overall, those laying at 25°C were more fecund and showed a positive relationship between body size and fecundity. Those laying at 20°C did not show a significant relationship between size and fecundity. As such, the reproductive allometry shows a pattern reverse to what would be needed for a larger size in the cold to be adaptive in this species. Although A. remigis follows the temperature-size rule over this temperature range, this is likely due to a constraint on growth and development rather than being adaptive plasticity.

Climate change is altering the availability of resources and the conditions that are crucial to plant performance. One way plants will respond to these changes is through environmentally induced shifts in phenotype (phenotypic plasticity). Understanding plastic responses is crucial for predicting and managing the effects of climate change on native species as well as crop plants. Here, we provide a toolbox with definitions of key theoretical elements and a synthesis of the current understanding of the molecular and genetic mechanisms underlying plasticity relevant to climate change. By bringing ecological, evolutionary, physiological and molecular perspectives together, we hope to provide clear directives for future research and stimulate cross-disciplinary dialogue on the relevance of phenotypic plasticity under climate change.

SUMMARYParental behavior contributes to the success of a diverse array of taxa, and female-only nest attendance is particularly widespread. Python egg-brooding behavior is an intriguing example of female-only nest attendance because it significantly influences several critical developmental variables, namely embryonic predation, hydration, respiration and temperature. During brooding, females predominately adopt a tightly coiled posture that reduces the exchange of heat, water vapor, O2 and CO2 between the nest and clutch environment, which benefits egg water balance at the cost of respiration. To determine the plasticity of this important behavior, we manipulated nest temperature and humidity while monitoring nest–clutch thermal, hydric and respiratory relationships to test the hypothesis that female Children's pythons (Antaresia childreni) modify their egg-brooding behavior due to an interaction between environmental thermal and hydric conditions. During moderate and high nest humidity treatments (23 and 32 g m−3 H2O, respectively), females spent more time coiling tightly when the nest was cooling than when it was warming, which benefited clutch temperature. However, brooding females in low-humidity nest environments (13 g m−3 H2O) showed a high frequency of tight coiling even when the nest was warming; thus, nest temperature and humidity had an interactive effect on egg-brooding behavior in support of our hypothesis. Our results also suggest that certain egg-brooding behaviors (i.e. postural adjustments) are more energetically costly to females than other behaviors (i.e. tight coiling). In sum, we provide empirical support for the adaptive plasticity of python egg-brooding behavior, which offers insight into the general significance of female-only nest attendance in animals.

Plants only interact with neighbors over restricted distances, so local conditions are of great significance for plants. In this study, a spatially-explicit, individual-based model was constructed to explore the effects of size variation and spatial structure on adaptive plasticity of plant height in response to light competition. In the model a plant maintains its height at an optimal value in order to maximize its growth rate, and this optimal height increases with the increase of the intensity of light competition experienced by the individual plant. When the spatial pattern of the population is non-uniform or there is size variation among individual plants, the height growth curves of individuals different from each other vary due to the differences in the local light environment, and there is also variation in the allocation of photosynthate to height growth among the individual plants. There is no ESS height or height growth strategy on which all plants will converge. Our results indicate that the plasticity of plants’ height growth reactions to the light competition should be considered at the individual level and they argue strongly for the importance of the spatial pattern and neighborhood effects in generating the diversity of heights and height growth strategies in plant population.