Plasticity In Physiological Traits Research Articles

Evolution and plasticity of physiological traits in the collembolan Orchesella villosa at fine spatial scales within the city

Abstract Divergent natural selection caused by spatial environmental variation can lead to local adaptation and evolutionary divergence between populations, even those within close proximity to one another. This, however, is only one possibility among other outcomes, such as the evolution of adaptive phenotypic plasticity or local maladaptation. Cities, as fragmented landscapes with high environmental variability across microgeographic scales, present an excellent venue to explore these possible outcomes. Here, we use common garden experiments to explore the potential for microgeographic divergence of physiological traits among populations of a collembolan, Orchesella villosa, living within the footprint of a single city. We assessed if intra-urban variation in the intensity of the heat island effect and soil salinity has led to evolutionary divergence in heat tolerance and salinity tolerance, respectively. While we found little variation in salinity tolerance among populations, there was evidence for both plasticity and evolutionary divergence among populations in response to variation in the urban heat island. Although the adaptive nature of these specific responses is not known, we suggest that cities, and human modified habitats in general, promote evolutionary divergence at small spatial scales by creating barriers to dispersal and imposing divergent selective environments within previously contiguous habitats.

Phenological and physiological advantages of invasive annuals are strengthened by nitrogen enrichment

Abstract Anthropogenic nitrogen (N) deposition exerts profound influence on the composition and function of native ecosystems, commonly resulting in reduced plant richness and increases in nonnative plant invasion. Identifying differences in plant N responses and functional traits could help to explain the ongoing invasion and biological impoverishment of ecosystems subject to N deposition. We compared the growth, emergence phenology and functional traits of 30 native and invasive annual plant species under high and low N availability, with the goal of evaluating if invasives exhibit functionally dissimilar responses to N compared with the native species they displace. Invasives grew larger than natives, especially under increased N availability. Overall, invasives and natives did not differ in emergence phenology. However, these groups of species differed in relationships between growth and days to emergence, and N addition further strengthened these differences; invasives consistently grew larger than natives that emerged around the same time, whereas natives showed a strong negative effect of delayed emergence on plant growth. Relative N responses for measures of plant growth and allocation did not differ between native and invasive species, but invasives exhibited greater plasticity in physiological traits. This included significantly lower leaf N content, higher CN ratios and greater water‐use efficiency (WUE) in plants grown under high N. Invasives also showed functionally different patterns of growth and water use. Across species, invasives showed a positive relationship between shoot growth and WUE. Native species showed a trade‐off between root allocation and WUE, whereas invasives displayed high values for WUE even despite reduced root: shoot ratios under high N. Our results highlight the ability of invasives to rapidly accrue biomass, disproportionately benefit from early emergence and N addition and use water efficiently despite rapid growth. Natives, on the other hand, pay a higher cost for delayed emergence and may experience trade‐offs between growth and water use. The more pronounced functional differences between natives and invasives observed under high N likely play an important role in driving invasion and reduced species diversity under N enrichment. These differences could be used to inform successful management strategies for N‐impacted and water‐limited ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Phenotypic plasticity in Pygoscelis adeliae physiology and immunity under anthropogenic pressure: a proteomic and biochemical scenario

The capacity of seabirds to shape their physiological and immune phenotypes may often be constrained by the ecological context. While phenotypic plasticity in physiological traits has been previously studied, the molecular mechanisms underlying phenotype plasticity in response to environmental stress have been little explored. This prompted us to enquire about how the nutritional and immune status are involved in physiological adaptations in breeding seabirds under anthropogenic pressure. At Esperanza (Hope) Bay, Antarctic Peninsula exists one of the biggest breeding penguin colony of Pygoscelis adeliae (Adélie). At this location, penguins nest nearby the Argentinian Esperanza Station and, therefore, are exposed to high levels of disturbance, whereas there is a low disturbed area, where penguins also breed far away from the Station. In both areas, the nutritional and immune status in breeding individuals was addressed and serum protein expression level was analyzed using a proteomic approach. Body mass, proteins, albumin, and triacylglycerol were higher in penguins from the low disturbance area, whereas uric acid increased in individuals from the disturbed area, indicating a poorer body condition of penguins under anthropogenic pressure. Immune responses were elevated in penguins from the disturbed area (IgY, γ-globulins and hemagglutinating activity). Finally, individuals breeding under anthropogenic pressure overexpressed proteins with immune, antioxidant, and metabolic functions. The poor nutritional status of penguins under disturbance may be the consequence of the reallocation of resources to the immune system. Altogether, this would constitute a potential strategy to preserve an adequate immune phenotype under stressed environments.

Shade‐induced plasticity in invasive Impatiens glandulifera populations

SummaryPhenotypic plasticity, which confers a fitness advantage under heterogeneous and novel environments, has been commonly suggested to contribute to the success of invasive plants in their introduced range. For example, plasticity in response to changes in light availability could facilitate invasiveness by allowing plants to both rapidly establish in unshaded, disturbed habitats, and tolerate shaded or crowded environments. The plastic responses of invasive plants to shade were mostly studied in morphological traits. However, plasticity in physiological traits might provide more rapid and reversible responses and thus be more effective in environments with rapid temporal variations. Here, we compared plasticity in a range of morphological and physiological traits that provide shade avoidance or tolerance between two native and six introduced populations of Impatiens glandulifera. In a common garden, we subjected second‐generation siblings of native and invasive plants to two light availability treatments and measured their morphological, physiological and performance responses. Impatiens glandulifera from invasive populations exhibited greater phenotypic plasticity in response to light availability in four out of 12 measured traits. Moreover, this greater plasticity was mostly limited to physiological traits associated with photosynthetic acclimation. These results suggest high phenotypic plasticity in response to light availability could have facilitated I. glandulifera's spread in both disturbed habitats and woodlands or under intense light competition. The results of this study highlight the importance of considering physiological traits when studying the role of plasticity in the success of invasive plants.

Developmental plasticity of thermal ecology traits in reptiles: Trends, potential benefits, and research needs.

A variety of phenotypic traits in reptiles are affected by conditions during embryonic development, a phenomenon known as developmental plasticity. In particular, many traits in which expression changes with temperature, such as locomotor performance or growth rates, are also developmentally plastic. However, much less is known about the extent to which traits associated with thermal ecology, such as thermal tolerance and behavioral thermoregulation, are developmentally plastic. Here, we review the literature on developmental plasticity in physiological and behavioral traits associated with thermal ecology in reptiles. Most studies on developmental plasticity of thermal traits have assessed plasticity in behavioral traits, such as selected temperature or time spent basking, and these studies have found mixed support for the presence of developmental plasticity in behavioral thermal traits. In contrast, very few studies have assessed developmental plasticity in physiological traits, yet these studies generally support a developmentally plastic basis for thermal tolerance. Most studies have only tested for developmental plasticity in thermal ecology traits at the hatchling stage, which limits our understanding of the benefits of developmental plasticity to individuals, or the adaptive significance of developmental plasticity in populations. We recommend that research on developmental plasticity in reptile thermal ecology be expanded to include incubation conditions other than mean temperature, consider traits associated with cold-tolerance, and endeavor to understand how developmental plasticity in thermal ecology traits is beneficial. In particular, determining how long differences persist over ontogeny, and testing for benefits of developmental plasticity across multiple life stages, are crucial first steps towards understanding the adaptive significance of developmental plasticity in thermal ecology traits.

Woody species in tropical dry forest exhibit plasticity in physiological traits in response to variations in soil properties

Plasticity in physiological traits is necessary for the survival and development of woody species in the severe conditions of tropical dry forest We selected five study sites in a gradient of soil moisture availability located in dry forest of India We identified physiological traits viz relative water content RWC leaf dry matter content LDMC specific leaf area SLA leaf carbon concentration LCC leaf nitrogen concentration LNC leaf phosphorus concentration LPC chlorophyll concentration Chl stomatal conductance Gsmax photosynthetic rate Amax intrinsic water use efficiency WUEi biomass increment Bio Incr relative growth rate RGR which are considered important for the survival and growth of plant species in tropical dry forest and measured their range and plasticity in woody species including trees and shrubs across the selected study sites Further we analysed the response of physiological traits to variations in soil moisture content SMC across species as well as across study sites Across the five study sites the selected traits exhibited remarkable plasticity both within as well as among species The associations of physiological traits with soil properties were also significant The study shows that all physiological traits under study affect RGR directly or indirectly However the strength of effect is determined by environmental parameters particularly the SMC Step wise multiple regression indicates that more than variability in RGR can be explained by SLA and WUEi alone We suggest that for predicting the vulnerability of tropical dry forest communities to changes in climatic conditions further investigations examining trade offs among physiological traits and habitat conditions are needed nbsp nbsp

Adjusting to climate: Acclimation, adaptation and developmental plasticity in physiological traits of a tropical rainforest lizard.

The impact of climate change may be felt most keenly by tropical ectotherms. In these taxa, it is argued, thermal specialization means a given shift in temperature will have a larger effect on fitness. For species with limited dispersal ability, the impact of climate change depends on the capacity for their climate-relevant traits to shift. Such shifts can occur through genetic adaptation, various forms of plasticity, or a combination of these processes. Here we assess the extent and causes of shifts in 7 physiological traits in a tropical lizard, the rainforest sunskink (Lampropholis coggeri). Two populations were sampled that differ from each other in both climate and physiological traits. We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions. We also compared trait values between populations in: (i) recently field-collected animals; (ii) the same animals following laboratory acclimation; and (iii) the laboratory-reared offspring of these animals. Our results reveal high trait lability, driven primarily by acclimation and local adaptation. By contrast, developmental plasticity, resulting from incubation temperature, had little to no effect on most traits. These results suggest that, while specialized, tropical ectotherms may be capable of rapid shifts in climate-relevant traits.

Phenotypic plasticity in sex pheromone production in Bicyclus anynana butterflies.

Phenotypic plasticity refers to the environmental control of phenotypes. Cues experienced during development (developmental plasticity) or during adulthood (acclimatization) can both affect adult phenotypes. Phenotypic plasticity has been described in many traits but examples of developmental plasticity in physiological traits, in particular, remain scarce. We examined developmental plasticity and acclimatization in pheromone production in the butterfly Bicyclus anynana in response to rearing temperature. B. anynana lives in the African tropics where warm rearing temperatures of the wet season produce active males that court and females that choose, whereas cooler temperatures of the dry season lead to choosy less active males and courting females. We hypothesized that if male pheromone production is costly, it should be reduced in the dry season form. After describing the ultrastructure of pheromone producing cells, we showed that dry season males produced significantly less sex pheromones than wet season males, partly due to acclimatization and partly due to developmental plasticity. Variation in levels of one of the compounds is associated with differential regulation of a pheromone biosynthetic enzyme gene. This plasticity might be an adaptation to minimize pheromone production costs during the stressful dry season.

Plasticity in thermal tolerance has limited potential to buffer ectotherms from global warming.

Global warming is increasing the overheating risk for many organisms, though the potential for plasticity in thermal tolerance to mitigate this risk is largely unknown. In part, this shortcoming stems from a lack of knowledge about global and taxonomic patterns of variation in tolerance plasticity. To address this critical issue, we test leading hypotheses for broad-scale variation in ectotherm tolerance plasticity using a dataset that includes vertebrate and invertebrate taxa from terrestrial, freshwater and marine habitats. Contrary to expectation, plasticity in heat tolerance was unrelated to latitude or thermal seasonality. However, plasticity in cold tolerance is associated with thermal seasonality in some habitat types. In addition, aquatic taxa have approximately twice the plasticity of terrestrial taxa. Based on the observed patterns of variation in tolerance plasticity, we propose that limited potential for behavioural plasticity (i.e. behavioural thermoregulation) favours the evolution of greater plasticity in physiological traits, consistent with the 'Bogert effect'. Finally, we find that all ectotherms have relatively low acclimation in thermal tolerance and demonstrate that overheating risk will be minimally reduced by acclimation in even the most plastic groups. Our analysis indicates that behavioural and evolutionary mechanisms will be critical in allowing ectotherms to buffer themselves from extreme temperatures.

Host expansion modifies activity of phosphatases in a legume store pest Acanthoscelides obtectus (Say)

Bean weevil, Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae, Bruchinae) is a cosmopolitan pest of legume stored products. Storages with various legume seeds can facilitate shifts of the weevil from its primary host, common bean (Phaseolus vulgaris L.), to other legume species and enable host expansion, i.e. broadening of the range of acceptable plant-hosts. In the first generation of host shift, survival of an insect depends on ability to adjust its physiology to altered content of nutrients and secondary metabolites in novel host. On a long-term scale, physiological adaptations to a new host can comprise modifications both in level and plasticity of physiological traits. Changes in activity of phosphatases play an essential role in this process due to their involvement in diverse functions. This study investigated alterations in activity of total acid, lysosomal acid and alkaline phosphatases using laboratory populations of A. obtectus which were maintained either on the optimal host (common bean) or on the suboptimal host (chickpea, Cicer arietinum L.) for 28 years. To determine short-term (plastic) effects, subsets of individuals from each population were exposed to the alternative host for one generation. Our results revealed that one-generation shift to chickpea significantly increased phosphatases' activity reflecting immediate plastic response to nutritional/allelochemical stress where these enzymes might be involved in defense mechanisms. On the other hand, both level and plasticity of phosphatases' activities significantly declined as a long-term response to Cicer-based diet suggesting that selection on chickpea favored resistance mechanisms that were less costly than phosphatases. Considering diverse roles of phosphatases we suggest that such modifications could be crucial for expanding host range and might have implications on efficiency of chemical and botanical insecticides.

Drought Response Diversification in African Protea Species

Premise of research. Evolutionary radiations can be driven by physiological tolerances. Protea is a species-rich genus in the Cape Floristic Region of South Africa and provides the opportunity to examine whether drought response traits may have contributed to differentiation in this stress-tolerant genus. Commonly utilized drought responses might be indicative of traits important to species diversification in stressful environments. Methodology. We studied how greenhouse-grown plants of six white Protea species physiologically responded to drought stress. We measured leaf-level physiological traits such as stomatal conductance, temperature, pubescence, chlorophyll, and abscisic acid (ABA) content. Pivotal results. Most traits showed similar drought responses across all six species and 29 populations we examined. Only for foliar ABA content, leaf hair density, and foliar chlorophyll content did species respond to drought in different ways, indicating that some differences in plasticity might be important to this evolutionary radiation. Conclusions. Our data support stomatal conductance as a trait important to stress tolerance across a range of environmental conditions. Moreover, population variation in the plasticity of physiological traits might be important to evolutionary trajectories in this system.

Tests of the contribution of acclimation to geographic variation in water loss rates of the West Indian lizard Anolis cristatellus

Phenotypic plasticity can contribute to the process of adaptive radiation by facilitating population persistence in novel environments. West Indian Anolis lizards provide a classic example of an adaptive radiation, in which divergence has occurred along two primary ecological axes: structural microhabitat and climate. Adaptive plasticity in limb morphology is hypothesized to have facilitated divergence along the structural niche axis in Anolis, but very little work has explored plasticity in physiological traits. Here, we experimentally ask whether Puerto Rican Anolis cristatellus from mesic and xeric habitats differ in desiccation rates, and whether these lizards exhibit an acclimation response to changes in relative humidity. We first present microclimatic data collected at lizard perch sites that demonstrate that abiotic conditions experienced by lizards differ between mesic and xeric habitat types. In Experiment 1, we measured desiccation rates of lizards from both habitats maintained under identical laboratory conditions. This experiment demonstrated that desiccation rates differ between populations; xeric lizards lose water more slowly than mesic lizards. In Experiment 2, lizards from each habitat were either maintained under the conditions of Experiment 1, or under extremely low relative humidity. Desiccation rates did not differ between lizards from the same habitat maintained under different treatments and xeric lizards maintained lower desiccation rates than mesic lizards within each treatment. Our results demonstrate that A. cristatellus does not exhibit an acclimation response to abrupt changes of hydric conditions, and suggest that tropical Anolis lizards might be unable to exhibit physiological plasticity in desiccation rates in response to varying climatic conditions.

Plasticity in physiological traits in conifers: Implications for response to climate change in the western U.S.

Population variation in ecophysiological traits of four co-occurring montane conifers was measured on a large latitudinal gradient to quantitatively assess their potential for response to environmental change. White fir ( Abies concolor) had the highest variability, gross photosynthetic rate (Pg), and foliar carbon (C) and nitrogen (N) content. Despite low water use efficiency (WUE), stomatal conductance (gs) of fir was the most responsive to unfavorable environmental conditions. Pinus lambertiana exhibited the least variability in Pg and WUE, and is likely to be the most vulnerable to environmental changes. Pinus ponderosa had an intermediate level of variability, and high needle growth at its higher elevational limits. Pinus Jeffreyi also had intermediate variability, but high needle growth at its southern latitudinal and lower elevational limits. The attributes used to assess tree vigor were effective in predicting population vulnerability to abiotic (drought) and biotic (herbivore) stresses.

Darwinism renewed: contemporary studies of plant adaptation

Darwinism renewed: contemporary studies of plant adaptation