Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental ...temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming.
Significance Tropical ectotherms are considered especially vulnerable to climate change because they have narrow thermal tolerance ranges, such that even small increases in environmental temperature are likely to be detrimental. Although evolutionary adaptation may prevent extinction, it is unclear whether climate change generates selection on thermal physiology in nature or whether the strength of this selection is sufficient for rapid evolution to occur. When we transplanted lizards from their preferred habitat to a warmer and more thermally variable site, strong natural selection favored individuals that ran faster at warmer temperatures and across a broader range of temperatures. If thermal performance traits are heritable, some tropical species may be capable of rapid evolutionary adaptation to changing climates.
Objective: In this study, we investigate extremists’ appraisals of and sensitivity to perceived sanction risk during the commission of arson. We pay specific attention to the decision-making ...processes of extremists leading up to and during the offending opportunity. Methods: We examined data collected from self-reported communiqués (n = 275) describing acts of arson committed by radical environmental extremists. Results: We found that extremists, like other criminals, are sensitive to situational factors that affect the certainty of apprehension. Additionally, extremists work to reduce the risk of detection by engaging in crime-specific risk management techniques prior to and during the offending opportunity. Conclusions: Analysis of the communiqués is consistent with recent works on extremism, situational crime prevention, and restrictive deterrence. We discuss our findings in the context of rational choice and situational crime prevention theory and the advancement of preventative policies aimed at ideological and political crime.
In situ
adaptation to climate change will be critical for the persistence of many ectotherm species due to their relative lack of dispersal capacity. Climate change is causing increases in both the ...mean and the variance of environmental temperature, each of which may act as agents of selection on different traits. Importantly, these traits may not be heritable or have the capacity to evolve independently from one another. When genetic constraints prevent the “baseline” values of thermal performance traits from evolving rapidly, phenotypic plasticity driven by gene expression might become critical. We review the literature for evidence that thermal performance traits in ectotherms are heritable and have genetic architectures that permit their unconstrained evolution. Next, we examine the relationship between gene expression and both the magnitude and duration of thermal stress. Finally, we identify genes that are likely to be important for adaptation to a changing climate and determine whether they show patterns consistent with thermal adaptation. Although few studies have measured narrow-sense heritabilities of thermal performance traits, current evidence suggests that the end points of thermal reaction norms (tolerance limits) are moderately heritable and have the potential to evolve rapidly. By contrast, performance at intermediate temperatures has substantially lower evolutionary potential. Moreover, evolution in many species appears to be constrained by genetic correlations such that populations can adapt to either increases in mean temperature or temperature variability, but not both. Finally, many species have the capacity for plastic expression of the transcriptome in response to temperature shifts, with the number of differentially expressed genes increasing with the magnitude, but not the duration, of thermal stress. We use these observations to develop a conceptual model that describes the likely trajectory of genome evolution in response to changes in environmental temperature. Our results indicate that extreme weather events, rather than gradual increases in mean temperature, are more likely to drive genetic and phenotypic change in wild ectotherms.
The current paper compares the prevalence and nature of childhood adversity among twenty former left-wing and right-wing extremists. Findings from the Adverse Childhood Experiences (ACE) ...questionnaire suggest that exposure to childhood adversity was common in the early lives of both extremist types. For example, 50 percent of LWE and 70 percent of RWE experienced four or more ACE exposures during the first eighteen years of their life. The results also demonstrate that participants in both samples experienced a range of adolescent conduct problems. These conduct issues highlight the cascading effects of childhood adversity, where negative events help produce a downward spiral that ultimately increases a person's susceptibility to extremism. Despite the relatively small sample, findings from this exploratory study build on the risk factor model of violent extremism by highlighting childhood adversity and adolescent misconduct as nonideological precursors to violent extremism among different types of extremists.
A classic question in evolutionary biology is whether behavioral flexibility hastens or hinders evolutionary change. The latter idea, that behavior reduces the number of environmental states ...experienced by an organism and buffers that organism against selection, has been dubbed the “Bogert Effect” after Charles Bogert, the biologist who first popularized the phenomenon using data from lizards. The Bogert Effect is pervasive when traits like body temperature, which tend to be invariant across space in species that behaviorally thermoregulate, are considered. Nevertheless, behavioral thermoregulation decreases or stops when spatial variation in operative temperature is low. We compared environmental temperatures, thermoregulatory behavior, and a suite of physiological and morphological traits between two populations of the southern rock agama (Agama atra) in South Africa that experience different climatic regimes. Individuals from both populations thermoregulated efficiently, maintaining body temperatures within their preferred temperature range throughout most of their activity cycle. Nevertheless, they differed in the thermal sensitivity of resting metabolic rate at cooler body temperatures and in morphology. Our results support the common assertion that thermoregulatory behavior may prevent divergence in traits like field-active body temperature, which are measured during periods of high environmental heterogeneity. Nevertheless, we show that other traits may be free to diverge if they are under selection during times when environments are homogenous. We argue that the importance of the Bogert Effect is critically dependent on the nature of environmental heterogeneity and will therefore be relevant to some traits and irrelevant to others in many populations.
Temperature and the pace of life Gopal, Akhila C.; Alujević, Karla; Logan, Michael L.
Behavioral ecology and sociobiology,
05/2023, Volume:
77, Issue:
5
Journal Article
Peer reviewed
The pace-of-life syndrome (POLS) is a framework that attempts to explain empirically observed covariation between physiological, behavioral, and life history traits, whereby individuals fall along ...slow-fast and shy-bold continuums. The fundamental driver of the position of individuals along these trait axes is thought to be their metabolic rates, with high metabolism leading to faster growth, greater reproductive output, and bolder behavior. However, numerous exceptions to these patterns have been observed in nature, suggesting that crucial components are missing from the classical POLS framework. As many metabolic, physiological, and life history traits are temperature dependent, a growing number of studies have begun to test the role played by the thermal physiology of individuals and the thermal environments in which they live in mediating the trait relationships within POLS. These studies have led to an expansion of classical POLS into what has been called “extended POLS.” Here, we review the recent literature on extended POLS and identify the major themes and patterns that are emerging in this nascent field. We further identify gaps and key outstanding questions in how temperature may drive or modify classical POLS. Finally, we address issues with how temperature and POLS are integrated in empirical studies and suggest pathways by which progress can be made towards a cohesive understanding of the physiology-behavior-life history nexus.
Significance statement
The pace of life syndrome (POLS) is an integrative framework that links life-history, behavioral, and physiological traits into covarying axes that are structured by metabolism. Recent studies have provided only mixed support for the original POLS hypothesis and instead have highlighted the potential importance of thermal physiology in explaining patterns of trait covariation. We review this nascent literature and argue that environmental temperature, the thermal sensitivity of traits, and acclimation to thermal environments can influence the presence and/or direction of trait covariations within individuals or populations. Though some patterns have emerged in the recent POLS literature, important remaining gaps are slowing progress in this field. We suggest avenues by which future investigations can test the proximate and ultimate mechanisms underlying trait covariation in wild animal populations.
Molecular dynamics simulations reveal substructures within the liquid-ordered phase of lipid bilayers. These substructures, identified in a 10 μs all-atom trajectory of ...liquid-ordered/liquid-disordered coexistence (Lo/Ld) are composed of saturated hydrocarbon chains packed with local hexagonal order and separated by interstitial regions enriched in cholesterol and unsaturated chains. Lipid hydrocarbon chain order parameters calculated from the Lo phase are in excellent agreement with 2H NMR measurements; the local hexagonal packing is also consistent with 1H-MAS NMR spectra of the Lo phase, NMR diffusion experiments, and small-angle X-ray and neutron scattering. The balance of cholesterol-rich to local hexagonal order is proposed to control the partitioning of membrane components into the Lo regions. The latter have been frequently associated with formation of so-called rafts, platforms in the plasma membranes of cells that facilitate interaction between components of signaling pathways.
Much attention has been given to recent predictions that widespread extinctions of tropical ectotherms, and tropical forest lizards in particular, will result from anthropogenic climate change. Most ...of these predictions, however, are based on environmental temperature data measured at a maximum resolution of 1 km2, whereas individuals of most species experience thermal variation on a much finer scale. To address this disconnect, we combined thermal performance curves for five populations of Anolis lizard from the Bay Islands of Honduras with high‐resolution temperature distributions generated from physical models. Previous research has suggested that open‐habitat species are likely to invade forest habitat and drive forest species to extinction. We test this hypothesis, and compare the vulnerabilities of closely related, but allopatric, forest species. Our data suggest that the open‐habitat populations we studied will not invade forest habitat and may actually benefit from predicted warming for many decades. Conversely, one of the forest species we studied should experience reduced activity time as a result of warming, while two others are unlikely to experience a significant decline in performance. Our results suggest that global‐scale predictions generated using low‐resolution temperature data may overestimate the vulnerability of many tropical ectotherms to climate change.
Mounting evidence suggests that rapid evolutionary adaptation may rescue some organisms from the impacts of climate change. However, evolutionary constraints might hinder this process, especially ...when different aspects of environmental change generate antagonistic selection on genetically correlated traits. Here, we use individual‐based simulations to explore how genetic correlations underlying the thermal physiology of ectotherms might influence their responses to the two major components of climate change—increases in mean temperature and thermal variability. We found that genetic correlations can influence population dynamics under climate change, with declines in population size varying three‐fold depending on the type of correlation present. Surprisingly, populations whose thermal performance curves were constrained by genetic correlations often declined less rapidly than unconstrained populations. Our results suggest that accurate forecasts of the impact of climate change on ectotherms will require an understanding of the genetic architecture of the traits under selection.
In the context of climate change, organisms might need to adapt to multiple concomitant alterations to their environments. However, due to the presence of evolutionary constraints, adaptive possibilities might be limited. Here, we simulate how evolutionary constraints (in the form genetic correlations on traits related to thermal physiology) might mediate the extinction risk of ectotherms under simultaneous increases in mean and thermal variability.
Phylogenetic comparative methods represent a major advance in integrative and comparative biology and have allowed researchers to rigorously test for adaptation in a macroevolutionary framework. ...However, phylogenetic comparative methods require trait data for many species, which is impractical for certain taxonomic groups and trait types. We propose that the philosophical principle of severity can be implemented in an integrative framework to generate strong inference of adaptation in studies that compare only a few populations or species. This approach requires (1) ensuring that the study system contains species that are relatively closely related; (2) formulating a specific, clear, overarching hypothesis that can be subjected to integrative testing across levels of biological organization (e.g., ecology, behavior, morphology, physiology, and genetics); (3) collecting data that avoid statistical underdetermination and thus allow severe tests of hypotheses; and (4) systematically refining and refuting alternative hypotheses. Although difficult to collect for more than a few species, detailed, integrative data can be used to differentiate among several potential agents of selection. In this way, integrative studies of small numbers of closely related species can complement and even improve on broadscale phylogenetic comparative studies by revealing the specific drivers of adaptation.
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