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Redana M, Gibbins C, Lancaster LT. Determining critical periods for thermal acclimatisation using a distributed lag non-linear modelling approach. Ecol Evol 2024; 14:e11451. [PMID: 38826161 PMCID: PMC11140238 DOI: 10.1002/ece3.11451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/30/2024] [Accepted: 05/07/2024] [Indexed: 06/04/2024] Open
Abstract
Rapid changes in thermal environments are threatening many species worldwide. Thermal acclimatisation may partially buffer species from the impacts of these changes, but currently, the knowledge about the temporal dynamics of acclimatisation remains limited. Moreover, acclimatisation phenotypes are typically determined in laboratory conditions that lack the variability and stochasticity that characterise the natural environment. Through a distributed lag non-linear model (DLNM), we use field data to assess how the timing and magnitude of past thermal exposures influence thermal tolerance. We apply the model to two Scottish freshwater Ephemeroptera species living in natural thermal conditions. Model results provide evidence that rapid heat hardening effects are dramatic and reflect high rates of change in temperatures experienced over recent hours to days. In contrast, temperature change magnitude impacted acclimatisation over the course of weeks but had no impact on short-term responses. Our results also indicate that individuals may de-acclimatise their heat tolerance in response to cooler environments. Based on the novel insights provided by this powerful modelling approach, we recommend its wider uptake among thermal physiologists to facilitate more nuanced insights in natural contexts, with the additional benefit of providing evidence needed to improve the design of laboratory experiments.
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Affiliation(s)
- Matteo Redana
- Department of ZoologyUniversity of CambridgeCambridgeUK
| | - Chris Gibbins
- School of Environmental and Geographical SciencesUniversity of Nottingham MalaysiaSemenyihMalaysia
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2
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Tanner RL, Gleason LU, Dowd WW. Environment-driven shifts in inter-individual variation and phenotypic integration within subnetworks of the mussel transcriptome and proteome. Mol Ecol 2022; 31:3112-3127. [PMID: 35363903 PMCID: PMC9321163 DOI: 10.1111/mec.16452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 03/18/2022] [Accepted: 03/28/2022] [Indexed: 11/28/2022]
Abstract
The environment can alter the magnitude of phenotypic variation among individuals, potentially influencing evolutionary trajectories. However, environmental influences on variation are complex and remain understudied. Populations in heterogeneous environments might exhibit more variation, the amount of variation could differ between benign and stressful conditions, and/or variation might manifest in different ways among stages of the gene‐to‐protein expression cascade or among physiological functions. Here, we explore these three issues by quantifying patterns of inter‐individual variation in both transcript and protein expression levels among California mussels, Mytilus californianus Conrad. Mussels were exposed to five ecologically relevant treatments that varied in the mean and interindividual heterogeneity of body temperature. To target a diverse set of physiological functions, we assessed variation within 19 expression subnetworks, including canonical stress‐response pathways and empirically derived coexpression clusters that represent a diffuse set of cellular processes. Variation in expression was particularly pronounced in the treatments with high mean and heterogeneous body temperatures. However, with few exceptions, environment‐dependent shifts of variation in the transcriptome were not reflected in the proteome. A metric of phenotypic integration provided evidence for a greater degree of constraint on relative expression levels (i.e., stronger correlation) within expression subnetworks in benign, homogeneous environments. Our results suggest that environments that are more stressful on average – and which also tend to be more heterogeneous – can relax these expression constraints and reduce phenotypic integration within biochemical subnetworks. Context‐dependent “unmasking” of functional variation may contribute to interindividual differences in physiological phenotype and performance in stressful environments.
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Affiliation(s)
- Richelle L Tanner
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.,Environmental Science & Policy Program, Chapman University, Orange, CA, 92866, USA
| | - Lani U Gleason
- Department of Biological Sciences, California State University, Sacramento, Sacramento, CA, 95819, USA
| | - W Wesley Dowd
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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Denny MW, Dowd WW. Physiological Consequences of Oceanic Environmental Variation: Life from a Pelagic Organism's Perspective. ANNUAL REVIEW OF MARINE SCIENCE 2022; 14:25-48. [PMID: 34314598 DOI: 10.1146/annurev-marine-040221-115454] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
To better understand life in the sea, marine scientists must first quantify how individual organisms experience their environment, and then describe how organismal performance depends on that experience. In this review, we first explore marine environmental variation from the perspective of pelagic organisms, the most abundant life forms in the ocean. Generation time, the ability to move relative to the surrounding water (even slowly), and the presence of environmental gradients at all spatial scales play dominant roles in determining the variation experienced by individuals, but this variation remains difficult to quantify. We then use this insight to critically examine current understanding of the environmental physiology of pelagic marine organisms. Physiologists have begun to grapple with the complexity presented by environmental variation, and promising frameworks exist for predicting and/or interpreting the consequences for physiological performance. However, new technology needs to be developed and much difficult empirical work remains, especially in quantifying response times to environmental variation and the interactions among multiple covarying factors. We call on the field of global-change biology to undertake these important challenges.
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Affiliation(s)
- Mark W Denny
- Hopkins Marine Station, Stanford University, Pacific Grove, California 93950, USA;
| | - W Wesley Dowd
- School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA;
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Denny MW, Dowd WW. Elevated Salinity Rapidly Confers Cross-Tolerance to High Temperature in a Splash-Pool Copepod. Integr Org Biol 2022; 4:obac037. [PMID: 36003414 PMCID: PMC9394168 DOI: 10.1093/iob/obac037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/07/2022] [Accepted: 08/04/2022] [Indexed: 12/11/2022] Open
Abstract
Accurate forecasting of organismal responses to climate change requires a deep mechanistic understanding of how physiology responds to present-day variation in the physical environment. However, the road to physiological enlightenment is fraught with complications: predictable environmental fluctuations of any single factor are often accompanied by substantial stochastic variation and rare extreme events, and several factors may interact to affect physiology. Lacking sufficient knowledge of temporal patterns of co-variation in multiple environmental stressors, biologists struggle to design and implement realistic and relevant laboratory experiments. In this study, we directly address these issues, using measurements of the thermal tolerance of freshly collected animals and long-term field records of environmental conditions to explore how the splash-pool copepod Tigriopus californicus adjusts its physiology as its environment changes. Salinity and daily maximum temperature-two dominant environmental stressors experienced by T. californicus-are extraordinarily variable and unpredictable more than 2-3 days in advance. However, they substantially co-vary such that when temperature is high salinity is also likely to be high. Copepods appear to take advantage of this correlation: median lethal temperature of field-collected copepods increases by 7.5°C over a roughly 120 parts-per-thousand range of ambient salinity. Complementary laboratory experiments show that exposure to a single sublethal thermal event or to an abrupt shift in salinity also elicits rapid augmentation of heat tolerance via physiological plasticity, although the effect of salinity dwarfs that of temperature. These results suggest that T. californicus's physiology keeps pace with the rapid, unpredictable fluctuations of its hypervariable physical environment by responding to the cues provided by recent sublethal stress and, more importantly, by leveraging the mechanistic cross-talk between responses to salinity and heat stress.
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Affiliation(s)
| | - W Wesley Dowd
- School of Biological Sciences, Washington State University, 100 Dairy Road, Eastlick G81, Pullman, WA99164, USA
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Clusella-Trullas S, Garcia RA, Terblanche JS, Hoffmann AA. How useful are thermal vulnerability indices? Trends Ecol Evol 2021; 36:1000-1010. [PMID: 34384645 DOI: 10.1016/j.tree.2021.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/23/2021] [Accepted: 07/06/2021] [Indexed: 10/20/2022]
Abstract
To forecast climate change impacts across habitats or taxa, thermal vulnerability indices (e.g., safety margins and warming tolerances) are growing in popularity. Here, we present their history, context, formulation, and current applications. We highlight discrepancies in terminology and usage, and we draw attention to key assumptions underpinning the main indices and to their ecological and evolutionary relevance. In the process, we flag biases influencing these indices that are not always evaluated. These biases affect both components of index formulations, namely: (i) the characterisation of the thermal environment; and (ii) an organism's physiological and behavioural responses to more frequent and severe warming. Presently, many outstanding questions weaken a thermal vulnerability index approach. We describe ways to validate vulnerability index applications and outline issues to be considered in further developing these indices.
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Affiliation(s)
| | - Raquel A Garcia
- Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - John S Terblanche
- Department of Conservation Ecology & Entomology, Stellenbosch University, Stellenbosch, South Africa
| | - Ary A Hoffmann
- School of BioSciences, Bio21 Institute, University of Melbourne, Melbourne, Australia
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Kingsolver JG, Moore ME, Augustine KE, Hill CA. Responses of Manduca sexta larvae to heat waves. J Exp Biol 2021; 224:238099. [PMID: 34424973 DOI: 10.1242/jeb.236505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 02/16/2021] [Indexed: 01/01/2023]
Abstract
Climate change is increasing the frequency of heat waves and other extreme weather events experienced by organisms. How does the number and developmental timing of heat waves affect survival, growth and development of insects? Do heat waves early in development alter performance later in development? We addressed these questions using experimental heat waves with larvae of the tobacco hornworm, Manduca sexta. The experiments used diurnally fluctuating temperature treatments differing in the number (0-3) and developmental timing (early, middle and/or late in larval development) of heat waves, in which a single heat wave involved three consecutive days with a daily maximum temperature of 42°C. Survival to pupation declined with increasing number of heat waves. Multiple (but not single) heat waves significantly reduced development time and pupal mass; the best models for the data indicated that both the number and developmental timing of heat waves affected performance. In addition, heat waves earlier in development significantly reduced growth and development rates later in larval development. Our results illustrate how the frequency and developmental timing of sublethal heat waves can have important consequences for life history traits in insects.
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Affiliation(s)
- Joel G Kingsolver
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - M Elizabeth Moore
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kate E Augustine
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christina A Hill
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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Ma CS, Ma G, Pincebourde S. Survive a Warming Climate: Insect Responses to Extreme High Temperatures. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:163-184. [PMID: 32870704 DOI: 10.1146/annurev-ento-041520-074454] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Global change includes a substantial increase in the frequency and intensity of extreme high temperatures (EHTs), which influence insects at almost all levels. The number of studies showing the ecological importance of EHTs has risen in recent years, but the knowledge is rather dispersed in the contemporary literature. In this article, we review the biological and ecological effects of EHTs actually experienced in the field, i.e., when coupled to fluctuating thermal regimes. First, we characterize EHTs in the field. Then, we summarize the impacts of EHTs on insects at various levels and the processes allowing insects to buffer EHTs. Finally, we argue that the mechanisms leading to positive or negative impacts of EHTs on insects can only be resolved from integrative approaches considering natural thermal regimes. Thermal extremes, perhaps more than the gradual increase in mean temperature, drive insect responses to climate change, with crucial impacts on pest management and biodiversity conservation.
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Affiliation(s)
- Chun-Sen Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Gang Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Sylvain Pincebourde
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS, Université de Tours, 37200 Tours, France;
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