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Ruthsatz K, Dahlke F, Alter K, Wohlrab S, Eterovick PC, Lyra ML, Gippner S, Cooke SJ, Peck MA. Acclimation capacity to global warming of amphibians and freshwater fishes: Drivers, patterns, and data limitations. GLOBAL CHANGE BIOLOGY 2024; 30:e17318. [PMID: 38771091 DOI: 10.1111/gcb.17318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 04/17/2024] [Accepted: 04/26/2024] [Indexed: 05/22/2024]
Abstract
Amphibians and fishes play a central role in shaping the structure and function of freshwater environments. These organisms have a limited capacity to disperse across different habitats and the thermal buffer offered by freshwater systems is small. Understanding determinants and patterns of their physiological sensitivity across life history is, therefore, imperative to predicting the impacts of climate change in freshwater systems. Based on a systematic literature review including 345 experiments with 998 estimates on 96 amphibian (Anura/Caudata) and 93 freshwater fish species (Teleostei), we conducted a quantitative synthesis to explore phylogenetic, ontogenetic, and biogeographic (thermal adaptation) patterns in upper thermal tolerance (CTmax) and thermal acclimation capacity (acclimation response ratio, ARR) as well as the influence of the methodology used to assess these thermal traits using a conditional inference tree analysis. We found globally consistent patterns in CTmax and ARR, with phylogeny (taxa/order), experimental methodology, climatic origin, and life stage as significant determinants of thermal traits. The analysis demonstrated that CTmax does not primarily depend on the climatic origin but on experimental acclimation temperature and duration, and life stage. Higher acclimation temperatures and longer acclimation times led to higher CTmax values, whereby Anuran larvae revealed a higher CTmax than older life stages. The ARR of freshwater fishes was more than twice that of amphibians. Differences in ARR between life stages were not significant. In addition to phylogenetic differences, we found that ARR also depended on acclimation duration, ramping rate, and adaptation to local temperature variability. However, the amount of data on early life stages is too small, methodologically inconsistent, and phylogenetically unbalanced to identify potential life cycle bottlenecks in thermal traits. We, therefore, propose methods to improve the robustness and comparability of CTmax/ARR data across species and life stages, which is crucial for the conservation of freshwater biodiversity under climate change.
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Affiliation(s)
- Katharina Ruthsatz
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Hamburg, Germany
| | - Flemming Dahlke
- Ecology of Living Marine Resources, Universität Hamburg, Hamburg, Germany
| | - Katharina Alter
- Department of Coastal Systems, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
| | - Sylke Wohlrab
- Alfred Wegner Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany
| | - Paula C Eterovick
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Mariana L Lyra
- New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Center for Research on Biodiversity Dynamics and Climate Change, State University of São Paulo-UNESP, Rio Claro, Brazil
| | - Sven Gippner
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, Ontario, Canada
| | - Myron A Peck
- Department of Coastal Systems, Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
- Marine Animal Ecology Group, Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands
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2
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Ørsted M, Willot Q, Olsen AK, Kongsgaard V, Overgaard J. Thermal limits of survival and reproduction depend on stress duration: A case study of Drosophila suzukii. Ecol Lett 2024; 27:e14421. [PMID: 38549250 DOI: 10.1111/ele.14421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 03/07/2024] [Accepted: 03/13/2024] [Indexed: 04/02/2024]
Abstract
Studies of ectotherm responses to heat extremes often rely on assessing absolute critical limits for heat coma or death (CTmax), however, such single parameter metrics ignore the importance of stress exposure duration. Furthermore, population persistence may be affected at temperatures considerably below CTmax through decreased reproductive output. Here we investigate the relationship between tolerance duration and severity of heat stress across three ecologically relevant life-history traits (productivity, coma and mortality) using the global agricultural pest Drosophila suzukii. For the first time, we show that for sublethal reproductive traits, tolerance duration decreases exponentially with increasing temperature (R2 > 0.97), thereby extending the Thermal Death Time framework recently developed for mortality and coma. Using field micro-environmental temperatures, we show how thermal stress can lead to considerable reproductive loss at temperatures with limited heat mortality highlighting the importance of including limits to reproductive performance in ecological studies of heat stress vulnerability.
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Affiliation(s)
- Michael Ørsted
- Section of Bioscience and Engineering, Department of Chemistry and Bioscience, Aalborg University, Aalborg E, Denmark
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Quentin Willot
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Andreas Kirk Olsen
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Viktor Kongsgaard
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Johannes Overgaard
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
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3
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Walberg PB. Competition Increases Risk of Species Extinction during Extreme Warming. Am Nat 2024; 203:323-334. [PMID: 38358815 DOI: 10.1086/728672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
AbstractTemperature and interspecific competition are fundamental drivers of community structure in natural systems and can interact to affect many measures of species performance. However, surprisingly little is known about the extent to which competition affects extinction temperatures during extreme warming. This information is important for evaluating future threats to species from extreme high-temperature events and heat waves, which are rising in frequency and severity around the world. Using experimental freshwater communities of rotifers and ciliates, this study shows that interspecific competition can lower the threshold temperature at which local extinction occurs, reducing time to extinction during periods of sustained warming by as much as 2 weeks. Competitors may lower extinction temperatures by altering biochemical characteristics of the natural environment that affect temperature tolerance (e.g., levels of dissolved oxygen, nutrients, and metabolic wastes) or by accelerating population decline through traditional effects of resource depletion on life history parameters that affect population growth rates. The results suggest that changes in community structure in space and time could drive variability in upper thermal limits.
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Lattuca ME, Vanella FA, Malanga G, Rubel MD, Manríquez PH, Torres R, Alter K, Marras S, Peck MA, Domenici P, Fernández DA. Ocean acidification and seasonal temperature extremes combine to impair the thermal physiology of a sub-Antarctic fish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159284. [PMID: 36209875 DOI: 10.1016/j.scitotenv.2022.159284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/26/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
To predict the potential impacts of climate change on marine organisms, it is critical to understand how multiple stressors constrain the physiology and distribution of species. We evaluated the effects of seasonal changes in seawater temperature and near-future ocean acidification (OA) on organismal and sub-organismal traits associated with the thermal performance of Eleginops maclovinus, a sub-Antarctic notothenioid species with economic importance to sport and artisanal fisheries in southern South America. Juveniles were exposed to mean winter and summer sea surface temperatures (4 and 10 °C) at present-day and near-future pCO2 levels (~500 and 1800 μatm). After a month, the Critical Thermal maximum and minimum (CTmax, CTmin) of fish were measured using the Critical Thermal Methodology and the aerobic scope of fish was measured based on the difference between their maximal and standard rates determined from intermittent flow respirometry. Lipid peroxidation and the antioxidant capacity were also quantified to estimate the oxidative damage potentially caused to gill and liver tissue. Although CTmax and CTmin were higher in individuals acclimated to summer versus winter temperatures, the increase in CTmax was minimal in juveniles exposed to the near-future compared to present-day pCO2 levels (there was a significant interaction between temperature and pCO2 on CTmax). The reduction in the thermal tolerance range under summer temperatures and near-future OA conditions was associated with a reduction in the aerobic scope observed at the elevated pCO2 level. Moreover, an oxidative stress condition was detected in the gill and liver tissues. Thus, chronic exposure to OA and the current summer temperatures pose limits to the thermal performance of juvenile E. maclovinus at the organismal and sub-organismal levels, making this species vulnerable to projected climate-driven warming.
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Affiliation(s)
- María E Lattuca
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos, Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410BFD Ushuaia, Argentina.
| | - Fabián A Vanella
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos, Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410BFD Ushuaia, Argentina
| | - Gabriela Malanga
- Fisicoquímica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (FFyB - UBA), Junín 956, C1113AAD CABA, Argentina; Instituto de Bioquímica y Medicina Molecular (IBIMOL - CONICET), Junín 956, C1113AAD CABA, Argentina
| | - Maximiliano D Rubel
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos, Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410BFD Ushuaia, Argentina
| | - Patricio H Manríquez
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Av. Bernardo Ossandón 877, 1781681 Coquimbo, Chile; Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Larrondo 1281, 1781421 Coquimbo, Chile
| | - Rodrigo Torres
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), José de Moraleda 16, 5951369 Coyhaique, Chile; Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Av. El Bosque 01789, 6200000 Punta Arenas, Chile
| | - Katharina Alter
- Royal Netherlands Institute for Sea Research (NIOZ), Department of Coastal Systems (COS), P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands
| | - Stefano Marras
- Consiglio Nazionale delle Ricerche, Istituto per l'Ambiente Marino Costiero (CNR-IAMC), Località Sa Mardini, 09070 Torregrande, Oristano, Italy
| | - Myron A Peck
- Royal Netherlands Institute for Sea Research (NIOZ), Department of Coastal Systems (COS), P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands
| | - Paolo Domenici
- Consiglio Nazionale delle Ricerche, Istituto per l'Ambiente Marino Costiero (CNR-IAMC), Località Sa Mardini, 09070 Torregrande, Oristano, Italy; Consiglio Nazionale delle Ricerche, Istituto di Biofisica (CNR-IBF), Area di Ricerca San Cataldo, Via G. Moruzzi N°1, 56124 Pisa, Italy
| | - Daniel A Fernández
- Laboratorio de Ecología, Fisiología y Evolución de Organismos Acuáticos, Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410BFD Ushuaia, Argentina; Universidad Nacional de Tierra del Fuego, Instituto de Ciencias Polares, Ambiente y Recursos Naturales (UNTDF - ICPA), Fuegia Basket 251, V9410BXE Ushuaia, Argentina
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5
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Pham LP, Nguyen MV, Jordal AEO, Rønnestad I. Metabolic rates, feed intake, appetite control, and gut transit of clownfish Amphiprion ocellaris exposed to increased temperature and limited feed availability. Comp Biochem Physiol A Mol Integr Physiol 2022; 274:111318. [PMID: 36115553 DOI: 10.1016/j.cbpa.2022.111318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 10/14/2022]
Abstract
Episodes of elevated temperature, combined with lower feed availability, are among the predicted scenarios of climate change representing a challenge for coral reef fish. We investigated the response of clownfish (Amphiprion ocellaris) to a scenario in which it received a single meal to satiety after 48 h fasting at 32 °C (climate change scenario) and 28 °C (control). We analysed the metabolic rate (MR), feed intake, gut transit, and expression of selected brain neuropeptides and one receptor believed to be involved in appetite control. Fish at 32 °C ingested 17.9% less feed and had a faster gut transit than did fish at 28 °C. MR in the unfed fish was 31% higher at 32 °C compared to 28 °C. In the fed fish, postprandial MR at 28 °C was 30% higher compared to that of unfed fish, while at 32 °C it was only 15% higher. The expression of agrp1 did not differ between unfed and refed fish. The levels of both pomca and mc4r increased immediately after the meal and subsequently declined, suggesting a possible anorexic role for these genes. Notably, this pattern was accelerated in fish kept at 32 °C compared with that in fish kept at 28 °C. The dynamics of these changes in expression correspond to a faster gut transition of ingested feed at elevated temperatures. For both agrp2 and pomcb there was an increase in expression following feeding in fish maintained at 32 °C, which was not observed in fish kept at 28 °C. These results suggest that low feed availability and elevated temperature stimulate anorexigenic pathways in clownfish, resulting in significantly lower feed intake despite the temperature-induced increase in metabolic rate. This may be a mechanism to ameliorate the decrease in aerobic scope that results from higher temperatures.
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Affiliation(s)
- Linh P Pham
- Institute of Aquaculture, Nha Trang University, Nha Trang, Viet Nam; Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Minh V Nguyen
- Institute of Aquaculture, Nha Trang University, Nha Trang, Viet Nam
| | | | - Ivar Rønnestad
- Department of Biological Sciences, University of Bergen, Bergen, Norway.
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6
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Thermal limits of Africanized honey bees are influenced by temperature ramping rate but not by other experimental conditions. J Therm Biol 2022; 110:103369. [DOI: 10.1016/j.jtherbio.2022.103369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022]
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7
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Ørsted M, Jørgensen LB, Overgaard J. Finding the right thermal limit: a framework to reconcile ecological, physiological and methodological aspects of CTmax in ectotherms. J Exp Biol 2022; 225:277015. [DOI: 10.1242/jeb.244514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ABSTRACT
Upper thermal limits (CTmax) are frequently used to parameterize the fundamental niche of ectothermic animals and to infer biogeographical distribution limits under current and future climate scenarios. However, there is considerable debate associated with the methodological, ecological and physiological definitions of CTmax. The recent (re)introduction of the thermal death time (TDT) model has reconciled some of these issues and now offers a solid mathematical foundation to model CTmax by considering both intensity and duration of thermal stress. Nevertheless, the physiological origin and boundaries of this temperature–duration model remain unexplored. Supported by empirical data, we here outline a reconciling framework that integrates the TDT model, which operates at stressful temperatures, with the classic thermal performance curve (TPC) that typically describes biological functions at permissive temperatures. Further, we discuss how the TDT model is founded on a balance between disruptive and regenerative biological processes that ultimately defines a critical boundary temperature (Tc) separating the TDT and TPC models. Collectively, this framework allows inclusion of both repair and accumulation of heat stress, and therefore also offers a consistent conceptual approach to understand the impact of high temperature under fluctuating thermal conditions. Further, this reconciling framework allows improved experimental designs to understand the physiological underpinnings and ecological consequences of ectotherm heat tolerance.
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Affiliation(s)
- Michael Ørsted
- Aarhus University Section for Zoophysiology, Department of Biology , , 8000 Aarhus C , Denmark
| | | | - Johannes Overgaard
- Aarhus University Section for Zoophysiology, Department of Biology , , 8000 Aarhus C , Denmark
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8
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Duffy GA, Kuyucu AC, Hoskins JL, Hay EM, Chown SL. Adequate sample sizes for improved accuracy of thermal trait estimates. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Grant A. Duffy
- School of Biological Sciences Monash University Clayton Vic. Australia
| | - Arda C. Kuyucu
- Department of Biology Hacettepe University Ankara Turkey
| | | | - Eleanor M. Hay
- School of Biological Sciences Monash University Clayton Vic. Australia
| | - Steven L. Chown
- School of Biological Sciences Monash University Clayton Vic. Australia
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9
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Saravia J, Paschke K, Oyarzún-Salazar R, Cheng CHC, Navarro JM, Vargas-Chacoff L. Effects of warming rates on physiological and molecular components of response to CTMax heat stress in the Antarctic fish Harpagifer antarcticus. J Therm Biol 2021; 99:103021. [PMID: 34420652 DOI: 10.1016/j.jtherbio.2021.103021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/25/2021] [Accepted: 05/30/2021] [Indexed: 12/28/2022]
Abstract
Maximum and minimum Critical thermal limits (CTMax and CTMin) have been studied extensively to assess thermal tolerance in ectotherms by means of ramping assays. Notothenioid fish have been proposed as particularly sensitive to temperature increases related to global climate change. However, there are large gaps in our understanding of the thermal responses of these extreme cold-adapted fish in assays with heating rates. We evaluated the effects of two commonly used heating rates (0.3 and 1 °C/min) on the cellular stress responses in the intertidal Antarctic fish Harpagifer antarcticus immediately after CTMax was reached, and at 2 and 4 h of recovery time in ambient water. We compared CTMax values, the relative transcript expression of genes relvant to heat shock response (Hsc70, Hsp70, Grp78), hypoxia (Hif1-α, LDHa, GR), ubiquitination (Ube2), and apoptosis (SMAC/DIABLO), and five plasma parameters - glucose, lactate, total protein, osmolality and cortisol. CTMax values between the two heating rates are not significantly different, and both rates elicited a similar stress response at molecular and physiological levels. We found a lack of up-regulated response of heat shock proteins, consistent with other Antarctic notothenioids. The general transcriptional pattern trended to downregulation, which was more evident in the slower 0.3 °C/min rate, and instances of upregulation were mainly related to ubiquitination. The faster 1 °C/min rate, rarely used for Antarctic fish, can be suitable for studying cold-adapted stenothermic fish without overestimating thermal tolerance or inducing damage from longer heat exposure.
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Affiliation(s)
- Julia Saravia
- Escuela de Graduados Programa de Doctorado en Ciencias de la Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile; Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile, Valdivia, Chile.
| | - Kurt Paschke
- Centro Fondap de Investigación de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile, Valdivia, Chile; Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile
| | - Ricardo Oyarzún-Salazar
- Escuela de Graduados Programa de Doctorado en Ciencias de la Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile; Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile, Valdivia, Chile
| | - C-H Christina Cheng
- Department of Evolution, Ecology, and Behavior, University of Illinois, Urbana-Champaign, IL, 61801, USA
| | - Jorge M Navarro
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile, Valdivia, Chile
| | - Luis Vargas-Chacoff
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (Fondap IDEAL), Universidad Austral de Chile, Valdivia, Chile.
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10
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Willot Q, Loos B, Terblanche JS. Interactions between developmental and adult acclimation have distinct consequences for heat tolerance and heat stress recovery. J Exp Biol 2021; 224:271049. [PMID: 34308995 DOI: 10.1242/jeb.242479] [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: 02/22/2021] [Accepted: 07/21/2021] [Indexed: 11/20/2022]
Abstract
Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat knockdown and recovery from heat stress is poorly understood but significant for establishing causal links between climate variability and population dynamics. Here, using Drosophila melanogaster in a full-factorial experimental design, we assessed the heat tolerance of flies in static stress assays, and document how developmental and adult acclimation interact with a distinct pattern to promote survival to heat stress in adults. We show that warmer adult acclimation is the initial factor enhancing survival to constant stressful high temperatures in flies, but also that the interaction between adult and developmental acclimation becomes gradually more important to ensure survival as the stress persists. This provides an important framework revealing the dynamic interplay between these two forms of acclimation that ultimately enhance thermal tolerance as a function of stress duration. Furthermore, by investigating recovery rates post-stress, we also show that the process of heat-hardening and recovery post-heat knockdown are likely to be based on set of (at least partially) divergent mechanisms. This could bear ecological significance as a trade-off may exist between increasing thermal tolerance and maximizing recovery rates post-stress, constraining population responses when exposed to variable and stressful climatic conditions.
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Affiliation(s)
- Quentin Willot
- Center for Invasion Biology, Department of Conservation Ecology & Entomology, Stellenbosch University, Stellenbosch 7602, South Africa
| | - Ben Loos
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7602, South Africa
| | - John S Terblanche
- Center for Invasion Biology, Department of Conservation Ecology & Entomology, Stellenbosch University, Stellenbosch 7602, South Africa
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11
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Jørgensen LB, Malte H, Ørsted M, Klahn NA, Overgaard J. A unifying model to estimate thermal tolerance limits in ectotherms across static, dynamic and fluctuating exposures to thermal stress. Sci Rep 2021; 11:12840. [PMID: 34145337 PMCID: PMC8213714 DOI: 10.1038/s41598-021-92004-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/02/2021] [Indexed: 11/09/2022] Open
Abstract
Temperature tolerance is critical for defining the fundamental niche of ectotherms and researchers classically use either static (exposure to a constant temperature) or dynamic (ramping temperature) assays to assess tolerance. The use of different methods complicates comparison between studies and here we present a mathematical model (and R-scripts) to reconcile thermal tolerance measures obtained from static and dynamic assays. Our model uses input data from several static or dynamic experiments and is based on the well-supported assumption that thermal injury accumulation rate increases exponentially with temperature (known as a thermal death time curve). The model also assumes thermal stress at different temperatures to be additive and using experiments with Drosophila melanogaster, we validate these central assumptions by demonstrating that heat injury attained at different heat stress intensities and durations is additive. In a separate experiment we demonstrate that our model can accurately describe injury accumulation during fluctuating temperature stress and further we validate the model by successfully converting literature data of ectotherm heat tolerance (both static and dynamic assays) to a single, comparable metric (the temperature tolerated for 1 h). The model presented here has many promising applications for the analysis of ectotherm thermal tolerance and we also discuss potential pitfalls that should be considered and avoided using this model.
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Affiliation(s)
| | - Hans Malte
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark
| | - Michael Ørsted
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark
| | | | - Johannes Overgaard
- Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark
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12
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Kearney MR, Jusup M, McGeoch MA, Kooijman SALM, Chown SL. Where do functional traits come from? The role of theory and models. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13829] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael R. Kearney
- School of BioSciences Faculty of Science The University of Melbourne Melbourne Vic. Australia
| | - Marko Jusup
- Tokyo Tech World Hub Research Initiative Institute of Innovative Research Tokyo Institute of Technology Tokyo Japan
| | - Melodie A. McGeoch
- Department of Ecology Environment and Evolution School of Life Sciences La Trobe University Melbourne Vic. Australia
| | | | - Steven L. Chown
- Securing Antarctica's Environmental Future School of Biological Sciences Monash University Melbourne Vic. Australia
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13
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Morgan R, Tunnah L, Tuong DD, Hjelmstedt P, Nhu PN, Stiller KT, Phuong NT, Huong DTT, Bayley M, Wang T, Milsom WK. Striped catfish (Pangasianodon hypophthalmus) use air-breathing and aquatic surface respiration when exposed to severe aquatic hypercarbia. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:820-830. [PMID: 33773086 DOI: 10.1002/jez.2453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 01/26/2021] [Indexed: 11/06/2022]
Abstract
We investigated the extent to which the facultative air-breathing fish, the striped catfish (Pangasianodon hypophthalmus), uses air-breathing to cope with aquatic hypercarbia, and how air-breathing is influenced by the experimental exposure protocol and level of hypercarbia. We exposed individuals to severe aquatic hypercarbia (up to Pw CO2 = 81 mmHg) using step-wise and progressive exposure protocols while measuring gill ventilation rate, heart rate, mean arterial blood pressure, and air-breathing frequency, as well as arterial blood pH and PCO2 . We confirm that P. hypophthalmus is tolerant of hypercarbia. Under both protocols gill ventilation rate, heart rate, and mean arterial blood pressure were maintained near control levels even at very high CO2 levels. We observed a marked amount of individual variation in the PwCO2 at which air-breathing was elicited, with some individuals not responding at all. The experimental protocol also influenced the onset of air-breathing. Air-breathing began at lower Pw CO2 in the step-wise protocol (23 ± 4.1 mmHg) compared with the progressive protocol (46 ± 7.8 mmHg). Air-breathing was often followed by aquatic surface respiration, at higher PCO2 (71 ± 5.2 mmHg) levels. On average, the blood PCO2 was approximately 43% lower (46 ± 2.5 mmHg) than water Pw CO2 (~81 mmHg) at our highest tested CO2 level. While this suggests that aerial CO2 elimination is an effective, and perhaps critical, respiratory strategy used by P. hypophthalmus to cope with severe hypercarbia, this observation may also be explained by a long lag time required for equilibration.
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Affiliation(s)
- Rachael Morgan
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Louise Tunnah
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Dang D Tuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Per Hjelmstedt
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Pham N Nhu
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Kevin T Stiller
- Production Biology - The Norwegian Institute of Food, Fisheries and Aquaculture Research, Nofima AS, Sjølseng, Sunndalsøra, Norway
| | - Nguyen Thanh Phuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Do Thi Thanh Huong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Mark Bayley
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - Tobias Wang
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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14
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Åsheim ER, Andreassen AH, Morgan R, Jutfelt F. Rapid-warming tolerance correlates with tolerance to slow warming but not growth at non-optimal temperatures in zebrafish. J Exp Biol 2020; 223:jeb229195. [PMID: 33071218 DOI: 10.1242/jeb.229195] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/12/2020] [Indexed: 12/16/2022]
Abstract
Global warming is predicted to increase both acute and prolonged thermal challenges for aquatic ectotherms. Severe short- and medium-term thermal stress over hours to days may cause mortality, while longer sub-lethal thermal challenges may cause performance declines. The inter-relationship between the responses to short, medium and longer thermal challenges is unresolved. We asked if the same individuals are tolerant to both rapid and slow warming challenges, a question that has so far received little attention. Additionally, we investigated the possibility of a thermal syndrome where individuals in a population are distributed along a warm-type to cold-type axis. We tested whether different thermal traits correlate across individuals by acclimating 200 juvenile zebrafish (Danio rerio) to sub- or supra-optimal temperatures for growth (22 and 34°C) for 40 days and measuring growth and thermal tolerance at two different warming rates. We found that tolerance to rapid warming correlated with tolerance to slow warming in the 22°C treatment. However, individual tolerance to neither rapid nor slow warming correlated with growth at the supra-optimal temperature. We thus find some support for a syndrome-like organisation of thermal traits, but the lack of connection between tolerance and growth performance indicates a restricted generality of a thermal syndrome. The results suggest that tolerance to rapid warming may share underlying physiological mechanisms with tolerance to slower heating, and indicate that the relevance of acute critical thermal tolerance extends beyond the rapid ramping rates used to measure them.
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Affiliation(s)
- Eirik R Åsheim
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Organismal and Evolutionary Biology Research Programme, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Anna H Andreassen
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Rachael Morgan
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Fredrik Jutfelt
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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15
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Comparison of Static and Dynamic Assays When Quantifying Thermal Plasticity of Drosophilids. INSECTS 2020; 11:insects11080537. [PMID: 32824251 PMCID: PMC7469138 DOI: 10.3390/insects11080537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
Abstract
Simple Summary Temperature directly affects many biological processes, from enzymatic reactions to population growth, and thermal stress tolerance is central to our understanding of the global distribution and abundance of species and populations. Given the importance of thermal stress tolerance in ecophysiology and evolutionary biology it is important to be able to measure thermal stress resistance accurately and in ecologically relevant ways. Several methods for such quantification exist in the arthropod literature and the comparability of different methods is currently being debated. Here we reconcile the two most commonly used thermal assays (dynamic ramping and static knockdown assays) for quantifying insect heat tolerance limits and plastic responses using a newly suggested modeling technique. We find that results obtained on the basis of the two assays are highly correlated and that data from one assay can therefore reasonably well predict estimates from the other. These data are of general relevance to the study of thermal biology of ectotherms. Abstract Numerous assays are used to quantify thermal tolerance of arthropods including dynamic ramping and static knockdown assays. The dynamic assay measures a critical temperature while the animal is gradually heated, whereas the static assay measures the time to knockdown at a constant temperature. Previous studies indicate that heat tolerance measured by both assays can be reconciled using the time × temperature interaction from “thermal tolerance landscapes” (TTLs) in unhardened animals. To investigate if this relationship remains true within hardened animals, we use a static assay to assess the effect of heat hardening treatments on heat tolerance in 10 Drosophila species. Using this TTL approach and data from the static heat knockdown experiments, we model the expected change in dynamic heat knockdown temperature (CTmax: temperature at which flies enter coma) and compare these predictions to empirical measurements of CTmax. We find that heat tolerance and hardening capacity are highly species specific and that the two assays report similar and consistent responses to heat hardening. Tested assays are therefore likely to measure the same underlying physiological trait and provide directly comparable estimates of heat tolerance. Regardless of this compliance, we discuss why and when static or dynamic assays may be more appropriate to investigate ectotherm heat tolerance.
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16
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Volkoff H, Rønnestad I. Effects of temperature on feeding and digestive processes in fish. Temperature (Austin) 2020; 7:307-320. [PMID: 33251280 PMCID: PMC7678922 DOI: 10.1080/23328940.2020.1765950] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/29/2020] [Accepted: 05/03/2020] [Indexed: 12/11/2022] Open
Abstract
As most fish are ectotherms, their physiology is strongly affected by temperature. Temperature affects their metabolic rate and thus their energy balance and behavior, including locomotor and feeding behavior. Temperature influences the ability/desire of the fish to obtain food, and how they process food through digestion, absorb nutrients within the gastrointestinal tract, and store excess energy. As fish display a large variability in habitats, feeding habits, and anatomical and physiological features, the effects of temperature are complex and species-specific. The effects of temperature depend on the timing, intensity, and duration of exposure as well as the speed at which temperature changes occur. Whereas acute short-term variations of temperature might have drastic, often detrimental, effects on fish physiology, long-term gradual variations might lead to acclimation, e.g. variations in metabolic and digestive enzyme profiles. The goal of this review is to summarize our current knowledge on the effects of temperature on energy homeostasis, with specific focus on metabolism, feeding, digestion, and how fish are often able to "adapt" to changing environments through phenotypic and physiological changes.
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Affiliation(s)
- Helene Volkoff
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Ivar Rønnestad
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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17
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Evaluation of the Methodology to Assess the Influence of Hydraulic Characteristics on Habitat Quality. WATER 2020. [DOI: 10.3390/w12041131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The article aims at assessing the impact of hydraulic characteristics on the habitat quality of mountain and piedmont watercourses. The solution results from the Riverine Habitat Simulation model, where the quality of the aquatic habitat is represented by the weighted usable area (WUA), which is determined using brown trout as the bioindicator. Flow velocity and water depth are basic abiotic characteristics that determine the ratio of suitability of the instream habitat represented by the weighted usable area. The influence of these parameters on the objective evaluation of the habitat quality is the essence of the paper. The measurements were carried out during the summer period at minimum discharges for 17 mountain and piedmont streams in Slovakia. Three methods for assessing the habitat quality were tested, and differences in the results were found to be significant. The evaluation shows the optimum design methods for calculating the weighted usable area.
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18
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Brandt EE, Roberts KT, Williams CM, Elias DO. Low temperatures impact species distributions of jumping spiders across a desert elevational cline. JOURNAL OF INSECT PHYSIOLOGY 2020; 122:104037. [PMID: 32087221 DOI: 10.1016/j.jinsphys.2020.104037] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
Temperature is known to influence many aspects of organisms and is frequently linked to geographical species distributions. Despite the importance of a broad understanding of an animal's thermal biology, few studies incorporate more than one metric of thermal biology. Here we examined an elevational assemblage of Habronattus jumping spiders to measure different aspects of their thermal biology including thermal limits (CTmin, CTmax), thermal preference, V̇CO2 as proxy for metabolic rate, locomotor behavior and warming tolerance. We used these data to test whether thermal biology helped explain how species were distributed across elevation. Habronattus had high CTmax values, which did not differ among species across the elevational gradient. The highest-elevation species had a lower CTmin than any other species. All species had a strong thermal preference around 37 °C. With respect to performance, one of the middle elevation species was significantly less temperature-sensitive in metabolic rate. Differences between species with respect to locomotion (jump distance) were likely driven by differences in mass, with no differences in thermal performance across elevation. We suggest that Habronattus distributions follow Brett's rule, a rule that predicts more geographical variation in cold tolerance than heat. Additionally, we suggest that physiological tolerances interact with biotic factors, particularly those related to courtship and mate choice to influence species distributions. Habronattus also had very high warming tolerance values (> 20 °C, on average). Taken together, these data suggest that Habronattus are resilient in the face of climate-change related shifts in temperature.
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Affiliation(s)
- Erin E Brandt
- Department of Environmental Sciences, Policy, and Management, University of California, Berkeley, Berkeley, United States.
| | - Kevin T Roberts
- Department of Integrative Biology, University of California, Berkeley, Berkeley, United States
| | - Caroline M Williams
- Department of Integrative Biology, University of California, Berkeley, Berkeley, United States
| | - Damian O Elias
- Department of Environmental Sciences, Policy, and Management, University of California, Berkeley, Berkeley, United States
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19
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Rubalcaba JG, Olalla-Tárraga MÁ. The biogeography of thermal risk for terrestrial ectotherms: Scaling of thermal tolerance with body size and latitude. J Anim Ecol 2020; 89:1277-1285. [PMID: 31990044 DOI: 10.1111/1365-2656.13181] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 12/02/2019] [Indexed: 11/28/2022]
Abstract
Many organisms are shrinking in size in response to global warming. However, we still lack a comprehensive understanding of the mechanisms linking body size and temperature of organisms across their geographical ranges. Here we investigate the biophysical mechanisms determining the scaling of body temperature with size across latitudes in terrestrial ectotherms. Using biophysical models, we simulated operative temperatures experienced by lizard-like ectotherms as a function of microclimatic variables, body mass and latitude and used them to generate null predictions for the effect of size on temperature across geographical gradients. We then compared model predictions against empirical data on lizards' field body temperature (Tb ) and thermal tolerance limits (CTmax and CTmin ). Our biophysical models predict that the allometric scaling of operative temperatures with body size varies with latitude, with a positive relationship at low latitudes that vanishes with increasing latitude. The analyses of thermal traits of lizards show a significant interaction of body size and latitude on Tb and CTmax and no effect of body mass on CTmin , consistent with model's predictions. The estimated scaling coefficients are within the ranges predicted by the biophysical model. The effect of body mass, however, becomes non-significant after controlling for the phylogenetic relatedness between species. We propose that large-bodied terrestrial ectotherms exhibit higher risk of overheating at low latitudes, while size differences in thermal sensitivity vanish towards higher latitudes. Our work highlights the potential of combining mechanistic models with empirical data to investigate the mechanisms underpinning broad-scale patterns and ultimately provide a null model to develop baseline expectations for further empirical research.
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Affiliation(s)
- Juan G Rubalcaba
- Department of Biology and Geology, Physics and Inorganic Chemistry, ESCET, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain
| | - Miguel Á Olalla-Tárraga
- Department of Biology and Geology, Physics and Inorganic Chemistry, ESCET, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain
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20
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Tsai CC, Childers RA, Nan Shi N, Ren C, Pelaez JN, Bernard GD, Pierce NE, Yu N. Physical and behavioral adaptations to prevent overheating of the living wings of butterflies. Nat Commun 2020; 11:551. [PMID: 31992708 PMCID: PMC6987309 DOI: 10.1038/s41467-020-14408-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/11/2019] [Indexed: 11/08/2022] Open
Abstract
The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.
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Affiliation(s)
- Cheng-Chia Tsai
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
| | - Richard A Childers
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Norman Nan Shi
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
- Western Digital, San Jose, CA, 95119, USA
| | - Crystal Ren
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
| | - Julianne N Pelaez
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Gary D Bernard
- Department of Electrical Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Naomi E Pierce
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA.
| | - Nanfang Yu
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA.
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21
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Javal M, Thomas S, Lehmann P, Barton MG, Conlong DE, Du Plessis A, Terblanche JS. The Effect of Oxygen Limitation on a Xylophagous Insect's Heat Tolerance Is Influenced by Life-Stage Through Variation in Aerobic Scope and Respiratory Anatomy. Front Physiol 2019; 10:1426. [PMID: 31824337 PMCID: PMC6879455 DOI: 10.3389/fphys.2019.01426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/04/2019] [Indexed: 12/21/2022] Open
Abstract
Temperature has a profound impact on insect fitness and performance via metabolic, enzymatic or chemical reaction rate effects. However, oxygen availability can interact with these thermal responses in complex and often poorly understood ways, especially in hypoxia-adapted species. Here we test the hypothesis that thermal limits are reduced under low oxygen availability - such as might happen when key life-stages reside within plants - but also extend this test to attempt to explain that the magnitude of the effect of hypoxia depends on variation in key respiration-related parameters such as aerobic scope and respiratory morphology. Using two life-stages of a xylophagous cerambycid beetle, Cacosceles (Zelogenes) newmannii we assessed oxygen-limitation effects on metabolic performance and thermal limits. We complement these physiological assessments with high-resolution 3D (micro-computed tomography scan) morphometry in both life-stages. Results showed that although larvae and adults have similar critical thermal maxima (CTmax) under normoxia, hypoxia reduces metabolic rate in adults to a greater extent than it does in larvae, thus reducing aerobic scope in the former far more markedly. In separate experiments, we also show that adults defend a tracheal oxygen (critical) setpoint more consistently than do larvae, indicated by switching between discontinuous gas exchange cycles (DGC) and continuous respiratory patterns under experimentally manipulated oxygen levels. These effects can be explained by the fact that the volume of respiratory anatomy is positively correlated with body mass in adults but is apparently size-invariant in larvae. Thus, the two life-stages of C. newmannii display key differences in respiratory structure and function that can explain the magnitude of the effect of hypoxia on upper thermal limits.
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Affiliation(s)
- Marion Javal
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Saskia Thomas
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Philipp Lehmann
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Madeleine G. Barton
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Desmond E. Conlong
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
- South African Sugarcane Research Institute, Mount Edgecombe, South Africa
| | - Anton Du Plessis
- CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch, South Africa
- Physics Department, Stellenbosch University, Stellenbosch, South Africa
| | - John S. Terblanche
- Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa
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