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Powers SD, Grayson KL, Martinez E, Agosta SJ. Ontogenetic variation in metabolic rate-temperature relationships during larval development. J Exp Biol 2024; 227:jeb247912. [PMID: 38940758 DOI: 10.1242/jeb.247912] [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: 04/18/2024] [Accepted: 06/18/2024] [Indexed: 06/29/2024]
Abstract
Predictive models of ectotherm responses to environmental change often rely on thermal performance data from the literature. For insects, the majority of these data focus on two traits, development rate and thermal tolerance limits. Data are also often limited to the adult stage. Consequently, predictions based on these data generally ignore other measures of thermal performance and do not account for the role of ontogenetic variation in thermal physiology across the complex insect life cycle. Theoretical syntheses for predicting metabolic rate also make similar assumptions despite the strong influence of body size as well as temperature on metabolic rate. The aim of this study was to understand the influence of ontogenetic variation on ectotherm physiology and its potential impact on predictive modeling. To do this, we examined metabolic rate-temperature (MR-T) relationships across the larval stage in a laboratory strain of the spongy moth (Lymantria dispar dispar). Routine metabolic rates (RMRs) of larvae were assayed at eight temperatures across the first five instars of the larval stage. After accounting for differences in body mass, larval instars showed significant variation in MR-T. Both the temperature sensitivity and allometry of RMR increased and peaked during the third instar, then declined in the fourth and fifth instar. Generally, these results show that insect thermal physiology does not remain static during larval ontogeny and suggest that ontogenetic variation should be an important consideration when modeling thermal performance.
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Affiliation(s)
- Sean D Powers
- Integrative Life Sciences Doctoral Program, Virginia Commonwealth University, Richmond, VA 2328, USA
| | | | - Eloy Martinez
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - Salvatore J Agosta
- Center for Environmental Studies, Virginia Commonwealth University, Richmond, VA 23284, USA
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2
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Sokolova IM. Ectotherm mitochondrial economy and responses to global warming. Acta Physiol (Oxf) 2023; 237:e13950. [PMID: 36790303 DOI: 10.1111/apha.13950] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/24/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Temperature is a key abiotic factor affecting ecology, biogeography, and evolution of species. Alterations of energy metabolism play an important role in adaptations and plastic responses to temperature shifts on different time scales. Mitochondrial metabolism affects cellular bioenergetics and redox balance making these organelles an important determinant of organismal performances such as growth, locomotion, or development. Here I analyze the impacts of environmental temperature on the mitochondrial functions (including oxidative phosphorylation, proton leak, production of reactive oxygen species(ROS), and ATP synthesis) of ectotherms and discuss the mechanisms underlying negative shifts in the mitochondrial energy economy caused by supraoptimal temperatures. Owing to the differences in the thermal sensitivity of different mitochondrial processes, elevated temperatures (beyond the species- and population-specific optimal range) cause reallocation of the electron flux and the protonmotive force (Δp) in a way that decreases ATP synthesis efficiency, elevates the relative cost of the mitochondrial maintenance, causes excessive production of ROS and raises energy cost for antioxidant defense. These shifts in the mitochondrial energy economy might have negative consequences for the organismal fitness traits such as the thermal tolerance or growth. Correlation between the thermal sensitivity indices of the mitochondria and the whole organism indicate that these traits experience similar selective pressures but further investigations are needed to establish whether there is a cause-effect relationship between the mitochondrial failure and loss of organismal performance during temperature change.
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Affiliation(s)
- Inna M Sokolova
- Department of Marine Biology, Institute of Biological Sciences, University of Rostock, Rostock, Germany
- Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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3
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Voituron Y, Roussel D, Teulier L, Vagner M, Ternon Q, Romestaing C, Dubillot E, Lefrancois C. Warm Acclimation Increases Mitochondrial Efficiency in Fish: A Compensatory Mechanism to Reduce the Demand for Oxygen. Physiol Biochem Zool 2021; 95:15-21. [PMID: 34813413 DOI: 10.1086/716904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractIn ectotherms, it is well described that thermal acclimation induces compensatory adjustments maintaining mitochondrial functions across large shifts in temperature. However, until now, studies mostly focused on fluxes of oxygen without knowing whether mitochondrial efficiency to produce ATP (ATP/O ratio) is also dependent on temperature acclimation. We thus measured thermal reaction norms of oxidative phosphorylation activity and efficiency in isolated mitochondria from skeletal muscle of sea bass (Dicentrarchus labrax) juveniles acclimated at optimal (22°C), low (18°C), and high (26°C) temperatures. The mitochondrial fluxes (oxygen consumption and ATP synthesis) increased with increasing assay temperatures and were on the whole higher in fishes acclimated at 18°C than in the other two groups. However, these mitochondrial rates were not significantly different between experimental groups when they were compared at the acclimation temperature. In contrast, we show that acclimation to high, and not low, temperature improved mitochondrial efficiency (on average >15%). This higher efficiency in high-temperature-acclimated fishes is also apparent when compared at respective acclimation temperatures. This mitochondrial phenotype would favor an economical management of oxygen in response to harsh energetic constraints associated with warming water.
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4
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Coggins BL, Anderson CE, Hasan R, Pearson AC, Ekwudo MN, Bidwell JR, Yampolsky LY. Breaking free from thermodynamic constraints: thermal acclimation and metabolic compensation in a freshwater zooplankton species. J Exp Biol 2021; 224:jeb237727. [PMID: 33328286 DOI: 10.1242/jeb.237727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/09/2020] [Indexed: 01/14/2023]
Abstract
Respiration rates of ectothermic organisms are affected by environmental temperatures, and sustainable metabolism at high temperatures sometimes limits heat tolerance. Organisms are hypothesized to exhibit acclimatory metabolic compensation effects, decelerating their metabolic processes below Arrhenius expectations based on temperature alone. We tested the hypothesis that either heritable or plastic heat tolerance differences can be explained by metabolic compensation in the eurythermal freshwater zooplankton crustacean Daphnia magna We measured respiration rates in a ramp-up experiment over a range of assay temperatures (5-37°C) in eight genotypes of D. magna representing a range of previously reported acute heat tolerances and, at a narrower range of temperatures (10-35°C), in D. magna with different acclimation history (either 10 or 25°C). We discovered no difference in temperature-specific respiration rates between heat-tolerant and heat-sensitive genotypes. In contrast, we observed acclimation-specific compensatory differences in respiration rates at both extremes of the temperature range studied. Notably, there was a deceleration of oxygen consumption at higher temperature in 25°C-acclimated D. magna relative to their 10°C-acclimated counterparts, observed in active animals, a pattern corroborated by similar changes in filtering rate and, partly, by changes in mitochondrial membrane potential. A recovery experiment indicated that the reduction of respiration was not caused by irreversible damage during exposure to a sublethal temperature. Response time necessary to acquire the respiratory adjustment to high temperature was lower than for low temperature, indicating that metabolic compensation at lower temperatures requires slower, possibly structural changes.
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Affiliation(s)
- B L Coggins
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
- Department of Biological Sciences, University of Notre Dame, Galvin Life Science Center, Notre Dame, IN 46556, USA
| | - C E Anderson
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
| | - R Hasan
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
| | - A C Pearson
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
| | - M N Ekwudo
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
| | - J R Bidwell
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
| | - L Y Yampolsky
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37691, USA
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5
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Acclimation temperature affects thermal reaction norms for energy reserves in Drosophila. Sci Rep 2020; 10:21681. [PMID: 33303846 PMCID: PMC7729904 DOI: 10.1038/s41598-020-78726-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Organisms have evolved various physiological mechanisms to cope with unfavourable environmental conditions. The ability to tolerate non-optimal thermal conditions can be substantially improved by acclimation. In this study, we examined how an early-life acclimation to different temperatures (19 °C, 25 °C and 29 °C) influences thermal reaction norms for energy stores in Drosophila adults. Our results show that acclimation temperature has a significant effect on the amount of stored fat and glycogen (and their relative changes) and the optimal temperature for their accumulation. Individuals acclimated to 19 °C had, on average, more energy reserves than flies that were initially maintained at 25 °C or 29 °C. In addition, acclimation caused a shift in optimal temperature for energy stores towards acclimation temperature. We also detected significant population differences in this response. The effect of acclimation on the optimal temperature for energy stores was more pronounced in flies from the temperate climate zone (Slovakia) than in individuals from the tropical zone (India). Overall, we found that the acclimation effect was stronger after acclimation to low (19 °C) than to high (29 °C) temperature. The observed sensitivity of thermal reaction norms for energy reserves to acclimation temperature can have important consequences for surviving periods of food scarcity, especially at suboptimal temperatures.
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6
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Abstract
Temperature is a critical abiotic factor shaping the distribution and abundance of species, but the mechanisms that underpin organismal thermal limits remain poorly understood. One possible mechanism underlying these limits is the failure of mitochondrial processes, as mitochondria play a crucial role in animals as the primary site of ATP production. Conventional measures of mitochondrial performance suggest that these organelles can function at temperatures much higher than those that limit whole-organism function, suggesting that they are unlikely to set organismal thermal limits. However, this conclusion is challenged by recent data connecting sequence variation in mitochondrial genes to whole-organism thermal tolerance. Here, we review the current state of knowledge of mitochondrial responses to thermal extremes and ask whether they are consistent with a role for mitochondrial function in shaping whole-organism thermal limits. The available data are fragmentary, but it is possible to draw some conclusions. There is little evidence that failure of maximal mitochondrial oxidative capacity as assessed in vitro sets thermal limits, but there is some evidence to suggest that temperature effects on ATP synthetic capacity may be important. Several studies suggest that loss of mitochondrial coupling is associated with the thermal limits for organismal growth, although this needs to be rigorously tested. Most studies have utilized isolated mitochondrial preparations to assess the effects of temperature on these organelles, and there remain many untapped opportunities to address these questions using preparations that retain more of their biological context to better connect these subcellular processes with whole-organism thermal limits.
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Affiliation(s)
- Dillon J Chung
- National Heart Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20814, USA
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia, Canada V6T 1Z4
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7
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Gangloff EJ, Schwartz TS, Klabacka R, Huebschman N, Liu AY, Bronikowski AM. Mitochondria as central characters in a complex narrative: Linking genomics, energetics, pace-of-life, and aging in natural populations of garter snakes. Exp Gerontol 2020; 137:110967. [DOI: 10.1016/j.exger.2020.110967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/11/2020] [Accepted: 05/01/2020] [Indexed: 12/18/2022]
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8
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Jiang T, Ma L, Liu XY, Xiao HJ, Zhang WN. Effects of starvation on respiratory metabolism and energy metabolism in the cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). JOURNAL OF INSECT PHYSIOLOGY 2019; 119:103951. [PMID: 31563619 DOI: 10.1016/j.jinsphys.2019.103951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/15/2019] [Accepted: 09/25/2019] [Indexed: 06/10/2023]
Abstract
Intermittent food shortages are commonly encountered in the wild. To cope with the threat of starvation, insects initiate a suite of behavioral activities and physiological countermeasures. The cotton bollworm, Helicoverpa armigera, is a major agricultural pest worldwide, but how H. armigera modulates its metabolism under starvation remains ambiguous. In the present study, the respiratory rates (V̇O2; ml g-1 h-1) from the third-larval instar to the pupal stage were first determined. Our results highlighted a transient rise during the larval-larval molt and larval-pupal transition, followed by a sharp decline in the pupal stage and, finally, an upward trend before eclosion. When subjected to food deprivation, the starved larvae experienced a significant decline in the rates of O2 consumed and CO2 produced, as well as in respiratory quotient (RQ) values, indicative of severe metabolic depression during starvation and a shift of metabolic substrates with prolonged starvation. For metabolic substrate analysis, an apparent decline in triglyceride and glycogen contents was observed in the starved larvae, and the hemolymph trehalose content was significantly reduced throughout starvation. In addition, comparative transcriptome analysis showed that 48 h of larval starvation caused substantial transcriptional regulations in several energetically costly processes, wherein the marked up-regulations were detected in the pathways of glycolysis and fatty acid metabolism. Overall, our work makes a comprehensive study on the respiratory rate and energy metabolism in the starved H. armigera larvae, and provides a deep insight into the physiological adaptive strategies to alleviate nutritional stress.
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Affiliation(s)
- Ting Jiang
- Institute of Entomology, Jiangxi Agricultural University, Nanchang 330045, China
| | - Long Ma
- College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang 330013, China
| | - Xiang-Ya Liu
- Institute of Entomology, Jiangxi Agricultural University, Nanchang 330045, China
| | - Hai-Jun Xiao
- Institute of Entomology, Jiangxi Agricultural University, Nanchang 330045, China.
| | - Wan-Na Zhang
- Institute of Entomology, Jiangxi Agricultural University, Nanchang 330045, China.
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9
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Salin K, Villasevil EM, Anderson GJ, Lamarre SG, Melanson CA, McCarthy I, Selman C, Metcalfe NB. Differences in mitochondrial efficiency explain individual variation in growth performance. Proc Biol Sci 2019; 286:20191466. [PMID: 31431161 DOI: 10.1098/rspb.2019.1466] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The physiological causes of intraspecific differences in fitness components such as growth rate are currently a source of debate. It has been suggested that differences in energy metabolism may drive variation in growth, but it remains unclear whether covariation between growth rates and energy metabolism is: (i) a result of certain individuals acquiring and consequently allocating more resources to growth, and/or is (ii) determined by variation in the efficiency with which those resources are transformed into growth. Studies of individually housed animals under standardized nutritional conditions can help shed light on this debate. Here we quantify individual variation in metabolic efficiency in terms of the amount of adenosine triphosphate (ATP) generated per molecule of oxygen consumed by liver and muscle mitochondria and examine its effects, both on the rate of protein synthesis within these tissues and on the rate of whole-body growth of individually fed juvenile brown trout (Salmo trutta) receiving either a high or low food ration. As expected, fish on the high ration on average gained more in body mass and protein content than those maintained on the low ration. Yet, growth performance varied more than 10-fold among individuals on the same ration, resulting in some fish on low rations growing faster than others on the high ration. This variation in growth for a given ration was related to individual differences in mitochondrial properties: a high whole-body growth performance was associated with high mitochondrial efficiency of ATP production in the liver. Our results show for the first time, to our knowledge, that among-individual variation in the efficiency with which substrates are converted into ATP can help explain marked variation in growth performance, independent of food intake. This study highlights the existence of inter-individual differences in mitochondrial efficiency and its potential importance in explaining intraspecific variation in whole-animal performance.
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Affiliation(s)
- Karine Salin
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Eugenia M Villasevil
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Graeme J Anderson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Simon G Lamarre
- Département de Biologie, Université de Moncton, Moncton, New Brunswick, Canada E1A 3E9
| | - Chloé A Melanson
- Département de Biologie, Université de Moncton, Moncton, New Brunswick, Canada E1A 3E9
| | - Ian McCarthy
- School of Ocean Sciences, Bangor University, Menai Bridge LL59 5AB, UK
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Neil B Metcalfe
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
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Chidawanyika F, Mudavanhu P, Nyamukondiwa C. Global Climate Change as a Driver of Bottom-Up and Top-Down Factors in Agricultural Landscapes and the Fate of Host-Parasitoid Interactions. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00080] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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11
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Abstract
Temperature has a profound impact on animal physiology. In this study, we examined the effect of ambient temperature on the energy stores of the model organism Drosophila melanogaster. By exposing adult males to 11 temperatures between 13 °C and 33 °C, we found that temperature significantly affects the amount of energy reserves. Whereas flies increase their fat stores at intermediate temperatures, exposure to temperatures below 15 °C or above 27 °C causes a reduction of fat reserves. Moreover, we found that glycogen stores followed a similar trend, although not so pronounced. To elucidate the underlying mechanism of these changes, we compared the temperature dependence of food consumption and metabolic rate. This analysis revealed that food intake and metabolic rate scale with temperature equally, suggesting that the temperature-induced changes in energy reserves are probably not caused by a mismatch between these two traits. Finally, we assessed the effect of temperature on starvation resistance. We found that starvation survival is a negative exponential function of temperature; however we did not find any clear evidence that implies the relative starvation resistance is compromised at non-optimal temperatures. Our results indicate that whilst optimal temperatures can promote accumulation of energy reserves, exposure to non-optimal temperatures reduces Drosophila energy stores.
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12
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Fiorini R, Ventrella V, Trombetti F, Fabbri M, Pagliarani A, Nesci S. Lipid-protein interactions in mitochondrial membranes from bivalve mollusks: molecular strategies in different species. Comp Biochem Physiol B Biochem Mol Biol 2019; 227:12-20. [DOI: 10.1016/j.cbpb.2018.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 01/28/2023]
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13
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May C, Hillerbrand N, Thompson LM, Faske TM, Martinez E, Parry D, Agosta SJ, Grayson KL. Geographic Variation in Larval Metabolic Rate Between Northern and Southern Populations of the Invasive Gypsy Moth. JOURNAL OF INSECT SCIENCE (ONLINE) 2018; 18:5052202. [PMID: 30010927 PMCID: PMC6041892 DOI: 10.1093/jisesa/iey068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Indexed: 05/29/2023]
Abstract
Thermal regimes can diverge considerably across the geographic range of a species, and accordingly, populations can vary in their response to changing environmental conditions. Both local adaptation and acclimatization are important mechanisms for ectotherms to maintain homeostasis as environments become thermally stressful, which organisms often experience at their geographic range limits. The spatial spread of the gypsy moth (Lymantria dispar L.) (Lepidoptera: Erebidae) after introduction to North America provides an exemplary system for studying population variation in physiological traits given the gradient of climates encompassed by its current invasive range. This study quantifies differences in resting metabolic rate (RMR) across temperature for four populations of gypsy moth, two from the northern and two from southern regions of their introduced range in North America. Gypsy moth larvae were reared at high and low thermal regimes, and then metabolic activity was monitored at four temperatures using stop-flow respirometry to test for an acclimation response. For all populations, there was a significant increase in RMR as respirometry test temperature increased. Contrary to our expectations, we did not find evidence for metabolic adaptation to colder environments based on our comparisons between northern and southern populations. We also found no evidence for an acclimation response of RMR to rearing temperature for three of the four pairwise comparisons examined. Understanding the thermal sensitivity of metabolic rate in gypsy moth, and understanding the potential for changes in physiology at range extremes, is critical for estimating continued spatial spread of this invasive species both under current and potential future climatic constraints.
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Affiliation(s)
- Carolyn May
- Department of Biology, University of Richmond, Richmond, VA
| | | | | | - Trevor M Faske
- Department of Biology, Virginia Commonwealth University, Richmond, VA
| | - Eloy Martinez
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL
| | - Dylan Parry
- Department of Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry, Forestry Drive, Syracuse, NY
| | - Salvatore J Agosta
- Department of Biology, Virginia Commonwealth University, Richmond, VA
- Center for Environmental Studies, Virginia Commonwealth University, Richmond, VA
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14
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Agosta SJ, Joshi KA, Kester KM. Upper thermal limits differ among and within component species in a tritrophic host-parasitoid-hyperparasitoid system. PLoS One 2018; 13:e0198803. [PMID: 29894508 PMCID: PMC5997305 DOI: 10.1371/journal.pone.0198803] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/27/2018] [Indexed: 12/02/2022] Open
Abstract
Understanding how climate change affects host-parasite systems and predicting the consequences for ecosystems, economies, and human health has emerged as an important task for science and society. Some basic insight into this complex problem can be gained by comparing the thermal physiology of interacting host and parasite species. In this study, we compared upper thermal tolerance among three component species in a natural host-parasitoid-hyperparasitoid system from Virginia, USA. To assess the ecological relevance of our results, we also examined a record of maximum daily air temperatures collected near the study site in the last 124 years. We found that the caterpillar host Manduca sexta had a critical thermal maximum (CTmax) about 4°C higher than the parasitic wasp, Cotesia congregata, and the hyperparasitic wasp, Conura sp., had a CTmax about 6°C higher than its host, C. congregata. We also found significant differences in CTmax among instars and between parasitized and non-parasitized M. sexta. The highest maximum daily air temperature recorded near the study in the last 124 years was 42°C, which equals the average CTmax of one species (C. congregata) but is several degrees lower than the average CTmax of the other two species (M. sexta, Conura sp.) in this study. Our results combined with other studies suggest that significant differences in thermal performance within and among interacting host and parasite species are common in nature and that climate change may be largely disruptive to these systems with responses that are highly variable and complex.
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Affiliation(s)
- Salvatore J. Agosta
- Center for Environmental Studies, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kanchan A. Joshi
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Karen M. Kester
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
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