Researchers and practitioners are increasingly using comparative assessments of critical thermal and physiological limits to assess the relative vulnerability of ectothermic species to extreme thermal and aridity cond...Researchers and practitioners are increasingly using comparative assessments of critical thermal and physiological limits to assess the relative vulnerability of ectothermic species to extreme thermal and aridity conditions occurring under climate change.In most assessments of vulnerability,critical limits are compared across taxa exposed to different environmental and developmental conditions.However,many aspects of vulnerability should ideally be compared when species are exposed to the same environmental conditions,allowing a partitioning of sources of variation such as used in quantitative genetics.This is particularly important when assessing the importance of different types of plasticity to critical limits,using phylogenetic analyses to test for evolutionary constraints,isolating genetic variants that contribute to limits,characterizing evolutionary interactions among traits limiting adaptive responses,and when assessing the role of cross generation effects.However,vulnerability assessments based on critical thermal/physiological limits also need to take place within a context that is relevant to field conditions,which is not easily provided under controlled environmental conditions where behavior,microhabitat,stress exposure rates and other factors will differ from field conditions.There are ways of reconciling these requirements,such as by taking organisms from controlled environments and then testing their performance under field conditions(or vice versa).While comparisons under controlled environments are challenging for many taxa,assessments of critical thermal limits and vulnerability will always be incomplete unless environmental effects within and across generations are considered,and where the ecological relevance of assays measuring critical limits can be established.展开更多
The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudina...The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudinal variation in the vulnerability of plateau ectotherms to climate warming,Qinghai toad-headed lizards(Phrynocephalus vlangalii)were subjected to semi-natural enclosure experiments with simulated warming at high(2,600 m)and superhigh(3,600 m)elevations of the Dangjin Mountain,China.Our results revealed that the thermoregulatory effectiveness and warming tolerance(WT)of the toad-headed lizards were significantly affected by climate warming at both elevations,but their thermal sensitivity remained unchanged.After warming,the thermoregulatory effectiveness of lizards at superhigh elevations decreased because of the improved environmental thermal quality,whereas that of lizards at high-elevation conditions increased.Although the body temperature selected by high-elevation lizards was also significantly increased,the proportion of their active body temperature falling within the set-point temperature range decreased.This indicates that it is difficult for high-elevation lizards to adjust their body temperatures within a comfortable range under climate warming.Variations in the WT and thermal safety margin(TSM)under climate warming revealed that lizards at the superhigh elevation benefited from improved environmental thermal quality,whereas those at the high elevation originally on the edge of the TSM faced more severe threats and became more vulnerable.Our study highlights the importance of thermal biological traits in evaluating the vulnerability of ectotherms in temperate plateau regions.展开更多
Studies of the seasonal acclimatisation of behavioural and physiological processes usually focus on aquatic or semi-aquatic ectotherms and focus less effort on terrestrial ectotherms that experience more thermally het...Studies of the seasonal acclimatisation of behavioural and physiological processes usually focus on aquatic or semi-aquatic ectotherms and focus less effort on terrestrial ectotherms that experience more thermally heterogeneous environments. We conducted comparative studies and thermal acclimation experiments on the locomotion of the Chinese skink （Plestiodon chinensis） to test whether seasonal acclimatisation in locomotion exists in these terrestrial ectothermic vertebrates, and whether seasonal acclimatisation is predominantly induced by thermal environments. In natural populations, skinks ran faster during the summer season than during the spring season at high-test temperatures ranging from 27℃ to 36℃ but not at low-test temperatures ranging from 18℃ to 24℃. In contrast, the thermal acclimation experiments showed that the cold-acclimated skinks ran faster than the warm-acclimated skinks at the low- test temperatures but not at high-test temperatures. Therefore, the seasonal acclimatisation occurs to P chinensis, and may be induced by temperature as well as other factors like food availability, as indicated by the seasonal variation in the thermal dependence of locomotion, and the discrepancy between seasonal acclimatisation and thermal acclimation on locomotion.展开更多
For species that have a broad geographic distribution, adaptive variation may be attributable to gene expression plasticity. Nanorana parkeri is an anuran endemic to the southern Tibetan Plateau where it has an extens...For species that have a broad geographic distribution, adaptive variation may be attributable to gene expression plasticity. Nanorana parkeri is an anuran endemic to the southern Tibetan Plateau where it has an extensive altitudinal range（2850 to 5100 m asl）. Low oxygen concentration is one of the main environmental characteristics of the Tibetan Plateau. Hypoxia-inducible factor α subunits（HIF-1α and HIF-2α, encoded by Endothelial PAS domain protein 1（EPAS1）） and associated genes（e.g., vascular endothelial growth factor（VEGF） and Erythropoietin（EPO）） play crucial roles in maintaining oxygen homeostasis. In this study, we compared the expression of HIF-1A, VEGF, EPAS1 and EPO mRNA between two populations of N. parkeri： one population inhabiting the native high altitudes, and the second living in, and being acclimated to, the lower plains（70 m asl）. The expression of HIF-1A, VEGF and EPAS1 mRNA in the high altitude population were significantly higher than in the acclimated population, whereas there was no significant difference for EPO between two groups. Our results indicated that gene expression plasticity may make significant contributions to local adaptation of species that have broad altitudinal distributions. In addition, we deepen our understanding of the adaptive potential of this species by evaluating the experiments in the scope of its evolutionary history.展开更多
Temperature tolerance restricts the distribution of a species. However, the molecular and cellular mechanisms that set the thermal tolerance limits of an organism are poorly understood. Here, we report on the function...Temperature tolerance restricts the distribution of a species. However, the molecular and cellular mechanisms that set the thermal tolerance limits of an organism are poorly understood. Here, we report on the function of dual-specificity phosphatase 1(DUSP1) in thermal tolerance regulation. Notably, we found that dusp1-/- zebrafish grew normally but survived within a narrowed temperature range. The higher susceptibility of these mutant fish to both cold and heat challenges was attributed to accelerated cell death caused by aggravated mitochondrial dysfunction and over-production of reactive oxygen species in the gills. The DUSP1-MAPK-DRP1 axis was identified as a key pathway regulating these processes in both fish and human cells. These observations suggest that DUSP1 may play a role in maintaining mitochondrial integrity and redox homeostasis. We therefore propose that maintenance of cellular redox homeostasis may be a key mechanism for coping with cellular thermal stress and that the interplay between signaling pathways regulating redox homeostasis in the most thermosensitive tissue(i.e., gills) may play an important role in setting the thermal tolerance limit of zebrafish.展开更多
Hypoxia-inducible factor 1 alpha（HIF-1α） and its target genes vascular endothelial growth factor（VEGF） and transferrins（TF） play an important role in native endothermic animals＇ adaptation to the high altitude...Hypoxia-inducible factor 1 alpha（HIF-1α） and its target genes vascular endothelial growth factor（VEGF） and transferrins（TF） play an important role in native endothermic animals＇ adaptation to the high altitude environments. For ectothermic animals – especially frogs – it remains undetermined whether HIF-1α and its target genes（VEGF and TF） play an important role in high altitude adaptation, too. In this study, we compared the gene sequences and expression of HIF-1α and its target genes（VEGF and TF） between three Nanorana parkeri populations from different altitudes（3008 m a.s.l., 3440 m a.s.l. and 4312 m a.s.l.）. We observed that the c DNA sequences of HIF-1A exhibited high sequence similarity（99.38%） among the three altitudinally separated populations; but with increasing altitude, the expression of HIF-1A and its target genes（VEGF and TF） increased significantly. These results indicate that HIF-1α plays an important role in N. parkeri adaptation to the high altitude, similar to its role in endothermic animals.展开更多
The impact of climate change may be felt most keenly by tropical ectotherms.In these taxa,it is argued,thermal specialization means a given shift in temperature will have a larger effect on fitness.For species with li...The impact of climate change may be felt most keenly by tropical ectotherms.In these taxa,it is argued,thermal specialization means a given shift in temperature will have a larger effect on fitness.For species with limited dispersal ability,the impact of climate change depends on the capacity for their climate-relevant traits to shift.Such shifts can occur through genetic adaptation,various forms of plasticity,or a combination of these processes.Here we assess the extent and causes of shifts in 7 physiological traits in a tropical lizard,the rainforest sunskink(Lampropholis coggeri).Two populations were sampled that differ from each other in both climate and physiological traits.We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions.We also compared trait values between populations in:(i)recently field-collected animals;(ii)the same animals following laboratory acclimation;and(iii)the laboratory-reared offspring of these animals.Our results reveal high trait lability,driven primarily by acclimation and local adaptation.By contrast,developmental plasticity,resulting from incubation temperature,had little to no effect on most traits.These results suggest that,while specialized,tropical ectotherms may be capable of rapid shifts in climate-relevant traits.展开更多
基金AAH held an NHMRC Fellowship during the completion of this paper.
文摘Researchers and practitioners are increasingly using comparative assessments of critical thermal and physiological limits to assess the relative vulnerability of ectothermic species to extreme thermal and aridity conditions occurring under climate change.In most assessments of vulnerability,critical limits are compared across taxa exposed to different environmental and developmental conditions.However,many aspects of vulnerability should ideally be compared when species are exposed to the same environmental conditions,allowing a partitioning of sources of variation such as used in quantitative genetics.This is particularly important when assessing the importance of different types of plasticity to critical limits,using phylogenetic analyses to test for evolutionary constraints,isolating genetic variants that contribute to limits,characterizing evolutionary interactions among traits limiting adaptive responses,and when assessing the role of cross generation effects.However,vulnerability assessments based on critical thermal/physiological limits also need to take place within a context that is relevant to field conditions,which is not easily provided under controlled environmental conditions where behavior,microhabitat,stress exposure rates and other factors will differ from field conditions.There are ways of reconciling these requirements,such as by taking organisms from controlled environments and then testing their performance under field conditions(or vice versa).While comparisons under controlled environments are challenging for many taxa,assessments of critical thermal limits and vulnerability will always be incomplete unless environmental effects within and across generations are considered,and where the ecological relevance of assays measuring critical limits can be established.
基金supported by grants from the National Natural Science Foundation of China(31861143023 and 31872252)the Fundamental Research Funds for the Central Universities(2572019AA09)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20050201).
文摘The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudinal variation in the vulnerability of plateau ectotherms to climate warming,Qinghai toad-headed lizards(Phrynocephalus vlangalii)were subjected to semi-natural enclosure experiments with simulated warming at high(2,600 m)and superhigh(3,600 m)elevations of the Dangjin Mountain,China.Our results revealed that the thermoregulatory effectiveness and warming tolerance(WT)of the toad-headed lizards were significantly affected by climate warming at both elevations,but their thermal sensitivity remained unchanged.After warming,the thermoregulatory effectiveness of lizards at superhigh elevations decreased because of the improved environmental thermal quality,whereas that of lizards at high-elevation conditions increased.Although the body temperature selected by high-elevation lizards was also significantly increased,the proportion of their active body temperature falling within the set-point temperature range decreased.This indicates that it is difficult for high-elevation lizards to adjust their body temperatures within a comfortable range under climate warming.Variations in the WT and thermal safety margin(TSM)under climate warming revealed that lizards at the superhigh elevation benefited from improved environmental thermal quality,whereas those at the high elevation originally on the edge of the TSM faced more severe threats and became more vulnerable.Our study highlights the importance of thermal biological traits in evaluating the vulnerability of ectotherms in temperate plateau regions.
基金supported by grants from the National Natural Science Foundation of China (30770274)the "One Hundred Talents Program" of the Chinese Academy of Sciences for W. G. DU
文摘Studies of the seasonal acclimatisation of behavioural and physiological processes usually focus on aquatic or semi-aquatic ectotherms and focus less effort on terrestrial ectotherms that experience more thermally heterogeneous environments. We conducted comparative studies and thermal acclimation experiments on the locomotion of the Chinese skink （Plestiodon chinensis） to test whether seasonal acclimatisation in locomotion exists in these terrestrial ectothermic vertebrates, and whether seasonal acclimatisation is predominantly induced by thermal environments. In natural populations, skinks ran faster during the summer season than during the spring season at high-test temperatures ranging from 27℃ to 36℃ but not at low-test temperatures ranging from 18℃ to 24℃. In contrast, the thermal acclimation experiments showed that the cold-acclimated skinks ran faster than the warm-acclimated skinks at the low- test temperatures but not at high-test temperatures. Therefore, the seasonal acclimatisation occurs to P chinensis, and may be induced by temperature as well as other factors like food availability, as indicated by the seasonal variation in the thermal dependence of locomotion, and the discrepancy between seasonal acclimatisation and thermal acclimation on locomotion.
基金supported by National Natural Science Foundation of China(No.31471994)
文摘For species that have a broad geographic distribution, adaptive variation may be attributable to gene expression plasticity. Nanorana parkeri is an anuran endemic to the southern Tibetan Plateau where it has an extensive altitudinal range（2850 to 5100 m asl）. Low oxygen concentration is one of the main environmental characteristics of the Tibetan Plateau. Hypoxia-inducible factor α subunits（HIF-1α and HIF-2α, encoded by Endothelial PAS domain protein 1（EPAS1）） and associated genes（e.g., vascular endothelial growth factor（VEGF） and Erythropoietin（EPO）） play crucial roles in maintaining oxygen homeostasis. In this study, we compared the expression of HIF-1A, VEGF, EPAS1 and EPO mRNA between two populations of N. parkeri： one population inhabiting the native high altitudes, and the second living in, and being acclimated to, the lower plains（70 m asl）. The expression of HIF-1A, VEGF and EPAS1 mRNA in the high altitude population were significantly higher than in the acclimated population, whereas there was no significant difference for EPO between two groups. Our results indicated that gene expression plasticity may make significant contributions to local adaptation of species that have broad altitudinal distributions. In addition, we deepen our understanding of the adaptive potential of this species by evaluating the experiments in the scope of its evolutionary history.
基金supported by the National Key Research and Development Program of China(2018YFD0900601)National Natural Science Foundation of China(32130109)。
文摘Temperature tolerance restricts the distribution of a species. However, the molecular and cellular mechanisms that set the thermal tolerance limits of an organism are poorly understood. Here, we report on the function of dual-specificity phosphatase 1(DUSP1) in thermal tolerance regulation. Notably, we found that dusp1-/- zebrafish grew normally but survived within a narrowed temperature range. The higher susceptibility of these mutant fish to both cold and heat challenges was attributed to accelerated cell death caused by aggravated mitochondrial dysfunction and over-production of reactive oxygen species in the gills. The DUSP1-MAPK-DRP1 axis was identified as a key pathway regulating these processes in both fish and human cells. These observations suggest that DUSP1 may play a role in maintaining mitochondrial integrity and redox homeostasis. We therefore propose that maintenance of cellular redox homeostasis may be a key mechanism for coping with cellular thermal stress and that the interplay between signaling pathways regulating redox homeostasis in the most thermosensitive tissue(i.e., gills) may play an important role in setting the thermal tolerance limit of zebrafish.
基金supported by National Natural Science Foundation of China(No.31471994)
文摘Hypoxia-inducible factor 1 alpha（HIF-1α） and its target genes vascular endothelial growth factor（VEGF） and transferrins（TF） play an important role in native endothermic animals＇ adaptation to the high altitude environments. For ectothermic animals – especially frogs – it remains undetermined whether HIF-1α and its target genes（VEGF and TF） play an important role in high altitude adaptation, too. In this study, we compared the gene sequences and expression of HIF-1α and its target genes（VEGF and TF） between three Nanorana parkeri populations from different altitudes（3008 m a.s.l., 3440 m a.s.l. and 4312 m a.s.l.）. We observed that the c DNA sequences of HIF-1A exhibited high sequence similarity（99.38%） among the three altitudinally separated populations; but with increasing altitude, the expression of HIF-1A and its target genes（VEGF and TF） increased significantly. These results indicate that HIF-1α plays an important role in N. parkeri adaptation to the high altitude, similar to its role in endothermic animals.
基金This study adhered to the legal requirements for animal research in Australia(JCU animal ethics permits:A1976 and A1726,collection permits:WISP10659412,WISP14625914,WITK15224114 and WITK10659112)Funding was provided by the Australian Research Council(DP1094646,1301003181,FL110100104 and FT160100198 to BLP and CM)the Tropical Landscapes Joint Venture between James Cook University and CSIRO(to JL and SLM).
文摘The impact of climate change may be felt most keenly by tropical ectotherms.In these taxa,it is argued,thermal specialization means a given shift in temperature will have a larger effect on fitness.For species with limited dispersal ability,the impact of climate change depends on the capacity for their climate-relevant traits to shift.Such shifts can occur through genetic adaptation,various forms of plasticity,or a combination of these processes.Here we assess the extent and causes of shifts in 7 physiological traits in a tropical lizard,the rainforest sunskink(Lampropholis coggeri).Two populations were sampled that differ from each other in both climate and physiological traits.We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions.We also compared trait values between populations in:(i)recently field-collected animals;(ii)the same animals following laboratory acclimation;and(iii)the laboratory-reared offspring of these animals.Our results reveal high trait lability,driven primarily by acclimation and local adaptation.By contrast,developmental plasticity,resulting from incubation temperature,had little to no effect on most traits.These results suggest that,while specialized,tropical ectotherms may be capable of rapid shifts in climate-relevant traits.
