In this study, we intended to construct an ethogram of the toad-headed lizard Phrynocephalus vlangalii by classifying and describing its behaviors using the Posture-act-environment （PAE） method. Through direct field...In this study, we intended to construct an ethogram of the toad-headed lizard Phrynocephalus vlangalii by classifying and describing its behaviors using the Posture-act-environment （PAE） method. Through direct field observation and video recording, we obtained eight postures, sixty-two acts and ten environments, and thus we formed an ethogram consisting of eighty-three behaviors encoded with PAE. A complete ethogram for a species could provide systematic behavioral information which helps to understand the connections among related behaviors and provides background information for specific behavioral study, hence the present ethogram will be greatly useful for future behavioral studies on P. vlangalii as well as other Phrynocephalus species.展开更多
Flexible-shelled eggs of the lizards Phrynocephalus przewalskii and P. versicolor were incubated under different thermal and hydric conditions to elicit the effects of incubation environment on hatching success, embry...Flexible-shelled eggs of the lizards Phrynocephalus przewalskii and P. versicolor were incubated under different thermal and hydric conditions to elicit the effects of incubation environment on hatching success, embryonic development and duration as well as hatchling phenotypes. Embryogenesis of the two species was not sensitive to changes in the hydric environment except P. przewalskii incubated in 30°C group. Temperature significantly altered the duration of embryogenesis, with cooler temperatures leading to a longer incubation period. Hatching success was greater at 26 and 30°C than at 34°C. The hatchlings incubated at 26 and 30°C had longer snout-vent length, larger body mass, and better locomotor performance than those incubated at 34°C. Compared to P. przewalskii, P. versicolor had a shorter incubation period and yielded smaller hatchlings, which then had a higher survival rate in cooler and drier habitats. We conclude that an incubation temperature of 30°C would produce the best balance among developmental rate, hatching success, and post-hatching performance. We speculate that the upper temperature limit for incubation of P. versicolor eggs may be slightly higher than 34°C.展开更多
We acclimated adults of two viviparous （Phrynocephalus guinanens＆ and P. vlangalii） and one oviparous （P. versicolor） species of toad-headed lizards （Agamidae） to 28 ℃, 33 ℃ and 38 ℃ to examine whether therm...We acclimated adults of two viviparous （Phrynocephalus guinanens＆ and P. vlangalii） and one oviparous （P. versicolor） species of toad-headed lizards （Agamidae） to 28 ℃, 33 ℃ and 38 ℃ to examine whether thermal preference （preferred body temperature, Tp） and thermal tolerance （critical thermal minimum, CTMin; critical thermal maximum, CTMax） were affected by acclimation temperature, and correlate with body size and habitat use. Both Tp and CTMax were highest in P. versicolor and lowest in P. vlangalii, with P. guinanensis in between. The two viviparous species did not differ in CTMin and thermal tolerance range, and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species. Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species. Tp was higher in the lizards acclimated to 33 ℃ than in those to 28 ℃ or 38 ℃. The range of thermal tolerance was wider in the lizards acclimated to 28 ℃ than in those to 33 ℃ or 38 ℃. The data showed that： 1） thermal preference and tolerance were affected by acclimation temperature, and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses; 2） both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment, and CTMin was higher in the species using warmer habitats during the active season; and 3） thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.展开更多
We incubated eggs of five Phrynocephalus species （P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii） at three constant temperatures （24℃, 28℃ and 32℃） to examine differences i...We incubated eggs of five Phrynocephalus species （P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii） at three constant temperatures （24℃, 28℃ and 32℃） to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size （snout-vent length and body mass） and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.展开更多
Global climate change is a threat to animals in nearly all biomes and ecosystems, especially for ectotherm whose life activities highly depend on environmental thermal regime. Population genetic diversity which is ess...Global climate change is a threat to animals in nearly all biomes and ecosystems, especially for ectotherm whose life activities highly depend on environmental thermal regime. Population genetic diversity which is essential for adaptation to environmental change is a useful index for long-term species survival. In this paper, genetic diversity of eight Phrynocephalus forsythii population which distributed in Tarim Basin, China, were evaluated based on three mtDNA gene and its correlation with environment factors were investigated using RDA. Our result revealed that, the level of genetic diversity of P. forsythii populations was related to its location but there was no significant correlation between genetic distances and geographic distances in P. forsythii. However, we find that mtDNA of P. forsythii was subjected to selection pressure during evolution and population genetic diversity was significantly positively related to variation coefficient of rainfall(VCR) and altitude(AL), while significantly negatively related to longitude(N) and annual average temperature(AAT). Our result supported the previous prediction that excessive ambient heat is a threat to P. forsythii.展开更多
The timing of reproduction can significantly affect an offspring＇s fitness, thereby also influencing the fitness of the parents, especially in species inhabiting extreme environments, such as deserts. Female reproduc...The timing of reproduction can significantly affect an offspring＇s fitness, thereby also influencing the fitness of the parents, especially in species inhabiting extreme environments, such as deserts. Female reproductive cycles in Phrynocephalus przewalskii were studied from April to September 2008. Significant cycles of gonadal volume were found in all studied populations and the cycles were similar among the various populations. Females began vitellogenesis in April and contained oviductal eggs form May to June. Gonad volume decreased significantly in July and reached minimum volume from August to September. The follicular growth was negatively correlated with increasing precipitation and temperature in all populations. Hatching occurs during summer and early fall, when most of the annual rainfall occurs. Mean clutch size based on all populations was 2.7 ± 0.9 SE （n = 71）.展开更多
Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competit...Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be- tween the two sexes （niche divergence hypothesis）, gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identified. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high （O = 0.989）. In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution ofP. przewalskii.展开更多
In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters o...In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters of Phrynocephalus przewalskii （Agamidae） in different populations within the same phylogenetic clade were compared in this study. Female SVL, clutch size, egg volume and clutch volume varied significantly among populations. With increase in latitude, clutch size increased, while egg size decreased. Relatively fewer but larger eggs were produced with increasing of population density. Food availability had positive effects on clutch size, but no effect on egg size. Our result indicated that latitude, food availability and population density may be the proximate factors affecting the reproductive parameters ofP. przewalskii.展开更多
Poikilothermic animals living in high-altitude environments can be greatly affected by the anaerobic metabolism and lactate recycling, which are catalyzed by an enzyme called lactate dehydrogenase(LDH). However, the f...Poikilothermic animals living in high-altitude environments can be greatly affected by the anaerobic metabolism and lactate recycling, which are catalyzed by an enzyme called lactate dehydrogenase(LDH). However, the function and possible regulatory mechanisms of their anaerobic glycolysis remained elusive. We compared the difference in LDH between a native high-altitude(4 353 m) lizard, Phrynocephalus erythrurus, and a closely related species, Phrynocephalus przewalskii that lives in intermediate altitude environment(1 400 m). The activity of LDH, the concentration of lactate, the distribution of isoenzyme, and the mRNA amounts of Ldh-A and Ldh-B were determined. In cardiac muscle, the lactate-forming activity of P. erythrurus in LDH was higher than of P. przewalskii LDH at all three temperatures tested(10 °C, 25 °C and 35 °C), while lactate-oxidation activity of LDH was significantly different between the two species only at 25 °C and 35 °C. In skeletal muscle, both lactate-forming and lactate-oxidation rates of P. erythrurus were lower than that of P. przewalskii. There was a higher proportion of H subunit and a significantly higher expression of Ldh-B, with a concomitant decrease of lactate concentration in P. erythrurus. These results indicate that P. erythrurus may have a strong potential for anaerobic metabolism, which is likely adapted to the hypoxic environment at high altitudes. Furthermore, P. erythrurus is capable of oxidizing more lactate than P. przewalskii. The Ldh-A cDNA of the two species consists of a 999 bp open reading frame(ORF), which encodes 332 amino acids, while Ldh-B cDNA consists of a 1 002 bp ORF encoding 333 amino acids. LDHA has the same amino acid sequence between the two species, but three amino acid substitutions(V12 I, N21S and N318K) were observed in LDHB. Structure analysis of LDH indicated that the substitutions of residues Val12 and Asp21 in P. erythrurus could be responsible for the highaltitude adaptation. The LDH characteristics of LDH in P. erythrurus suggest unique a展开更多
The plateau environments are typically arid,cool,and high altitude,posing formidable challenges to wildlife survival due to resource scarcity and harsh conditions.Unraveling ecological adaptability in severe condition...The plateau environments are typically arid,cool,and high altitude,posing formidable challenges to wildlife survival due to resource scarcity and harsh conditions.Unraveling ecological adaptability in severe conditions requires a deeper understanding of the niche characteristics of plateau species.Trophic niche,which is a comprehensive indicator describing the energy acquisition strategy of animals,remains relatively understudied in plateau species.Here,by combining stable isotopes and morphological data,we quantified the trophic niches of two allopatric lizard species(Phrynocephalus vlangalii and P.erythrurus)that live in the hinterland of the Qinghai–Tibetan Plateau,and explored how their trophic niches correlate with morphological and environmental factors.While both trophic niche and morphological traits were similar between species,noteworthy distinctions were observed between male and female Phrynocephalus lizards.The morphological traits associated with predation(i.e.limb length and head size)and reproduction(i.e.abdomen length),annual mean temperature,and sex played influential roles in shifting trophic niches.These results imply that sexual dimorphism may facilitate inter-sex divergence in resource utilization,leading to trophic niche variations in the highland lizards.Furthermore,extreme environmental stress can constrain interspecific divergence in morphological and trophic traits.Our findings illustrate the dynamic variations of trophic niches in highland lizards,contributing to a more comprehensive understanding of the adaptation strategies employed by lizard species in plateau environments.展开更多
Spatial distribution patterns are associated with life history and behavioral adaptations of animals. For studying the spatial distribution pattern of the steppe toad-headed lizard(Phrynocephalus frontalis) and its in...Spatial distribution patterns are associated with life history and behavioral adaptations of animals. For studying the spatial distribution pattern of the steppe toad-headed lizard(Phrynocephalus frontalis) and its influencing factors,we conducted experiments in Hunshandake Sandy Land in Inner Mongolia,China in July 2009. By calculating the clustered indices,we found that the lizard was aggregately distributed when the sampling quadrat was smaller than 10 m × 10 m,and uniformly distributed when it was greater than 10 m × 10 m. The Nearest Neighbor Rule showed a clustering distribution pattern for P. frontalis and the distribution pattern was quadrat-sampling dependent. Furthermore,the cluster was determined by environmental factors when the sampling quadrat was smaller than 20 m × 20 m,but it was determined by both environmental factors and characteristics of the lizard when it was larger than 20 m × 20 m. Our results suggested that the steppe toad-headed lizards tended to aggregate into suitable habitat patches in desert areas. Additionally,we discussed that the lizard aggregation could be potentially used as an indictor of movement of sand dunes.展开更多
Using data from nine microsatellite DNA loci and a population genetic approach,we evaluate the barrier effect of the Qinghai-Tibet Railway on toad-headed lizard,Phrynocephalus vlangalii. The study area is along a 20 k...Using data from nine microsatellite DNA loci and a population genetic approach,we evaluate the barrier effect of the Qinghai-Tibet Railway on toad-headed lizard,Phrynocephalus vlangalii. The study area is along a 20 km stretch of the railway on northern Qinghai-Tibet Plateau,and this section of the railway was constructed between 1958–1979. Both assignment tests and analysis of molecular variance(AMOVA) were used for data analysis. We found significant genetic differentiation between the populations from the study area and those from a further southeastern area,which are separated by a 20 km gap. This suggests the existence of population substructure at a fine-scale. However,we did not detect any difference between samples from the western and eastern sides of the railway within the study area,and concluded that the railway may not impose a significant barrier effect on these lizard populations at the present time. Available suitable habitat alongside the railway and bridge underpasses may have facilitated the gene exchange between the sides. The relatively short time since the completion of the railway may not allow the differentiation to accumulate to a detectable level. Since the Qinghai-Tibet Plateau maintains a unique and fragile ecosystem,long-term monitoring of such man-made landscape features is imperative for protecting this ecosystem.展开更多
Sympatric reptiles are the ideal system for investigating temperature-driven coexistence. Understanding thermally physiological responses of sympatric lizards is necessary to reveal the physiological mechanisms that u...Sympatric reptiles are the ideal system for investigating temperature-driven coexistence. Understanding thermally physiological responses of sympatric lizards is necessary to reveal the physiological mechanisms that underpin the sympatric occurrence of reptiles. In this study, we used three lizard species, Eremias argus, E. multiocellata, and Phrynocephalus przewalskii, which are sympatric in the Inner Mongolia desert steppe, as a study system. By comparing their resting metabolic rates(RMR) and locomotion at different body temperatures, we aimed to better understand their physiological responses to thermal environments, which may explain the sympatric occurrence of these lizards. Our results showed that E. argus had significantly higher RMR and sprint speed than E. multiocellata, and higher RMR than P. przewalskii. In addition, the optimal temperature that maximized metabolic rates and locomotion for E. argus and E. multiocellata was 36°C, whereas for P. przewalskii it was 39°C. Our study revealed the physiological responses to temperatures that justify the sympatric occurrence of these lizards with different thermal and microhabitat preferences and active body temperatures. Eremias argus and E. multiocellata, which have lower body temperatures than P. przewalskii, depend on higher RMR and locomotion to compensate for their lower body temperatures in field conditions. Our study also highlights the importance of using an integrative approach, combining behavior and physiology, to explore the basis of sympatric occurrence in ectothermic species.展开更多
基金supported by agrant of the National Natural Science Foundation of China to Yuezhao WANG(No.31071892)
文摘In this study, we intended to construct an ethogram of the toad-headed lizard Phrynocephalus vlangalii by classifying and describing its behaviors using the Posture-act-environment （PAE） method. Through direct field observation and video recording, we obtained eight postures, sixty-two acts and ten environments, and thus we formed an ethogram consisting of eighty-three behaviors encoded with PAE. A complete ethogram for a species could provide systematic behavioral information which helps to understand the connections among related behaviors and provides background information for specific behavioral study, hence the present ethogram will be greatly useful for future behavioral studies on P. vlangalii as well as other Phrynocephalus species.
基金funded by the National Natural Science Foundation of China(NSFC 31071918)
文摘Flexible-shelled eggs of the lizards Phrynocephalus przewalskii and P. versicolor were incubated under different thermal and hydric conditions to elicit the effects of incubation environment on hatching success, embryonic development and duration as well as hatchling phenotypes. Embryogenesis of the two species was not sensitive to changes in the hydric environment except P. przewalskii incubated in 30°C group. Temperature significantly altered the duration of embryogenesis, with cooler temperatures leading to a longer incubation period. Hatching success was greater at 26 and 30°C than at 34°C. The hatchlings incubated at 26 and 30°C had longer snout-vent length, larger body mass, and better locomotor performance than those incubated at 34°C. Compared to P. przewalskii, P. versicolor had a shorter incubation period and yielded smaller hatchlings, which then had a higher survival rate in cooler and drier habitats. We conclude that an incubation temperature of 30°C would produce the best balance among developmental rate, hatching success, and post-hatching performance. We speculate that the upper temperature limit for incubation of P. versicolor eggs may be slightly higher than 34°C.
基金supported by the grants from the National Natural Science Foundation of China(31071910 and 31200282)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We acclimated adults of two viviparous （Phrynocephalus guinanens＆ and P. vlangalii） and one oviparous （P. versicolor） species of toad-headed lizards （Agamidae） to 28 ℃, 33 ℃ and 38 ℃ to examine whether thermal preference （preferred body temperature, Tp） and thermal tolerance （critical thermal minimum, CTMin; critical thermal maximum, CTMax） were affected by acclimation temperature, and correlate with body size and habitat use. Both Tp and CTMax were highest in P. versicolor and lowest in P. vlangalii, with P. guinanensis in between. The two viviparous species did not differ in CTMin and thermal tolerance range, and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species. Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species. Tp was higher in the lizards acclimated to 33 ℃ than in those to 28 ℃ or 38 ℃. The range of thermal tolerance was wider in the lizards acclimated to 28 ℃ than in those to 33 ℃ or 38 ℃. The data showed that： 1） thermal preference and tolerance were affected by acclimation temperature, and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses; 2） both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment, and CTMin was higher in the species using warmer habitats during the active season; and 3） thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.
基金supported by grants from the National Natural Science Foundation of China (31071910 and 31200282)Priority Academic Program Development of Jiangsu Higher Education Institutions and High Academic Talent Foundation of Nanjing Forestry University (GXL201306)
文摘We incubated eggs of five Phrynocephalus species （P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii） at three constant temperatures （24℃, 28℃ and 32℃） to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size （snout-vent length and body mass） and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.
基金supported by the National Natural Science Foundation of China (No. 31471988 and 31200287)
文摘Global climate change is a threat to animals in nearly all biomes and ecosystems, especially for ectotherm whose life activities highly depend on environmental thermal regime. Population genetic diversity which is essential for adaptation to environmental change is a useful index for long-term species survival. In this paper, genetic diversity of eight Phrynocephalus forsythii population which distributed in Tarim Basin, China, were evaluated based on three mtDNA gene and its correlation with environment factors were investigated using RDA. Our result revealed that, the level of genetic diversity of P. forsythii populations was related to its location but there was no significant correlation between genetic distances and geographic distances in P. forsythii. However, we find that mtDNA of P. forsythii was subjected to selection pressure during evolution and population genetic diversity was significantly positively related to variation coefficient of rainfall(VCR) and altitude(AL), while significantly negatively related to longitude(N) and annual average temperature(AAT). Our result supported the previous prediction that excessive ambient heat is a threat to P. forsythii.
文摘The timing of reproduction can significantly affect an offspring＇s fitness, thereby also influencing the fitness of the parents, especially in species inhabiting extreme environments, such as deserts. Female reproductive cycles in Phrynocephalus przewalskii were studied from April to September 2008. Significant cycles of gonadal volume were found in all studied populations and the cycles were similar among the various populations. Females began vitellogenesis in April and contained oviductal eggs form May to June. Gonad volume decreased significantly in July and reached minimum volume from August to September. The follicular growth was negatively correlated with increasing precipitation and temperature in all populations. Hatching occurs during summer and early fall, when most of the annual rainfall occurs. Mean clutch size based on all populations was 2.7 ± 0.9 SE （n = 71）.
基金founded by the National Natural Science Foundation of China (31200287)the Fundamental Research Funds for the Central Universities (lzujbky-2012-114)
文摘Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be- tween the two sexes （niche divergence hypothesis）, gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identified. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high （O = 0.989）. In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution ofP. przewalskii.
文摘In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters of Phrynocephalus przewalskii （Agamidae） in different populations within the same phylogenetic clade were compared in this study. Female SVL, clutch size, egg volume and clutch volume varied significantly among populations. With increase in latitude, clutch size increased, while egg size decreased. Relatively fewer but larger eggs were produced with increasing of population density. Food availability had positive effects on clutch size, but no effect on egg size. Our result indicated that latitude, food availability and population density may be the proximate factors affecting the reproductive parameters ofP. przewalskii.
基金supported by the National Natural Science Foundation of China (No. 31501860 to Xiaolong TANG, No. 31272313 and No. 31472005 to Qiang CHEN) Fundamental Research Funds for the Central Universities (lzujbky-2017-150 to Xiaolong TANG)Natural Science Foundation of Gansu Province: 1506RJYA243
文摘Poikilothermic animals living in high-altitude environments can be greatly affected by the anaerobic metabolism and lactate recycling, which are catalyzed by an enzyme called lactate dehydrogenase(LDH). However, the function and possible regulatory mechanisms of their anaerobic glycolysis remained elusive. We compared the difference in LDH between a native high-altitude(4 353 m) lizard, Phrynocephalus erythrurus, and a closely related species, Phrynocephalus przewalskii that lives in intermediate altitude environment(1 400 m). The activity of LDH, the concentration of lactate, the distribution of isoenzyme, and the mRNA amounts of Ldh-A and Ldh-B were determined. In cardiac muscle, the lactate-forming activity of P. erythrurus in LDH was higher than of P. przewalskii LDH at all three temperatures tested(10 °C, 25 °C and 35 °C), while lactate-oxidation activity of LDH was significantly different between the two species only at 25 °C and 35 °C. In skeletal muscle, both lactate-forming and lactate-oxidation rates of P. erythrurus were lower than that of P. przewalskii. There was a higher proportion of H subunit and a significantly higher expression of Ldh-B, with a concomitant decrease of lactate concentration in P. erythrurus. These results indicate that P. erythrurus may have a strong potential for anaerobic metabolism, which is likely adapted to the hypoxic environment at high altitudes. Furthermore, P. erythrurus is capable of oxidizing more lactate than P. przewalskii. The Ldh-A cDNA of the two species consists of a 999 bp open reading frame(ORF), which encodes 332 amino acids, while Ldh-B cDNA consists of a 1 002 bp ORF encoding 333 amino acids. LDHA has the same amino acid sequence between the two species, but three amino acid substitutions(V12 I, N21S and N318K) were observed in LDHB. Structure analysis of LDH indicated that the substitutions of residues Val12 and Asp21 in P. erythrurus could be responsible for the highaltitude adaptation. The LDH characteristics of LDH in P. erythrurus suggest unique a
基金supported by the Natural Science Foundation of Sichuan Province(2022NSFSC0125)the National Natural Science Foundation of China(32071544,31770568,and 32271737)+1 种基金the Qinghai Natural Science Fund Innovation Team Project(2021-ZJ-902)the Interdisciplinary Innovation Team of the Chinese Academy of Sciences(CAS)“Light ofWest China”Program(xbzgzdsys-202207).
文摘The plateau environments are typically arid,cool,and high altitude,posing formidable challenges to wildlife survival due to resource scarcity and harsh conditions.Unraveling ecological adaptability in severe conditions requires a deeper understanding of the niche characteristics of plateau species.Trophic niche,which is a comprehensive indicator describing the energy acquisition strategy of animals,remains relatively understudied in plateau species.Here,by combining stable isotopes and morphological data,we quantified the trophic niches of two allopatric lizard species(Phrynocephalus vlangalii and P.erythrurus)that live in the hinterland of the Qinghai–Tibetan Plateau,and explored how their trophic niches correlate with morphological and environmental factors.While both trophic niche and morphological traits were similar between species,noteworthy distinctions were observed between male and female Phrynocephalus lizards.The morphological traits associated with predation(i.e.limb length and head size)and reproduction(i.e.abdomen length),annual mean temperature,and sex played influential roles in shifting trophic niches.These results imply that sexual dimorphism may facilitate inter-sex divergence in resource utilization,leading to trophic niche variations in the highland lizards.Furthermore,extreme environmental stress can constrain interspecific divergence in morphological and trophic traits.Our findings illustrate the dynamic variations of trophic niches in highland lizards,contributing to a more comprehensive understanding of the adaptation strategies employed by lizard species in plateau environments.
基金financially supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KSCX2-EW-J-2,KSCX2-EW-Z-4)the State Key Basic Research and Development Program of China(2007CB106801)
文摘Spatial distribution patterns are associated with life history and behavioral adaptations of animals. For studying the spatial distribution pattern of the steppe toad-headed lizard(Phrynocephalus frontalis) and its influencing factors,we conducted experiments in Hunshandake Sandy Land in Inner Mongolia,China in July 2009. By calculating the clustered indices,we found that the lizard was aggregately distributed when the sampling quadrat was smaller than 10 m × 10 m,and uniformly distributed when it was greater than 10 m × 10 m. The Nearest Neighbor Rule showed a clustering distribution pattern for P. frontalis and the distribution pattern was quadrat-sampling dependent. Furthermore,the cluster was determined by environmental factors when the sampling quadrat was smaller than 20 m × 20 m,but it was determined by both environmental factors and characteristics of the lizard when it was larger than 20 m × 20 m. Our results suggested that the steppe toad-headed lizards tended to aggregate into suitable habitat patches in desert areas. Additionally,we discussed that the lizard aggregation could be potentially used as an indictor of movement of sand dunes.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Y1C2021203, Y0S3011)the Talent Reward Grant (Y1D3011) from Sichuan Provincial Government, China the NSERC (Canada) discovery grant to Jinzhong FU
文摘Using data from nine microsatellite DNA loci and a population genetic approach,we evaluate the barrier effect of the Qinghai-Tibet Railway on toad-headed lizard,Phrynocephalus vlangalii. The study area is along a 20 km stretch of the railway on northern Qinghai-Tibet Plateau,and this section of the railway was constructed between 1958–1979. Both assignment tests and analysis of molecular variance(AMOVA) were used for data analysis. We found significant genetic differentiation between the populations from the study area and those from a further southeastern area,which are separated by a 20 km gap. This suggests the existence of population substructure at a fine-scale. However,we did not detect any difference between samples from the western and eastern sides of the railway within the study area,and concluded that the railway may not impose a significant barrier effect on these lizard populations at the present time. Available suitable habitat alongside the railway and bridge underpasses may have facilitated the gene exchange between the sides. The relatively short time since the completion of the railway may not allow the differentiation to accumulate to a detectable level. Since the Qinghai-Tibet Plateau maintains a unique and fragile ecosystem,long-term monitoring of such man-made landscape features is imperative for protecting this ecosystem.
基金Animal Ethics Committees at the Institute of Zoology, Chinese Academy of Sciences approved the ethics and protocol (IOZ14001) for the collection, handling, and husbandry of the study animalsBI J. H. (No.31660615) and SUN B. J. (No. 31870391 and 31500324) are supported by grants from the National Natural Science Foundation of China
文摘Sympatric reptiles are the ideal system for investigating temperature-driven coexistence. Understanding thermally physiological responses of sympatric lizards is necessary to reveal the physiological mechanisms that underpin the sympatric occurrence of reptiles. In this study, we used three lizard species, Eremias argus, E. multiocellata, and Phrynocephalus przewalskii, which are sympatric in the Inner Mongolia desert steppe, as a study system. By comparing their resting metabolic rates(RMR) and locomotion at different body temperatures, we aimed to better understand their physiological responses to thermal environments, which may explain the sympatric occurrence of these lizards. Our results showed that E. argus had significantly higher RMR and sprint speed than E. multiocellata, and higher RMR than P. przewalskii. In addition, the optimal temperature that maximized metabolic rates and locomotion for E. argus and E. multiocellata was 36°C, whereas for P. przewalskii it was 39°C. Our study revealed the physiological responses to temperatures that justify the sympatric occurrence of these lizards with different thermal and microhabitat preferences and active body temperatures. Eremias argus and E. multiocellata, which have lower body temperatures than P. przewalskii, depend on higher RMR and locomotion to compensate for their lower body temperatures in field conditions. Our study also highlights the importance of using an integrative approach, combining behavior and physiology, to explore the basis of sympatric occurrence in ectothermic species.
