Light is an essential environmental cue influencing the endogenous circadian clocks that regulate behavioral and physiological processes in animals.Despite extensive research on the circadian rhythms of avian behavior...Light is an essential environmental cue influencing the endogenous circadian clocks that regulate behavioral and physiological processes in animals.Despite extensive research on the circadian rhythms of avian behavior and physiology,the mechanisms by which they adapt and adjust to abnormal photoperiod conditions,such as artificial light,have yet to be fully elucidated.Here,the circadian rhythms of the body mass,activity,and core and peripheral body temperatures of the Eurasian Tree Sparrow(Passer montanus,ETS)-a diurnal passerine-were examined under three different lighting conditions:constant light(LL),constant darkness(DD),and normal light-dark cycles(LD).Our results showed that the activity,body mass,core,tarsometatarsus,and eye temperatures of the ETSs varied significantly with treatment,time,and the interaction between treatment and time;however,there was no significant change in body mass in response to the interaction between time and treatment.Under LD conditions,the ETSs exhibited significant circadian rhythms in activity and core,tarsometatarsus,and eye temperatures.Under LL conditions,only the core temperature exhibited significant rhythmicity.Under DD conditions,there were no significant circadian rhythms in activity,body mass,and eye temperature;however,the core and tarsometatarsus temperatures remained rhythmic.Our results indicate that the core body temperature rhythm of ETS is endogenous and can be maintained under abnormal photoperiods.In contrast,the activity and body surface temperature,uncoupled from the core body temperature under abnormal photoperiod conditions,strongly depend on light.These results differ from those of other diurnal avian species,suggesting a unique coping mechanism of ETS in response to an abnormal photoperiod.展开更多
With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adap...With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adapt to these changes? To elucidate this question,we studied the effect of urbanization on the abundance and distribution of Tree Sparrows in Beijing.We found the abundance of the Tree Sparrow negatively correlated with an urbanization score.Sparrow abundance was very low in residential areas with high-rise buildings,commercial centers and main roads,while their numbers were significantly higher in parks,university campuses,low building residential and suburban areas.Environmental factors within the 50 m and 200 m scales were most suitable in predicting the distribution of Tree Sparrows during winter,while factors within 50 m and 400 m scales are suitable during the breeding season.During winter,the number of conifer trees and pedestrians were the major factors at the 50 m scale,while the area of high-rise buildings and vegetation become the predominant factors on a 200 m scale.Alternatively,during the breeding season the area of low buildings and the number of conifers and pedestrians were the main factors on the 50 m scale while the area of high-rise buildings and vegetation remained the most important factors on the 400 m scale.These results indicate that highly urbanized areas are not suitable habitats for the Tree Sparrow,although this species can adapt to human environments.Food and nest sites for urban birds should be considered in urban planning of big cities in developing countries.展开更多
BMR （basal metabolic rate）, body mass and organ masses of tree sparrows （Passer montanus） were measured to analyze the correlation between organ masses and BMR in tree sparrows, and to evaluate the underlying phys...BMR （basal metabolic rate）, body mass and organ masses of tree sparrows （Passer montanus） were measured to analyze the correlation between organ masses and BMR in tree sparrows, and to evaluate the underlying physiological causes of difference in BMR. Adult tree sparrows were live-trapped by mist net in Qiqihar City, Heilongjiang Province （47°29′N, 124°02′E）. The closed circuit respirometer was used to measure the metabolic rate （MR）, and controlled the ambient temperature by using a water bath （±0.5℃）. Body masses were measured to the nearest 0.01 g before and after BMR measurements with a Sartorius balance （model BT25S）. The mean value was recorded as body mass. Wet and dry masses of several organs were measured, too. BMR was （4.276± 0.385） mL O2/（g·h） and mean body mass was （18.522±0.110） g. Since not all the variables were normal distributed, a log10- transformation of those variables was employed to linearize them, prior to analyses. Simple regression analyses indicated that most organ masses showed a significant high correlation with body mass. Both the small intestine and rectum masses were notable exception to that trend. The body-mass-adjusted residual analysis showed that only the kidney wet mass, brain mass, stomach mass, small mass and rectum wet mass correlated with BMR. In addition, correlations between several organ masses and BMR were observed. Because of the inter-correlations of organ masses, a principal component analysis （PCA） was performed to redefine the morphological variability. The first four components whose eigenvalues were greater than 1 could explain 75.2% variance of BMR. The first component, whose proportion reached 30.19%, was affected mainly by stomach mass, small intestine mass and rectum mass. Therefore, the results supported the hypothesis that BMR was controlled by some ＂expensive metabolic＂ organs展开更多
Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate ...Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate utilization of highland animals varies with evolutionary history and phylogeny.The heart is a proxy for the cardiopulmonary system,and the metabolic substrate utilization in the myocardium is also under the strong selective pressure of chronically hypoxic and hypothermic environments.However,little information is available on the physiological adjustments in relation to metabolic substrate utilization in the myocardium for coping with high-altitude environments.Methods:We compared the metabolic enzyme activities,including hexokinase(HK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),carnitine palmitoyl transferase 1(CPT-1),lactic dehydrogenase(LDH),and creatine kinase(CK),and metabolic substrate contents including glucose(Glu),triglyceride(TG),and free fatty acid(FFA)in the myocardium of a typical human commensal species,Eurasian Tree Sparrows(Passer montanus)between the Qinghai-Tibet Plateau(the QTP,3230 m)and low altitude population(Shijiazhuang,80 m),and between sexes.Results:Among the seven metabolic enzymes and three substrates investigated,we identified no significant differences in PK,CPT-1,HK,CS,LDH,and CK activities and TG content of the myocardium between high and low altitude populations.However,the QTP sparrows had significantly lower Glu content and PFK activities but higher FFA content relative to their lowland counterparts.In addition,male sparrows had higher myocardial HK and CS activities relative to females,independent of altitude.Conclusions:Our results showed that the QTP sparrows elevated fatty acid utilization rather than glucose preference in the myocardium relative to lowland counterpart,which contributes to uncovering both the physiological adjustments for adapting to the extreme conditions of the QTP,intraspecifically.展开更多
Concentrations of copper （Cu）, zinc （Zn） and manganese （Mn） were measured in four tissues of Tree Sparrow （Passer montanus） from three sites in Heilongjiang province, China, during four seasons. Among the four...Concentrations of copper （Cu）, zinc （Zn） and manganese （Mn） were measured in four tissues of Tree Sparrow （Passer montanus） from three sites in Heilongjiang province, China, during four seasons. Among the four measured tissues （primary feathers, liver, heart, and pectoral muscle）, the highest concentrations were found in feathers （Zn） or liver （Cu and Mn）, and the lowest concentrations were in muscle, except Cu. For Mn, mean concentrations of the birds from the three study sites were, in decreasing order： Didao mining area （DMA） 〉 urban district of Jixi （UDJ） 〉 Phoenix Mountain national nature reserve （PMR, the reference site）, but not for Zn and Cu. There were significant differences between metal concentrations at the three sites, but differences were not significant for Mn （in muscle and feathers） and Cu （in feathers）. For most elements, the mean concentrations were greatest in summer.展开更多
Background:Small birds in temperate habitats must either migrate,or adjust aspects of their morphology,physiology and behavior to cope with seasonal change in temperature and photoperiod.It is,however,difficult to acc...Background:Small birds in temperate habitats must either migrate,or adjust aspects of their morphology,physiology and behavior to cope with seasonal change in temperature and photoperiod.It is,however,difficult to accurately measure how seasonal changes in temperature and photoperiod affect physiological processes such as basal metabolic rate(BMR)and metabolic activity.To address this problem,we collected data in each month of the year on body mass(Mb)and BMR,and conducted a series of experiments to determine the effect of temperature and photoperiod on Mb,BMR and physiological markers of metabolic activity,in the Eurasian Tree Sparrow(Passer montanus).Methods:In one experiment,we measured monthly change in Mb and BMR in a captive group of birds over a year.In another experiment,we examined the effects of acclimating birds to two different temperatures,10 and 30℃,and a long and a short photoperiod(16 h light:8 h dark and 8 h light:16 h dark,respectively)for 4 weeks.Results:We found that these treatments induced sparrows to adjust their Mb and metabolic rate processes.Acclimation to 30℃for 4 weeks significantly decreased sparrows’Mb,BMR,and energy intake,including both gross energy intake and digestible energy intake,compared to birds acclimated to 10℃.The dry mass of the liver,kidneys and digestive tract of birds acclimated to 30℃also significantly decreased,although their heart and skeletal muscle mass did not change significantly relative to those acclimated to 10℃.Birds acclimated to 30℃also had lower mitochondrial state-4 respiration(S4R)and cytochrome c oxidase(COX)activity in their liver and skeletal muscle,compared to those acclimated to 10℃.Birds acclimated to the long photoperiod also had lower mitochondrial S4R and COX activity in their liver,compared to those acclimated to the short photoperiod.Conclusions:These results illustrate the changes in morphology,physiology,and enzyme activity induced by seasonal change in temperature and photoperiod in a small temperate passerine.Both temperature and photoperiod probably have a strong effect on seasonal variation in metabolic heat production in small birds in temperate regions.The effect of temperature is,however,stronger than that of photoperiod.展开更多
The hypothalamic-pituitary-gonadal(HPG)axis ubiquitously regulates seasonal reproduction,following the rhythmicity of a suite of environmental cues.Birds display prominent seasonal variations in gonad size regulated b...The hypothalamic-pituitary-gonadal(HPG)axis ubiquitously regulates seasonal reproduction,following the rhythmicity of a suite of environmental cues.Birds display prominent seasonal variations in gonad size regulated by two hypothalamic peptides,gonadotropin-releasing hormone-1(GnRH-I)and gonadotropin-inhibiting hormone(GnIH).How multi-brooded avian species adjust GnRH-I and GnIH to regulate gonadal morphology seasonally remains largely unknown.Here,we studied the variations in the hypothalamic immunoreactivity(ir)of GnRH-I and GnIH,gonadal proliferation,and apoptosis in a typical multi-brooded species,the Eurasian Tree Sparrow(Passer montanus),across the pre-breeding(PB),first breeding(FB),second breeding(SB),pre-basic molt(PM),and wintering stages(WS).Our results showed that both sexes had higher preoptic area(POA)-GnRH-I-ir but lower paraventricular nucleus(PVN)-GnIH-ir neurons during the breeding stages(FB and SB)relative to other life-history stages,with no significant differences between two broods.The testes and ovaries were significantly larger during the breeding stages.Testicular volume increased during the two broods due to anincreased diameter of seminiferous tubules.Furthermore,there were more testicular apoptotic cells in PB and WS stages than in breeding stages,and in PB stage than in PM stage.Males had higher POA-GnRH-I expression than females during the breeding stages,but both sexes had comparable PVN-GnIH expression throughout the annual cycle.Both sexes of the sparrows may undergo a similar pattern of life-history stage-dependent variation in the hypothalamic GnRH-I,GnIH,and gonadal morphology,except that during breeding stages,males may display higher expression of POA-GnRH-I relative to females.The higher expression of POA-GnRH-I-ir in breeding male sparrows may be critical for male-dependent parental care.展开更多
Global surface air temperatures increased during the past 100 years. Many long-term studies of birds have reported a climatic influence on breeding performance. We analysed long-term changes in first laying date and c...Global surface air temperatures increased during the past 100 years. Many long-term studies of birds have reported a climatic influence on breeding performance. We analysed long-term changes in first laying date and clutch size for first clutches of sedentary, hole-nesting and socially monogamous tree sparrows Passer montanus during 1980-2009 in northwestern Croatia. Laying date advanced and spring temperature increased significantly during the study. Date of laying was significantly correlated with mean air spring temperature and advanced by 8.6 days during the 30 years period. Laying date was delayed in extremely cold, but not in extremely warm springs compared to years with normal temperatures. These results suggest that current climate change including extreme change does not have negative effects on timing of laying or clutch size. In contrast to laying date, clutch size did not vary systematically during the study period or with mean spring air temperature changes [Current Zoology 57 （3）： 414-418, 2011].展开更多
Habitat suitability models have been used to predict the present and future potential distribution of a variety of spe- cies. Eurasian tree sparrows Passer montanus, native to Eurasia, have established populations in ...Habitat suitability models have been used to predict the present and future potential distribution of a variety of spe- cies. Eurasian tree sparrows Passer montanus, native to Eurasia, have established populations in other parts of the world. In North America, their current distribution is limited to a relatively small region around its original introduction to St. Louis, Missouri. We combined data from the Global Biodiversity Information Facility with current and future climate data to create habitat suitability models using Maxent for this species. Under projected climate change scenarios, our models show that the distribution and range of the Eurasian tree sparrow could increase as far as the Pacific Northwest and Newfoundland. This is potentially important in-formation for prioritizing the management and control of this non-native species [Current Zoology 57 （5）： 648--654, 2011].展开更多
The Tree Sparrow(Passer montanus)is a dom-inant species in urban bird communities.With the devel-opment of urbanization,the habitats and sources of food for Tree Sparrows are decreasing.Can the urban Tree Sparrow adap...The Tree Sparrow(Passer montanus)is a dom-inant species in urban bird communities.With the devel-opment of urbanization,the habitats and sources of food for Tree Sparrows are decreasing.Can the urban Tree Sparrow adapt to changes in the urban environment?To answer this question,we studied the habitat use of Tree Sparrows in eight types of urban areas in Beijing.The results show that the number of both breeding and winter-ing Tree Sparrows decreased with increasing urbanization.The habitat use of Tree Sparrows,analyzed using stepwise discriminant analysis,was positively correlated with the number of brick bungalows,coniferous and broad-leaved trees and air conditioners.It was negatively correlated with the area of high buildings and hardened roads,pedestrian and automobile flux.This indicates that the Tree Sparrow had not adapted to rapid urbanization even though it is a generally adaptable species.Urban planning should take birds such as the Tree Sparrow into consideration.展开更多
基金the National Natural Science Foundation of China(NSFC,31971413)the Natural Science Foundation of Hebei Province(C2020205038)to Dongming Li.
文摘Light is an essential environmental cue influencing the endogenous circadian clocks that regulate behavioral and physiological processes in animals.Despite extensive research on the circadian rhythms of avian behavior and physiology,the mechanisms by which they adapt and adjust to abnormal photoperiod conditions,such as artificial light,have yet to be fully elucidated.Here,the circadian rhythms of the body mass,activity,and core and peripheral body temperatures of the Eurasian Tree Sparrow(Passer montanus,ETS)-a diurnal passerine-were examined under three different lighting conditions:constant light(LL),constant darkness(DD),and normal light-dark cycles(LD).Our results showed that the activity,body mass,core,tarsometatarsus,and eye temperatures of the ETSs varied significantly with treatment,time,and the interaction between treatment and time;however,there was no significant change in body mass in response to the interaction between time and treatment.Under LD conditions,the ETSs exhibited significant circadian rhythms in activity and core,tarsometatarsus,and eye temperatures.Under LL conditions,only the core temperature exhibited significant rhythmicity.Under DD conditions,there were no significant circadian rhythms in activity,body mass,and eye temperature;however,the core and tarsometatarsus temperatures remained rhythmic.Our results indicate that the core body temperature rhythm of ETS is endogenous and can be maintained under abnormal photoperiods.In contrast,the activity and body surface temperature,uncoupled from the core body temperature under abnormal photoperiod conditions,strongly depend on light.These results differ from those of other diurnal avian species,suggesting a unique coping mechanism of ETS in response to an abnormal photoperiod.
基金supported by the National Natural Science Foundation of China (Grant No. 30900181)“111 Project” (2008-B08044)
文摘With rapid urbanization occurring throughout China,the existence of Tree Sparrows (Passer montanus) in big cities is likely to be affected by a decrease in habitat and food availability.Can the urban Tree Sparrow adapt to these changes? To elucidate this question,we studied the effect of urbanization on the abundance and distribution of Tree Sparrows in Beijing.We found the abundance of the Tree Sparrow negatively correlated with an urbanization score.Sparrow abundance was very low in residential areas with high-rise buildings,commercial centers and main roads,while their numbers were significantly higher in parks,university campuses,low building residential and suburban areas.Environmental factors within the 50 m and 200 m scales were most suitable in predicting the distribution of Tree Sparrows during winter,while factors within 50 m and 400 m scales are suitable during the breeding season.During winter,the number of conifer trees and pedestrians were the major factors at the 50 m scale,while the area of high-rise buildings and vegetation become the predominant factors on a 200 m scale.Alternatively,during the breeding season the area of low buildings and the number of conifers and pedestrians were the main factors on the 50 m scale while the area of high-rise buildings and vegetation remained the most important factors on the 400 m scale.These results indicate that highly urbanized areas are not suitable habitats for the Tree Sparrow,although this species can adapt to human environments.Food and nest sites for urban birds should be considered in urban planning of big cities in developing countries.
基金Supported by Natural Foundation for Youth of Daqing Normal College (YZQ004)
文摘BMR （basal metabolic rate）, body mass and organ masses of tree sparrows （Passer montanus） were measured to analyze the correlation between organ masses and BMR in tree sparrows, and to evaluate the underlying physiological causes of difference in BMR. Adult tree sparrows were live-trapped by mist net in Qiqihar City, Heilongjiang Province （47°29′N, 124°02′E）. The closed circuit respirometer was used to measure the metabolic rate （MR）, and controlled the ambient temperature by using a water bath （±0.5℃）. Body masses were measured to the nearest 0.01 g before and after BMR measurements with a Sartorius balance （model BT25S）. The mean value was recorded as body mass. Wet and dry masses of several organs were measured, too. BMR was （4.276± 0.385） mL O2/（g·h） and mean body mass was （18.522±0.110） g. Since not all the variables were normal distributed, a log10- transformation of those variables was employed to linearize them, prior to analyses. Simple regression analyses indicated that most organ masses showed a significant high correlation with body mass. Both the small intestine and rectum masses were notable exception to that trend. The body-mass-adjusted residual analysis showed that only the kidney wet mass, brain mass, stomach mass, small mass and rectum wet mass correlated with BMR. In addition, correlations between several organ masses and BMR were observed. Because of the inter-correlations of organ masses, a principal component analysis （PCA） was performed to redefine the morphological variability. The first four components whose eigenvalues were greater than 1 could explain 75.2% variance of BMR. The first component, whose proportion reached 30.19%, was affected mainly by stomach mass, small intestine mass and rectum mass. Therefore, the results supported the hypothesis that BMR was controlled by some ＂expensive metabolic＂ organs
基金supported by the National Natural Science Foundation of China(NSFC,No.31971413)to DL and NSFC(No.31770445)to YWthe Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501)+2 种基金the Natural Science Foundation of Hebei Province(NSFHB,C2020205038)to DLthe Foundation of Hebei Normal University(L2019B26)to CJthe Post-doctoral Research Programm to PD。
文摘Background:Efficient and selective utilization of metabolic substrates is one of the key strategies in high-altitude animals to cope with hypoxia and hypothermia.Previous findings have shown that the energy substrate utilization of highland animals varies with evolutionary history and phylogeny.The heart is a proxy for the cardiopulmonary system,and the metabolic substrate utilization in the myocardium is also under the strong selective pressure of chronically hypoxic and hypothermic environments.However,little information is available on the physiological adjustments in relation to metabolic substrate utilization in the myocardium for coping with high-altitude environments.Methods:We compared the metabolic enzyme activities,including hexokinase(HK),phosphofructokinase(PFK),pyruvate kinase(PK),citrate synthase(CS),carnitine palmitoyl transferase 1(CPT-1),lactic dehydrogenase(LDH),and creatine kinase(CK),and metabolic substrate contents including glucose(Glu),triglyceride(TG),and free fatty acid(FFA)in the myocardium of a typical human commensal species,Eurasian Tree Sparrows(Passer montanus)between the Qinghai-Tibet Plateau(the QTP,3230 m)and low altitude population(Shijiazhuang,80 m),and between sexes.Results:Among the seven metabolic enzymes and three substrates investigated,we identified no significant differences in PK,CPT-1,HK,CS,LDH,and CK activities and TG content of the myocardium between high and low altitude populations.However,the QTP sparrows had significantly lower Glu content and PFK activities but higher FFA content relative to their lowland counterparts.In addition,male sparrows had higher myocardial HK and CS activities relative to females,independent of altitude.Conclusions:Our results showed that the QTP sparrows elevated fatty acid utilization rather than glucose preference in the myocardium relative to lowland counterpart,which contributes to uncovering both the physiological adjustments for adapting to the extreme conditions of the QTP,intraspecifically.
基金financially supported by Outstanding Youth Science Foundation of Heilongjiang Province (JC200709)
文摘Concentrations of copper （Cu）, zinc （Zn） and manganese （Mn） were measured in four tissues of Tree Sparrow （Passer montanus） from three sites in Heilongjiang province, China, during four seasons. Among the four measured tissues （primary feathers, liver, heart, and pectoral muscle）, the highest concentrations were found in feathers （Zn） or liver （Cu and Mn）, and the lowest concentrations were in muscle, except Cu. For Mn, mean concentrations of the birds from the three study sites were, in decreasing order： Didao mining area （DMA） 〉 urban district of Jixi （UDJ） 〉 Phoenix Mountain national nature reserve （PMR, the reference site）, but not for Zn and Cu. There were significant differences between metal concentrations at the three sites, but differences were not significant for Mn （in muscle and feathers） and Cu （in feathers）. For most elements, the mean concentrations were greatest in summer.
基金This study was financially supported by grants from the National Natural Science Foundation of China(No.31470472 and 31971420).
文摘Background:Small birds in temperate habitats must either migrate,or adjust aspects of their morphology,physiology and behavior to cope with seasonal change in temperature and photoperiod.It is,however,difficult to accurately measure how seasonal changes in temperature and photoperiod affect physiological processes such as basal metabolic rate(BMR)and metabolic activity.To address this problem,we collected data in each month of the year on body mass(Mb)and BMR,and conducted a series of experiments to determine the effect of temperature and photoperiod on Mb,BMR and physiological markers of metabolic activity,in the Eurasian Tree Sparrow(Passer montanus).Methods:In one experiment,we measured monthly change in Mb and BMR in a captive group of birds over a year.In another experiment,we examined the effects of acclimating birds to two different temperatures,10 and 30℃,and a long and a short photoperiod(16 h light:8 h dark and 8 h light:16 h dark,respectively)for 4 weeks.Results:We found that these treatments induced sparrows to adjust their Mb and metabolic rate processes.Acclimation to 30℃for 4 weeks significantly decreased sparrows’Mb,BMR,and energy intake,including both gross energy intake and digestible energy intake,compared to birds acclimated to 10℃.The dry mass of the liver,kidneys and digestive tract of birds acclimated to 30℃also significantly decreased,although their heart and skeletal muscle mass did not change significantly relative to those acclimated to 10℃.Birds acclimated to 30℃also had lower mitochondrial state-4 respiration(S4R)and cytochrome c oxidase(COX)activity in their liver and skeletal muscle,compared to those acclimated to 10℃.Birds acclimated to the long photoperiod also had lower mitochondrial S4R and COX activity in their liver,compared to those acclimated to the short photoperiod.Conclusions:These results illustrate the changes in morphology,physiology,and enzyme activity induced by seasonal change in temperature and photoperiod in a small temperate passerine.Both temperature and photoperiod probably have a strong effect on seasonal variation in metabolic heat production in small birds in temperate regions.The effect of temperature is,however,stronger than that of photoperiod.
基金supported by the National Natural Science Foundation of China(NSFC,31971413)to DL and NSFC(31770445)to YWthe Natural Science Foundation of Hebei Province,China(NSFHB,C2020205038)to DL and NSFHB(C2020205005)the Postdoctoral Research Foundation of China(PRFC,2020M670685)to LW。
文摘The hypothalamic-pituitary-gonadal(HPG)axis ubiquitously regulates seasonal reproduction,following the rhythmicity of a suite of environmental cues.Birds display prominent seasonal variations in gonad size regulated by two hypothalamic peptides,gonadotropin-releasing hormone-1(GnRH-I)and gonadotropin-inhibiting hormone(GnIH).How multi-brooded avian species adjust GnRH-I and GnIH to regulate gonadal morphology seasonally remains largely unknown.Here,we studied the variations in the hypothalamic immunoreactivity(ir)of GnRH-I and GnIH,gonadal proliferation,and apoptosis in a typical multi-brooded species,the Eurasian Tree Sparrow(Passer montanus),across the pre-breeding(PB),first breeding(FB),second breeding(SB),pre-basic molt(PM),and wintering stages(WS).Our results showed that both sexes had higher preoptic area(POA)-GnRH-I-ir but lower paraventricular nucleus(PVN)-GnIH-ir neurons during the breeding stages(FB and SB)relative to other life-history stages,with no significant differences between two broods.The testes and ovaries were significantly larger during the breeding stages.Testicular volume increased during the two broods due to anincreased diameter of seminiferous tubules.Furthermore,there were more testicular apoptotic cells in PB and WS stages than in breeding stages,and in PB stage than in PM stage.Males had higher POA-GnRH-I expression than females during the breeding stages,but both sexes had comparable PVN-GnIH expression throughout the annual cycle.Both sexes of the sparrows may undergo a similar pattern of life-history stage-dependent variation in the hypothalamic GnRH-I,GnIH,and gonadal morphology,except that during breeding stages,males may display higher expression of POA-GnRH-I relative to females.The higher expression of POA-GnRH-I-ir in breeding male sparrows may be critical for male-dependent parental care.
文摘Global surface air temperatures increased during the past 100 years. Many long-term studies of birds have reported a climatic influence on breeding performance. We analysed long-term changes in first laying date and clutch size for first clutches of sedentary, hole-nesting and socially monogamous tree sparrows Passer montanus during 1980-2009 in northwestern Croatia. Laying date advanced and spring temperature increased significantly during the study. Date of laying was significantly correlated with mean air spring temperature and advanced by 8.6 days during the 30 years period. Laying date was delayed in extremely cold, but not in extremely warm springs compared to years with normal temperatures. These results suggest that current climate change including extreme change does not have negative effects on timing of laying or clutch size. In contrast to laying date, clutch size did not vary systematically during the study period or with mean spring air temperature changes [Current Zoology 57 （3）： 414-418, 2011].
文摘Habitat suitability models have been used to predict the present and future potential distribution of a variety of spe- cies. Eurasian tree sparrows Passer montanus, native to Eurasia, have established populations in other parts of the world. In North America, their current distribution is limited to a relatively small region around its original introduction to St. Louis, Missouri. We combined data from the Global Biodiversity Information Facility with current and future climate data to create habitat suitability models using Maxent for this species. Under projected climate change scenarios, our models show that the distribution and range of the Eurasian tree sparrow could increase as far as the Pacific Northwest and Newfoundland. This is potentially important in-formation for prioritizing the management and control of this non-native species [Current Zoology 57 （5）： 648--654, 2011].
基金This study was supported by the National Nature Science Foundation of China(Grant No.30170187)the Young Teacher Research Foundation of Central University for Nationality,China.
文摘The Tree Sparrow(Passer montanus)is a dom-inant species in urban bird communities.With the devel-opment of urbanization,the habitats and sources of food for Tree Sparrows are decreasing.Can the urban Tree Sparrow adapt to changes in the urban environment?To answer this question,we studied the habitat use of Tree Sparrows in eight types of urban areas in Beijing.The results show that the number of both breeding and winter-ing Tree Sparrows decreased with increasing urbanization.The habitat use of Tree Sparrows,analyzed using stepwise discriminant analysis,was positively correlated with the number of brick bungalows,coniferous and broad-leaved trees and air conditioners.It was negatively correlated with the area of high buildings and hardened roads,pedestrian and automobile flux.This indicates that the Tree Sparrow had not adapted to rapid urbanization even though it is a generally adaptable species.Urban planning should take birds such as the Tree Sparrow into consideration.
