Background: Bringing free-living animals into captivity subjects them to the stress of both capture and captivity, leading to the alteration of normal physiological processes and behaviors through activation of the hy...Background: Bringing free-living animals into captivity subjects them to the stress of both capture and captivity, leading to the alteration of normal physiological processes and behaviors through activation of the hypothalamic– pituitary–adrenal axis. In free-living birds, although elevated plasma corticosterone (CORT) is an important adaptation regulating physiological and behavioral responses during the process of capture and captivity stress, little information is currently available on the effects of such stress on plasma metabolite levels. Methods: We examined the effects of immediate capture and 24-h captivity on body mass, body condition, plasma CORT, and metabolite levels including glucose (Glu), triglyceride (TG), total cholesterol (TC), uric acid (UA), in breeding Eurasian Tree Sparrows (Passer montanus). Results: CORT and Glu levels were increased significantly by the stress of capture, whereas TC and UA levels decreased. Body mass, body condition declined notably after 24 h in captivity, but CORT, Glu, and UA levels increased. Furthermore, male sparrows had lower TG levels after both capture and captivity than those of females. The relationships between plasma CORT and metabolite levels varied between sexes. Conclusions: Our results revealed that the metabolic status of Eurasian Tree Sparrows could be dramatically altered by capture and captivity. Monitoring the dynamic effects of both capture and captivity on plasma CORT, metabolite levels in a free-living bird contributes to a better understanding of the stress-induced pathways involved in sexdependent energy mobilization.展开更多
Background:Unlike resident birds,migratory birds are generally believed to have evolved to enhance flight efficiency;however,direct evidence is still scarce due to the difficulty of measuring the flight speed and mech...Background:Unlike resident birds,migratory birds are generally believed to have evolved to enhance flight efficiency;however,direct evidence is still scarce due to the difficulty of measuring the flight speed and mechanical power.Methods:We studied the differences in morphology,flight kinematics,and energy cost between two passerines with comparable size,a migrant(Fringilla montifringilla,Brambling,BRAM),and a resident(Passer montanus,Eurasian Tree Sparrow,TRSP).Results:The BRAM had longer wings,higher aspect ratio,lower wingbeat frequency,and stroke amplitude compared to the TRSP despite the two species had a comparable body mass.The BRAM had a significantly lower maximum speed,lower power at any specific speed,and thus lower flight energy cost in relative to the TRSP although the two species had a comparable maximum vertical speed and acceleration.Conclusions:Our results suggest that adaptation for migration may have led to reduced power output and maximum speed to increase energy efficiency for migratory flight while residents increase flight speed and speed range adapting to diverse habitats.展开更多
The avian hippocampus,akin to its mammalian counterpart,plays a critical role in cognitive and physiological processes despite notable structural differences.Initially thought to be less developed,recent studies over ...The avian hippocampus,akin to its mammalian counterpart,plays a critical role in cognitive and physiological processes despite notable structural differences.Initially thought to be less developed,recent studies over the past two decades have revealed it as a complex brain region essential for diverse functions in both laboratory and free-living birds.This review synthesizes current knowledge on the avian hippocampus’organization,functionality,and neurophysiological significance.We first examine its anatomical structure and neuronal connectivity,comparing it with the mammalian hippocampus.We then highlight how its volume,neuronal density,and neurogenesis support spatial memory and navigation,influencing behaviors such as migration,food storing,brood parasitism,and homing.Beyond spatial functions,the avian hippocampus mediates emotion and stress physiology through interactions with the endocrine system,particularly via glucocorticoid receptors.It also influences spatial memory through sex hormones,especially estradiol,with local estrogen production through aromatase activity enhancing memory and plasticity.Therefore,the avian hippocampus serves as a central neural hub,integrating sensory information with internal states to facilitate essential behaviors and responses to external environmental stimuli.This review underscores the progress made in understanding this brain structure’s roles,highlighting conserved neurophysiological functions across vertebrate taxa.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
Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogeneti...Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,31672292)the Natural Science Foundation of Hebei Province(C2017205059)+1 种基金the foundation of China Scholarship Council(201408130068) to D.Lithe NSFC(31770445)to Y.Wu,the NSFC(31372201)to X.Gao
文摘Background: Bringing free-living animals into captivity subjects them to the stress of both capture and captivity, leading to the alteration of normal physiological processes and behaviors through activation of the hypothalamic– pituitary–adrenal axis. In free-living birds, although elevated plasma corticosterone (CORT) is an important adaptation regulating physiological and behavioral responses during the process of capture and captivity stress, little information is currently available on the effects of such stress on plasma metabolite levels. Methods: We examined the effects of immediate capture and 24-h captivity on body mass, body condition, plasma CORT, and metabolite levels including glucose (Glu), triglyceride (TG), total cholesterol (TC), uric acid (UA), in breeding Eurasian Tree Sparrows (Passer montanus). Results: CORT and Glu levels were increased significantly by the stress of capture, whereas TC and UA levels decreased. Body mass, body condition declined notably after 24 h in captivity, but CORT, Glu, and UA levels increased. Furthermore, male sparrows had lower TG levels after both capture and captivity than those of females. The relationships between plasma CORT and metabolite levels varied between sexes. Conclusions: Our results revealed that the metabolic status of Eurasian Tree Sparrows could be dramatically altered by capture and captivity. Monitoring the dynamic effects of both capture and captivity on plasma CORT, metabolite levels in a free-living bird contributes to a better understanding of the stress-induced pathways involved in sexdependent energy mobilization.
基金This study was funded by the National Natural Science Foundation of China(NSFC,31672292)to DL,NSFC(31770445)to Y.Wu,NSFC(31800338)and the Foundation of Hebei Normal University(L042017B03)to Y.Wang.
文摘Background:Unlike resident birds,migratory birds are generally believed to have evolved to enhance flight efficiency;however,direct evidence is still scarce due to the difficulty of measuring the flight speed and mechanical power.Methods:We studied the differences in morphology,flight kinematics,and energy cost between two passerines with comparable size,a migrant(Fringilla montifringilla,Brambling,BRAM),and a resident(Passer montanus,Eurasian Tree Sparrow,TRSP).Results:The BRAM had longer wings,higher aspect ratio,lower wingbeat frequency,and stroke amplitude compared to the TRSP despite the two species had a comparable body mass.The BRAM had a significantly lower maximum speed,lower power at any specific speed,and thus lower flight energy cost in relative to the TRSP although the two species had a comparable maximum vertical speed and acceleration.Conclusions:Our results suggest that adaptation for migration may have led to reduced power output and maximum speed to increase energy efficiency for migratory flight while residents increase flight speed and speed range adapting to diverse habitats.
基金supported by the National Natural Science Foundation of China(NSFC,31971413)to Dongming Lithe Hebei Natural Science Foundation(C2023205016)to Limin Wang.
文摘The avian hippocampus,akin to its mammalian counterpart,plays a critical role in cognitive and physiological processes despite notable structural differences.Initially thought to be less developed,recent studies over the past two decades have revealed it as a complex brain region essential for diverse functions in both laboratory and free-living birds.This review synthesizes current knowledge on the avian hippocampus’organization,functionality,and neurophysiological significance.We first examine its anatomical structure and neuronal connectivity,comparing it with the mammalian hippocampus.We then highlight how its volume,neuronal density,and neurogenesis support spatial memory and navigation,influencing behaviors such as migration,food storing,brood parasitism,and homing.Beyond spatial functions,the avian hippocampus mediates emotion and stress physiology through interactions with the endocrine system,particularly via glucocorticoid receptors.It also influences spatial memory through sex hormones,especially estradiol,with local estrogen production through aromatase activity enhancing memory and plasticity.Therefore,the avian hippocampus serves as a central neural hub,integrating sensory information with internal states to facilitate essential behaviors and responses to external environmental stimuli.This review underscores the progress made in understanding this brain structure’s roles,highlighting conserved neurophysiological functions across vertebrate taxa.
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.
基金supported by the National Natural Science Foundation of China (NSFC, 31000191, 31330073)the Postdoctoral Science Foundation of China (2011 M500537)+2 种基金the Natural Science Foundation of Hebei Province (NSFHB, 2012205018)the Natural Science Foundation of the Department of Education, Hebei Province (YQ2014024) to D. LiNSFHB (2013205018) to Y. Wu
文摘Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.
