Jankowski’s Bunting (Emberiza jankowskii) is a small bird with narrow distribution ranges. It has experienced a drastic population decline during recent years and vanished from most of its historic breeding sites. It...Jankowski’s Bunting (Emberiza jankowskii) is a small bird with narrow distribution ranges. It has experienced a drastic population decline during recent years and vanished from most of its historic breeding sites. It has been recently up-graded as Endangered in the IUCN Red List of globally threatened species. By integrating unpublished data of field surveys conducted by us and published information on the species, we provide information on the status of distribution, breeding biology of the remaining population at the Dagang Forest Farm, population trends at currently known breeding sites, selection of breeding habitats and threats faced by the Jankowski’s Bunting. In light of its current status we also suggest ways and future research work related to protecting this bird species.展开更多
Sex differences in morphology provide key information for understanding a species'morphological adaptations in relation to the evolution of sexual selection.In migratory birds,morphological traits have adapted to ...Sex differences in morphology provide key information for understanding a species'morphological adaptations in relation to the evolution of sexual selection.In migratory birds,morphological traits have adapted to long-distance travel,and sexual dimorphism is typically related to sex-differential migration phenology.Little Buntings(Emberiza pusilla)have one of the longest migrations and are the least dichromatic species among the Emberiza buntings.In this study,we measured sexual size dimorphism and sexual dichromatism of Little Buntings in relation to the spring arrival dates at a stopover site in Korea.Wing length was the most important predictor for identifying sex;the wings of males were longer than those of females.Males also had a significantly stronger chestnut color of the head feathers than females,but this color difference was more prominent in the spring than in the fall.Males arrived earlier than females by four days.Arrival dates correlated with both size and color,but unlike other bunting species previously studied in the same area,there was no clear sex-differential trend in the relationship between arrival date and morphological characteristics.Seasonal differences in the degree of sexual dichromatism suggest that chestnut plumage coloration can be used as a social or sexual signal of males in the breeding season.The correlation of size and color to early arrival regardless of sex may indicate that a preference for assortative mating exists or that a sex-differential migration strategy is not clearly defined in the early stages of northward migration.Our findings on the sexual dimorphism of Little Buntings provide insight into the evolution of the sex-differential migration of buntings in the East Asian Flyway.展开更多
Natural hybridization,which often occurs between closely related species exhibiting sympatric or parapatric distributions,is an important source of genetic variation within populations.The closely related Jankowski’s...Natural hybridization,which often occurs between closely related species exhibiting sympatric or parapatric distributions,is an important source of genetic variation within populations.The closely related Jankowski’s Bunting(Emberiza jankowskii)and Meadow Bunting(E.cioides)are similar in morphology and genetics,occupy overlapping niches,and are sympatric in eastern Inner Mongolia.Previous studies have reported trans-species polymorphisms of alleles between the two species,as well as an unexpectedly high genetic diversity of the endangered E.jankowskii.We speculate that introgressive hybridization has occurred between the two species and contributed to the additional unexpected variation to E.jankowskii.We used mitochondrial NADH dehydrogenase subunit 2(ND2)gene and 15 nuclear microsatellite markers to compare the genetic diversity of E.jankowskii and E.cioides,and inferred the origin of trans-species polymorphisms between the two species by phylogenetic reconstruction and Bayesian cluster analysis.The two species could be clearly distinguished by population cluster analysis.Despite the large number of mutational differences,we still detected sharing of major haplotypes and the presence of hybrids between the two species.Our study confirmed that weak introgressive hybridization has occurred between sympatric E.jankowskii and E.cioides,which may be mediated by female E.cioides individuals,and that interspecific introgression has contributed to the maintenance of high genetic diversity in E.jankowskii.While being wary of the potential negative effects of introgressive hybridization,we suggest that expanding the habitat of E.jankowskii remains the most effective conservation strategy at present.展开更多
Background:The capacity for thermogenesis is considered part of an animal's adaptive strategy for survival,and basal metabolic rate(BMR) is one of the fundamental physiological standards for assessing the energy c...Background:The capacity for thermogenesis is considered part of an animal's adaptive strategy for survival,and basal metabolic rate(BMR) is one of the fundamental physiological standards for assessing the energy cost of thermoregulation in endotherms.BMR has been shown to be a highly flexible phenotypic trait both between,and within,species,but the metabolic mechanisms involved in the regulation of BMR,which range from variation in organ mass to biochemical adjustments,remain unclear.In this study,we investigated the relationship between organ mass,biochemical markers of metabolic tissue activity,and thermogenesis,in three species of small passerines:wild Bramblings(Fringilla montifringilla),Little Buntings(Emberiza pusilla) and Eurasian Tree Sparrows(Passer montanus),caught in Wenzhou,southeastern China.Methods:Oxygen consumption was measured using an open-circuit respirometry system.Mitochondrial state-4 respiration and cytochrome c oxidase(COX) activity in liver and pectoral muscle were measured with a Clark electrode.Results:Our results show that Eurasian Tree Sparrows had significantly higher BMR,digestive organ mass,mitochondrial state-4 respiration capacity and COX activity in liver and muscle,than Bramblings and Little Buntings.Furthermore,interspecific differences in BMR were strongly correlated with those indigestive tract mass,state-4 respiration and COX activity.Conclusions:Our findings suggest that the digestive organ mass,state-4 respiration and COX activity play an important role in determining interspecific differences in BMR.展开更多
基金supported by the National Natural Science Foundation of China (Grants 30370183, 39870117)
文摘Jankowski’s Bunting (Emberiza jankowskii) is a small bird with narrow distribution ranges. It has experienced a drastic population decline during recent years and vanished from most of its historic breeding sites. It has been recently up-graded as Endangered in the IUCN Red List of globally threatened species. By integrating unpublished data of field surveys conducted by us and published information on the species, we provide information on the status of distribution, breeding biology of the remaining population at the Dagang Forest Farm, population trends at currently known breeding sites, selection of breeding habitats and threats faced by the Jankowski’s Bunting. In light of its current status we also suggest ways and future research work related to protecting this bird species.
基金supported by the New Faculty Startup Fund from Seoul National University (Grant No.500-20200268)supported by the National Research Foundation of Korea (NRF) grants funded by the Republic of Korea Government (Ministry of EducationNRF2018R1D1A1B07050135 & NRF-2019R1I1A1A01063760)
文摘Sex differences in morphology provide key information for understanding a species'morphological adaptations in relation to the evolution of sexual selection.In migratory birds,morphological traits have adapted to long-distance travel,and sexual dimorphism is typically related to sex-differential migration phenology.Little Buntings(Emberiza pusilla)have one of the longest migrations and are the least dichromatic species among the Emberiza buntings.In this study,we measured sexual size dimorphism and sexual dichromatism of Little Buntings in relation to the spring arrival dates at a stopover site in Korea.Wing length was the most important predictor for identifying sex;the wings of males were longer than those of females.Males also had a significantly stronger chestnut color of the head feathers than females,but this color difference was more prominent in the spring than in the fall.Males arrived earlier than females by four days.Arrival dates correlated with both size and color,but unlike other bunting species previously studied in the same area,there was no clear sex-differential trend in the relationship between arrival date and morphological characteristics.Seasonal differences in the degree of sexual dichromatism suggest that chestnut plumage coloration can be used as a social or sexual signal of males in the breeding season.The correlation of size and color to early arrival regardless of sex may indicate that a preference for assortative mating exists or that a sex-differential migration strategy is not clearly defined in the early stages of northward migration.Our findings on the sexual dimorphism of Little Buntings provide insight into the evolution of the sex-differential migration of buntings in the East Asian Flyway.
基金supported by the National Natural Science Foundation of China(Grant Nos.31601856 and 31670398)。
文摘Natural hybridization,which often occurs between closely related species exhibiting sympatric or parapatric distributions,is an important source of genetic variation within populations.The closely related Jankowski’s Bunting(Emberiza jankowskii)and Meadow Bunting(E.cioides)are similar in morphology and genetics,occupy overlapping niches,and are sympatric in eastern Inner Mongolia.Previous studies have reported trans-species polymorphisms of alleles between the two species,as well as an unexpectedly high genetic diversity of the endangered E.jankowskii.We speculate that introgressive hybridization has occurred between the two species and contributed to the additional unexpected variation to E.jankowskii.We used mitochondrial NADH dehydrogenase subunit 2(ND2)gene and 15 nuclear microsatellite markers to compare the genetic diversity of E.jankowskii and E.cioides,and inferred the origin of trans-species polymorphisms between the two species by phylogenetic reconstruction and Bayesian cluster analysis.The two species could be clearly distinguished by population cluster analysis.Despite the large number of mutational differences,we still detected sharing of major haplotypes and the presence of hybrids between the two species.Our study confirmed that weak introgressive hybridization has occurred between sympatric E.jankowskii and E.cioides,which may be mediated by female E.cioides individuals,and that interspecific introgression has contributed to the maintenance of high genetic diversity in E.jankowskii.While being wary of the potential negative effects of introgressive hybridization,we suggest that expanding the habitat of E.jankowskii remains the most effective conservation strategy at present.
基金financially supported by Grants from the National Natural Science Foundation of China (No. 31470472)the National Undergraduate "Innovation" Project and Zhejiang Province’s "Xinmiao" Project
文摘Background:The capacity for thermogenesis is considered part of an animal's adaptive strategy for survival,and basal metabolic rate(BMR) is one of the fundamental physiological standards for assessing the energy cost of thermoregulation in endotherms.BMR has been shown to be a highly flexible phenotypic trait both between,and within,species,but the metabolic mechanisms involved in the regulation of BMR,which range from variation in organ mass to biochemical adjustments,remain unclear.In this study,we investigated the relationship between organ mass,biochemical markers of metabolic tissue activity,and thermogenesis,in three species of small passerines:wild Bramblings(Fringilla montifringilla),Little Buntings(Emberiza pusilla) and Eurasian Tree Sparrows(Passer montanus),caught in Wenzhou,southeastern China.Methods:Oxygen consumption was measured using an open-circuit respirometry system.Mitochondrial state-4 respiration and cytochrome c oxidase(COX) activity in liver and pectoral muscle were measured with a Clark electrode.Results:Our results show that Eurasian Tree Sparrows had significantly higher BMR,digestive organ mass,mitochondrial state-4 respiration capacity and COX activity in liver and muscle,than Bramblings and Little Buntings.Furthermore,interspecific differences in BMR were strongly correlated with those indigestive tract mass,state-4 respiration and COX activity.Conclusions:Our findings suggest that the digestive organ mass,state-4 respiration and COX activity play an important role in determining interspecific differences in BMR.
