Background:Sperm motility parameters,which can be measured objectively and repeatedly by a computer-assisted sperm analysis(CASA)system,are important indicators of sperm quality.However,the sperm motility parameters a...Background:Sperm motility parameters,which can be measured objectively and repeatedly by a computer-assisted sperm analysis(CASA)system,are important indicators of sperm quality.However,the sperm motility parameters assessed by a CASA system can be affected by various factors,including instrument components and settings,sperm preparation or analysis procedures.To date,no standardized protocol is available that would permit to assess sperm kinetic characteristics in passerine birds and this lack precludes any comparison of sperm swimming ability and sperm quality across species.Methods:In this study,we chose the Tree Sparrow(Passer montanus)as the object to evaluate sperm motility parameters,including sperm motility,sperm velocity and sperm movement trajectory,at different analysis time,temperatures and pH using the WLJY-9000 CASA system.Results:Sperm motility parameters remained statistically unchanged at 1‒9 min.Progressive motility was similar at 38℃ and 40℃,but a greater percentage of slow progressive sperm was detected at 38℃ compared to 40℃ and 42℃.Additionally,progressive motility was lower and immotility was higher at 42℃than 38℃and/or 40℃(close to the body temperature of the Tree Sparrow).The percentages of rapid progressive sperm,progressive sperm and immotile sperm were statistically similar at pH 7.0,7.5 and 8.0 with the exception of lower percentage of progressive sperm at pH 7.0 compared to pH 7.5.In addition,slower sperm velocity and worse sperm movement trajectory were found at pH 6.0 and 9.0 than those at pH 8.0,7.5 or 7.0.Conclusions:Our study indicates that the ideal conditions for sperm motility parameters assessment in Tree Sparrow are obtained between 1 and 9 min after dilution,an environment at body temperature(40℃)and a pH around 7.5-8.0.The results of this study provide a reference for the evaluation of sperm characteristics and sperm quality using a CASA system in passerine birds.展开更多
Genetic diversity is one of the three dimensions of biodiversity and fundamental to various life forms on the Earth.Understanding the distribution pattern of genetic diversity and its driving forces has been an import...Genetic diversity is one of the three dimensions of biodiversity and fundamental to various life forms on the Earth.Understanding the distribution pattern of genetic diversity and its driving forces has been an important topic in ecology,biogeography and conservation biology since the last decade.We investigated the genetic diversity pattern of passerine birds in the Mountains of Southwest China,a global biodiversity hotspot with the highest species richness of birds in the entire Eurasia,and explored the influencing forces of environmental variables on genetic diversity.We compiled 1189 Cytochrome b sequences of 27 passerine species from 152 geographic sites,covering the range of Mountains of Southwest China and its adjoining areas.We generated genetic diversity distribution maps using a grid-cell method based on nucleotide diversity and haplotype diversity indices.We further analyzed the variation pattern of the two indices along latitudinal,longitudinal,and elevational gradients.The correlations between the two indices and environmental variables were also evaluated.The nucleotide diversity hotspots were mostly located in the southern Hengduan Mountains,while for haplotype diversity,three hotspots were detected:the southeast edge of the Qinghai-Tibetan Plateau,the southern Hengduan Mountains and the Qinling Mountains.There was no monotonic increasing or decreasing pattern in nucleotide diversity or haplotype diversity along latitudinal,longitudinal or elevational gradients except for altitudinal range.Correlation and model selection analyses detected multiple environmental variables in driving genetic diversity patterns,including temperature,precipitation,vegetation,human influence,longitude and altitude range.Similar to the pattern of species richness,the nucleotide diversity pattern of passerine birds in the Mountains of Southwest China presents a decreasing trend from southwest to northeast,while the haplotype diversity pattern is more likely decreased from west to east.Our results indicate that the distribution pattern of genetic diversity may be derived from the complex topography and diverse microclimates in the Mountains of Southwest China.展开更多
Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change o...Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change on arrival at breeding grounds have been relatively well documented,little is known about the impacts of climate change on post-breeding migration,especially at stopover sites.Here we use long-term(11 years)banding data(11,118 captures)from 7 species at Mai Po Marshes Nature Reserve in Hong Kong,a key stopover site for migratory birds along the East Asian–Australasian Flyway,to describe long-term changes in migration phenology and to compare observed changes to annual weather variation.We also examine changes in wing length over a longer time period(1985–2020)as wing length often correlates positively with migration distance.We found that observed changes in migratory phenology vary by species;three species had later estimated arrival(by 1.8 days per year),peak(by 2.6 days per year)or departure(by 2.5 days per year),one showed an earlier peak date(by 1.8days per year)and two showed longer duration of passage(2.7 days longer and 3.2 days longer per year).Three species exhibited no long-term change in migration phenology.For two of the four species with shifting phenology,temperature was an important predictor of changing peak date,departure dates and duration of passage.Wing length was shorter in three species and longer in two species,but these changes did not correlate with observed phenological changes.The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites.Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.展开更多
Reedbeds are crucial breeding habitats for vulnerable songbird species.Irrespective of their protection status,these habitats may be threatened by organic matter accumulation,progressively leading to structural homoge...Reedbeds are crucial breeding habitats for vulnerable songbird species.Irrespective of their protection status,these habitats may be threatened by organic matter accumulation,progressively leading to structural homoge-nization and habitat succession towards woodland.Managers prevent excessive litter build-up with various in-terventions opening-up the reedbeds,such as grazing,which may be detrimental or suitable for some reed bird species.We assessed the effects of extensive grazing by horses and its cessation in the medium and long terms on reedbed structure,and the consequences on reed-nesting songbird densities in Estagnol Nature Reserve,a pro-tected wetland near the French Mediterranean coast.We compared reedbed structural features between grazed,newly ungrazed and old-ungrazed plots.During nine years,we censused four songbird species in spring and collected water level data in the same survey plots.Grazing reduced reedbed extent,rejuvenated the vegetation with more short green stems on a thinner litter,and produced higher structural heterogeneity and discontinuity compared to long-lasting non grazing.Newly ungrazed plot showed intermediate effects.All surveyed songbird total densities were similar among plots while species numbers and densities differed.Grazed reedbed was more attractive to Moustached Warblers(Acrocephalus melanopogon)and Great Reed Warblers(Acrocephalus arundi-naceus),likely due to the large edges and the high vegetation structural heterogeneity.However,Moustached Warblers were more negatively affected by higher water level in grazed reedbed,presumably because flooding prevents litter foraging.The newly ungrazed reedbed was not preferred by any species.All warbler species were found under low density in the old-ungrazed reedbed,where Reed Buntings(Emberiza schoeniclus)were exclu-sively found.Food availability related to thick litter layer may explain this predilection.Common Reed Warblers(Acrocephalus scirpaceus)were found everywhere in similar densities.We conclude that reedbed management by extensive horse grazing and also its long-term cessation may benefit several songbird species.Within a context of wetland degradation and disappearance,both management strategies are useful to establish and maintain suitable habitats for reed-nesting songbird communities.展开更多
Females actively seek extra-pair paternity(EPP)to acquire a fitness advantage for their offspring.The“contextdependence hypothesis”posits that female extra-pair mate choice has plasticity in response to environmenta...Females actively seek extra-pair paternity(EPP)to acquire a fitness advantage for their offspring.The“contextdependence hypothesis”posits that female extra-pair mate choice has plasticity in response to environmental conditions,and therefore magnitude of female genetic benefits from EPP depends on the environmental variation.Furthermore,chronic heavy metal pollution can cause adverse effects on fitness-related traits of wild birds.However,few studies were available on the interactions between heavy metal pollution and EPP.We selected an area that was contaminated by heavy metals for more than 60 years(Baiyin,BY),a relatively unpolluted area(Liujiaxia,LJX),and Tree Sparrows(Passer montanus)as study species to explore the response of female extrapair mate choice and genetic benefits from EPP to heavy metal pollution in socially monogamous birds.The relatedness between social mates and extra-pair mates was investigated.Additionally,we compared the body size and heterozygosity of extra-pair offspring(EPO),within-pair offspring(WPO),social males and extra-pair males from the two Tree Sparrow populations.We found that at BY,female Tree Sparrows tended to choose extra-pair males with larger body size and lower genetic similarity,thereby producing higher heterozygosity and larger body size of EPO compared with those of WPO.However,no similar phenomenon was observed in the Tree Sparrow population from LJX.In addition,there was a significant interaction between population and paternity in the analyses of the fitness-related traits,suggesting that environmental variation could affect female genetic benefits from EPP.This study confirmed the existence of presumed interactions between environmental pollution and EPP within the natural population of socially monogamous Tree Sparrows.Our findings shed lights on the possible effects of long-term environmental stress on mating system in wild birds.展开更多
Sequence and intensity are two essential components of bird moult.While the moult sequences of remex tracts are highly homogenous across passerines,other tracts apparently show a high variability.Moreover,order of mou...Sequence and intensity are two essential components of bird moult.While the moult sequences of remex tracts are highly homogenous across passerines,other tracts apparently show a high variability.Moreover,order of moult activation among tracts are insufficiently known.Likewise,dynamics of moult intensity as moult progresses remains poorly known.Here,we provide detailed quantitative description of moult sequence and intensity in the House Sparrow(Passer domesticus).To understand their role,we tested two hypotheses on the:1) protection function of moult sequence,and 2) aerodynamic and physiological constraints on moult intensity.We scored percentage growth of 313 captured sparrows using the mass of the feathers of each tract(also length for remiges)to monitor moult intensity throughout the complete moult progress,which is defined as the fraction of new and growing feathers in a moulting bird relative to the total plumage.Moult sequence was highly variable both within wing coverts and among feather tracts,with moult sequence differing among all birds to some degree.We only found support for the protection function between greater coverts and both tertials and secondaries.Remex-moult intensity conformed to theoretical predictions,therefore lending support to the aerodynamic-constraint hypothesis.Furthermore,remex-moult speed plateaued during the central stages of moult progress.However,overall plumage-moult speed did not fit predictions of the physiological-constraint hypothesis,showing that the remex moult is only constrained by aerodynamics.Our results indicate that aerodynamic loss is not simply the inevitable effect of moult,but that moult is finely regulated to reduce aerodynamic loss.We propose that the moult of the House Sparrow is controlled through sequence and intensity adjustments in order to:1) avoid body and wing growth peaks;2) fulfil the protection function between some key feather tracts;3) reduce detrimental effects on flight ability;4) keep remex sequence fixed;and 5) relax remex replacement to last the whole moult duration.展开更多
Mediterranean woodland environments are characterised by high spatial and temporal heterogeneity,which means the inhabiting species face a wide variety of selective pressures.Species may respond differently to habitat...Mediterranean woodland environments are characterised by high spatial and temporal heterogeneity,which means the inhabiting species face a wide variety of selective pressures.Species may respond differently to habitat heterogeneity and so distinct eco-evolutionary scenarios may be responsible for the inter-habitat variability in reproductive strategies observed in certain species.The inter-forest variability of some reproductive traits in passerines has been examined by comparing forest patches or separated fragments.However,there is still little information regarding how such highly mobile animals adjust their breeding performance across continuous and heterogeneous woodlands.Here we studied the reproductive performance of a population of Blue Tits(Cyanistes caeruleus) in an area of continuous Mediterranean woodland that included two mountain slopes and four different types of forest,ranging from deciduous oak forests to perennial non-oak forests.We studied the habitat heterogeneity and inter-forest phenotypic variation in terms of reproductive performance and adult and nestling biometry,besides also exploring the effects of ectoparasites on Blue Tit reproduction.Eggs were laid earliest in deciduous Pyrenean Oak(Quercus pyrenaica) forests,while clutch size and the number of fledglings were highest in the humid Pyrenean Oak forest,which had the greatest tree coverage and most humid climate,and lowest in the coniferous Scots Pine(Pinus sylvestris) forest.There were no inter-forest differences in hatching(percentage of nests with at least one egg hatched) and fledging(percentage of nests in which at least one nestling fledged)success.Similarly,there were no inter-forest differences in adult and nestling biometry,but adults that raised more fledglings had a lower body mass,while males whose females laid larger clutches had smaller tarsi.Most ectoparasites did not affect Blue Tit reproduction,although Culicoides had a negative impact on nestling body mass.These results suggest that Blue Tits can adjust their reproductive effort to the forest where they breed even across a very small spatial scale.Different eco-evolutionary scenarios,such as phenotypic plasticity or genetic structuring and local adaptation,might explain the phenotypic differentiation in the reproductive strategies observed over small areas in woodlands.展开更多
Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of S...Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of Siberian landbird migrants,which either cross or circumvent the deserts and mountain ranges of Central Asia en route to their non-breeding sites in Southeast Asia.Here we compare data on migration phenology and morphology from two bird ringing stations in eastern Russia,situated at similar latitudes but with a longitudinal difference of 1500 km,to hypothesise migration patterns.We found significant differences in timing between the two sites(birds migrated significantly earlier in spring and significantly later in autumn in the east),suggesting longitudinal migration as a result of migration detour.However,morphological differences show a less clear pattern.We argue that most Siberian landbirds might opt for a detour through the Russian Far East instead of a direct route in order to avoid unfavourable stop-over habitat in Central Asia.However,tracking studies will be necessary to prove this.展开更多
Background: Evolutionary biology endeavours to explain biological diversity,and as such it is critical to develop an understanding of the adaptive and functional significance of trait variation.Spermatozoa exhibit rem...Background: Evolutionary biology endeavours to explain biological diversity,and as such it is critical to develop an understanding of the adaptive and functional significance of trait variation.Spermatozoa exhibit remarkable levels of morphological diversification.However,our understanding of the evolutionary causes and functional significance of this variation is limited,especially at the intraspecific level.Methods: We quantified variation in sperm morphology and performance between two subspecies of Long-tailed Finch(Poephila acuticauda acuticauda and P.a.hecki),a small grassfinch found in tropical northern Australia.Despite a zone of secondary contact,these subspecies are maintained as two distinct forms: P.a.acuticauda occurs in the western part of the species' range and has a yellow bill,while P.a.hecki exhibits a red bill and is found in the eastern part of the range.Results: We found small,but significant differences in sperm size between these subspecies(P.a.acuticauda had longer and narrower sperm than P.a.hecki),which was surprising given the recent evolutionary origins of these two taxa(i.e.0.3 million years ago).Additionally,both subspecies exhibited high values of between- and within-male variation in sperm morphology,though in the case of sperm midpiece length this variation was significantly lower in P.a.acuticauda relative to P.a.hecki.Conclusions: We suggest these observed differences in sperm morphology are the result of genetic drift and reflect historical processes associated with divergence between the eastern and western populations of these two subspecies.Finally,we discuss the potential implications of our findings for the process of population divergence and reproductive isolation.展开更多
This paper describes and analyzes floristic, structural and conservation features of the shrubland occupied by Chersophilus duponti in the northwest corner of its world distribution range. This study relates the cover...This paper describes and analyzes floristic, structural and conservation features of the shrubland occupied by Chersophilus duponti in the northwest corner of its world distribution range. This study relates the coverage, floristic composition with estimated lark density in the area. We identified four types of shrublands, three of them varied significantly in floristic composition for the habitats of this species in contrast with those of their world distribution: Cistus ladanifer scrubs;heaths dominated by Ericaceae, and scrubs dominated by the genera Lavandula, Thymus and Cytisus. The fourth type, dominated by aromatic chamaephytes and grass, fits descriptions of the bird’s typical habitat. The areas sampled are subject to different categories of threats, the most significant being the natural succession process due to the cessation of grazing, reforestation measures and the use of flat areas for farmlands or other uses. The density of larks in this area was directly related to coverage-composition of plant community.展开更多
By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants＇ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compe...By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants＇ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 （5）： 660-669, 2014].展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.31572216)
文摘Background:Sperm motility parameters,which can be measured objectively and repeatedly by a computer-assisted sperm analysis(CASA)system,are important indicators of sperm quality.However,the sperm motility parameters assessed by a CASA system can be affected by various factors,including instrument components and settings,sperm preparation or analysis procedures.To date,no standardized protocol is available that would permit to assess sperm kinetic characteristics in passerine birds and this lack precludes any comparison of sperm swimming ability and sperm quality across species.Methods:In this study,we chose the Tree Sparrow(Passer montanus)as the object to evaluate sperm motility parameters,including sperm motility,sperm velocity and sperm movement trajectory,at different analysis time,temperatures and pH using the WLJY-9000 CASA system.Results:Sperm motility parameters remained statistically unchanged at 1‒9 min.Progressive motility was similar at 38℃ and 40℃,but a greater percentage of slow progressive sperm was detected at 38℃ compared to 40℃ and 42℃.Additionally,progressive motility was lower and immotility was higher at 42℃than 38℃and/or 40℃(close to the body temperature of the Tree Sparrow).The percentages of rapid progressive sperm,progressive sperm and immotile sperm were statistically similar at pH 7.0,7.5 and 8.0 with the exception of lower percentage of progressive sperm at pH 7.0 compared to pH 7.5.In addition,slower sperm velocity and worse sperm movement trajectory were found at pH 6.0 and 9.0 than those at pH 8.0,7.5 or 7.0.Conclusions:Our study indicates that the ideal conditions for sperm motility parameters assessment in Tree Sparrow are obtained between 1 and 9 min after dilution,an environment at body temperature(40℃)and a pH around 7.5-8.0.The results of this study provide a reference for the evaluation of sperm characteristics and sperm quality using a CASA system in passerine birds.
基金National Natural Science Foundation of China(3213000355,32070434,and 31900320)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19050202)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0304,2019QZKK0501)。
文摘Genetic diversity is one of the three dimensions of biodiversity and fundamental to various life forms on the Earth.Understanding the distribution pattern of genetic diversity and its driving forces has been an important topic in ecology,biogeography and conservation biology since the last decade.We investigated the genetic diversity pattern of passerine birds in the Mountains of Southwest China,a global biodiversity hotspot with the highest species richness of birds in the entire Eurasia,and explored the influencing forces of environmental variables on genetic diversity.We compiled 1189 Cytochrome b sequences of 27 passerine species from 152 geographic sites,covering the range of Mountains of Southwest China and its adjoining areas.We generated genetic diversity distribution maps using a grid-cell method based on nucleotide diversity and haplotype diversity indices.We further analyzed the variation pattern of the two indices along latitudinal,longitudinal,and elevational gradients.The correlations between the two indices and environmental variables were also evaluated.The nucleotide diversity hotspots were mostly located in the southern Hengduan Mountains,while for haplotype diversity,three hotspots were detected:the southeast edge of the Qinghai-Tibetan Plateau,the southern Hengduan Mountains and the Qinling Mountains.There was no monotonic increasing or decreasing pattern in nucleotide diversity or haplotype diversity along latitudinal,longitudinal or elevational gradients except for altitudinal range.Correlation and model selection analyses detected multiple environmental variables in driving genetic diversity patterns,including temperature,precipitation,vegetation,human influence,longitude and altitude range.Similar to the pattern of species richness,the nucleotide diversity pattern of passerine birds in the Mountains of Southwest China presents a decreasing trend from southwest to northeast,while the haplotype diversity pattern is more likely decreased from west to east.Our results indicate that the distribution pattern of genetic diversity may be derived from the complex topography and diverse microclimates in the Mountains of Southwest China.
基金Funding was provided by an RAE Improvement Grant to(TCB)from the Faculty of Science at The University of Hong Kong。
文摘Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change on arrival at breeding grounds have been relatively well documented,little is known about the impacts of climate change on post-breeding migration,especially at stopover sites.Here we use long-term(11 years)banding data(11,118 captures)from 7 species at Mai Po Marshes Nature Reserve in Hong Kong,a key stopover site for migratory birds along the East Asian–Australasian Flyway,to describe long-term changes in migration phenology and to compare observed changes to annual weather variation.We also examine changes in wing length over a longer time period(1985–2020)as wing length often correlates positively with migration distance.We found that observed changes in migratory phenology vary by species;three species had later estimated arrival(by 1.8 days per year),peak(by 2.6 days per year)or departure(by 2.5 days per year),one showed an earlier peak date(by 1.8days per year)and two showed longer duration of passage(2.7 days longer and 3.2 days longer per year).Three species exhibited no long-term change in migration phenology.For two of the four species with shifting phenology,temperature was an important predictor of changing peak date,departure dates and duration of passage.Wing length was shorter in three species and longer in two species,but these changes did not correlate with observed phenological changes.The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites.Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.
基金supported by the French Ministry of Ecological Transition through the Direction Regionale de l’Environnement,de l’Amenagement et du Logement d’Occitanie,the Office Francais de la Biodiversite,and the Conservatoire d’Espaces Naturels d’Occitanie.
文摘Reedbeds are crucial breeding habitats for vulnerable songbird species.Irrespective of their protection status,these habitats may be threatened by organic matter accumulation,progressively leading to structural homoge-nization and habitat succession towards woodland.Managers prevent excessive litter build-up with various in-terventions opening-up the reedbeds,such as grazing,which may be detrimental or suitable for some reed bird species.We assessed the effects of extensive grazing by horses and its cessation in the medium and long terms on reedbed structure,and the consequences on reed-nesting songbird densities in Estagnol Nature Reserve,a pro-tected wetland near the French Mediterranean coast.We compared reedbed structural features between grazed,newly ungrazed and old-ungrazed plots.During nine years,we censused four songbird species in spring and collected water level data in the same survey plots.Grazing reduced reedbed extent,rejuvenated the vegetation with more short green stems on a thinner litter,and produced higher structural heterogeneity and discontinuity compared to long-lasting non grazing.Newly ungrazed plot showed intermediate effects.All surveyed songbird total densities were similar among plots while species numbers and densities differed.Grazed reedbed was more attractive to Moustached Warblers(Acrocephalus melanopogon)and Great Reed Warblers(Acrocephalus arundi-naceus),likely due to the large edges and the high vegetation structural heterogeneity.However,Moustached Warblers were more negatively affected by higher water level in grazed reedbed,presumably because flooding prevents litter foraging.The newly ungrazed reedbed was not preferred by any species.All warbler species were found under low density in the old-ungrazed reedbed,where Reed Buntings(Emberiza schoeniclus)were exclu-sively found.Food availability related to thick litter layer may explain this predilection.Common Reed Warblers(Acrocephalus scirpaceus)were found everywhere in similar densities.We conclude that reedbed management by extensive horse grazing and also its long-term cessation may benefit several songbird species.Within a context of wetland degradation and disappearance,both management strategies are useful to establish and maintain suitable habitats for reed-nesting songbird communities.
基金supported by the National Natural Science Foundation of China(No.32370508)the Foundation for Excellent Doctoral Student of Science and Technology Program of Gansu Province(No.23JRRA1125)。
文摘Females actively seek extra-pair paternity(EPP)to acquire a fitness advantage for their offspring.The“contextdependence hypothesis”posits that female extra-pair mate choice has plasticity in response to environmental conditions,and therefore magnitude of female genetic benefits from EPP depends on the environmental variation.Furthermore,chronic heavy metal pollution can cause adverse effects on fitness-related traits of wild birds.However,few studies were available on the interactions between heavy metal pollution and EPP.We selected an area that was contaminated by heavy metals for more than 60 years(Baiyin,BY),a relatively unpolluted area(Liujiaxia,LJX),and Tree Sparrows(Passer montanus)as study species to explore the response of female extrapair mate choice and genetic benefits from EPP to heavy metal pollution in socially monogamous birds.The relatedness between social mates and extra-pair mates was investigated.Additionally,we compared the body size and heterozygosity of extra-pair offspring(EPO),within-pair offspring(WPO),social males and extra-pair males from the two Tree Sparrow populations.We found that at BY,female Tree Sparrows tended to choose extra-pair males with larger body size and lower genetic similarity,thereby producing higher heterozygosity and larger body size of EPO compared with those of WPO.However,no similar phenomenon was observed in the Tree Sparrow population from LJX.In addition,there was a significant interaction between population and paternity in the analyses of the fitness-related traits,suggesting that environmental variation could affect female genetic benefits from EPP.This study confirmed the existence of presumed interactions between environmental pollution and EPP within the natural population of socially monogamous Tree Sparrows.Our findings shed lights on the possible effects of long-term environmental stress on mating system in wild birds.
基金the Natural Sciences Museum of Barcelona(PASSERCAT-2 project)to JQ.
文摘Sequence and intensity are two essential components of bird moult.While the moult sequences of remex tracts are highly homogenous across passerines,other tracts apparently show a high variability.Moreover,order of moult activation among tracts are insufficiently known.Likewise,dynamics of moult intensity as moult progresses remains poorly known.Here,we provide detailed quantitative description of moult sequence and intensity in the House Sparrow(Passer domesticus).To understand their role,we tested two hypotheses on the:1) protection function of moult sequence,and 2) aerodynamic and physiological constraints on moult intensity.We scored percentage growth of 313 captured sparrows using the mass of the feathers of each tract(also length for remiges)to monitor moult intensity throughout the complete moult progress,which is defined as the fraction of new and growing feathers in a moulting bird relative to the total plumage.Moult sequence was highly variable both within wing coverts and among feather tracts,with moult sequence differing among all birds to some degree.We only found support for the protection function between greater coverts and both tertials and secondaries.Remex-moult intensity conformed to theoretical predictions,therefore lending support to the aerodynamic-constraint hypothesis.Furthermore,remex-moult speed plateaued during the central stages of moult progress.However,overall plumage-moult speed did not fit predictions of the physiological-constraint hypothesis,showing that the remex moult is only constrained by aerodynamics.Our results indicate that aerodynamic loss is not simply the inevitable effect of moult,but that moult is finely regulated to reduce aerodynamic loss.We propose that the moult of the House Sparrow is controlled through sequence and intensity adjustments in order to:1) avoid body and wing growth peaks;2) fulfil the protection function between some key feather tracts;3) reduce detrimental effects on flight ability;4) keep remex sequence fixed;and 5) relax remex replacement to last the whole moult duration.
基金funded by two projects in the National Plan of the Spanish Ministry of Economy and Competition (CGL2014-55969-P and CGL2017-84938-P)a project of the Andalusian Regional Government (A-RNM-48-UGR20)+4 种基金financed with ERDF funds from the European Union (EU)JGB was supported by a FPU pre-doctoral contract from the Spanish Ministry of Education (FPU18/03034)MC by a grant from the Spanish Ministry of Economy and Competition through the SeveroOchoa Programme for Centres of Excellence in ResearchDevelopment and Innovation (R+D+I)(SEV-2012-0262),contract No.SVP-2014-068620JLRS and EP were funded by Erasmus+grants from the EU.
文摘Mediterranean woodland environments are characterised by high spatial and temporal heterogeneity,which means the inhabiting species face a wide variety of selective pressures.Species may respond differently to habitat heterogeneity and so distinct eco-evolutionary scenarios may be responsible for the inter-habitat variability in reproductive strategies observed in certain species.The inter-forest variability of some reproductive traits in passerines has been examined by comparing forest patches or separated fragments.However,there is still little information regarding how such highly mobile animals adjust their breeding performance across continuous and heterogeneous woodlands.Here we studied the reproductive performance of a population of Blue Tits(Cyanistes caeruleus) in an area of continuous Mediterranean woodland that included two mountain slopes and four different types of forest,ranging from deciduous oak forests to perennial non-oak forests.We studied the habitat heterogeneity and inter-forest phenotypic variation in terms of reproductive performance and adult and nestling biometry,besides also exploring the effects of ectoparasites on Blue Tit reproduction.Eggs were laid earliest in deciduous Pyrenean Oak(Quercus pyrenaica) forests,while clutch size and the number of fledglings were highest in the humid Pyrenean Oak forest,which had the greatest tree coverage and most humid climate,and lowest in the coniferous Scots Pine(Pinus sylvestris) forest.There were no inter-forest differences in hatching(percentage of nests with at least one egg hatched) and fledging(percentage of nests in which at least one nestling fledged)success.Similarly,there were no inter-forest differences in adult and nestling biometry,but adults that raised more fledglings had a lower body mass,while males whose females laid larger clutches had smaller tarsi.Most ectoparasites did not affect Blue Tit reproduction,although Culicoides had a negative impact on nestling body mass.These results suggest that Blue Tits can adjust their reproductive effort to the forest where they breed even across a very small spatial scale.Different eco-evolutionary scenarios,such as phenotypic plasticity or genetic structuring and local adaptation,might explain the phenotypic differentiation in the reproductive strategies observed over small areas in woodlands.
基金Funding supply on Baikal Bird Ringing Station was conducted by Baikalsky State Nature Reserve。
文摘Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of Siberian landbird migrants,which either cross or circumvent the deserts and mountain ranges of Central Asia en route to their non-breeding sites in Southeast Asia.Here we compare data on migration phenology and morphology from two bird ringing stations in eastern Russia,situated at similar latitudes but with a longitudinal difference of 1500 km,to hypothesise migration patterns.We found significant differences in timing between the two sites(birds migrated significantly earlier in spring and significantly later in autumn in the east),suggesting longitudinal migration as a result of migration detour.However,morphological differences show a less clear pattern.We argue that most Siberian landbirds might opt for a detour through the Russian Far East instead of a direct route in order to avoid unfavourable stop-over habitat in Central Asia.However,tracking studies will be necessary to prove this.
基金the authority of the Macquarie University Animal Ethics Committee (ARA No. 2007/037)supported by Australian Research Council Discovery Project Grant DP0881019 (to SCG)+1 种基金supported by the Research Council of Norway Grant 196554Young Research Talent grant from the Research Council of Norway (230434/F20)
文摘Background: Evolutionary biology endeavours to explain biological diversity,and as such it is critical to develop an understanding of the adaptive and functional significance of trait variation.Spermatozoa exhibit remarkable levels of morphological diversification.However,our understanding of the evolutionary causes and functional significance of this variation is limited,especially at the intraspecific level.Methods: We quantified variation in sperm morphology and performance between two subspecies of Long-tailed Finch(Poephila acuticauda acuticauda and P.a.hecki),a small grassfinch found in tropical northern Australia.Despite a zone of secondary contact,these subspecies are maintained as two distinct forms: P.a.acuticauda occurs in the western part of the species' range and has a yellow bill,while P.a.hecki exhibits a red bill and is found in the eastern part of the range.Results: We found small,but significant differences in sperm size between these subspecies(P.a.acuticauda had longer and narrower sperm than P.a.hecki),which was surprising given the recent evolutionary origins of these two taxa(i.e.0.3 million years ago).Additionally,both subspecies exhibited high values of between- and within-male variation in sperm morphology,though in the case of sperm midpiece length this variation was significantly lower in P.a.acuticauda relative to P.a.hecki.Conclusions: We suggest these observed differences in sperm morphology are the result of genetic drift and reflect historical processes associated with divergence between the eastern and western populations of these two subspecies.Finally,we discuss the potential implications of our findings for the process of population divergence and reproductive isolation.
文摘This paper describes and analyzes floristic, structural and conservation features of the shrubland occupied by Chersophilus duponti in the northwest corner of its world distribution range. This study relates the coverage, floristic composition with estimated lark density in the area. We identified four types of shrublands, three of them varied significantly in floristic composition for the habitats of this species in contrast with those of their world distribution: Cistus ladanifer scrubs;heaths dominated by Ericaceae, and scrubs dominated by the genera Lavandula, Thymus and Cytisus. The fourth type, dominated by aromatic chamaephytes and grass, fits descriptions of the bird’s typical habitat. The areas sampled are subject to different categories of threats, the most significant being the natural succession process due to the cessation of grazing, reforestation measures and the use of flat areas for farmlands or other uses. The density of larks in this area was directly related to coverage-composition of plant community.
文摘By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants＇ flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 （5）： 660-669, 2014].
