Roadkill has become a pivotal issue in the global decline of amphibian populations.Conventional research methods have typically relied on the examination of dried carcasses found long after wildlife-vehicle collisions...Roadkill has become a pivotal issue in the global decline of amphibian populations.Conventional research methods have typically relied on the examination of dried carcasses found long after wildlife-vehicle collisions, which influnce the accuracy of the taxonomic classification and assessment of roadkill rates. To overcome these limitations, we conducted a nocturnal survey on National Road G108in the Qinling Mountains immediately following a night rainstorm in July 2016. We employed molecular techniques to distinguish species that are morphologically identical but share overlapping habitats. Our investigation revealed that within five hours, 92 amphibians from five different species were documented across three 2-km road transects. Among these, 31 individuals were identified as roadkill,resulting in an overall rate of 33%, or roughly five fatalities per kilometer. Significantly, the mountain stream frogs Nanorana quadranus and N. taihangnica comprised 40.2% and 30.4% of the total individuals observed, with mortality rates of 35.1% and 25.0%,respectively. We found no significant variation in mortality rates between different age groups or genders for either species. Our research suggests that conducting surveys at night, immediately following summer rainstorms, is an efficient strategy for evaluating the impacts of roadkill. The post-rain foraging behaviors and the dispersal of juveniles are key factors contributing to road crossings outside of the breeding season. Consequently, this study recommends that traffic authorities in mountainous areas take measures to reduce vehicle traffic following summer rainstorms in order to minimize the threat to amphibian lives.展开更多
Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban ...Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban landscapes,few studies have investigated the infuence of thehabitat quality on the life history of anurans.We assessed life history traits such as snout-vent length(SVL),body condition,and reproductiveinvestment in the South American common toad Rhinella arenarum,to determine whether urbanization is harmful or benefcial to this species.We sampled wetlands with different levels of urbanization in Río Cuarto city,Córdoba,Argentina.We recorded males with lower SVL in mediumurbanized wetlands and those with the highest SVL in both low and high urbanization categories,similar to what was found for body conditionswith males with low body conditions inhabiting wetlands with a medium degree of urbanization.In females,lower SVL was recorded in mediumurbanization and highest SVL in high and low urbanization.It is observed that females recorded in highly urbanized wetlands have a very lowbody condition.The reproductive investment parameters were not signifcantly different,but we observed an association between a greaternumber of eggs and clutch size with wetlands of low urbanization.These results show a variability of responses of R.arenarum to urbanization,which could be due to phenotypic plasticity in its life history parameters,allowing it to inhabit urban areas.Continuous monitoring of the speciesin these wetlands is needed to determine if these biological responses are temporary or persistent.展开更多
The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processin...The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.展开更多
A genetic study was carried out on spadefoot toads (Pelobates syriacus) from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic varia...A genetic study was carried out on spadefoot toads (Pelobates syriacus) from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic variation based on five DNA polymorphisms and for RAPD PCR. The nucleotide sequences of the mitochondrial DNA fragments were determined from a 460 bp clone of cytochrome b and a 380 bp clone of 12S (GenBank accession numbers, FJ595199-FJ59-5203). No genetic variation was found among the populations with regard to 12S. According to the analysis of five sequences using Arlequin software, there was a high gene identity among the populations (98.7%-99.6%). Both populations, Elrom Pond breeding site, at the highest altitude and Fara Pond, at the lowest, had the lowest identities as compared to other populations. The DNA variation among P. syri-acus populations from various breeding sites, according to band sharing (BS), when using the OP-4 primer, was 0.92-1.00. Similarity was low between the population of Elrom Pond and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS), as well as between the population of Fara Pond at the lowest altitude, and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS). Similar results were obtained when comparing the results obtained using primer OPA-3. The lowest similarity was found between populations of the highest altitude (Elrom Pond) and lowest altitude (Fara Pond), relative to the other ponds (Kash Pond, Raihania Pond and Sasa Pond) with a BS of 0.93.展开更多
The distribution and diversity of the species are closely related to the global climate.As the most widely distributed species of Bufonidae in China,the study of the distribution pattern and habitat suitability of the...The distribution and diversity of the species are closely related to the global climate.As the most widely distributed species of Bufonidae in China,the study of the distribution pattern and habitat suitability of the Asiatic toad under climate change can help us understand the reply pattern of Bufonidae habitat to climate change.Here,combined with the Maxent model and GIS technology,the effects of climate change on the distribution pattern and habitat suitability of the Asiatic toad were comprehensively analyzed.The results show that the rainfall during the wettest season(Bio16)and the mean temperature of the driest season(Bio9)have a considerable impact on the distribution of the Asiatic toad.In the next 30 to 50 years,across the overall spacial scale of the Chinese mainland,the habitat of the Asiatic toad will be primarily in the eastern part of China and less in south part,while its distribution area will expand to the midwest and northwest parts of China.Overall,the area in which it can be distributed will be reduced and suitable habitat will shift to some regions of higher latitude and elevation.In a word,we systematically analyzed the changes of the distribution pattern and habitat suitability of the Asiatic toad with climate change,and we aim to provide data on how climatic variation may impact amphibians.展开更多
Mating preferences are common in natural populations of animals.Numerous studies have shown that male mate choice can occur in a wide range of taxa.However,male mating preferences are still poorly understood in anuran...Mating preferences are common in natural populations of animals.Numerous studies have shown that male mate choice can occur in a wide range of taxa.However,male mating preferences are still poorly understood in anurans.Sexual selection theory predicts that male mate choice is not expected to arise if 1) adult population exhibited a highly male-biased sex ratio which will diminish male mating success;2) males provide less parental care;3) mating success of males is associated with chorus tenure in which males would maximize their fitness by mating with multiple mates.We tested these predictions in the Asian common toad Duttaphrynus melanostictus from southeastern Tibet,China.Our field experimental results indicated that,the breeding population exhibited a highly male-biased sex ratio,called males did not defend sites which contain significant resources required by females and offspring,both sexes provided no parental care after egg-laying,and the toad species was characterized with prolonged breeding season chorus attendance.In male mate choice experiment,males did not show preferences for a larger gravid female over a smaller gravid female.We suggest that male mating success in the Asian common toad is likely determined by the number but not the quality of mates.Future research should focus on how sexual selection on male acoustic signaling and how female preference exert different types of selection pressure on male call traits in this Tibet toad.展开更多
基金supported by the National Natural Science Foundation of China (32170435)。
文摘Roadkill has become a pivotal issue in the global decline of amphibian populations.Conventional research methods have typically relied on the examination of dried carcasses found long after wildlife-vehicle collisions, which influnce the accuracy of the taxonomic classification and assessment of roadkill rates. To overcome these limitations, we conducted a nocturnal survey on National Road G108in the Qinling Mountains immediately following a night rainstorm in July 2016. We employed molecular techniques to distinguish species that are morphologically identical but share overlapping habitats. Our investigation revealed that within five hours, 92 amphibians from five different species were documented across three 2-km road transects. Among these, 31 individuals were identified as roadkill,resulting in an overall rate of 33%, or roughly five fatalities per kilometer. Significantly, the mountain stream frogs Nanorana quadranus and N. taihangnica comprised 40.2% and 30.4% of the total individuals observed, with mortality rates of 35.1% and 25.0%,respectively. We found no significant variation in mortality rates between different age groups or genders for either species. Our research suggests that conducting surveys at night, immediately following summer rainstorms, is an efficient strategy for evaluating the impacts of roadkill. The post-rain foraging behaviors and the dispersal of juveniles are key factors contributing to road crossings outside of the breeding season. Consequently, this study recommends that traffic authorities in mountainous areas take measures to reduce vehicle traffic following summer rainstorms in order to minimize the threat to amphibian lives.
基金Financial support was provided by Secretaría de Cienciay Técnica-Universidad Nacional de Río Cuarto(SECyTUNRC,Grant PPI 18/C416)Fondo para la Investigación Científca y Tecnológica(FONCyT,Grant PICT BIDPICT 0981-20182530-2019).
文摘Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban landscapes,few studies have investigated the infuence of thehabitat quality on the life history of anurans.We assessed life history traits such as snout-vent length(SVL),body condition,and reproductiveinvestment in the South American common toad Rhinella arenarum,to determine whether urbanization is harmful or benefcial to this species.We sampled wetlands with different levels of urbanization in Río Cuarto city,Córdoba,Argentina.We recorded males with lower SVL in mediumurbanized wetlands and those with the highest SVL in both low and high urbanization categories,similar to what was found for body conditionswith males with low body conditions inhabiting wetlands with a medium degree of urbanization.In females,lower SVL was recorded in mediumurbanization and highest SVL in high and low urbanization.It is observed that females recorded in highly urbanized wetlands have a very lowbody condition.The reproductive investment parameters were not signifcantly different,but we observed an association between a greaternumber of eggs and clutch size with wetlands of low urbanization.These results show a variability of responses of R.arenarum to urbanization,which could be due to phenotypic plasticity in its life history parameters,allowing it to inhabit urban areas.Continuous monitoring of the speciesin these wetlands is needed to determine if these biological responses are temporary or persistent.
基金supported by the National Natural Science Foundation of China,No,90707005,61001046 and 61204018the Natural Science Foundation of Education Department of Jiangsu Province,No.11KJB510023the Special Foundation and Open Foundation of State Key Laboratory of Bioelectronics of Southeast University,No.2011E05
文摘The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.
文摘A genetic study was carried out on spadefoot toads (Pelobates syriacus) from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic variation based on five DNA polymorphisms and for RAPD PCR. The nucleotide sequences of the mitochondrial DNA fragments were determined from a 460 bp clone of cytochrome b and a 380 bp clone of 12S (GenBank accession numbers, FJ595199-FJ59-5203). No genetic variation was found among the populations with regard to 12S. According to the analysis of five sequences using Arlequin software, there was a high gene identity among the populations (98.7%-99.6%). Both populations, Elrom Pond breeding site, at the highest altitude and Fara Pond, at the lowest, had the lowest identities as compared to other populations. The DNA variation among P. syri-acus populations from various breeding sites, according to band sharing (BS), when using the OP-4 primer, was 0.92-1.00. Similarity was low between the population of Elrom Pond and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS), as well as between the population of Fara Pond at the lowest altitude, and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS). Similar results were obtained when comparing the results obtained using primer OPA-3. The lowest similarity was found between populations of the highest altitude (Elrom Pond) and lowest altitude (Fara Pond), relative to the other ponds (Kash Pond, Raihania Pond and Sasa Pond) with a BS of 0.93.
文摘The distribution and diversity of the species are closely related to the global climate.As the most widely distributed species of Bufonidae in China,the study of the distribution pattern and habitat suitability of the Asiatic toad under climate change can help us understand the reply pattern of Bufonidae habitat to climate change.Here,combined with the Maxent model and GIS technology,the effects of climate change on the distribution pattern and habitat suitability of the Asiatic toad were comprehensively analyzed.The results show that the rainfall during the wettest season(Bio16)and the mean temperature of the driest season(Bio9)have a considerable impact on the distribution of the Asiatic toad.In the next 30 to 50 years,across the overall spacial scale of the Chinese mainland,the habitat of the Asiatic toad will be primarily in the eastern part of China and less in south part,while its distribution area will expand to the midwest and northwest parts of China.Overall,the area in which it can be distributed will be reduced and suitable habitat will shift to some regions of higher latitude and elevation.In a word,we systematically analyzed the changes of the distribution pattern and habitat suitability of the Asiatic toad with climate change,and we aim to provide data on how climatic variation may impact amphibians.
基金supported by the Joint Funds for Fostering Talents of NSFC and the People's Government of Henan Province(No.U1304309)National Sciences Foundation of China(No.31501870, No.31670392 and No.31872216)+2 种基金Natural Sciences Foundation for Distinguished Young Scholar of Sichuan (No.2016JQ0038)Key Foundation of Sichuan Provincial Department of Education (No.18ZA0255)Technology Foundation for Selected Overseas Chinese Scholar (No.HGQD02)。
文摘Mating preferences are common in natural populations of animals.Numerous studies have shown that male mate choice can occur in a wide range of taxa.However,male mating preferences are still poorly understood in anurans.Sexual selection theory predicts that male mate choice is not expected to arise if 1) adult population exhibited a highly male-biased sex ratio which will diminish male mating success;2) males provide less parental care;3) mating success of males is associated with chorus tenure in which males would maximize their fitness by mating with multiple mates.We tested these predictions in the Asian common toad Duttaphrynus melanostictus from southeastern Tibet,China.Our field experimental results indicated that,the breeding population exhibited a highly male-biased sex ratio,called males did not defend sites which contain significant resources required by females and offspring,both sexes provided no parental care after egg-laying,and the toad species was characterized with prolonged breeding season chorus attendance.In male mate choice experiment,males did not show preferences for a larger gravid female over a smaller gravid female.We suggest that male mating success in the Asian common toad is likely determined by the number but not the quality of mates.Future research should focus on how sexual selection on male acoustic signaling and how female preference exert different types of selection pressure on male call traits in this Tibet toad.
