Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans.Biodiversity is hypoth-esized to be closely related to pathogen prevalence through multiple direct and indirect pathways.For exampl...Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans.Biodiversity is hypoth-esized to be closely related to pathogen prevalence through multiple direct and indirect pathways.For example,the presence of non-host species can reduce contact rates of the main reservoir host and thus reduce the risk of transmission(“dilution effect”).In addition,an overlap in ecological niches between two species could lead to increased interspecific competition,potentially limiting host densities and reducing density-dependent pathogen transmission processes.In this study,we investigated the relative impact of population-level regulation of direct and indirect drivers of the prevalence of Puumala orthohantavirus(PUUV)in bank voles(Clethrionomys glareolus)during years with high abundance.We compiled data on small mammal community composition from four regions in Germany between 2010 and 2013.Structural equation modeling revealed a strong seasonality in PUUV control mechanisms in bank voles.The abundance of shrews tended to have a negative relationship with host abundance,and host abundance positively influenced PUUV seroprevalence,while at the same time increasing the abundance of competing non-hosts like the wood mouse(Apodemus sylvaticus)and the yellow-neckedfield mouse(Apodemusflavicollis)were associated with reduced PUUV seroprevalence in the host.These results indicate that for PUUV in bank voles,dilution is associated with increased interspecific competition.Anthropogenic pressures leading to the decline of Apodemus spp.in a specific habitat could lead to the amplification of mechanisms promoting PUUV transmission within the host populations.展开更多
Hepatitis E virus(HEV)is the prototype of the family Hepeviridae and the causative agent of common acute viral hepatitis.Genetically diverse HEV-related viruses have been detected in a variety of mammals and some of t...Hepatitis E virus(HEV)is the prototype of the family Hepeviridae and the causative agent of common acute viral hepatitis.Genetically diverse HEV-related viruses have been detected in a variety of mammals and some of them may have zoonotic potential.In this study,we tested 278 specimens collected from seven wild small mammal species in Yunnan province,China,for the presence and prevalence of orthohepevirus by broad-spectrum reverse transcription(RT)-PCR.HEV-related sequences were detected in two rodent species,including Chevrier’s field mouse(Apodemus chevrieri,family Muridae)and Père David’s vole(Eothenomys melanogaster,family Cricetidae),with the infection rates of 29.20%(59/202)and 7.27%(4/55),respectively.Further four representative full-length genomes were generated:two each from Chevrier’s field mouse(named Rd HEVAc14 and Rd HEVAc86)and Père David’s vole(Rd HEVEm40 and Rd HEVEm67).Phylogenetic analyses and pairwise distance comparisons of whole genome sequences and amino acid sequences of the gene coding regions showed that orthohepeviruses identified in Chinese Chevrier’s field mouse and Père David’s vole belonged to the species Orthohepevirus C but were highly divergent from the two assigned genotypes:HEV-C1 derived from rat and shrew,and HEV-C2 derived from ferret and possibly mink.Quantitative real-time RT-PCR demonstrated that these newly discovered orthohepeviruses had hepatic tropism.In summary,our work discovered two putative novel genotypes orthohepeviruses preliminarily named HEVC3 and HEV-C4 within the species Orthohepevirus C,which expands our understanding of orthohepevirus infection in the order Rodentia and gives new insights into the origin,evolution,and host range of orthohepevirus.展开更多
The present review is a compilation of the published data on the ecology and social behavior of the social vole.Field studies provide evidence that these voles live in family groups consisting of 1 adult male,1 or 2 b...The present review is a compilation of the published data on the ecology and social behavior of the social vole.Field studies provide evidence that these voles live in family groups consisting of 1 adult male,1 or 2 breeding females,and their offspring(1 or 2 litters).The social vole is capable of year-round reproduction,but in arid regions,the voles demonstrate seasonality in breeding.The mating system of this species may be defined as behavioral monogamy.A typical feature of the space use system is territoriality characterized by a locus-dependent dominance in relationships between neighboring breeding pairs as well as family groups.The family group social organization may be defined as consistent relationships without a dominant hierarchy.Social voles are cooperative in defending their territories,constructing burrows,digging underground tunnels,maintaining nests,and raising young.Cooperation appears to enhance the survival of family groups of this species under the extreme climaticconditionsof Central Asia.展开更多
To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Mi...To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research.Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles.During same sex encounters,mandarin voles attacked their opponents for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions.However,no significant behavioral differences were found during encounters of two individual reed voles,regardless of gender composition of the pair.Using c-Fos as an indicator of neural activation,we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb(MOB)and the accessory olfactory bulb(AOB)of mandarin voles compared with reed voles.Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex.Anterior-posterior ratios of Fos-ir neurons in the AOBM(AOBMR)and the AOBG(AOBGR)in male-female interaction were significantly higher than those in interaction of the same sex.The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions.Behavioral patterns are consistent with cellular activity patterns.Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species.展开更多
The Yangtze vole(Microtus fortis Buechner,1889)is a small herbivore species that inhabits lake beaches in the Dongting Lake region along the Yangtze River in Southern China.Its population shows strong oscillations dur...The Yangtze vole(Microtus fortis Buechner,1889)is a small herbivore species that inhabits lake beaches in the Dongting Lake region along the Yangtze River in Southern China.Its population shows strong oscillations during the wet season due to summer precipitation-induced immigration away from the lake into adjacent rice fields.The effect of El Niño-Southern Oscillation-driven precipitation on population abundance and growth of the vole species is not fully understood.We undertook an analysis of the combined data of 4 time series covering 1981–2006 from 4 different sites and a separate analysis on a single time series(1981–2006)from one site.Our results demonstrate that a dual effect of El Niño-Southern Oscillation-driven precipitation on the population abundance of voles is timedependent:precipitation in the current year has a positive effect,whereas precipitation in the previous year has a negative effect.The dual effect of precipitation on vole population is well explained by the unique interactions among vole population,precipitation water level and the lake beach habitat around Dongting Lake.We found that drier than average weather of the previous year benefited voles because their breeding habitats,lake beaches,were exposed for long stretches of time.Wet weather was found to increase the number of voles inhabiting rice fields because as the water level of the lake rose they were forced from beaches into surrounding rice fields.Summer precipitation in the Dongting Lake region was found to be positively associated with the sea surface temperature(SST)of the eastern tropical Pacific Ocean of the previous year and winter SST and spring SST of the current year.Annual rates of increase in the vole population of the reconstructed time series are negatively associated with the vole abundance and autumn precipitation of the previous year and winter precipitation of the current years.These results suggest that both extrinsic and density-dependent intrinsic factors may affect population dynamics of the Yangtze vo展开更多
It is widely believed that intensive forestry has influenced small mammal population dynamics,and thereby the entire mammalian community in Fennoscandian boreal forests.The nature of these impacts on the different spe...It is widely believed that intensive forestry has influenced small mammal population dynamics,and thereby the entire mammalian community in Fennoscandian boreal forests.The nature of these impacts on the different species is subject to debate.We live-trapped voles between 2006 and 2009 in 2 commercially harvested forests in south-eastern Norway.We investigated the variation in vole abundance among habitat types(e.g.mature forest and clear-cut)and the hypothesis that graminivorous species such as field voles(Microtus agrestis L.)benefit from clear-cuts at the expense of forest dwellers(i.e.the bank vole,Myodes glareolus Schreb.),using fine-scale descriptors of the ground vegetation.We could not find support for the hypothesis that field voles show a preference for clear-cuts,and their overall abundance was low,while bank voles were the dominant species in all habitat types,including clear-cuts in the peak and pre-peak years.We found a positive association between bank vole abundance and bilberry(Vaccinium myrtillus L.)availability rather than a specific habitat type.Low field vole density in clear-cuts might be due to variation in local productivity and ground vegetation as well as to large variation in the species temporal dynamics.The latter is particularly associated with the widespread decline of field voles in Scandinavia.Logging has the potential to negatively affect bank vole population dynamics because of the negative effect on bilberry development.展开更多
Age structure and seasonality influence the population fluctuations of small rodents.Age determines body weight and social experience,while seasonality regulates the duration of the breeding season and onset of sex...Age structure and seasonality influence the population fluctuations of small rodents.Age determines body weight and social experience,while seasonality regulates the duration of the breeding season and onset of sexual maturity in newborn offspring.Therefore,reproductive success and skew usually occur in different age groups.Brandt’s vole(Lasiopodomys brandtii)is a social,short-lived and seasonal breeding small rodent with a dramatic seasonal population fluctuation,but reproductive skew is not fully understood in this species.In the present study,we determined kinship in semi-natural enclosure populations using microsatellite markers based on genotyping,analyzed the reproductive skew between sexes and between overwintered and newborn voles,and monitored variation in male reproductive activity by testing fecal testosterone levels throughout the year.Overwintered voles had the most reproductive success along with a striking increase in the population size in the enclosures,with all biological fathers and 77.8%of biological mothers,which had 100%and 87%of the total offspring,respectively.Compared to overwintered voles,reproductive skews were significantly higher in potential overwintered and newborn parents,implying the possible reproductive suppression of newborn voles by dominant overwintered voles.Moreover,both heavier body weight and higher testosterone levels in overwintered males supported their potential social status in the population.Our study provided new evidence for reproductive skew and differentiation of postnatal gonadal development patterns of different age groups in Brandt’s vole.展开更多
No-till farming is an important approach to sustainable agriculture because it can conserve soil and water resources.Unfortunately, rodent populations can thrive under no-till conditions because burrow systems are not...No-till farming is an important approach to sustainable agriculture because it can conserve soil and water resources.Unfortunately, rodent populations can thrive under no-till conditions because burrow systems are not disrupted byannual plowing and plant residues build-up on the surface, providing cover and insulation. This can result in substantialcrop damage. We assessed rodent populations, habitat use, food habits, and crop damage in a no-till croppingsystem in Washington, USA. We also conducted preliminary trials of methods to reduce rodent populationsand crop damage. In the fall, many more rodents were captured in fields with unharvested crops than in fieldscontaining only plant stubble, suggesting that rodents leave fields after crop harvest, providing that suitable habitatsare nearby, even when adequate cover is still available in harvested crop fields. By spring, the number of volescaptured was much lower relative to fall. Despite this, capture rates were much higher in surrounding permanentgrass areas than in crop (barley, wheat, pea) fields, suggesting that these grassy areas serve as refugia for rodents.Furthermore, the permanent grass cover type was the landscape variable most associated with rodent capture rates.In three winter pea fields, rodents removed 5–15% of the pea plants over winter. Examination of stomach contentsrevealed that voles mainly fed on grain plants in spring, but that their diet was more diversified in fall. Deer micefed heavily on grain plants in both spring and fall, but also used insects as food. Metal barrier exclosures (9 m × 9m), extending above and below ground, did not prevent access by rodents. Rodent populations in areas treated withzinc phosphide on grain were comparable to untreated areas 1 year after application of the rodenticide, perhaps becauseof immigration and recruitment, suggesting that baiting does not provide a long-term solution to rodent damagein no-till agricultural fields.展开更多
Human-made agro-ecosystems lack negative feedback controls, which may result in rodent population explosions,causing considerable economic loss and thus increasing human–wildlife conflicts. The traditional solution i...Human-made agro-ecosystems lack negative feedback controls, which may result in rodent population explosions,causing considerable economic loss and thus increasing human–wildlife conflicts. The traditional solution is theextensive use of rodenticides, which have a negative impact on the environment. In Beit-Sheaan Valley, Israel,which is located on a major route for migrating birds, poisoning of voles may result in the death of birds that preyon the dead voles (e.g. storks and herons). In the present essay we discuss some integrated methods, based on theimplementation of ecological principles in agro-ecosystems, that could be used to decrease the use of rodenticides.The first method is light interference during winter (long scotophase), which can result in the death of the socialvole Microtus socialis kept in enclosures under natural conditions. Under laboratory conditions such interferencecauses a decrease in thermoregulatory ability in the cold. As light interference is a source of pollution, only activevole burrows should be illuminated. The second method involves using the mobile irrigation pipelines to flood thevole burrows and force them to escape into the open, where diurnal birds such as storks and herons will prey onthem. The third method involves the use of nesting boxes for barn owls and stands for diurnal raptors, both ofwhich prey on voles. The great advantage of using an integrated approach is that voles cannot become adapted toany one of the methods. Such integrated methods, together with appropriate treatment of alfalfa fields by farmers,can provide an efficient and sustainable pest control approach.展开更多
We studied the behavioral and endocrine responses of the fossorial s ocial rodent, mole vole Ellobius talpinus Pall., to intrusions of strangers int o burrow systems that were occupied by intact families. Both in repr...We studied the behavioral and endocrine responses of the fossorial s ocial rodent, mole vole Ellobius talpinus Pall., to intrusions of strangers int o burrow systems that were occupied by intact families. Both in reproductive and non-reproductive seasons, all intruders disappeared from the burrow systems of residents within two days of introduction, whereas 4 of 7 individuals introduced into empty burrows remained there at least for two days. Introduction of strang ers led to the concentration of residents at the point of release and to an incr ease of plasma corticosterone in both residents and intruders. During the breedi ng season, introduction of strangers was also accompanied by an increase of plas ma testosterone of residents on the day of introduction. Thus, simulation of int rusion of strangers demonstrated the efficient social fence of resident mole vol es that seems to be an important mechanism of stabilization of size and structur e of mole vole families. Encounters of residents and intruders resulted in activ ation of physiological mechanisms of stress, especially during the breeding seas on .展开更多
Mercury chloride exposure through drinking water in adult male prairie voles(Microtus ochrogaster)has been shown to alter their social behavior.Here,we examined the potential disruption of adult social behavior in pra...Mercury chloride exposure through drinking water in adult male prairie voles(Microtus ochrogaster)has been shown to alter their social behavior.Here,we examined the potential disruption of adult social behavior in prairie voles that were exposed to 60 ppm mercury during early development.We used a cross-fostering approach to test the effects of mercury exposure:(1)from conception until birth;(ii)from birth until weaning;and(iii)from conception until weaning,on adult affiliative behavior.Untreated and mercury-treated voles were given the option of remaining in an empty cage or affiliating with a same-sex conspecific in a 3-h choice test.We found that early developmental mercury exposure had little if any effect on the reproductive success of breeder pairs or on affiliative behavior by either sex when subjects were tested as adults.These results suggest that,at least in the context of the behavior tested,the effects of early developmental exposure to mercury do not permanently alter adult prairie vole affiliative behavior,or do so in a way that is too subtle to be detected using the current testing paradigm.展开更多
基金This study was commissioned and funded by the Federal Environ-ment Agency(UBA)within the Environment Research Plan of the German Federal Ministry for the Environ-ment,Nature Conservation,Building and Nuclear Safety(BMUB)(Grant numbers 370941401 and 371348401 to J.J.)The work was supported by the Federal Min-istry of Education and Research(BMBF)through the National Research Platform for Zoonoses(Network“Rodent-borne pathogens”project numbers 01KI1018 and 01KI1303 to R.G.U.)。
文摘Rodents are important reservoirs for zoonotic pathogens that cause diseases in humans.Biodiversity is hypoth-esized to be closely related to pathogen prevalence through multiple direct and indirect pathways.For example,the presence of non-host species can reduce contact rates of the main reservoir host and thus reduce the risk of transmission(“dilution effect”).In addition,an overlap in ecological niches between two species could lead to increased interspecific competition,potentially limiting host densities and reducing density-dependent pathogen transmission processes.In this study,we investigated the relative impact of population-level regulation of direct and indirect drivers of the prevalence of Puumala orthohantavirus(PUUV)in bank voles(Clethrionomys glareolus)during years with high abundance.We compiled data on small mammal community composition from four regions in Germany between 2010 and 2013.Structural equation modeling revealed a strong seasonality in PUUV control mechanisms in bank voles.The abundance of shrews tended to have a negative relationship with host abundance,and host abundance positively influenced PUUV seroprevalence,while at the same time increasing the abundance of competing non-hosts like the wood mouse(Apodemus sylvaticus)and the yellow-neckedfield mouse(Apodemusflavicollis)were associated with reduced PUUV seroprevalence in the host.These results indicate that for PUUV in bank voles,dilution is associated with increased interspecific competition.Anthropogenic pressures leading to the decline of Apodemus spp.in a specific habitat could lead to the amplification of mechanisms promoting PUUV transmission within the host populations.
基金the National Natural Science Foundation of China (81660558,81260437,and 81290341)a Scientific and Technological Basis Special Project grant (2013FY113500) from the Ministry of Science and Technology of PR China+1 种基金Yunnan Provincial Collaborative Innovation Centre for Public Health and Disease Prevention and Control (2015YNPHXT05)the China Scholarship Council (CSC),Beijing,China
文摘Hepatitis E virus(HEV)is the prototype of the family Hepeviridae and the causative agent of common acute viral hepatitis.Genetically diverse HEV-related viruses have been detected in a variety of mammals and some of them may have zoonotic potential.In this study,we tested 278 specimens collected from seven wild small mammal species in Yunnan province,China,for the presence and prevalence of orthohepevirus by broad-spectrum reverse transcription(RT)-PCR.HEV-related sequences were detected in two rodent species,including Chevrier’s field mouse(Apodemus chevrieri,family Muridae)and Père David’s vole(Eothenomys melanogaster,family Cricetidae),with the infection rates of 29.20%(59/202)and 7.27%(4/55),respectively.Further four representative full-length genomes were generated:two each from Chevrier’s field mouse(named Rd HEVAc14 and Rd HEVAc86)and Père David’s vole(Rd HEVEm40 and Rd HEVEm67).Phylogenetic analyses and pairwise distance comparisons of whole genome sequences and amino acid sequences of the gene coding regions showed that orthohepeviruses identified in Chinese Chevrier’s field mouse and Père David’s vole belonged to the species Orthohepevirus C but were highly divergent from the two assigned genotypes:HEV-C1 derived from rat and shrew,and HEV-C2 derived from ferret and possibly mink.Quantitative real-time RT-PCR demonstrated that these newly discovered orthohepeviruses had hepatic tropism.In summary,our work discovered two putative novel genotypes orthohepeviruses preliminarily named HEVC3 and HEV-C4 within the species Orthohepevirus C,which expands our understanding of orthohepevirus infection in the order Rodentia and gives new insights into the origin,evolution,and host range of orthohepevirus.
文摘The present review is a compilation of the published data on the ecology and social behavior of the social vole.Field studies provide evidence that these voles live in family groups consisting of 1 adult male,1 or 2 breeding females,and their offspring(1 or 2 litters).The social vole is capable of year-round reproduction,but in arid regions,the voles demonstrate seasonality in breeding.The mating system of this species may be defined as behavioral monogamy.A typical feature of the space use system is territoriality characterized by a locus-dependent dominance in relationships between neighboring breeding pairs as well as family groups.The family group social organization may be defined as consistent relationships without a dominant hierarchy.Social voles are cooperative in defending their territories,constructing burrows,digging underground tunnels,maintaining nests,and raising young.Cooperation appears to enhance the survival of family groups of this species under the extreme climaticconditionsof Central Asia.
基金supported by National Natural Science Foundation of China(No.30670273No.30200026)Ministry of Education Key Project of Peoples Republic of China(20060718)
文摘To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research.Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles.During same sex encounters,mandarin voles attacked their opponents for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions.However,no significant behavioral differences were found during encounters of two individual reed voles,regardless of gender composition of the pair.Using c-Fos as an indicator of neural activation,we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb(MOB)and the accessory olfactory bulb(AOB)of mandarin voles compared with reed voles.Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex.Anterior-posterior ratios of Fos-ir neurons in the AOBM(AOBMR)and the AOBG(AOBGR)in male-female interaction were significantly higher than those in interaction of the same sex.The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions.Behavioral patterns are consistent with cellular activity patterns.Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species.
基金supported by the State Basic Research Program of Ministry of Science and Technology(2007CB109100)CAS project(GJHZ 200810)the ISZS international research program Biological Consequences of Global Change(BCGC)sponsored by Bureau of International Cooperation,Chinese Academy of Sciences(GJHZ200810).
文摘The Yangtze vole(Microtus fortis Buechner,1889)is a small herbivore species that inhabits lake beaches in the Dongting Lake region along the Yangtze River in Southern China.Its population shows strong oscillations during the wet season due to summer precipitation-induced immigration away from the lake into adjacent rice fields.The effect of El Niño-Southern Oscillation-driven precipitation on population abundance and growth of the vole species is not fully understood.We undertook an analysis of the combined data of 4 time series covering 1981–2006 from 4 different sites and a separate analysis on a single time series(1981–2006)from one site.Our results demonstrate that a dual effect of El Niño-Southern Oscillation-driven precipitation on the population abundance of voles is timedependent:precipitation in the current year has a positive effect,whereas precipitation in the previous year has a negative effect.The dual effect of precipitation on vole population is well explained by the unique interactions among vole population,precipitation water level and the lake beach habitat around Dongting Lake.We found that drier than average weather of the previous year benefited voles because their breeding habitats,lake beaches,were exposed for long stretches of time.Wet weather was found to increase the number of voles inhabiting rice fields because as the water level of the lake rose they were forced from beaches into surrounding rice fields.Summer precipitation in the Dongting Lake region was found to be positively associated with the sea surface temperature(SST)of the eastern tropical Pacific Ocean of the previous year and winter SST and spring SST of the current year.Annual rates of increase in the vole population of the reconstructed time series are negatively associated with the vole abundance and autumn precipitation of the previous year and winter precipitation of the current years.These results suggest that both extrinsic and density-dependent intrinsic factors may affect population dynamics of the Yangtze vo
文摘It is widely believed that intensive forestry has influenced small mammal population dynamics,and thereby the entire mammalian community in Fennoscandian boreal forests.The nature of these impacts on the different species is subject to debate.We live-trapped voles between 2006 and 2009 in 2 commercially harvested forests in south-eastern Norway.We investigated the variation in vole abundance among habitat types(e.g.mature forest and clear-cut)and the hypothesis that graminivorous species such as field voles(Microtus agrestis L.)benefit from clear-cuts at the expense of forest dwellers(i.e.the bank vole,Myodes glareolus Schreb.),using fine-scale descriptors of the ground vegetation.We could not find support for the hypothesis that field voles show a preference for clear-cuts,and their overall abundance was low,while bank voles were the dominant species in all habitat types,including clear-cuts in the peak and pre-peak years.We found a positive association between bank vole abundance and bilberry(Vaccinium myrtillus L.)availability rather than a specific habitat type.Low field vole density in clear-cuts might be due to variation in local productivity and ground vegetation as well as to large variation in the species temporal dynamics.The latter is particularly associated with the widespread decline of field voles in Scandinavia.Logging has the potential to negatively affect bank vole population dynamics because of the negative effect on bilberry development.
基金the National Nature Science Foundation of China(31471790)the Agricultural Agricultural Science and Technology Innovation Program(National Key Technology R&D Program,2012BAD19B02)the National Basic Research Program of China(973 Program,2007CB109104)。
文摘Age structure and seasonality influence the population fluctuations of small rodents.Age determines body weight and social experience,while seasonality regulates the duration of the breeding season and onset of sexual maturity in newborn offspring.Therefore,reproductive success and skew usually occur in different age groups.Brandt’s vole(Lasiopodomys brandtii)is a social,short-lived and seasonal breeding small rodent with a dramatic seasonal population fluctuation,but reproductive skew is not fully understood in this species.In the present study,we determined kinship in semi-natural enclosure populations using microsatellite markers based on genotyping,analyzed the reproductive skew between sexes and between overwintered and newborn voles,and monitored variation in male reproductive activity by testing fecal testosterone levels throughout the year.Overwintered voles had the most reproductive success along with a striking increase in the population size in the enclosures,with all biological fathers and 77.8%of biological mothers,which had 100%and 87%of the total offspring,respectively.Compared to overwintered voles,reproductive skews were significantly higher in potential overwintered and newborn parents,implying the possible reproductive suppression of newborn voles by dominant overwintered voles.Moreover,both heavier body weight and higher testosterone levels in overwintered males supported their potential social status in the population.Our study provided new evidence for reproductive skew and differentiation of postnatal gonadal development patterns of different age groups in Brandt’s vole.
文摘No-till farming is an important approach to sustainable agriculture because it can conserve soil and water resources.Unfortunately, rodent populations can thrive under no-till conditions because burrow systems are not disrupted byannual plowing and plant residues build-up on the surface, providing cover and insulation. This can result in substantialcrop damage. We assessed rodent populations, habitat use, food habits, and crop damage in a no-till croppingsystem in Washington, USA. We also conducted preliminary trials of methods to reduce rodent populationsand crop damage. In the fall, many more rodents were captured in fields with unharvested crops than in fieldscontaining only plant stubble, suggesting that rodents leave fields after crop harvest, providing that suitable habitatsare nearby, even when adequate cover is still available in harvested crop fields. By spring, the number of volescaptured was much lower relative to fall. Despite this, capture rates were much higher in surrounding permanentgrass areas than in crop (barley, wheat, pea) fields, suggesting that these grassy areas serve as refugia for rodents.Furthermore, the permanent grass cover type was the landscape variable most associated with rodent capture rates.In three winter pea fields, rodents removed 5–15% of the pea plants over winter. Examination of stomach contentsrevealed that voles mainly fed on grain plants in spring, but that their diet was more diversified in fall. Deer micefed heavily on grain plants in both spring and fall, but also used insects as food. Metal barrier exclosures (9 m × 9m), extending above and below ground, did not prevent access by rodents. Rodent populations in areas treated withzinc phosphide on grain were comparable to untreated areas 1 year after application of the rodenticide, perhaps becauseof immigration and recruitment, suggesting that baiting does not provide a long-term solution to rodent damagein no-till agricultural fields.
文摘Human-made agro-ecosystems lack negative feedback controls, which may result in rodent population explosions,causing considerable economic loss and thus increasing human–wildlife conflicts. The traditional solution is theextensive use of rodenticides, which have a negative impact on the environment. In Beit-Sheaan Valley, Israel,which is located on a major route for migrating birds, poisoning of voles may result in the death of birds that preyon the dead voles (e.g. storks and herons). In the present essay we discuss some integrated methods, based on theimplementation of ecological principles in agro-ecosystems, that could be used to decrease the use of rodenticides.The first method is light interference during winter (long scotophase), which can result in the death of the socialvole Microtus socialis kept in enclosures under natural conditions. Under laboratory conditions such interferencecauses a decrease in thermoregulatory ability in the cold. As light interference is a source of pollution, only activevole burrows should be illuminated. The second method involves using the mobile irrigation pipelines to flood thevole burrows and force them to escape into the open, where diurnal birds such as storks and herons will prey onthem. The third method involves the use of nesting boxes for barn owls and stands for diurnal raptors, both ofwhich prey on voles. The great advantage of using an integrated approach is that voles cannot become adapted toany one of the methods. Such integrated methods, together with appropriate treatment of alfalfa fields by farmers,can provide an efficient and sustainable pest control approach.
文摘We studied the behavioral and endocrine responses of the fossorial s ocial rodent, mole vole Ellobius talpinus Pall., to intrusions of strangers int o burrow systems that were occupied by intact families. Both in reproductive and non-reproductive seasons, all intruders disappeared from the burrow systems of residents within two days of introduction, whereas 4 of 7 individuals introduced into empty burrows remained there at least for two days. Introduction of strang ers led to the concentration of residents at the point of release and to an incr ease of plasma corticosterone in both residents and intruders. During the breedi ng season, introduction of strangers was also accompanied by an increase of plas ma testosterone of residents on the day of introduction. Thus, simulation of int rusion of strangers demonstrated the efficient social fence of resident mole vol es that seems to be an important mechanism of stabilization of size and structur e of mole vole families. Encounters of residents and intruders resulted in activ ation of physiological mechanisms of stress, especially during the breeding seas on .
基金This work was supported in part by a grant from The Eunice Kennedy Shriver National Institute for Child Health and Development(HD48462)by a Robberson Summer Dissertation Fellowship from the Oklahoma State University Center for Health Sciences.
文摘Mercury chloride exposure through drinking water in adult male prairie voles(Microtus ochrogaster)has been shown to alter their social behavior.Here,we examined the potential disruption of adult social behavior in prairie voles that were exposed to 60 ppm mercury during early development.We used a cross-fostering approach to test the effects of mercury exposure:(1)from conception until birth;(ii)from birth until weaning;and(iii)from conception until weaning,on adult affiliative behavior.Untreated and mercury-treated voles were given the option of remaining in an empty cage or affiliating with a same-sex conspecific in a 3-h choice test.We found that early developmental mercury exposure had little if any effect on the reproductive success of breeder pairs or on affiliative behavior by either sex when subjects were tested as adults.These results suggest that,at least in the context of the behavior tested,the effects of early developmental exposure to mercury do not permanently alter adult prairie vole affiliative behavior,or do so in a way that is too subtle to be detected using the current testing paradigm.
