For songbirds,the post-fledging period is critical for development and survival,as young must learn to get food,practice flying,and identify predators to become independent from their parents and disperse or migrate.O...For songbirds,the post-fledging period is critical for development and survival,as young must learn to get food,practice flying,and identify predators to become independent from their parents and disperse or migrate.Obligate avian brood parasites,like cuckoos and cowbirds,lay eggs in nests of other bird species that provide parental care until the parasite’s young become independent.The information on the post-fledging period in songbirds is limited due to the difficulty in following and observing fledglings and it is even scarcer for brood parasites.We studied the behavior,survival,and age of independence of Shiny Cowbird(Molothrus bonariensis)fledglings raised by 2 hosts that differ markedly in body size:the House Wren(Troglodytes aedon)and the Chalk-Browed Mockingbird(Mimus saturninus).We radio-tracked individuals from a few days before they left the nest until they disappeared from the natal territory.We found:(1)chicks left the nest when they were 11-15 days of age and the age of fledgling did not differ between the 2 host species,(2)after leaving the nest,they spent most of the time perched in a hidden place without begging but as they grew,the proportion of time perched without begging decreased and begging in hidden and exposed places increased,(3)we observed approaches between adult parasitic females and young in host territories,(4)young abandoned the host territory and joined conspecific flocks when they were 35-39 days of age,and(5)the estimated post-fledging survival was between 12.5%and 20.8%.展开更多
Drosophila buzzatii and D.koepferae are sibling cactophilie species.The former breeds primarily on prickly pears (genus Opuntia)whereas the latter breeds on columnar cacti of the genera Cereus and Trichocereus,althoug...Drosophila buzzatii and D.koepferae are sibling cactophilie species.The former breeds primarily on prickly pears (genus Opuntia)whereas the latter breeds on columnar cacti of the genera Cereus and Trichocereus,although with certain degree of niche overlapping.We examined the interspecific differences in diurnal temporal patterns of adult emergence from puparia and evaluated whether this behavior is affected by rearing in the different cactus hosts available in nature.We detected important host-dependent genetic variation for this trait differentially affecting the emergence schedule of these species.Diumal pattern of emergence time was directly correlated with developmental time and negatively correlated with adult wing size,suggesting that early emergences are at least indirectly correlated with increased fitness.We discussed our results in terms of their putative effects on fitness and the genetic-metabolic pathways that would be presumably affected by host's nutritional-chemical differences.展开更多
It has been demonstrated that phenotypic plasticity and genotype by envi-ronment interaction are important for coping with new and heterogeneous environments during invasions.Zaprionus indianus Gupta(Diptera:Drosophil...It has been demonstrated that phenotypic plasticity and genotype by envi-ronment interaction are important for coping with new and heterogeneous environments during invasions.Zaprionus indianus Gupta(Diptera:Drosophilidae)is an Afrotropical invasive fly species introduced to the South American continent in 1999.This species is generalist and polyphagous,since it develops and feeds in several different fruit species.These characteristics of Z.indianus suggest that phenotypic plasticity and genotype by environment interaction may be important in this species invasion process.In this sense,our aim was to investigate the role of genetic variation for phenotypic plasticity(geno-type by environment interaction)in Z.indianus invasion of the South American continent.Specifically,we quantified quantitative genetic variation and genotype by environment in-teractions of morphological and life history traits in different developmental environments,that is,host fruits.This was done in different populations in the invasive range of Z.indi-anus in Argentina.Results showed that Z.indianus populations have considerable amounts of quantitative genetic variation.Also,genotype by environment interactions was detected for the different traits analyzed in response to the different developmental environments.Interestingly,the amounts and patterns of these parameters differed between populations.We interpreled these results as the existence of diferences in evolutionary potential be-tween populations that have an important role in the short-and long-term success of the Z.indianus invasion process.展开更多
Hantavirus pulmonary syndrome is a severe cardio pulmonary disease transmitted to humans by sylvan rodents found in natural and rural environments.Disease transmission is closely linked to the ecology of animal reserv...Hantavirus pulmonary syndrome is a severe cardio pulmonary disease transmitted to humans by sylvan rodents found in natural and rural environments.Disease transmission is closely linked to the ecology of animal reservoirs and abiotic factors such as habitat characteristics,season or climatic conditions.The main goals of this research were:to determine the biotic and abiotic factors affecting richness and abundance of rodent species at different spatial scales,to evaluate different methodologies for studying population of small rodents,and to describe and analyze an ecologically-based rodent management experience in a highly touristic area.A 4-year study of small rodent ecology was conducted between April 2007 and August 2011 in the most relevant habitats of El Palmar National Park,Argentina.Management involved a wide range of control and prevention measures,including poisoning,culling and habitat modification.A total of 172 individuals of 5 species were captured with a trapping effort of 13860 traps-nights(1.24 individuals/100 traps-nights).Five rodent species were captured,including 2 hantavirus-host species,Oligoryzomys nigripes and Akodon azarae.Oligoryzomys nigripes,host of a hantavirus that is pathogenic in humans,was the most abundant species and the only one found in all the studied habitats.Our results are inconsistent with the dilution effect hypothesis.The present study demonstrates that sylvan rodent species,including the hantavirus-host species,have distinct local habitat selection and temporal variation patterns in abundance,which may influence the risk of human exposure to hantavirus and may have practical implications for disease transmission as well as for reservoir management.展开更多
Background:As no globally accepted dengue vaccines or specific antiviral therapies are currently available,controlling breeding sites of Aedes aegypti is a target to prevent dengue outbreaks.The present study aimed to...Background:As no globally accepted dengue vaccines or specific antiviral therapies are currently available,controlling breeding sites of Aedes aegypti is a target to prevent dengue outbreaks.The present study aimed to characterize outdoor artificial breeding sites in urban households using an exhaustive classification system.Methods:A cross-sectional entomological survey was carried out in Colón city,Entre Ríos,Argentina,using a two-stage stratified sampling design during March and April 2014.The city was stratified given the degree of urbanization of each block,and blocks and households were randomly selected.All outdoor containers with water were inspected,and the presence of immature mosquitoes was recorded.Containers were classified according to physical,functional,and location attributes.Generalized linear mixed models were applied to take into account the aggregated nature of the data(containers in houses and houses in blocks).Results:Overall,207 houses were inspected.Out of 522 containers with water,25%had immatures ofAe.aegypti(7336).In adjusted models,the abundance of immatures was higher in containers with increasing opening surface and volume,without roof cover,exposed to shadow,out of use or with functions related to gardening activities,household chores,water storage,or construction.At block level,immatures abundance was positively associated with the degree of urbanization.Conclusions:We detected high immatures abundance in containers associated with water utilization.This suggests that containers involved in these activities,whether directly(e.g.,water storage)or indirectly(e.g.,incomplete water drainage in the last use),are susceptible to present a high immature abundance.Although our results indicate the importance of the type of use over the type of container,we encourage the use of both classification criteria for artificial breeding sites of mosquitoes,mainly because these are complementary.Additionally,generalized linear mixed models allowed us to analyse predictor variables at different scales(container/house/block)and consider the lack of independence between observations.An exhaustive analysis of artificial breeding sites that use this analytical methodology can lead to new information that could help designing more appropriate tools for dengue surveillance and control.展开更多
基金supported by Grants from the Agencia Nacional de Promoción Científica y Tecnológica,from Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)and the University of Buenos Aires.
文摘For songbirds,the post-fledging period is critical for development and survival,as young must learn to get food,practice flying,and identify predators to become independent from their parents and disperse or migrate.Obligate avian brood parasites,like cuckoos and cowbirds,lay eggs in nests of other bird species that provide parental care until the parasite’s young become independent.The information on the post-fledging period in songbirds is limited due to the difficulty in following and observing fledglings and it is even scarcer for brood parasites.We studied the behavior,survival,and age of independence of Shiny Cowbird(Molothrus bonariensis)fledglings raised by 2 hosts that differ markedly in body size:the House Wren(Troglodytes aedon)and the Chalk-Browed Mockingbird(Mimus saturninus).We radio-tracked individuals from a few days before they left the nest until they disappeared from the natal territory.We found:(1)chicks left the nest when they were 11-15 days of age and the age of fledgling did not differ between the 2 host species,(2)after leaving the nest,they spent most of the time perched in a hidden place without begging but as they grew,the proportion of time perched without begging decreased and begging in hidden and exposed places increased,(3)we observed approaches between adult parasitic females and young in host territories,(4)young abandoned the host territory and joined conspecific flocks when they were 35-39 days of age,and(5)the estimated post-fledging survival was between 12.5%and 20.8%.
文摘Drosophila buzzatii and D.koepferae are sibling cactophilie species.The former breeds primarily on prickly pears (genus Opuntia)whereas the latter breeds on columnar cacti of the genera Cereus and Trichocereus,although with certain degree of niche overlapping.We examined the interspecific differences in diurnal temporal patterns of adult emergence from puparia and evaluated whether this behavior is affected by rearing in the different cactus hosts available in nature.We detected important host-dependent genetic variation for this trait differentially affecting the emergence schedule of these species.Diumal pattern of emergence time was directly correlated with developmental time and negatively correlated with adult wing size,suggesting that early emergences are at least indirectly correlated with increased fitness.We discussed our results in terms of their putative effects on fitness and the genetic-metabolic pathways that would be presumably affected by host's nutritional-chemical differences.
基金The authors wish to thank Bryant Hillas for revision of the final version of the manuscript.This work was sup-ported by grants from the Agencia Nacional de Promocion Cientifica y Tecnologica(Argentina)(PICT 2012-0640)the Universidad de Buenos Aires(Argentina)(UBA-CyT 20020100100482).NJL and JJF are members of Carrera del Investigador Cientifico of CONICET(Ar-gentina).MI,NE,and VEO are recipients of a scholarship from CONICET(Argentina).
文摘It has been demonstrated that phenotypic plasticity and genotype by envi-ronment interaction are important for coping with new and heterogeneous environments during invasions.Zaprionus indianus Gupta(Diptera:Drosophilidae)is an Afrotropical invasive fly species introduced to the South American continent in 1999.This species is generalist and polyphagous,since it develops and feeds in several different fruit species.These characteristics of Z.indianus suggest that phenotypic plasticity and genotype by environment interaction may be important in this species invasion process.In this sense,our aim was to investigate the role of genetic variation for phenotypic plasticity(geno-type by environment interaction)in Z.indianus invasion of the South American continent.Specifically,we quantified quantitative genetic variation and genotype by environment in-teractions of morphological and life history traits in different developmental environments,that is,host fruits.This was done in different populations in the invasive range of Z.indi-anus in Argentina.Results showed that Z.indianus populations have considerable amounts of quantitative genetic variation.Also,genotype by environment interactions was detected for the different traits analyzed in response to the different developmental environments.Interestingly,the amounts and patterns of these parameters differed between populations.We interpreled these results as the existence of diferences in evolutionary potential be-tween populations that have an important role in the short-and long-term success of the Z.indianus invasion process.
文摘Hantavirus pulmonary syndrome is a severe cardio pulmonary disease transmitted to humans by sylvan rodents found in natural and rural environments.Disease transmission is closely linked to the ecology of animal reservoirs and abiotic factors such as habitat characteristics,season or climatic conditions.The main goals of this research were:to determine the biotic and abiotic factors affecting richness and abundance of rodent species at different spatial scales,to evaluate different methodologies for studying population of small rodents,and to describe and analyze an ecologically-based rodent management experience in a highly touristic area.A 4-year study of small rodent ecology was conducted between April 2007 and August 2011 in the most relevant habitats of El Palmar National Park,Argentina.Management involved a wide range of control and prevention measures,including poisoning,culling and habitat modification.A total of 172 individuals of 5 species were captured with a trapping effort of 13860 traps-nights(1.24 individuals/100 traps-nights).Five rodent species were captured,including 2 hantavirus-host species,Oligoryzomys nigripes and Akodon azarae.Oligoryzomys nigripes,host of a hantavirus that is pathogenic in humans,was the most abundant species and the only one found in all the studied habitats.Our results are inconsistent with the dilution effect hypothesis.The present study demonstrates that sylvan rodent species,including the hantavirus-host species,have distinct local habitat selection and temporal variation patterns in abundance,which may influence the risk of human exposure to hantavirus and may have practical implications for disease transmission as well as for reservoir management.
基金This study was supported by the grants:UBACyT 20020100200151,UBANEX 5 and UBANEX 6 from the University of Buenos Aires.
文摘Background:As no globally accepted dengue vaccines or specific antiviral therapies are currently available,controlling breeding sites of Aedes aegypti is a target to prevent dengue outbreaks.The present study aimed to characterize outdoor artificial breeding sites in urban households using an exhaustive classification system.Methods:A cross-sectional entomological survey was carried out in Colón city,Entre Ríos,Argentina,using a two-stage stratified sampling design during March and April 2014.The city was stratified given the degree of urbanization of each block,and blocks and households were randomly selected.All outdoor containers with water were inspected,and the presence of immature mosquitoes was recorded.Containers were classified according to physical,functional,and location attributes.Generalized linear mixed models were applied to take into account the aggregated nature of the data(containers in houses and houses in blocks).Results:Overall,207 houses were inspected.Out of 522 containers with water,25%had immatures ofAe.aegypti(7336).In adjusted models,the abundance of immatures was higher in containers with increasing opening surface and volume,without roof cover,exposed to shadow,out of use or with functions related to gardening activities,household chores,water storage,or construction.At block level,immatures abundance was positively associated with the degree of urbanization.Conclusions:We detected high immatures abundance in containers associated with water utilization.This suggests that containers involved in these activities,whether directly(e.g.,water storage)or indirectly(e.g.,incomplete water drainage in the last use),are susceptible to present a high immature abundance.Although our results indicate the importance of the type of use over the type of container,we encourage the use of both classification criteria for artificial breeding sites of mosquitoes,mainly because these are complementary.Additionally,generalized linear mixed models allowed us to analyse predictor variables at different scales(container/house/block)and consider the lack of independence between observations.An exhaustive analysis of artificial breeding sites that use this analytical methodology can lead to new information that could help designing more appropriate tools for dengue surveillance and control.
