Diversity measurements can be influenced by space and time scales of the samples. The resource u... more Diversity measurements can be influenced by space and time scales of the samples. The resource use of rates by a population of a species were determined by the slope of a body mass x density power regression curves for mammals on different scales. The slope obtained for Neotropical mammals was -.075 and on a local scale was -0,71, but was variable along the time axis when we used instantaneous samples on local scales. This may be due to changes in resource availability as well as in population sizes and species richness at a given moment. These factors together with habitat fragmentation and isolation can influence diversity measurements. We propose that diversity studies should be done over large space and time scales
A five-year capture-mark-recapture study of small mammals was carried out in a Brazilian coastal ... more A five-year capture-mark-recapture study of small mammals was carried out in a Brazilian coastal shrubby vegetation (restinga). Five species of small mammals (rodents and marsupials) were trapped and had their population dynamics characterized. Akodon cursor and Philander opossum presented the highest population densities, which were correlated chiefly with recruitment. They displaiyed frequent population fluctuations with high coefficients of variation, low survivorship rates most of the time and short residence times. Proechimys iheringi was characterized by stable population densities, high survivorship rates and long residence time. Didelphis anrita and Metachirus nudicaudatus presented low densities, disappearing occasionally from the study area, and they can be characterized by the absence of permanent population center. No regular pattern of seasonal population fluctuations was detected for any species in the assemblage, but populations seem to present pluriannual patterns of fluctuation. The marsupials reproduce seasonally from late winter until the end of the summer. Rodents did not show a clear reproductive season. The mammalian fauna of the Restinga de Barra de Maricä seems to be a subset of the Atlantic Forest fauna, impoverished by its habitat configuration.
Abstrat.-Three species of Callitrichidae occur in Rio de Janeiro State, southeastern Brazil. Leon... more Abstrat.-Three species of Callitrichidae occur in Rio de Janeiro State, southeastern Brazil. Leontopithecus rosalia and Callithrix aurita are natural inhabitants of this State. Callithrix jacchus has been introduced by man. The distribution of each species was analysed in relation to thirteen climatic averages, altitude and vegetation for each locality recorded. A hypothesis of potential distribution is presented for C. aurita and L. rosalia. L. rosalia has a distribution related to mosaics of rainforest and hygrophilous vegetation, to high temperatures and rainfall in Rio de Janeiro low-lands and to a maximum known altitude record of 150 m. This distribution pattern in hygrophi-lous forests and low altitudes for lion-tamarins disagrees with the current idea that these endangered primates are inhabitants of Atlantic forest (sensu lato). C. aurita lives in rainforests on the mountain ranges of the State under a climate of high humidity and rainfall but with lower temperatures , and also in deciduous and semideciduous mountain forests. Although C. jacchus has being continuously introduced, its range still remains reduced and it inhabits mainly disturbed habitats in tropical climates. C. aurita and L. rosalia do not have overlapping distributions. The latter species occurred, in the past, in some areas that are presently altered and where C. jacchus now occurs.
A ética distingue-se da moral. Esta última é um sistema de valores do qual resultam normas de con... more A ética distingue-se da moral. Esta última é um sistema de valores do qual resultam normas de conduta consideradas corretas por uma sociedade ou grupo social. Uma formação social determinada, por exemplo, os Estados Unidos, pode ter um conjunto de normas morais próprias distintas de outra formação similar. Uma categoria profissional, como os médicos, é um grupo social que tem um código de "ética" próprio que prescrever certas regras consideradas morais pelo grupo. Cada grupo religioso também prescreve regras morais particulares a seus adeptos. Neste caso a lei moral ou códigos vem de uma autoridade (Deus, juizes, associação profissional, etc.) que as impõe. A moral tem três características: seus valores não são questionados, são impostos e a desobediência às regras impõe um castigo 2 . Os autores citados dizem que, segundo Freud, a religião afasta o ser humano da liberdade, pois ao perturbar a livre eleição e impor um único caminho, Deus, leva a que só reste o sofrimento e a submissão incondicional como único consolo e fonte de gozo.
We analyzed ontogenetic patterns of landmarks for 169 laboratory-raised specimens of Calomys expu... more We analyzed ontogenetic patterns of landmarks for 169 laboratory-raised specimens of Calomys expulsus, at 0, 5 , 10, 20, 30, SO, 100, 200, and 300 days of age, using two-dimensional geometric morphometrics. There is sexual dimorphism in size, with males smaller than females at earlier ages, but larger after SO days. Differences in shape between sexes are strong only until 10 days of age, suggesting that shape is more constrained than size. Combining sexes, there is strong variation in size with age, reduced after 200 days, while most of the variation in shape occurs before 20 days. This dissociation is common for sigmodontine rodents, and might be the basis of heterochronic processes responsible for the morphological variation of this South American group. Centroid size does not show m y reduction in the coefficient of variation over ages, while Procrustes distances within sucessive ages are reduced after 20 days. Uniform component and the more global partial warps explain most of the shape changes with age. Cranial and Facial parts of the skull increase in size at different rates with a relative lengthening of the snout and decrease in height of the braincase. We were unable to detect a clear pattern of integration for the rostrum and braincase, besides that shown by landmark displacements.
... vertebrate preys found in feces of D. aurita was larger (H'=0.61) than M. nudicaudatus (... more ... vertebrate preys found in feces of D. aurita was larger (H'=0.61) than M. nudicaudatus (H'=0.41), although not significant by (Hutcheson t-test t=1.511, 0.1 < p <0.2 (Zar 1984)). Lizards were the most frequent vertebrate prey in both animals. They can be found from dawn to dusk ...
By means of complex segregation analysis we studied the inheritance of litter size in two large p... more By means of complex segregation analysis we studied the inheritance of litter size in two large pedigrees of captive-bred colonies of the Brazilian grass mouse Akodon cursor. Genetic analysis has revealed a highly significant influence of genetic factors on the variation of litter size (heritability, h#, was estimated as 0n44). The inheritance followed the classical polygene model : neither the major-gene model nor the polygene with unequal contribution model described the data significantly better.
We suggest here that the onset of the breeding season of Monodelphis domestica may be controled b... more We suggest here that the onset of the breeding season of Monodelphis domestica may be controled by photoperiod. This phenomenon is well known in Australian marsupials, but it is the first time that such factor can be interpreted as influencing the breeding season of a Neotropical marsupial.
Com 7 figuras) RUI CERQUEIRA 2 RESUMO: Pequenos mamíferos (roedores e marsupiais) neotropicais do... more Com 7 figuras) RUI CERQUEIRA 2 RESUMO: Pequenos mamíferos (roedores e marsupiais) neotropicais do leste do Brasil foram estudados em relação aos fatores responsáveis pelo início da estação reprodutora. Os primeiros estudos utilizaram os dados de espécies depositados no Museu Nacional e, posteriormente, trabalhos de campo e de laboratório. Dois modos de reprodução foram concebidos. Constatou-se que os marsupiais têm o início da estação reprodutora determinado pela variação do fotoperíodo. Os roedores Sigmodontini no Nordeste do Brasil têm sua reprodução iniciada pela chegada da estação chuvosa. O modo de reprodução dos marsupiais é, portanto, marcadamente estacional e relativamente independente das condições ambientais com solstícios e equinócios funcionando como fatores próximos. O modo de reprodução dos Sigmodontini é determinado pela possibilidade das fêmeas acumularem reservas e está ligado diretamente aos fatores primários. Palavras-chave: Marsupiais, roedores, fatores ambientais, reprodução, estação reprodutiva, ecologia da reprodução, chuva, duração do dia.
Diversity measurements can be influenced by space and time scales of the samples. The resource u... more Diversity measurements can be influenced by space and time scales of the samples. The resource use of rates by a population of a species were determined by the slope of a body mass x density power regression curves for mammals on different scales. The slope obtained for Neotropical mammals was -.075 and on a local scale was -0,71, but was variable along the time axis when we used instantaneous samples on local scales. This may be due to changes in resource availability as well as in population sizes and species richness at a given moment. These factors together with habitat fragmentation and isolation can influence diversity measurements. We propose that diversity studies should be done over large space and time scales
A five-year capture-mark-recapture study of small mammals was carried out in a Brazilian coastal ... more A five-year capture-mark-recapture study of small mammals was carried out in a Brazilian coastal shrubby vegetation (restinga). Five species of small mammals (rodents and marsupials) were trapped and had their population dynamics characterized. Akodon cursor and Philander opossum presented the highest population densities, which were correlated chiefly with recruitment. They displaiyed frequent population fluctuations with high coefficients of variation, low survivorship rates most of the time and short residence times. Proechimys iheringi was characterized by stable population densities, high survivorship rates and long residence time. Didelphis anrita and Metachirus nudicaudatus presented low densities, disappearing occasionally from the study area, and they can be characterized by the absence of permanent population center. No regular pattern of seasonal population fluctuations was detected for any species in the assemblage, but populations seem to present pluriannual patterns of fluctuation. The marsupials reproduce seasonally from late winter until the end of the summer. Rodents did not show a clear reproductive season. The mammalian fauna of the Restinga de Barra de Maricä seems to be a subset of the Atlantic Forest fauna, impoverished by its habitat configuration.
Abstrat.-Three species of Callitrichidae occur in Rio de Janeiro State, southeastern Brazil. Leon... more Abstrat.-Three species of Callitrichidae occur in Rio de Janeiro State, southeastern Brazil. Leontopithecus rosalia and Callithrix aurita are natural inhabitants of this State. Callithrix jacchus has been introduced by man. The distribution of each species was analysed in relation to thirteen climatic averages, altitude and vegetation for each locality recorded. A hypothesis of potential distribution is presented for C. aurita and L. rosalia. L. rosalia has a distribution related to mosaics of rainforest and hygrophilous vegetation, to high temperatures and rainfall in Rio de Janeiro low-lands and to a maximum known altitude record of 150 m. This distribution pattern in hygrophi-lous forests and low altitudes for lion-tamarins disagrees with the current idea that these endangered primates are inhabitants of Atlantic forest (sensu lato). C. aurita lives in rainforests on the mountain ranges of the State under a climate of high humidity and rainfall but with lower temperatures , and also in deciduous and semideciduous mountain forests. Although C. jacchus has being continuously introduced, its range still remains reduced and it inhabits mainly disturbed habitats in tropical climates. C. aurita and L. rosalia do not have overlapping distributions. The latter species occurred, in the past, in some areas that are presently altered and where C. jacchus now occurs.
A ética distingue-se da moral. Esta última é um sistema de valores do qual resultam normas de con... more A ética distingue-se da moral. Esta última é um sistema de valores do qual resultam normas de conduta consideradas corretas por uma sociedade ou grupo social. Uma formação social determinada, por exemplo, os Estados Unidos, pode ter um conjunto de normas morais próprias distintas de outra formação similar. Uma categoria profissional, como os médicos, é um grupo social que tem um código de "ética" próprio que prescrever certas regras consideradas morais pelo grupo. Cada grupo religioso também prescreve regras morais particulares a seus adeptos. Neste caso a lei moral ou códigos vem de uma autoridade (Deus, juizes, associação profissional, etc.) que as impõe. A moral tem três características: seus valores não são questionados, são impostos e a desobediência às regras impõe um castigo 2 . Os autores citados dizem que, segundo Freud, a religião afasta o ser humano da liberdade, pois ao perturbar a livre eleição e impor um único caminho, Deus, leva a que só reste o sofrimento e a submissão incondicional como único consolo e fonte de gozo.
We analyzed ontogenetic patterns of landmarks for 169 laboratory-raised specimens of Calomys expu... more We analyzed ontogenetic patterns of landmarks for 169 laboratory-raised specimens of Calomys expulsus, at 0, 5 , 10, 20, 30, SO, 100, 200, and 300 days of age, using two-dimensional geometric morphometrics. There is sexual dimorphism in size, with males smaller than females at earlier ages, but larger after SO days. Differences in shape between sexes are strong only until 10 days of age, suggesting that shape is more constrained than size. Combining sexes, there is strong variation in size with age, reduced after 200 days, while most of the variation in shape occurs before 20 days. This dissociation is common for sigmodontine rodents, and might be the basis of heterochronic processes responsible for the morphological variation of this South American group. Centroid size does not show m y reduction in the coefficient of variation over ages, while Procrustes distances within sucessive ages are reduced after 20 days. Uniform component and the more global partial warps explain most of the shape changes with age. Cranial and Facial parts of the skull increase in size at different rates with a relative lengthening of the snout and decrease in height of the braincase. We were unable to detect a clear pattern of integration for the rostrum and braincase, besides that shown by landmark displacements.
... vertebrate preys found in feces of D. aurita was larger (H'=0.61) than M. nudicaudatus (... more ... vertebrate preys found in feces of D. aurita was larger (H'=0.61) than M. nudicaudatus (H'=0.41), although not significant by (Hutcheson t-test t=1.511, 0.1 < p <0.2 (Zar 1984)). Lizards were the most frequent vertebrate prey in both animals. They can be found from dawn to dusk ...
By means of complex segregation analysis we studied the inheritance of litter size in two large p... more By means of complex segregation analysis we studied the inheritance of litter size in two large pedigrees of captive-bred colonies of the Brazilian grass mouse Akodon cursor. Genetic analysis has revealed a highly significant influence of genetic factors on the variation of litter size (heritability, h#, was estimated as 0n44). The inheritance followed the classical polygene model : neither the major-gene model nor the polygene with unequal contribution model described the data significantly better.
We suggest here that the onset of the breeding season of Monodelphis domestica may be controled b... more We suggest here that the onset of the breeding season of Monodelphis domestica may be controled by photoperiod. This phenomenon is well known in Australian marsupials, but it is the first time that such factor can be interpreted as influencing the breeding season of a Neotropical marsupial.
Com 7 figuras) RUI CERQUEIRA 2 RESUMO: Pequenos mamíferos (roedores e marsupiais) neotropicais do... more Com 7 figuras) RUI CERQUEIRA 2 RESUMO: Pequenos mamíferos (roedores e marsupiais) neotropicais do leste do Brasil foram estudados em relação aos fatores responsáveis pelo início da estação reprodutora. Os primeiros estudos utilizaram os dados de espécies depositados no Museu Nacional e, posteriormente, trabalhos de campo e de laboratório. Dois modos de reprodução foram concebidos. Constatou-se que os marsupiais têm o início da estação reprodutora determinado pela variação do fotoperíodo. Os roedores Sigmodontini no Nordeste do Brasil têm sua reprodução iniciada pela chegada da estação chuvosa. O modo de reprodução dos marsupiais é, portanto, marcadamente estacional e relativamente independente das condições ambientais com solstícios e equinócios funcionando como fatores próximos. O modo de reprodução dos Sigmodontini é determinado pela possibilidade das fêmeas acumularem reservas e está ligado diretamente aos fatores primários. Palavras-chave: Marsupiais, roedores, fatores ambientais, reprodução, estação reprodutiva, ecologia da reprodução, chuva, duração do dia.
Nutritional requirements of 12 species of Neotropical opossums (Didelphidae) were inferred throug... more Nutritional requirements of 12 species of Neotropical opossums (Didelphidae) were inferred through a laboratory food preference experiment. Nutritional contents of experimental diets follow predictions based on field diet data, with more frugivorous species showing high non-structural carbohydrate proportions and more carnivorous species high protein contents in their selected diets. Mouse opossums selected nutritional and fibre proportions that suggested that they may be more frugivorous and less strictly insectivorous than previously thought. The species form a gradient of differential food specialisation from frugivory to car-nivory, and significant differences are found only between extremes of this gradient. Nutritional contents established here are consistent with natural diet patterns and can be used as important complementary data to field diet studies and to prepare diets for captive maintenance of the species.
A estrutura do habitat pode variar tanto na escala temporal quanto na escala espacial [1] . Na es... more A estrutura do habitat pode variar tanto na escala temporal quanto na escala espacial [1] . Na escala temporal, a estrutura do habitat apresenta desde alterações sutis (ex: clareiras), até a sua fragmentação ou destruição completa. A mudança na estrutura do habitat com o passar do tempo pode ser observada durante o processo de sucessão ecológica ou em ambientes que sofreram impactos antrópicos. Essa mudança pode gerar diferentes efeitos sobre os organismos presentes na área, já que as relações entre os organismos e a estrutura de habitat são dinâmicas .
Conectividade da rede de estradas como indicador de fragmentação florestal antropogênica: Uma apl... more Conectividade da rede de estradas como indicador de fragmentação florestal antropogênica: Uma aplicação à bacia do rio Macacu, RJ
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