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1.
J Evol Biol ; 35(10): 1387-1395, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36117406

RESUMO

Major hypotheses on sex evolution predict that resource abundance and heterogeneity should either select for or against sexual reproduction. However, seldom have these predictions been explicitly tested in the field. Here, we investigated this question using soil oribatid mites, a diverse and abundant group of soil arthropods whose local communities can be dominated by either sexual or asexual species. First, we refined theoretical predictions by addressing how the effects of resource abundance, heterogeneity and abiotic conditions could modify each other. Then, we estimated the strength of selection for sexual species in local communities while controlling for phylogeny and neutral processes (ecological drift and dispersal), and tested its relation to resource and abiotic gradients. We show that sexual species tended to be favoured with increasing litter amount, a measure of basal resource abundance. Further, there was some evidence that this response occurred mainly under higher tree species richness, a measure of basal resource heterogeneity. This response to resources is unlikely to reflect niche partitioning between reproductive modes, as sexual and asexual species overlapped in trophic niche according to a comparative analysis using literature data on stable isotope ratios. Rather, these findings are consistent with the hypothesis that sex facilitates adaptation by breaking unfavourable genetic associations, an advantage that should increase with effective population size when many loci are under selection and, thus, with resource abundance.


Assuntos
Fome , Ácaros , Animais , Ácaros/genética , Filogenia , Reprodução , Reprodução Assexuada , Solo
2.
Oecologia ; 198(1): 193-203, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34853902

RESUMO

Understanding the direct and indirect effects of niche and neutral processes in structuring species diversity is particularly challenging because environmental factors are often geographically structured. Here, we used Structural Equation Modeling to quantify direct and indirect effects of geographic distance, the Amazon River's opposite margins, and environmental differences in temperature, precipitation, and vegetation density (Normalized Difference Vegetation Index-NDVI) on ant beta diversity (Jaccard's dissimilarity) across Amazon basin. We used a comprehensive survey of ground-dwelling ant species from 126 plots distributed across eight sampling sites along a broad environmental gradient. We found that geographic distance and NDVI differences were the major direct predictors of ant composition dissimilarity. The major indirect effect was that of temperature through NDVI, whereas precipitation neither had direct or indirect detectable effects on beta diversity. Thus, ant compositional dissimilarity seems to be mainly driven by a combination of isolation by distance (through dispersal limitation) and selection imposed by vegetation density, and indirectly, by temperature. Our results suggest that neutral and niche processes have been similarly crucial in driving the current beta diversity patterns of Amazonian ground-dwelling ants.


Assuntos
Formigas , Animais , Biodiversidade , Temperatura
3.
Oecologia ; 196(3): 805-814, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34085106

RESUMO

Three processes can explain contemporary community assembly: natural selection, ecological drift and dispersal. However, quantifying their effects has been complicated by confusion between different processes and neglect of expected interactions among them. One possible solution is to simultaneously model the expected effects of each process within species, across communities and across species, thus providing more integrative tests of ecological theory. Here, we used generalized linear mixed models to assess the effects of selection, drift and dispersal on the occurrence probability of 135 soil oribatid mite species across 55 sites over an Amazonian rainforest landscape (64 km2). We tested for interactions between process-related factors and partitioned the explained variation among them. We found that occurrence probability (1) responded to soil P content and litter mass depending on body size and reproductive mode (sexual or parthenogenetic), respectively (selection); (2) increased with community size (drift); and (3) decreased with distance to the nearest source population, and more so in rare species (dispersal limitation). Processes did not interact significantly, and our best model explained 67% of the overall variation in species occurrence probability. However, most of the variation was attributable to dispersal limitation (55%). Our results challenge the seldom-tested theoretical prediction that ecological processes should interact. Rather, they suggest that dispersal limitation overrides the signatures of drift and selection at the landscape level, thus rendering soil microarthropod species ecologically equivalent and possibly contributing to the maintenance of metacommunity diversity.


Assuntos
Ácaros , Solo , Animais , Biodiversidade
4.
An Acad Bras Cienc ; 92(1): e20181093, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236298

RESUMO

Larvae of Psychodidae develop in a variety of breeding sites, including vertebrate feces. As searching for the larvae can be an extremely difficult task, immatures of many species are little known, with descriptions of coprophagous moth flies all from outside the Neotropics. In an attempt to mitigate this challenge, we tested an oviposition trap using cattle dung as attractant, measured the efficiency and specificity of the traps and the most efficient period of exposition in the field. With 60 traps installed in one fragment of ombrophilous forest, 344 immatures were collected, distributed in four species of Psychoda and one of Feuerborniella. Psychodidae accounted for 75% of the collected Diptera. The high specificity of the trap to Psychodidae contrasts with other studies on coprophagous fauna where they appear in low abundance. Based on the metrics in this study, the most efficient period of trapping exposition was between five to eight days, but the difference was not significant probably due to the high number of zero observations among the traps. Many questions pertaining to coprophagous moth flies remain unanswered. Further research is needed to improve trapping efficiency, elucidate the effects of attractants and determine how environmental factors influence the attractiveness of bait.


Assuntos
Controle de Insetos/instrumentação , Oviposição , Psychodidae/fisiologia , Animais , Bovinos , Fezes , Feminino , Psychodidae/classificação
5.
Biol Lett ; 14(5)2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29720446

RESUMO

In most ectotherms, adult body size decreases with warming, the so-called 'temperature-size rule' (TSR). However, the extent to which the strength of the TSR varies naturally within species is little known, and the significance of this phenomenon for tropical biota has been largely neglected. Here, we show that the adult body mass of the soil mite Rostrozetes ovulum declined as maximum temperature increased over seasons in a central Amazonian rainforest. Further, per cent decline per °C was fourfold higher in riparian than in upland forests, possibly reflecting differences in oxygen and/or resource supply. Adding our results to a global dataset revealed that, across terrestrial arthropods, the seasonal TSR is generally stronger in hotter environments. Our study suggests that size thermal dependence varies predictably with the environment both locally and globally.


Assuntos
Peso Corporal/fisiologia , Ácaros/fisiologia , Temperatura , Animais , Brasil , Florestas , Solo , Clima Tropical
6.
Environ Entomol ; 45(2): 301-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26643123

RESUMO

This study investigated the spatial distribution of an Amazonian fruit-feeding butterfly assemblage by linking species taxonomic and functional approaches. We hypothesized that: 1) vegetation richness (i.e., resources) and abundance of insectivorous birds (i.e., predators) should drive changes in butterfly taxonomic composition, 2) larval diet breadth should decrease with increase of plant species richness, 3) small-sized adults should be favored by higher abundance of birds, and 4) communities with eyespot markings should be able to exploit areas with higher predation pressure. Fruit-feeding butterflies were sampled with bait traps and insect nets across 25 km(2) of an Amazonian ombrophilous forest in Brazil. We measured larval diet breadth, adult body size, and wing marking of all butterflies. Our results showed that plant species richness explained most of the variation in butterfly taxonomic turnover. Also, community average diet breadth decreased with increase of plant species richness, which supports our expectations. In contrast, community average body size increased with the abundance of birds, refuting our hypothesis. We detected no influence of environmental gradients on the occurrence of species with eyespot markings. The association between butterfly taxonomic and functional composition points to a mediator role of the functional traits in the environmental filtering of butterflies. The incorporation of the functional approach into the analyses allowed for the detection of relationships that were not observed using a strictly taxonomic perspective and provided an extra insight into comprehending the potential adaptive strategies of butterflies.


Assuntos
Biodiversidade , Borboletas/fisiologia , Floresta Úmida , Animais , Aves/fisiologia , Brasil , Borboletas/crescimento & desenvolvimento , Comportamento Alimentar , Cadeia Alimentar , Frutas/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Dinâmica Populacional , Árvores/crescimento & desenvolvimento
7.
Exp Appl Acarol ; 55(1): 39-63, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21476120

RESUMO

Small-scale spatial distribution of oribatid mites has been investigated in Amazonia. In addition, medium- and large-scale studies are needed to establish the utility of these mites in detecting natural environmental variability, and to distinguish this variability from anthropogenic impacts. We are expanding the knowledge about oribatid mites in a wet upland forest reserve, and investigate whether a standardized and integrated protocol is an efficient way to assess the effects of environmental variables on their qualitative and quantitative composition on a large spatial scale inside an ecological reserve in Central Amazonia, Brazil. Samples for Berlese-Tullgren extraction were taken in 72 plots of 250 × 6 m distributed over 64 km(2). In total 3,182 adult individuals, from 82 species and 79 morphospecies were recorded, expanding the number of species known in the reserve from 149 to 254. Galumna, Rostrozetes and Scheloribates were the most speciose genera, and 57 species were rare. Rostrozetes ovulum, Pergalumna passimpuctata and Archegozetes longisetosus were the most abundant species, and the first two were the most frequent. Species number and abundance were not correlated with clay content, slope, pH and litter quantity. However, Principal Coordinate Analysis indicated that as the percentage of clay content, litter quantity and pH changed, the oribatid mite qualitative and quantitative composition also changed. The standardized protocol effectively captured the diversity, as we collected one of the largest registers of oribatid mites' species for Amazonia. Moreover, biological and ecological data were integrated to capture the effects of environmental variables accounting for their diversity and abundance.


Assuntos
Altitude , Biodiversidade , Ácaros , Solo/química , Animais , Brasil , Geografia , Concentração de Íons de Hidrogênio , Densidade Demográfica , Clima Tropical
8.
Acta amaz. ; 41(4)2011.
Artigo em Inglês | VETINDEX | ID: vti-450703

RESUMO

Despite the importance of citriculture in Brazil, very little is known about mite populations in citrus crops in the Northern Region. In the municipality of Manaus, 12 sprayed sweet orange orchards were surveyed every two weeks during seven months to record mite species amount, and to describe the abundance and distribution of the most important species. The size and age of the orchards varied from 3,360 to 88,080 m² and seven to 25 years, respectively. In the fourteen sampling period, leaves, twigs and fruits were collected from 12 trees, one per orchard. In total, 3,360 leaves, 672 twigs and 1,344 fruits were sampled from 168 trees. Mites were manually extracted from the fruits, and by the washing method on leaves and twigs. We identified pests with the potential to cause economic loss. Fourteen species of phytophagous and mycophagous mites from Eriophyidae, Tarsonemidae, Tenuipalpidae, and Tetranychidae were recorded. Brevipalpus phoenicis (Geijskes 1939) and Phyllocoptruta oleivora (Ashm., 1879), the two commonest phytophagous mites in other Brazilian regions were dominant, showing that local orchards are susceptible to their infestation. Eleven predatory mites were recorded, comprising 10% of the mite population, belonging to Phytoseiidae and Ascidae. Phytoseiidae was the richest family, with ten species. The results are discussed in relation to the temporal variation aspects and habitat use of the most important species. Long-term research encompassing chemical applications followed by evaluations of the mite community are necessary for a better management of the orchards, taking into consideration the seasonal phenology of key pests.


Apesar da importância da citricultura no Brasil, pouco se conhece sobre as populações de ácaros em plantações de citros no norte do país. No município de Manaus, 12 pomares de laranja doce pulverizados foram avaliados a cada duas semanas, durante sete meses, para o registro de ácaros plantícolas e para descrever a abundância e a distribuição das espécies mais importantes. O tamanho e a idade dos pomares variaram de 3.360 a 88.0080 m² e de sete a 25 anos, respectivamente. Nos 14 períodos de coleta, folhas, galhos e frutos foram coletados de uma árvore em cada pomar. No total, 3.360 folhas, 672 galhos e 1.344 frutos foram coletados de 168 árvores. Os ácaros foram extraídos dos frutos manualmente e pelo método de lavagem nas folhas e galhos. Identificamos espécies pragas com potencial de causar danos econômicos. Registramos 14 espécies de fitófagos em quatro famílias (Eriophyidae, Tarsonemidae, Tenuipalpidae, and Tetranychidae). Brevipalpus phoenicis (Geijskes 1939) (Tenuipalpidae) e Phyllocoptruta oleivora (Ashm., 1879) (Eriophyidae), as duas espécies fitófagas mais abundantes em outras regiões, foram dominantes, mostrando que a cultura de citros local é suscetível à infestação. Registramos 11 espécies de predadores das famílias Phytoseiidae e Ascidae, compreendendo 10% da população total. Phytoseiidae foi a família mais diversa, com 10 espécies. Foram discutidos aspectos da variação temporal e utilização de hábitat das espécies mais abundantes. Estudos de longo prazo, envolvendo a aplicação de acaricidas e avaliações da comunidade de ácaros, são necessários para um melhor manejo dos pomares, levando-se em consideração a fenologia das pragas-chave.

9.
Acta amaz ; Acta amaz;41(4): 557-566, 2011. graf, tab
Artigo em Inglês | LILACS, VETINDEX | ID: lil-601765

RESUMO

Despite the importance of citriculture in Brazil, very little is known about mite populations in citrus crops in the Northern Region. In the municipality of Manaus, 12 sprayed sweet orange orchards were surveyed every two weeks during seven months to record mite species amount, and to describe the abundance and distribution of the most important species. The size and age of the orchards varied from 3,360 to 88,080 m² and seven to 25 years, respectively. In the fourteen sampling period, leaves, twigs and fruits were collected from 12 trees, one per orchard. In total, 3,360 leaves, 672 twigs and 1,344 fruits were sampled from 168 trees. Mites were manually extracted from the fruits, and by the washing method on leaves and twigs. We identified pests with the potential to cause economic loss. Fourteen species of phytophagous and mycophagous mites from Eriophyidae, Tarsonemidae, Tenuipalpidae, and Tetranychidae were recorded. Brevipalpus phoenicis (Geijskes 1939) and Phyllocoptruta oleivora (Ashm., 1879), the two commonest phytophagous mites in other Brazilian regions were dominant, showing that local orchards are susceptible to their infestation. Eleven predatory mites were recorded, comprising 10 percent of the mite population, belonging to Phytoseiidae and Ascidae. Phytoseiidae was the richest family, with ten species. The results are discussed in relation to the temporal variation aspects and habitat use of the most important species. Long-term research encompassing chemical applications followed by evaluations of the mite community are necessary for a better management of the orchards, taking into consideration the seasonal phenology of key pests.


Apesar da importância da citricultura no Brasil, pouco se conhece sobre as populações de ácaros em plantações de citros no norte do país. No município de Manaus, 12 pomares de laranja doce pulverizados foram avaliados a cada duas semanas, durante sete meses, para o registro de ácaros plantícolas e para descrever a abundância e a distribuição das espécies mais importantes. O tamanho e a idade dos pomares variaram de 3.360 a 88.0080 m² e de sete a 25 anos, respectivamente. Nos 14 períodos de coleta, folhas, galhos e frutos foram coletados de uma árvore em cada pomar. No total, 3.360 folhas, 672 galhos e 1.344 frutos foram coletados de 168 árvores. Os ácaros foram extraídos dos frutos manualmente e pelo método de lavagem nas folhas e galhos. Identificamos espécies pragas com potencial de causar danos econômicos. Registramos 14 espécies de fitófagos em quatro famílias (Eriophyidae, Tarsonemidae, Tenuipalpidae, and Tetranychidae). Brevipalpus phoenicis (Geijskes 1939) (Tenuipalpidae) e Phyllocoptruta oleivora (Ashm., 1879) (Eriophyidae), as duas espécies fitófagas mais abundantes em outras regiões, foram dominantes, mostrando que a cultura de citros local é suscetível à infestação. Registramos 11 espécies de predadores das famílias Phytoseiidae e Ascidae, compreendendo 10 por cento da população total. Phytoseiidae foi a família mais diversa, com 10 espécies. Foram discutidos aspectos da variação temporal e utilização de hábitat das espécies mais abundantes. Estudos de longo prazo, envolvendo a aplicação de acaricidas e avaliações da comunidade de ácaros, são necessários para um melhor manejo dos pomares, levando-se em consideração a fenologia das pragas-chave.


Assuntos
Animais , Ácaros
10.
Acta amaz. ; 37(4)2007.
Artigo em Português | VETINDEX | ID: vti-450315

RESUMO

Ants are largely used for monitoring and inventory programs, resulting in great amounts of material sampled with several methodologies, financial limitations and lack of experts to do the taxonomy of many taxa. To contribute for the elaboration of alternative protocols, we analyzed the complementarity of two sampling methods in the detection of species richness. In 6 plots of 1 km² distributed in an area of 33,000 ha of continuous primary forest, in the Brazilian state of Pará, the diversity and the frequency of species of genera Crematogaster,Gnamptogenys and Pachycondyla were investigated, as part of the "Ant methodology Protocol" of the Project TEAM. Using the Winkler extractor and pitfall traps, 10 sub-samples were collected per transect. In each plot, 4 transects of 100 m were installed. We registered 36 species, and 15 are new records for the state, and 29 for the study site. Seventeen species were common to both sampling methods, 11 were captured with pitfall and 8 with Winkler. The proportions of singletons were high for both methods (>0,4). Nineteen species were captured by only one method and three were represented by only one individual in both methods. Ordination analysis (SSH, Semi-Strong Hybrid Multi-Dimensional Scaling) indicated differences in community structure between both sampling methods. There was a complementarity's effect between these two methods in order to obtain a more complete inventory of the species richness, indicating that both must be used in the protocol. Other resources like rarefaction and/or sample dilution must be evaluated in future investigations.


As formigas são muito usadas em programas de inventários e monitoramentos, resultando em grande quantidade de material coletado com vários métodos, limitações financeiras e na falta de taxonomos para vários táxons. Para contribuir na elaboração de protocolos alternativos, analisamos a complementaridade de dois métodos de amostragem na detecção da riqueza de espécies. Em seis parcelas de 1 km² distribuídas em 33.000 ha de floresta primária, investigamos a diversidade e a freqüência das espécies de Crematogaster,Gnamptogenys e Pachycondyla, como parte do protocolo de formigas de serapilheira do Projeto TEAM. Em cada parcela, quatro transectos de 100 m foram instalados. Dez sub-amostras foram efetuadas por transecto, usando extrator de Winkler e armadilha de fosso. Registramos 36 espécies, sendo 15 novos registros para o Pará e 29 para a área de estudo. Dezessete espécies foram comuns aos dois métodos, onze foram capturadas com armadilhas de fosso e oito com Winkler. As proporções de espécies representadas por um indivíduo ("singletons") foram altas para ambos os métodos (> 0,4). Dezenove espécies foram coletadas por apenas um método e três foram representadas por apenas um indivíduo em cada método. A análise de ordenação (escalonamento multidimensional semi-híbrido) revelou diferenças na estrutura das comunidades de formigas obtidas pelos dois métodos de amostragem. Houve um efeito de complementaridade entre os dois métodos para a obtenção de um levantamento mais completo da riqueza de espécies, significando que ambos devem ser usados no protocolo. Outros recursos, como a rarefação e/ou diluição das amostras são recursos a serem avaliados em futuras investigações.

11.
Acta amaz ; Acta amaz;37(4): 649-656, 2007. ilus, tab
Artigo em Português | LILACS | ID: lil-476619

RESUMO

As formigas são muito usadas em programas de inventários e monitoramentos, resultando em grande quantidade de material coletado com vários métodos, limitações financeiras e na falta de taxonomos para vários táxons. Para contribuir na elaboração de protocolos alternativos, analisamos a complementaridade de dois métodos de amostragem na detecção da riqueza de espécies. Em seis parcelas de 1 km² distribuídas em 33.000 ha de floresta primária, investigamos a diversidade e a freqüência das espécies de Crematogaster,Gnamptogenys e Pachycondyla, como parte do protocolo de formigas de serapilheira do Projeto TEAM. Em cada parcela, quatro transectos de 100 m foram instalados. Dez sub-amostras foram efetuadas por transecto, usando extrator de Winkler e armadilha de fosso. Registramos 36 espécies, sendo 15 novos registros para o Pará e 29 para a área de estudo. Dezessete espécies foram comuns aos dois métodos, onze foram capturadas com armadilhas de fosso e oito com Winkler. As proporções de espécies representadas por um indivíduo ("singletons") foram altas para ambos os métodos (> 0,4). Dezenove espécies foram coletadas por apenas um método e três foram representadas por apenas um indivíduo em cada método. A análise de ordenação (escalonamento multidimensional semi-híbrido) revelou diferenças na estrutura das comunidades de formigas obtidas pelos dois métodos de amostragem. Houve um efeito de complementaridade entre os dois métodos para a obtenção de um levantamento mais completo da riqueza de espécies, significando que ambos devem ser usados no protocolo. Outros recursos, como a rarefação e/ou diluição das amostras são recursos a serem avaliados em futuras investigações.


Ants are largely used for monitoring and inventory programs, resulting in great amounts of material sampled with several methodologies, financial limitations and lack of experts to do the taxonomy of many taxa. To contribute for the elaboration of alternative protocols, we analyzed the complementarity of two sampling methods in the detection of species richness. In 6 plots of 1 km² distributed in an area of 33,000 ha of continuous primary forest, in the Brazilian state of Pará, the diversity and the frequency of species of genera Crematogaster,Gnamptogenys and Pachycondyla were investigated, as part of the "Ant methodology Protocol" of the Project TEAM. Using the Winkler extractor and pitfall traps, 10 sub-samples were collected per transect. In each plot, 4 transects of 100 m were installed. We registered 36 species, and 15 are new records for the state, and 29 for the study site. Seventeen species were common to both sampling methods, 11 were captured with pitfall and 8 with Winkler. The proportions of singletons were high for both methods (>0,4). Nineteen species were captured by only one method and three were represented by only one individual in both methods. Ordination analysis (SSH, Semi-Strong Hybrid Multi-Dimensional Scaling) indicated differences in community structure between both sampling methods. There was a complementarity's effect between these two methods in order to obtain a more complete inventory of the species richness, indicating that both must be used in the protocol. Other resources like rarefaction and/or sample dilution must be evaluated in future investigations.


Assuntos
Formigas , Ecossistema Amazônico , Himenópteros
12.
Acta amaz ; Acta amaz;31(2)jun. 2001.
Artigo em Português | LILACS-Express | LILACS, VETINDEX | ID: biblio-1454812

RESUMO

Specimens of Rostrozetes foveolatus were obtained from two inundated forest areas ("várzea" and "igapó") and from two nonflooded secondary forests in the Central Amazon Region. The survival rates of their populations under submerged and nonsubmerged conditions were compared in laboratory conditions. The "igapó" population was sampled during three periods in 1992: before (February: litter nonsubmerged), in the beginning (April: litter submerged) and in the peak of the inundation phase (July: litter submerged). At "igapó", the animals survived better when submitted to nonsubmerged conditions, meaning that submersion is a stress factor. The same result did not occur at "várzea", signifying a better adaptation of this population to the submersion stress. The lowest flood resistance (27 days) was found in animals from "terra firme" secondary forest, away from the igapó. A considerable submersion resistance in the population sampled in the secondary forest, near the igapó forest, was comparable to the populations of the inundated areas and greater than the resistence at "terra-firme", far away from the "igapó". Animals sampled in February of 1996 (reared individually in plastic containers), from the flooded forests had significantly higher survival rates than those from secondary forests. Three situations in relation to the submersion period were registered: a) one of "várzea", with a more resistant population, b) one of "igapó", with a intermediate resistance and c) one of "terra-firme", away from the "igapó", with a lower resistant population. In twelve of the fifteen species studied, a high resistance to submersion was also registered.


Espécimens de Rostrozetes foveolatus foram obtidos de duas florestas inundáveis (várzea e igapó) e de duas florestas secundárias (terra firme) da Amazônia Central. As populações foram comparadas para a obtenção da taxa de sobrevivência em experimentos de laboratório nas condições submersas e não submersas. As coletas no igapó foram efetuadas em três períodos de 1992: antes (fevereiro: serapilheira não submersa), no início (abril: serapilheira submersa) e no pico da inundação (julho: serapilheira submersa). No igapó, os animais sobreviveram melhor em condição não submersa, significando que a submersão é um fator de estresse. O mesmo não ocorreu na várzea, indicando que esta população está melhor adaptada ao estresse da submersão. A menor resistência à submersão (27 dias) foi registrada nos animais de uma floresta secundária da terra firme, situada longe do igapó. Na população da terra firme próxima ao igapó, a resistência a submersão foi comparável à registrada para as populações das áreas inundáveis e maior do que a registrada em terra firme longe do igapó. Em experimentos com animais coletados em fevereiro de 1996 (mantidos individualmente em recipientes plásticos), as populações das florestas inundáveis tiveram taxa de sobrevivência significativamente maior em relação aos das florestas não inundáveis. Três situações foram registradas quanto a resistência à submersão: a) a da várzea, com população mais resistente, b) a do igapó, com uma população intermediária e c) a da terra-firme longe do igapó, com uma população menos resistente. Em doze das outras quinze espécies estudadas foi registrada alta resistência às condições de submersão.

13.
Acta amaz. ; 31(2)2001.
Artigo em Português | VETINDEX | ID: vti-449859

RESUMO

Specimens of Rostrozetes foveolatus were obtained from two inundated forest areas ("várzea" and "igapó") and from two nonflooded secondary forests in the Central Amazon Region. The survival rates of their populations under submerged and nonsubmerged conditions were compared in laboratory conditions. The "igapó" population was sampled during three periods in 1992: before (February: litter nonsubmerged), in the beginning (April: litter submerged) and in the peak of the inundation phase (July: litter submerged). At "igapó", the animals survived better when submitted to nonsubmerged conditions, meaning that submersion is a stress factor. The same result did not occur at "várzea", signifying a better adaptation of this population to the submersion stress. The lowest flood resistance (27 days) was found in animals from "terra firme" secondary forest, away from the igapó. A considerable submersion resistance in the population sampled in the secondary forest, near the igapó forest, was comparable to the populations of the inundated areas and greater than the resistence at "terra-firme", far away from the "igapó". Animals sampled in February of 1996 (reared individually in plastic containers), from the flooded forests had significantly higher survival rates than those from secondary forests. Three situations in relation to the submersion period were registered: a) one of "várzea", with a more resistant population, b) one of "igapó", with a intermediate resistance and c) one of "terra-firme", away from the "igapó", with a lower resistant population. In twelve of the fifteen species studied, a high resistance to submersion was also registered.


Espécimens de Rostrozetes foveolatus foram obtidos de duas florestas inundáveis (várzea e igapó) e de duas florestas secundárias (terra firme) da Amazônia Central. As populações foram comparadas para a obtenção da taxa de sobrevivência em experimentos de laboratório nas condições submersas e não submersas. As coletas no igapó foram efetuadas em três períodos de 1992: antes (fevereiro: serapilheira não submersa), no início (abril: serapilheira submersa) e no pico da inundação (julho: serapilheira submersa). No igapó, os animais sobreviveram melhor em condição não submersa, significando que a submersão é um fator de estresse. O mesmo não ocorreu na várzea, indicando que esta população está melhor adaptada ao estresse da submersão. A menor resistência à submersão (27 dias) foi registrada nos animais de uma floresta secundária da terra firme, situada longe do igapó. Na população da terra firme próxima ao igapó, a resistência a submersão foi comparável à registrada para as populações das áreas inundáveis e maior do que a registrada em terra firme longe do igapó. Em experimentos com animais coletados em fevereiro de 1996 (mantidos individualmente em recipientes plásticos), as populações das florestas inundáveis tiveram taxa de sobrevivência significativamente maior em relação aos das florestas não inundáveis. Três situações foram registradas quanto a resistência à submersão: a) a da várzea, com população mais resistente, b) a do igapó, com uma população intermediária e c) a da terra-firme longe do igapó, com uma população menos resistente. Em doze das outras quinze espécies estudadas foi registrada alta resistência às condições de submersão.

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