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《Journal of Natural History》2012,46(19-20):1435-1444
Habitat use affects food intake, reproductive fitness and body temperature control in reptiles. Habitat use depends on both the characteristics of the animal and the environmental heterogeneity. In this study we investigated habitat use in a population of the South‐American rattlesnake, Crotalus durissus, in a cerrado (the Brazilian savanna) remnant, in south‐eastern Brazil. In general, snakes appeared to be thermal generalists. However, they showed substrate temperature preferences in the rainy season, when they selected colder substrates during the day and warmer substrates at night. Individuals were predominantly active on the surface and more frequently found under bushes. Furthermore, in general, the principal component analysis results indicate that rattlesnakes are generalists regarding the microhabitat variables examined in this study. These habitat characteristics, associated with a low thermal selectivity, indicate that rattlesnakes are able to colonize deforested areas where shade occurrence and vegetation cover are similar to those in the cerrado. 相似文献
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《Journal of Natural History》2012,46(19-20):1421-1434
We studied a population of Crossodactylus bokermanni in a stream at the Reserva Particular do Patrimônio Natural, Santuário do Caraça, south‐eastern Brazil, with respect to microhabitat use and diet. We characterized microhabitats based on substrate, distance to water and exposure level of the occupying individual (exposed or sheltered), and adjacent aquatic microhabitats (evaluated as potential nesting sites based on observed nests), according to water current (absent, slow or fast), substrate and depth. Calling males, silent males, ovigerous females, non‐ovigerous females and juveniles showed spatial niche overlap higher than that expected by chance, with calling males showing the strongest preference for microhabitats close to potential nesting sites (with intermediate depths, fast current and sandy bottom). Only 14 males out of 48 individuals examined for stomach contents had prey in their stomachs. The food items with the highest electivity values were Coleoptera and Diptera, but preys with both high and low mobility were exploited. 相似文献
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《Journal of Natural History》2012,46(19-20):1263-1272
The effect of forest fragmentation on the abundance of the whip spiders Heterophrynus longicornis (Butler 1973) in land-bridge island fragments created by the lake formed by Tucuruí Dam, Pará, Brazil, was investigated. These fragments have been isolated for at least 23 years, on small islands that range in size from 12.9 to 91.3 ha. The abundance of whip spiders was calculated in 100 m transects on eight islands, both in the edge and in the interior of the islands. There were no differences in whip spider abundance between the edge or interior of islands, but the whip spiders strongly preferred areas with greater numbers of trees, trees with a DBH between 10 to 50 cm, and trees with termite nests. Over 31% of the whip spiders were found in association with other individuals on the same tree. Individuals were found in mother–offspring associations, mating pairs, and in mixed-age sex groups. 相似文献
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《Journal of Natural History》2012,46(13-16):925-936
Morphological and genetic data for the Iberian golden‐striped salamander, Chioglossa lusitanica, demonstrate the existence of two groups with southern and northern ranges, connected by a zone of intergradation in central Portugal. Because reproductive isolation between them is incomplete we consider the groups to be subspecies. The type locality of C. lusitanica (Buçaco near Lousã) is situated inside the mixed zone. This necessitates identification of the nominotypical subspecies. We sequenced a fragment of mitochondrial DNA from one of the species' syntypes and we determined what position over a latitudinal transect maximizes the morphological discrimination between the groups. Both approaches indicate that C. lusitanica from Buçaco represents the southern subspecies. A new subspecies of C. lusitanica is described from a northern locality (Valongo near Porto in north‐western Portugal). A lectotype is designated for Chioglossa lusitanica. 相似文献
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《Journal of Natural History》2012,46(23):2163-2177
The spatial distribution of the ghost crab Ocypode quadrata (Crustacea, Brachyura) was described in five low‐energy tide‐dominated sandy beaches in São Sebastião Channel (Grande, Zimbro, Pitangueiras, Cabelo Gordo, and Segredo). On each beach, the zonation study was performed on five random 1?m wide transects sampled from the water line to the vegetation. In general, individuals occurred above 1?m in height in relation to mean low water (MLW) and peaked between 1.5 and 2.0?m. The sandy beaches were then divided into three 1?m wide strips (tidal levels) parallel to the water line and equivalent to medium intertidal, upper intertidal, and subterrestrial fringe to test the effect of beach and tidal level on the abundance and size of O. quadrata. These strips were sampled as a whole using adjacent 1 m2 squares. A previous evaluation showed a positive significant relationship between carapace length and burrow diameter, thus supporting crab size estimates from burrow openings. The smallest individuals occurred mainly in the medium intertidal, but were also recorded in the subterrestrial fringe, which was occupied mainly by large‐sized individuals. In general, the individuals were randomly dispersed within the strips and concentrated in the upper intertidal zone on all the sandy beaches. The density of O. quadrata varied among beaches, with a tendency to lower values on areas with very fine and poorly or moderately sorted sediments and on that most used for recreational activities (Grande). Burrow size also varied among beaches, with a tendency of smaller burrows in areas with coarser sand grains and higher tourism. These results indicate that the effect of human impact on density and size of O. quadrata may be confounded by the high environmental heterogeneity of the studied system, which may make it difficult to utilize this species as an indicator of the conservation status of low‐energy tide‐dominated sandy beaches. 相似文献
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《Journal of Natural History》2012,46(19-20):1409-1420
The objective of this study was to record and analyze the prevalence of ciliated protozoa associated with prosobranchian snails of the species Pomacea figulina collected from an urban stream in south‐eastern Brazil. Four collections were carried out between December, 2005, and March, 2006, from which 23 snails and 10 ‘empty’ shells were obtained. The shells and opercula were scraped over Petri dishes and the ciliates were observed using bright field and phase contrast microscopy. Seven species of ciliates were recorded on the snails of P. figulina. Of the 23 snails analyzed, 82.60% (n = 19) were infested with at least one species of ciliate. No ciliates were found on the ‘empty’ shells and opercula. The results are discussed in terms of ecological aspects involved in this association. 相似文献
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《Journal of Natural History》2012,46(7-8):447-468
Three hundred and three individuals representing 14 species of lizards (Scincidae), collected in Papua New Guinea, were examined for metazoan endoparasites. Two species of Digenea, four species of Cestoda, 21 species of Nematoda (adults and larvae in cysts), two species of Acanthocephala and one species of Pentastomida were found. Forty-two new host records and two new locality records are reported. Skinks from Papua New Guinea are infected by “generalist” endoparasites, which parasitize a variety of reptile or amphibian hosts. Mean endoparasite species diversity per skink species was 5.0 ± 3.3 SD, range: 1–11. 相似文献