摘要:

A cave bat community from a semiarid region in eastern Brazil was studied during the dry season. A high diversity was observed, with thirteen species recorded. Except for Micronycteris minuta and Lionycteris spurrelli, these bats were also found in other Brazilian karstic areas. The commonest species were the hematophague Desmodus rotundus, the omnivore Carollia perspicillata, and the insectivore Natalus stramineus. The bats formed itinerant colonies, moving frequently inside the cave. L. spurrelli was previously known from Amazonia, usually associated with evergreen forests. The present record extends its range 1600 km to the south. A disjunct distribution explains some morphological differentiation between Amazonia and Olhos d'Água cave populations. The latter may be a relict of former continuous forest vegetation, which has been fragmented after the climatic optimum. Dispersion through the Cerrado forest gallery is also possible.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.69.2156

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Distributional evidence bearing on cospeciation of New World bats (superfamily Noctilionoidea) and associated bat flies (Diptera: Streblidae) was analyzed and revealed substantial phylogenetic structure, especially when we focused on "normal" host associations and encoded the data set hierarchically. Brooks' parsimony analyses of bat fly occurrences among hosts recovered generally accepted sets of host relationships. Putatively monophyletic host taxa provide a necessary but insufficient condition for coevolution via cospeciation.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.76.2152

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The recovery of tropical ecosystems after disturbance is of interest for future programs of sustainable development. The dynamics of such processes was evaluated at 26 sites in Venezuela. Ant and plant diversity were compared between disturbed forests and surrounding savannas, different stages of recovery and nearby plots with primary vegetation. We estimated the species composition for ants, the number of species and equitability for ants and plants, and the plant coverage at each site. Of these indices, percentage of plant cover showed the most rapid return to pre-disturbance values. In a few cases, full return occurred after around 25 years in both savanna and forest. A multiple factorial analysis of ant composition showed that species structure in old recovered sites converged sometimes, but not always, to that in surrounding natural habitats. Therefore, ant diversity may be used to monitor ecosystem recovery. However, even small scale human intervention may have irreversible effects on tropical habitats. The estimated time constant for forest recovery could serve to calculate human carrying capacity of forest sites for eventual sustainable use of these ecosystems in the Neotropics.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.85.2163

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Eleutherodactylus olivaceus sp. n., a member of the E. unistrigatus group is described. The new species is known from montane rainforests of the Departamento Cochabamba, Bolivia, as well as from lowland rainforest of the Departamento Madre de Dios, Perú. E. olivaceus is mainly characterized by its predominantly olive green dorsal color and a papilla on the tip of the snout. Advertisement call and habitat of E. olivaceus are described. The occurrence of Eleutherodactylus mendax in Bolivia is briefly discussed.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.93.2158

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The piranha, Serrasalmus marginatus is an abundant fish in the floodplains of the upper ParanáÝ river. We studied the stomach content of juvenile and adult piranhas over a year and determined the food items. Fragments of fish were the main diet components with age-dependent differences. There was no seasonal variation in the prey. This piranha is basically a diurnal predator with some differences in daily periods of feeding activity between juveniles and adults.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.100.2167

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In the subtropical Atlantic rain forest of southern Brazil, reproduction of the catfish Pimelodella pappenheimi was studied over a two years period in a small coastal stream representing a widely undisturbed aquatic habitat. According to analyses of the gonad status, reproduction is mainly seasonal with a peak in the rainy summer months, consisting of multiple spawning. The average body length of the fishes attaining sexual maturity was the same in both sexes. At the study site summer storms cause flash floods, and heavy rainfalls can suddenly increase the river flow. Reproductive females were found to burrow in the clay palisades of the river sediments which is regarded a behavioural adaptation protecting the offspring from being washed away.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.106.2164

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A study in a remnant of cerrado vegetation in São Paulo State, Brazil, was carried out to investigate the possible role of leaf-cutting ants in the creation of nutrient-rich patches and their consequent influence on plant establishment and growth. The results showed that leaf-cutting ants had neither detectable effect on local nutrient enrichment nor on plant community structure. It is suggested that leaf-cutting ants may affect early successional stages of the vegetation, when colonies are more abundant and disperse into the habitat. Foi feito um estudo em um remanescente de vegetação de cerrado no Estado de São Paulo, com o objetivo de testar o papel das sa£vas na criação de manchas ricas em nutrientes e sua conseqüente influência no estabelecimento e crescimento das plantas. Os resultados mostraram que as saúvas não tiveram nenhum efeito detectável no enriquecimento local de nutrientes e nem na estrutura das comunidades vegetais. Sugere-se que as saúvas possam afetar os estádios iniciais da sucessão vegetal, quando as colônias são mais abundantes e dispersam-se mais no habitat.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.111.2161

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper deals with the taxonomic composition of parasitoid assemblages reared from agromyzid leaf-miners of 28 species collected in Cordoba, Central Argentina. The relative representation of each parasitic family was estimated, taking into consideration their species richness and abundance. Sample size affected the total species richness in each complex, and also that of Eulophidae and Pteromalidae, indicating that not only size but also taxonomic structure of parasitic assemblages are influenced by sampling effort. 3 superfamilies and 5 families of Hymenoptera Parasitica were represented, with Eulophidae (Chalcidoidea) specifically and numerically dominant both in the total community of parasitoids and in the parasitic assemblages of individual hosts. Chrysonotomyia, Chrysocharis (Eulophidae), Halticoptera (Pteromalidae) and Phaedrotoma (Braconidae) were the most relevant genera in terms of number of species and number of specimens reared. The parasitoids obtained from samples taken in agroecosystems differed from the global spectrum of taxa mainly by showing a numerical dominance of Braconidae, despite a noticeable specific impoverishment of this family.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.116.2157

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Twenty five South American species of the genus Selenops (Araneae, Selenopidae) are revised, of which three new taxa are described and illustrated: S. angelae and S. marilus (?, from Ecuador and Venezuela, respectively) and S. tiky (?, from Venezuela). Selenops ecuadorensis Berland, S. galapagoensis Banks, S. isopodus Mello-Leitão and S. melanurus Mello-Leitão are redescribed. Diagnostic characters of previously known species are given and the male palp and female genitalia are described and illustrated, some for the first time. New data on geographic distribution extend the ranges of some previously known species. A key to South American species is provided for the first time. En este trabajo se revisa el género Selenops (Araneae, Selenopidae) para América del Sur. Este género está representado por 25 especies, de las cuales aqu¡ se describen e ilustran tres especies nuevas, S. angelae y S. marilus (conocidas sólo por el macho de Ecuador y Venezuela, respectivamente) y S. tiky (sólo por la hembra de Venezuela). Se redescriben Selenops ecuadorensis Berland, S. galapagoensi s Banks, S. isopodus Mello-Leitão y S. melanurus Mello-Leitão y se ilustran, en algunos casos por primera vez, la genitalia de la hembra y el palpo del macho de todas las especies sudamericanas de Selenops. Se da la diagnosis de cada especie, se presentan mapas ampliando el área de distribución de la mayoría de las especies conocidas y se proporciona la primera clave para las especies sudamericanas.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.124.2153

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

New data on the genus Anyphaenoides are presented. A. paraguana Brescovit and A. lecta (Chickering) are synonymized with A. irusa Brescovit and Sillus placens (O.P.-Cambridge), respectively. The latter species is transferred to Anyphaenoides. The first records of an anyphaenine, A. pacifica (Banks), are given from Chile. Four new species are described: A. volcan from Panama; A. xiboreninho and A. coddingtoni from Brazil; and A. samiria from Peru.

ISSN:0165-0521    

DOI:10.1076/snfe.33.2.149.2155

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor