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Abstract:The Brazilian Atlantic Forest has a rich biodiversity increasingly threatened by human activities. Since the colonial period, the coast of the state of Bahia is among the most affected regions of Brazil by anthropic pressure. Bahia encloses Atlantic Forest remnants distributed in an area reaching 100-200 km along the east-west axis, by 1,000 km along the north-south axis, parallel to the coast of the Atlantic Ocean. We report hereafter the results of an intensive field survey of leaf litter and epigaeic ants realized in forest remnants of the Atlantic Forest landscapes within the original extension of the biome in 11 localities distributed along four degrees of latitude in the state of Bahia. In each site, 16 plots were collected using pitfall and eight using Winkler traps. We identified 391 ant species belonging to 71 genera and nine subfamilies. Among all species recorded, 21 were common to the whole 11 localities, while 98 species were recorded in a single locality. This study highlights the richness and diversity of epigaeic and leaf-litter ants living in the northern part of the Brazilian Atlantic Forest, and is one of the most representative soil ants' inventories ever done in this biome for a single state of Brazil.

In order to evaluate which are the synanthropic spiders of Salvador and also to know if there exists any relationship between spider composition and time of urban occupation, this study analized 677 spiders, captured in three city neighbourhoods with different urbanization times: Santo Antonio Além do Carmo (300-400 years), Itapuã (100-300 years) and Pituba (less than 50 years). Sample size inside and outside of residences was calculated based on 10% district census and collections were carried out always by six collectors, who were also responsible for the interviews, totalling a sampling effort of 30 minutes/residence (n=71), from November/2002 to June/2003. Of a total of 329 adults, 13 species and 17 morfospecies distributed in 10 families, were recognized. Pholcidae (n=256), Oecobiidae (n=184) and Uloboridae (n=59) were the most abundant families. Oecobius concinnus, the only one Oecobiidae, appeared restricted to recent districts. Its unexpected absence in the oldest district suggests the existence of some limiting factor, that shows the need of more investigation on this poorly known species. In contrast, Smeringopus pallidus was more frequent in the oldest district and Physocyclus globosus (Pholcidae) occured in all three. There was significant differences in species abundance and structural organization of residences between the more ancient and the more recent districts. Thus, we suggest that the fact that the buildings structure remained untouched throughout the years is as a factor that favours the permanence of these species. Key words: synanthropic, spiders, residences, Salvador. ResumoPara avaliar quais as aranhas sinantrópicas de Salvador e relacionar a sua distribuição com a estrutura física das residências, e a composição das espécies com o tempo de ocupação urbana, investigou-se 3 bairros escolhidos segundo sua idade aproximada: Santo Antônio Além do Carmo (300-400 anos), Itapuã (100-300) e Pituba (menos de 50). A base amostral para residências correspondeu a 10% do setor censitário, com 6 capturadores realizando entrevistas concomitantes às capturas, nos domicílios e peridomicílios. Foram coletados 677 aranhas, 329 adultos, identificados em 13 espécies e 17 morfoespécies, distribuídas em 10 famílias, de novembro 2002 a junho 2003, num esforço amostral de 30 minutos/domicílio (n=71) ou peridomicílio. Pholcidae (n=256), Oecobiidae (n=184) e Uloboridae (n=59) foram as três famílias mais abundantes. Oecobius concinnus, única espécie de Oecobiidae registrada, esteve restrita aos bairros recentes e a sua ausência inesperada no bairro mais antigo sugere a existência de algum fator restritivo à sua permanência, havendo necessidade de continuar a investigação. Smeringopus pallidus foi mais freqüente no bairro mais antigo e Physocyclus globosus (Pholcidae) ocorreu nos três bairros. Houve diferença significativa tanto na abundância das espécies como na estrutura física dos domicílios entre os bairros mais antigo e mais recente, indicando que as características coloniais do primeiro devem favorece...

Spider species respond differently to variations in habitat structure; thus, differences in habitat structure may be responsible for variations in species composition of assemblages. However, little information exists on patterns of variation in spider species composition in tropical rainforests. We collected spiders and measured five different microhabitat characteristics in 20 sampling plots distributed among secondary and primary forest patches in an Atlantic rainforest, Brazil. Using multivariate analysis (non-metric multidimensional scaling -NMS), we checked for the existence of nonrandom patterns in the species composition of aerial (AG) and ground (GG) macroguilds, respectively. We also explored the relationships of those patterns with gradients in microhabitat characteristics and the infiuence of forest type (primary or secondary forest). We detected non-random patterns in spider species composition unrelated to microhabitat characteristics but differing between primary and secondary forest plots for both macroguilds. We discuss possible implications for studies of spider species composition and spider conservation in tropical forests.

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