A COMUNIDADE DE ARANHAS EM UM FRAGMENTO DE FLORESTA OMBRÓFILA MISTA, GUARAPUAVA - PR

Abstract

A survey of spiders was carried in a fragment of Araucaria Forest in the Parque Municipal das Araucárias, Guarapuava, Paraná, Brazil. Samples were collected between July 2010 and July 2011, the methods used were pitfall traps, entomological umbrella and nocturnal manual collection. It were obtained 5285 spiders being 3826 young (72,3%) and 1.459 adults (27,7%). Those were distributed in 138 morphospecies belonging to 23 families. Araneidae (N = 524), Theridiidae (N = 272) e Salticidae (N = 219), accounted 57.24% of total specimens collected. Theridiidae was the richest (31 spp.) followed by Araneidae (26 spp.) and Salticidae (22 spp.). Gelanor sp. (Mimetidae) and Maeota dicrura (Salticidae) were the most abundant morphospecies. The guild of orb weavers spiders were prevalent throughout the collection period X2 crít. (7,81) = 248,4; p = 0,05, with changes in the composition of the guilds during the year. In order to analyze seasonality, sampling sessions were grouped by weather station (hot and rainy: spring and summer; cold and dry: autumn and winter). At the hot and rainy seasons it were recorded the highest abundance of adult (t = 5.30; gl = 22; p < 0,05), and higher wealth (t = 5.80; gl = 22; p < 0,05), being the temperature one of the factors responsible by this standard. The richness estimates ranged from 160 for Chao1 to 166,8 for Chao 2. None of the estimators exhibited a tendency to reach the asymptote, once that the number of rare species (singletons, doubletons) showed a steady increase. Although the species accumulation curve indicates that inventory is still incomplete, the number of species recorded was relatively high when compared with surveys of the subtropical regions. Thereby, it is clear the importance of new researches in areas of Araucaria Forest, showing that these ecosystems still require much study to become the knowledge about the arachnids at least satisfactory, in both ecological and taxonomic levels.