Processo de colonização do folhiço pela caranguejeira Masteria sp. (Mygalomorphae, Dipluridae): o efeito da palmeira palha branca Attalea attaleoides (Arecaceae) em uma floresta de terra firme na Amazônia Central

Abstract

The space distribution and the process of colonization of the spider Masteria sp. in the microhábitat of the base of the palm tree Attalea attaleoides and in the forest ground was verified. The study was developed in two plateau areas and beginning of forest slope, in the proximities of Manaus, Central Amazon. The collections were accomplished in ten field trips, from February to October, 2007. First the leaf litter accumulate in the base of 60 palm trees and in the area adjacent to each palm tree was removed, measured and manually sorted for spiders. The volume and the mass dries of all samples were measured. In second phase, litter bags were introduced in the bases of the palm trees and in their adjacent areas to verify the process of colonization of Masteria sp. The medium value of the litter total volume found in the first phase was used as measure standard of the bags. Two nylon bags were inserted in each palm tree base: a willing one in the superior layer of the base and on other in the inferior layer. The same was applied in the adjacent area within a ray of 2,0 meters of each palm tree base. A total of 240 leaf litter bags were introduced in the two microhábitats. This experiment was applied along six months, and every month, 40 bags were removed. The comparison of abundance data of the spiders among the microhábitats was made in terms of absolute abundance and occurrence frequency (presence and absence). In both study phases, the abundance of Masteria sp. was influenced significantly by the microhábitats. 175 individuals of Masteria sp. were found, where 135 (77,1%) were collected from the palm tree bases and only 40 (22,9%) in the adjacent areas. There were significant differences in the abundance of Masteria sp. regarding the time of colonization. Moreover the microhábitat selection was important in the dispersion of those spiders. Masteria sp. selects the habitat colonizing the different leaf leaf litter layers, particularly in the base of the palm tree A. attaleoides.