Species composition of the orb-weaving families Araneidae and Tetragnathidae (Araneae: Araneoidea) in natural habitats in Trinidad, West Indies

Abstract

ABSTRACTThe biodiversity of some spider groups in the neotropics is poorly documented. The species composition of two orb-weaving spider families, Araneidae and Tetragnathidae in 16 natural habitats was examined. Specimens were collected using visual search and sweep-netting methods. Very few species were found to be abundant in natural habitats while some were common and the majority considered rare. There was also little overlap of species among the localities sampled in each habitat type; overlap ranged from one to three species. Species abundance models showed that natural habitats followed a log series model, indicating that they are characterised by low species richness, the presence of few dominant species, and governed by a single factor. Multi-dimensional scaling analysis showed that four habitats (savanna, mangrove woodland, littoral woodland, and herbaceous swamp) possessed distinct species assemblages. However, the savanna habitat was the most dissimilar, probably due to a greater presence of specialist species.