Web-building spiders are defined as those which use their webs primarily to capture prey. They comprise 15 families and currently 67 known species in Trinidad, still too large a subject for a comprehensive survey. A subset of this guild has been selected as more manageable, the three families Araneidae, Nephilidae and Tetragnathidae, which construct orb webs.

These spiders lead a rather uniform lifestyle, and regional keys are available for the identification of species newly discovered in Trinidad. However, although identification is possible, very little is known about the natural history of most of the species. Using this group of spiders, the study will determine the contribution of habitat to their diversity, including both natural and man-modified habitats as classified by Beard (1946).

One point of general ecological interest is how much the diversity of spider faunas will be influenced by taxonomic diversity of the vegetation. Spiders are at a higher trophic level to most insects, which are the subject of most studies of arthropod diversity, and may be less closely related to vegetation composition than are herbivores; in contrast, structural diversity is predicted to be more important to spiders.

Other questions of interest include diversity in the monospecies Mora forest (dominated by Mora excelsa) compared to multispecies forests more typical of tropical areas; the effects of disturbance on diversity in areas of forest of different logging history; and the diversity and thus conservation value of more modified habitats. Overall, the study will produce a comprehensive picture of the biodiversity of orb-weaving spiders in Trinidad in the early 21st Century, as the country embarks on the path to developed country status ("Vision 2020").