Guild structure of spiders in major crops

The ecological guild concept has been of great interest to arachnologists, and the different manner in which spiders forage for a common resource-prey arthropods-has led to numerous attempts to classify them into guilds. Howe ver, questions have been raised about the validity of guilds and the taxon- centered basis of their definition. Here, we propose an alternative approac h to guild classification, using quantitative analysis of ecological charac teristics of spider families. While generalizations may not apply to all sp ecies within a taxon, results from this approach suggest eight major spider guilds similar to earlier guild assignments by some authors and provide a reasonable framework for future studies. We used this classification in a c omparison of spider guild composition across several major crops (from publ ished studies). While total species richness varied widely among crops, the proportion of the total species within each guild was remarkably even acro ss crops. The relative abundance of guilds (based on numbers of individuals ) varied greatly, which may reflect availability of resources within a crop type. Patterns of similarity in guild composition suggest the possibility of plant habitat structure as an influence on the spider community. Further detailed analyses of spider guilds in various crops have been constrained by both a lack of comparable quantitative data and the paucity of behaviora l and natural history information available for many taxa. As recent studie s have shown that assemblages of spiders can impact pest populations and re duce crop damage, a better understanding of spider guild composition and va riation in spider community structure among crops is essential in future st udies of the arthropod fauna in agroecosystems.