Influence of urbanization characteristics on ant (Hymenoptera: Formicidae) and spider (Arachnida: Araneae) diversity

Abstract

Demographic characteristics and length of land use occupation time are important factors in the evaluation of the influence of urbanization on biodiversity. Thus, the aim of this study was to evaluate how population density and human occupation history influence taxonomic and guild spider (Arachnida: Araneae) and ant (Hymenoptera: Formicidae) diversities in four distinct Administrative Regions (ARs) of the municipality of Salvador (Bahia, Brazil). The ants and spiders in the ARs were collected in different types of green areas: forest fragments, vacant lots, and gardens/backyards, using three capture techniques (Winkler trap, entomological umbrella, and manual collection). We tested for eventual differences in myrmecofauna and araneofauna richness and composition, in addition to guilds (FGs) according to population density level (high vs. low) and urbanization time (old vs. recent). A total of 148 ant species were collected and classified into 15 guilds. Whereas a total of 97 spider species were captured and classified into 10 guilds. Spider richness varied significantly between the ARs, instead of to ant richness. There were also significant differences between ARs for the taxonomic composition of spiders, but not for ants. Those of the guild compositions of ants and spiders were not significant. Finally, our results indicate the importance of how historical processes of neighborhood occupation influence the distribution of spiders, demonstrating increased richness in areas with lower population densities, while other factors related to urban landscapes may be related to the distribution of ant and spider species.