Patterns of nesting activity and community structure of cavity-nesting solitary bees and wasps associated with urbanization

Abstract

Abstract Given the sensitivity of cavity-nesting solitary bees and wasps to environmental changes in urban areas, this study evaluated the effects of urbanization on nest establishment, local diversity, and parasitism rates along an urbanization gradient in the Semiarid region of Bahia, Brazil. Sampling was conducted using trap nests constructed from bamboo segments between September 2023 and August 2024. The gradient was characterized according to the urbanization intensity and vegetation cover. Nonparametric Kruskal–Wallis tests, Spearman rank correlations, and Nonmetric Multidimensional Scaling (NMDS) were used to evaluate community structure. A total of 407 nests were recorded along the urbanization gradient, with reductions of approximately 74.46% in the brood cell number and 92.3% in species richness between sites with the lowest and highest urbanization intensity. The parasitism rate varied significantly across gradient levels and was correlated with urbanization intensity. Responses of these metrics to environmental changes in urban areas indicate that ecological interactions are affected by anthropogenic disturbances earlier than the taxonomic structure of the community. The characterization of these communities and their ecological interactions along urbanization gradients can provide indicators of environmental quality, with potential applications in the planning and management of urban green spaces to promote urban development with lower environmental impacts.