Plant-pollinator interactions in the neotropics are affected by urbanization and the invasive bee Apis mellifera

Urbanization is one of the most intense forms of landscape change, and it is likely to increase in the coming years. Although there is a consensus that urbanization has drastic effects on biodiversity, recent discussions on the conservation of urban plant-pollinator interactions have not properly included biodiverse tropical regions. Here, we investigate how the structure of plant-pollinator networks changes along the urbanization gradient. We examined changes in structure of 21 plant-pollinator networks along six urbanization gradients. We also accessed the centrality of Apis mellifera (an exotic bee) and Trigona spinipes (a native bee), both generalist species, highly abundant and tolerant to urban environments. Finally, we identified important species of plants in urban pollination networks. We found that connectance and interaction evenness increases with urbanization, probably due to the loss of bee species. Complementary specialization (H2’) and modularity were not affected by the urban landscape. Closeness centrality of A. mellifera increased with increasing impermeable cover reinforcing the hypothesis that invasive and super-generalist species are generally more central in more urbanized areas. In contrast, eigenvector centrality of T. spinipes decreased with the increase in urbanization, suggesting a decrease in the importance of this species for the network as urban areas get denser. Our results support to understand the effects of urbanization on mutualistic networks in tropical environments and can contribute to the protection of native biodiversity against urban expansion. Implications for insect conservation: Our results show that plant-bee interactions networks become simplified as urbanization increases. We also show that the invasive non-native bee Apis mellifera dominate urban plant-bee interactions in neotropical cities. To improve insect conservation in cities, it is recommended to plant native plant species and manage invasive non-native species.