Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.

There is growing concern, locally and globally, about the health of pollinating insects and their decreasing abundance and diversity. While roads may also be contributing to insect pollinator declines (roads can contribute to habitat fragmentation and habitat destruction), roadsides may provide opportunities for pollinating insect conservation. Yet to use these areas to support local pollinating insects, we need to understand which plants will support wild pollinators, especially of conservation concern. To that end, we researched the potential plant-pollinator networks of three existing seed mixes in western New York (USA)- a roadside seed mix, a pollinator-friendly planting mix, and a lawn seed mix. We used publicly available information and built bipartite graphs to show the resulting networks. The pollinator-friendly seed mix supported the most pollinating insects overall and taxa of conservation concern. Yet the roadside mix, with the same species richness as the lawn seed mix, supported a different network based on the plants in the mix. Our results inform which particular plant species in existing seed mixes in western New York can support wild pollinating insect species of concern in the region. Additionally, our results show potentially how roadside and lawn plantings may be altered to support a broader network of pollinating insects.

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